U.S. patent application number 15/173372 was filed with the patent office on 2016-09-29 for aerosolized fluoroquinolones and uses thereof.
This patent application is currently assigned to Raptor Pharmaceuticals, Inc.. The applicant listed for this patent is Raptor Pharmaceuticals, Inc.. Invention is credited to Keith A. Bostian, Michael N. Dudley, David C. Griffith, Olga Rodny, Mark W. Surber.
Application Number | 20160279138 15/173372 |
Document ID | / |
Family ID | 46206205 |
Filed Date | 2016-09-29 |
United States Patent
Application |
20160279138 |
Kind Code |
A1 |
Surber; Mark W. ; et
al. |
September 29, 2016 |
AEROSOLIZED FLUOROQUINOLONES AND USES THEREOF
Abstract
Disclosed herein are formulations of fluoroquinolones suitable
for aerosolization and use of such formulations for aerosol
administration of fluoroquinolone antimicrobials for the treatment
of pulmonary bacterial infections. In particular, inhaled
levofloxacin specifically formulated and delivered for bacterial
infections of the lungs is described. Methods include inhalation
protocols and manufacturing procedures for production and use of
the compositions described.
Inventors: |
Surber; Mark W.; (San Diego,
CA) ; Bostian; Keith A.; (Atherton, CA) ;
Dudley; Michael N.; (San Diego, CA) ; Rodny;
Olga; (Mill Valley, CA) ; Griffith; David C.;
(San Marcos, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Raptor Pharmaceuticals, Inc. |
Novato |
CA |
US |
|
|
Assignee: |
Raptor Pharmaceuticals,
Inc.
Novato
CA
|
Family ID: |
46206205 |
Appl. No.: |
15/173372 |
Filed: |
June 3, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14012307 |
Aug 28, 2013 |
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15173372 |
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12604340 |
Oct 22, 2009 |
8546423 |
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14012307 |
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11436875 |
May 18, 2006 |
7838532 |
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12604340 |
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60682530 |
May 18, 2005 |
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60696160 |
Jul 1, 2005 |
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60773300 |
Feb 13, 2006 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61P 31/04 20180101;
A61K 31/5383 20130101; A61K 9/0075 20130101; Y02A 50/473 20180101;
Y02A 50/401 20180101; A61K 9/5123 20130101; A61K 47/02 20130101;
A61K 9/0073 20130101; Y02A 50/47 20180101; A61K 9/0078 20130101;
Y02A 50/478 20180101; Y02A 50/30 20180101; Y02A 50/483 20180101;
Y02A 50/469 20180101; Y02A 50/475 20180101; Y02A 50/471
20180101 |
International
Class: |
A61K 31/5383 20060101
A61K031/5383; A61K 47/02 20060101 A61K047/02; A61K 9/00 20060101
A61K009/00 |
Claims
1. A method of treating a bacterial lung infection in a subject
with sinusitis in need thereof comprising administering to the
subject with sinusitis a therapeutically effective amount of an
aerosol of a solution comprising about 100 mM to about 625 mM of
levofloxacin or ofloxacin and about 25 mM to about 400 mM of a
divalent or trivalent cation, to treat the bacterial lung
infection.
2. The method of claim 1, wherein the solution has a pH from about
5.5 to about 6.5, and an osmolality from about 350 mOsmol/kg to
about 750 mOsmol/kg.
3. The method of claim 1, wherein the divalent or trivalent cation
is calcium, iron, or zinc.
4. method of claim 1, wherein the divalent or trivalent cation is
magnesium.
5. The method of claim 4, wherein the magnesium is magnesium
chloride.
6. The method of claim 5, wherein the solution comprises about 100
mM to about 625 mM levofloxacin and about 25 mM to about 400 mM
magnesium chloride; and wherein the solution has a pH from about
5.5 to about 6.5, and an osmolality from about 350 mOsmol/kg to
about 750 mOsmol/kg.
7. The method of claim 1, wherein the solution comprises about 100
mM to about 625 mM levofloxacin and about 25 mM to about 400 mM of
a divalent or trivalent cation selected from the group consisting
of magnesium, calcium, iron, and zinc.
8. The method of claim 1, wherein the lung infection is caused by a
gram negative bacteria, a gram negative anaerobic bacteria, a gram
positive bacteria, a gram positive anaerobic bacteria, or a
combination of two or more thereof.
9. The method of claim 1, wherein the lung infection is caused by
one or more bacteria selected from the group consisting of
Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas
acidovorans, Pseudomonas alcaligenes, Pseudomonas putida,
Stenotrophomonas maltophilia, Aeromonas hydrophilia, Escherichia
coli, Citrobacter freundii, Salmonella typhimurium, Salmonella
typhi, Salmonella paratyphi, Salmonella enteritidis, Shigella
dysenteriae, Shigella flexneri, Shigella sonnei, Enterobacter
cloacae, Enterobacter aerogenes, Klebsiella pneumoniae, Klebsiella
oxytoca, Serratia marcescens, Morganella morganii, Proteus
mirabilis, Proteus vulgaris, Providencia alcalifaciens, Providencia
rettgeri, Providencia stuartii, Acinetobacter calcoaceticus,
Acinetobacter haemolyticus, Yersinia enterocolitica, Yersinia
pestis, Yersinia pseudotuberculosis, Yersinia intermedia,
Bordetella pertussis, Bordetella parapertussis, Bordetella
bronchiseptica, Pasteurella multocida, Pasteurella haemolytica,
Helicobacter pylori, Campylobacter fetus, Campylobacter jejune,
Campylobacter coli, Borrelia burgdorferi, Vibrio cholera, Vibrio
parahaemolyticus, Legionella pneumophila, Listeria monocytogenes,
Neisseria gonorrhoeae, Neisseria meningitidis, Burkholderia
cepacia, Francisella tularensis, Kingella, and Moraxella.
10. The method of claim 1, wherein the lung infection is caused by
one or more bacteria selected from the group consisting of
Pseudomonas aeruginosa, Moraxella, Haemophilus influenzae,
Haemophilus parainfluenzae, Haemophilus haemolyticus, Haemophilus
parahaemolyticus, and Haemophilus ducreyi.
11. The method of claim 1, wherein the lung infection is caused by
one or more bacteria selected from the group consisting of
Corynebacterium diphtherias, Corynebacterium ulcerans,
Streptococcus pneumoniae, Streptococcus agalactiae, Streptococcus
pyogenes, Streptococcus milleri; Streptococcus (Group G);
Streptococcus (Group C/F); Enterococcus faecalis, Enterococcus
faecium, Staphylococcus aureus, Staphylococcus epidermidis,
Staphylococcus saprophyticus, Staphylococcus intermedius,
Staphylococcus hyicus subsp. hyicus, Staphylococcus haemolyticus,
Staphylococcus hominis, and Staphylococcus saccharolyticus.
12. A method of treating sinusitis in a subject in need thereof
comprising administering to the subject a therapeutically effective
amount of an aerosol of a solution comprising about 100 mM to about
625 mM levofloxacin or ofloxacin and about 25 mM to about 400 mM of
a divalent or trivalent cation to treat the sinusitis.
13. The method of claim 12, wherein the solution has a pH from
about 5.5 to about 6.5, and an osmolality from about 350 mOsmol/kg
to about 750 mOsmol/kg.
14. The method of claim 12, wherein the divalent or trivalent
cation is calcium, iron, or zinc.
15. The method of claim 12, wherein the divalent or trivalent
cation is magnesium.
16. The method of claim 15, wherein the magnesium is magnesium
chloride.
17. The method of claim 16, wherein the solution comprises about
100 mM to about 625 mM levofloxacin and about 25 mM to about 400 mM
magnesium chloride; and wherein the solution has a pH from about
5.5 to about 6.5, and an osmolality from about 350 mOsmol/kg to
about 750 mOsmol/kg.
18. The method of claim 12, wherein the solution comprises about
100 mM to about 625 mM levofloxacin and about 25 mM to about 400 mM
of a divalent or trivalent cation selected from the group
consisting of magnesium, calcium, iron, and zinc.
19. The method of claim 12, wherein the subject has a bacterial
lung infection caused by a gram negative bacteria, a gram negative
anaerobic bacteria, a gram positive bacteria, a gram positive
anaerobic bacteria, or a combination of two or more thereof.
20. The method of claim 12, wherein the subject has a bacterial
lung infection caused by one or more bacteria selected from the
group consisting of Pseudomonas aeruginosa, Pseudomonas
fluorescens, Pseudomonas acidovorans, Pseudomonas alcaligenes,
Pseudomonas putida, Stenotrophomonas maltophilia, Aeromonas
hydrophilia, Escherichia coli, Citrobacter freundii, Salmonella
typhimurium, Salmonella typhi, Salmonella paratyphi, Salmonella
enteritidis, Shigella dysenteriae, Shigella flexneri, Shigella
sonnei, Enterobacter cloacae, Enterobacter aerogenes, Klebsiella
pneumoniae, Klebsiella oxytoca, Serratia marcescens, Morganella
morganii, Proteus mirabilis, Proteus vulgaris, Providencia
alcalifaciens, Providencia rettgeri, Providencia stuartii,
Acinetobacter calcoaceticus, Acinetobacter haemolyticus, Yersinia
enterocolitica, Yersinia pestis, Yersinia pseudotuberculosis,
Yersinia intermedia, Bordetella pertussis, Bordetella
parapertussis, Bordetella bronchiseptica, Pasteurella multocida,
Pasteurella haemolytica, Helicobacter pylori, Campylobacter fetus,
Campylobacter jejune, Campylobacter coli, Borrelia burgdorferi,
Vibrio cholera, Vibrio parahaemolyticus, Legionella pneumophila,
Listeria monocytogenes, Neisseria gonorrhoeae, Neisseria
meningitidis, Burkholderia cepacia, Francisella tularensis,
Kingella, and Moraxella.
21. The method of claim 12, wherein the subject has a bacterial
lung infection caused by one or more bacteria selected from the
group consisting of Pseudomonas aeruginosa, Moraxella, Haemophilus
influenzae, Haemophilus parainfluenzae, Haemophilus haemolyticus,
Haemophilus parahaemolyticus, and Haemophilus ducreyi.
22. The method of claim 12, wherein the subject has a bacterial
lung infection caused by one or more bacteria selected from the
group consisting of Corynebacterium diphtherias, Corynebacterium
ulcerans, Streptococcus pneumoniae, Streptococcus agalactiae,
Streptococcus pyogenes, Streptococcus milleri; Streptococcus (Group
G); Streptococcus (Group C/F); Enterococcus faecalis, Enterococcus
faecium, Staphylococcus aureus, Staphylococcus epidermidis,
Staphylococcus saprophyticus, Staphylococcus intermedius,
Staphylococcus hyicus subsp. hyicus, Staphylococcus haemolyticus,
Staphylococcus hominis, and Staphylococcus saccharolyticus.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 14/012,307 filed Aug. 28, 2013, which is a continuation of U.S.
application Ser. No. 12/604,340 filed Oct. 22, 2009, issued as U.S.
Pat. No. 8,546,423, which is a divisional of U.S. application Ser.
No. 11/436,875 filed May 18, 2006, issued as U.S. Pat. No.
7,838,532, which claims priority to U.S. Provisional Application
No. 60/682,530 filed May 18, 2005, U.S. Provisional Application No.
60/696,160 filed Jul. 1, 2005, and U.S. Provisional Application No.
60/773,300 filed Feb. 13, 2006, all of which are incorporated
herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] Antibiotics have been effective tools in the treatment of
infectious diseases during the last half-century. From the
development of antimicrobial therapy to the late 1980s, most
bacterial infections occurring in patients in developed countries
could be controlled unless the infection occurred in an organ or
environment where antibiotics were difficult to deliver or were
ineffective, such as bacterial infections of the circulatory system
in sepsis patients, or bacterial infections of the lungs in cystic
fibrosis. However, even in ordinary infections, in response to the
pressure of antimicrobial usage, multiple resistance mechanisms
have become widespread and are threatening the clinical utility of
even the most aggressive antibacterial therapy. The increase in
antimicrobial resistant strains has been particularly common in
major hospitals and care centers. The consequences of the increase
in resistant strains include higher morbidity and mortality, longer
patient hospitalization, and an increase in treatment costs.
[0003] Bacteria have developed several different mechanisms to
overcome the action of antimicrobials. These mechanisms of
resistance can be specific for a molecule or a family of
antimicrobials, or can be non-specific and be involved in
resistance to unrelated antimicrobials. Several mechanisms of
resistance can exist in a single bacterial strain, and those
mechanisms may act independently or they may act synergistically to
overcome the action of an antimicrobial or a combination of
antimicrobials. Specific mechanisms include degradation of the
drug, inactivation of the drug by enzymatic.
[0004] Modification and alteration of the drug target. There are,
however, more general mechanisms of drug resistance, in which
access of the antimicrobial to the target is prevented or reduced
by decreasing the transport of the antimicrobial into the cell or
by increasing the efflux of the drug from the cell to the outside
medium. Both mechanisms can lower the concentration of drug at the
target site and allow bacterial survival in the presence of one or
more antimicrobials that would otherwise inhibit or kill the
bacterial cells. Some bacteria utilize both mechanisms, combining a
low permeability of the cell wall (including membranes) with an
active efflux of antimicrobials.
SUMMARY OF THE INVENTION
[0005] Various embodiments provide compositions and methods for
optimal antimicrobial activity for the treatment of respiratory
tract and pulmonary infections in human and/or veterinary subjects
using short-term, rapid aerosol administration, and through the
delivery of high-concentration drug exposure directly to the
affected tissue. Specifically, in some embodiments, concentrated
doses of agents from the fluoroquinolone class of antibiotic are
delivered to produce maximum concentrations of active drug to the
respiratory, pulmonary, and other non-oral topical compartments
including, but not limited to the skin, rectum, vagina, urethra,
urinary bladder, eye, and ear. Because different drug products are
known to produce different antimicrobial effects depending on the
dose, form, concentration and delivery profile, some embodiments
provide specific formulation and delivery parameters that produce
antimicrobial results that are therapeutically significant. The
invention includes, but is not limited to, specific fluoroquinolone
antibiotics, such as levofloxacin, formulated to enable aerosol
administration meeting specific concentrations and antimicrobial
criteria necessary to treat patients with distinct bacterial
infections. These formulations and methods are useful with
commercially available inhalation devices for one or more aerosol
therapeutic product opportunities.
[0006] Aerosol administration directly to the nasal, sinus,
respiratory tract and pulmonary compartments through intra-nasal or
oral inhalation enables high concentration drug delivery to a site
of respiratory infection with decreased risk of extra-respiratory
toxicity associated with non-respiratory routes of drug delivery.
Furthermore, direct administration to the site of infection permits
very high local drug levels, a property that enables "rapid
administration, high concentration, local exposure" killing effect
special to this class of antibiotic. Accordingly, because the
microbial killing effect of a particular antibiotic compound and
therapeutic composition varies depending on the formulation and
delivery parameters, newer compositions and delivery methods can be
developed for existing drug compounds that are re-formulated and
administered through novel delivery techniques. Other topical
infections may also benefit from this discovery through high
concentration, direct exposure of fluoroquinolone to infected skin,
rectum, vagina, urethra, urinary bladder, eye, and ear.
[0007] Members of the fluoroquinolone drug class exhibit unique
pharmacologic properties, including bioavailability (F), mean
absorption time (MAT) from the lung, maximal drug concentrations in
the epithelial lining fluid, bronchial lavage fluid, sputum and/or
lung tissue (Cmax) following aerosol administration, pulmonary
retention time, area under the curve (AUC), minimal inhibitory
concentrations (MIC) of the antibiotic required for antibacterial
activity, AUC/MIC ratio, and local and systemic safety. Specific to
the invention is the use short-term, rapid aerosol administration,
delivering high concentration drug exposure directly to the
affected tissue (ELF, sputum, BAL, tissue) via aerosol delivery for
treatment of bacterial infection in animals and humans.
[0008] In addition to the clinical and pharmacological requirements
present in any composition intended for therapeutic administration,
many physicochemical factors unique to a drug compound must also be
considered. These include, but are not limited to aqueous
solubility, viscosity, partitioning coefficient (Log P), predicted
stability in various formulations, osmolality, surface tension, pH,
pKa, pKb, dissolution rate, sputum permeability, sputum
binding/inactivation, taste, throat irritability and acute
tolerability.
[0009] Other factors to consider when designing the product form
include fluoroquinolone physical chemistry and antibacterial
activity, disease indication, clinical acceptance, and patient
compliance. By non-limiting example, if desired the aerosol
fluoroquinolone product may be in the form of a simple liquid (e.g.
soluble fluoroquinolone with non-encapsulating soluble
excipients/salts), complex liquid (e.g. fluoroquinolone
encapsulated or complexed with soluble excipients such as lipids,
liposomes, cyclodextrins, microencapsulations, and emulsions),
complex suspension (e.g. fluoroquinolone as a low-solubility,
stable nanosuspension alone, co-crystal/co-precipitate complexes,
and mixtures with low solubility lipids such as solid-lipid
nanoparticles), or dry powder (dry powder fluoroquinolone alone or
in co-crystal/co-precipitate/spray-dried complex or mixture with
low solubility excipients/salts or readily soluble blends such as
lactose).
[0010] Combined with product form is a packaging consideration. By
non-limiting example, considerations for packaging include
intrinsic product stability, the need for stability-providing
lyophilization, device selection (e.g. liquid nebulizer, dry-powder
inhaler, meter-dose inhaler), and packaging form (e.g. simple
liquid or complex liquid formulation in a vial as liquid or
lyophilisate to be dissolved prior to or upon insertion into the
device; complex suspension formulations in a vial as a liquid or
lyophilisate with or without a soluble salt/excipient component to
be dissolved prior to or upon insertion into the device, or
separate packaging of liquid and solid components; dry powder
formulations in a vial, capsule or blister pack; and other
formulations packaged as readily soluble or low-solubility solid
agents in separate containers alone or together with readily
soluble or low-solubility solid agents. Any separately packaged
agent will be manufactured to be mixed prior to or upon insertion
into the delivery device).
[0011] In some aspects, the present invention relates to the
aerosol and topical delivery of fluoroquinolone antimicrobials,
such as levofloxacin. Levofloxacin has favorable solubility
characteristics enabling dosing of clinically-desirable
fluoroquinolone levels by aerosol (e.g. through liquid
nebulization, dry powder dispersion or meter-dose administration)
or topically (e.g. aqueous suspension, oily preparation or the like
or as a drip, spray, suppository, salve, or an ointment or the
like) and can be used in methods for acute or prophylactic
treatment of an infected vertebrate, e.g. a bacterial infection, or
a subject at risk of an infection.
[0012] Others include: ofloxacin, lomefloxacin, pefloxacin,
ciprofloxacin, gatifloxacin, gemifloxacin, moxifloxacin,
tosufloxacin, pazufloxacin, rufloxacin, fleroxacin, balofloxacin,
sparfloxacin, trovafloxacin, enoxacin, norfloxacin, clinafloxacin,
grepafloxacin, sitafloxacin, marbofloxacin, orbifloxacin,
sarafloxacin, danofloxacin, difloxacin, enrofloxacin, garenoxacin,
prulifloxacin, olamufloxacin, DX-619, TG-873870 and DW-276.
[0013] In a preferred embodiment, the method treats a bacterial
infection in a subject using concentrated aerosol levofloxacin
administered to a subject infected with a pathogenic bacteria in
the lungs.
[0014] The therapeutic method may also include a diagnostic step,
such as identifying a patient infected with a particular pathogenic
bacteria, or a resistant bacteria. In some embodiments, the method
further includes identifying a patient as colonized with a bacteria
that is capable of developing resistance to fluoroquinolone
antimicrobials. In some embodiments, the delivered amount of
aerosol levofloxacin is sufficient to overcome resistance or
prevent resistance development to levofloxacin. In one embodiment,
the MIC of the fluoroquinolone antibacterial compound for the
microbe is greater than about 2 ug/ml.
[0015] In another embodiment, the delivered amount of aerosol
levofloxacin is sufficient to overcome resistance or prevent
further resistance of an organism exhibiting an MIC of the
fluoroquinolone antibacterial compound that is greater than about 4
ug/ml.
[0016] In another embodiment, the delivered amount of aerosol
fluoroquinolone is sufficient to overcome resistance or prevent
further resistance of an organism exhibiting an MIC of the
fluoroquinolone antibacterial compound that is greater than about 8
ug/ml.
[0017] In another embodiment, the delivered amount of aerosol
fluoroquinolone is sufficient to overcome resistance or prevent
further resistance of an organism exhibiting an MIC of the
fluoroquinolone antibacterial compound that is greater than about
16 ug/ml.
[0018] In another embodiment, the delivered amount of aerosol
fluoroquinolone is sufficient to overcome resistance or prevent
further resistance of an organism exhibiting an MIC of the
fluoroquinolone antibacterial compound that is greater than about
32 ug/ml.
[0019] In another embodiment, a method is provided for prophylactic
treatment of a subject, including administering to a subject,
susceptible to microbial infection or a chronic carrier of an
asymptomatic or low symptomatic microbial infection, a
fluoroquinolone antimicrobial to achieve a minimal inhibitory
concentration of antimicrobial at a site of potential or current
infection. In one embodiment, the method further comprising
identifying a subject as a subject at risk of a bacterial infection
or at risk for an exacerbation of an infection.
[0020] In another embodiment, a method is provided for acute or
prophylactic treatment of a patient through aerosol administration
of fluoroquinolone to produce and maintain threshold drug
concentrations in the lung, which may be measured as drug levels in
epithelial lining fluid (ELF), sputum, lung tissue or bronchial
lavage fluid (BAL). One embodiment includes the use of short-term,
rapid aerosol administration, delivering high concentration drug
exposure directly to the affected tissue for treatment of bacterial
infections in animals and humans.
[0021] In another embodiment, a method is provided for treating a
microbial infection in a subject, including administering to a
subject infected with a microbe a fluoroquinolone antimicrobial to
achieve a minimal inhibitory concentration of antimicrobial at a
site of infection. In one embodiment, the method further comprising
identifying the subject as infected with a microbe that is
resistant to an antimicrobial agent.
[0022] In another embodiment, a method is provided for acute or
prophylactic treatment of a patient through non-oral or non-nasal
topical administration of fluoroquinolone to produce and maintain
threshold drug concentrations at the site of infection or at risk
of infection. One embodiment includes the use of short-term, rapid
aerosol administration, delivering high concentration drug exposure
directly to the affected tissue for treatment or prevention of
bacterial infections in skin, rectal, vaginal, urethral, ocular,
and auricular tissues.
[0023] In another embodiment, a method is provided for
administering a fluoroquinolone antimicrobial by inhalation,
wherein the inhaled liquid or dry powder aerosol has a mean
particle size from about 1 micron to 10 microns mass median
aerodynamic diameter and a particle size geometric standard
deviation of less than or equal to about 3 microns. In another
embodiment, the particle size is 2 microns to about 5 microns mass
median aerodynamic diameter and a particle size geometric standard
deviation of less than or equal to about 2 microns. In one
embodiment, the particle size geometric standard deviation is less
than or equal to about 1.8 microns.
[0024] In some embodiments of the methods described above,
fluoroquinolone antimicrobial minimal inhibitory concentration
remains at the site of infection for at least about a 5 minute
period, at least about a 10 min period, at least about a 20 min
period, at least about a 30 min period, at least about a 1 hour
period, 2 hour period, at least about a 4 hour period or other time
values on the quarter hour interval. The effective fluoroquinolone
antimicrobial minimal inhibitory concentration (MIC) is sufficient
to cause a therapeutic effect and the effect may be localized to
the site of infection. In some embodiments, one or more
levofloxacin administrations achieve an ELF, BAL, and/or sputum
fluoroquinolone concentration of at least 1-fold to 5000-fold the
infecting or potentially infecting organisms MIC, including all
integral values therein such as 2-fold, 4-fold, 8-fold, 16-fold,
32-fold, 64-fold, 128-fold, 256-fold, 512-fold, 1028-fold,
2056-fold, and 4112-fold the microbials MIC.
[0025] In some embodiments, such as a pulmonary site, the
fluoroquinolone antimicrobial is administered in one or more
administrations so as to achieve a respirable delivered dose daily
of at least about 5 mg to about 50 mg, including all integral
values therein such as 10, 15, 20, 25, 30, 35, 40 and 45
milligrams. Similarly, the fluoroquinolone antimicrobial is
administered in one or more administrations so as to achieve a
respirable delivered dose daily of at least about 50 to about 100
mg including all integral values therein, such as 55, 60, 65, 70,
75, 80, 85, 90, and 95 mg. In some embodiments of the methods
described above, the fluoroquinolone antimicrobial is administered
in one or more administrations so as to achieve a respirable
delivered daily dose of up to 150 mg including all integral values
therein such as 105, 110, 115, 120, 125, 130, 135, 140 and 145 mg.
The fluoroquinolone antimicrobial is administered in the described
respirable delivered dose in less than 20 minutes, less than 10
minutes, less than 7 minutes, less than 5 minutes, in less than 3
minutes and in less than 2 minutes. In some embodiments of the
methods described above, the antimicrobial agent is selected from
the group consisting of ofloxacin, lomefloxacin, pefloxacin,
ciprofloxacin, gatifloxacin, gemifloxacin, moxifloxacin,
tosufloxacin, pazufloxacin, rufloxacin, fleroxacin, balofloxacin,
sparfloxacin, trovafloxacin, enoxacin, norfloxacin, clinafloxacin,
grepafloxacin, sitafloxacin, marbofloxacin, orbifloxacin,
sarafloxacin, danofloxacin, difloxacin, enrofloxacin, garenoxacin,
prulifloxacin, olamufloxacin, DX-619, TG-873870 and DW-276,
although levofloxacin is preferred.
[0026] In some embodiments of the methods described above, the
bacteria is a gram-negative bacteria such as Pseudomonas
aeruginosa, Pseudomonas fluorescens, Pseudomonas acidovorans,
Pseudomonas alcaligenes, Pseudomonas putida, Stenotrophomonas
maltophilia, Burkholderia cepacia, Aeromonas hydrophilia,
Escherichia coli, Citrobacter freundii, Salmonella typhimurium,
Salmonella typhi, Salmonella paratyphi, Salmonella enteritidis,
Shigella dysenteriae, Shigella flexneri, Shigella sonnei,
Enterobacter cloacae, Enterobacter aerogenes, Klebsiella
pneumoniae, Klebsiella oxytoca, Serratia marcescens, Francisella
tularensis, Morganella morganii, Proteus mirabilis, Proteus
vulgaris, Providencia alcalifaciens, Providencia rettgeri,
Providencia stuartii, Acinetobacter calcoaceticus, Acinetobacter
haemolyticus, Yersinia enterocolitica, Yersinia pestis, Yersinia
pseudotuberculosis, Yersinia intermedia, Bordetella pertussis,
Bordetella parapertussis, Bordetella bronchiseptica, Haemophilus
influenzae, Haemophilus parainfluenzae, Haemophilus haemolyticus,
Haemophilus parahaemolyticus, Haemophilus ducreyi, Pasteurella
multocida, Pasteurella haemolytica, Branhamella catarrhalis,
Helicobacter pylori, Campylobacter fetus, Campylobacter jejuni,
Campylobacter coli, Borrelia burgdorferi, Vibrio cholerae, Vibrio
parahaemolyticus, Legionella pneumophila, Listeria monocytogenes,
Neisseria gonorrhoeae, Neisseria meningitidis, Kingella, Moraxella,
Gardnerella vaginalis, Bacteroides fragilis, Bacteroides
distasonis, Bacteroides 3452A homology group, Bacteroides vulgatus,
Bacteroides ovalus, Bacteroides thetaiotaomicron, Bacteroides
uniformis, Bacteroides eggerthii, and Bacteroides splanchnicus. In
some embodiments of the methods described above, the bacteria is a
gram-negative anaerobic bacteria, by non-limiting example these
include Bacteroides fragilis, Bacteroides distasonis, Bacteroides
3452A homology group, Bacteroides vulgatus, Bacteroides ovalus,
Bacteroides thetaiotaomicron, Bacteroides uniformis, Bacteroides
eggerthii, and Bacteroides splanchnicus. In some embodiments of the
methods described above, the bacteria is a gram-positive bacteria,
by non-limiting example these include: Corynebacterium diphtherias,
Corynebacterium ulcerans, Streptococcus pneumoniae, Streptococcus
agalactiae, Streptococcus pyogenes, Streptococcus milleri;
Streptococcus (Group G); Streptococcus (Group C/F); Enterococcus
faecalis, Enterococcus faecium, Staphylococcus aureus,
Staphylococcus epidermidis, Staphylococcus saprophyticus,
Staphylococcus intermedius, Staphylococcus hyicus subsp. hyicus,
Staphylococcus haemolyticus, Staphylococcus hominis, and
Staphylococcus saccharolyticus. In some embodiments of the methods
described above, the bacteria is a gram-positive anaerobic
bacteria, by non-limiting example these include Clostridium
difficile, Clostridium perfringens, Clostridium tetini, and
Clostridium botulinum. In some embodiments of the methods described
above, the bacteria is a acid-fast bacteria, by non-limiting
example these include Mycobacterium tuberculosis, Mycobacterium
avium, Mycobacterium intracellulare, and Mycobacterium leprae. In
some embodiments of the methods described above, the bacteria is a
atypical bacteria, by non-limiting example these include Chlamydia
pneumoniae and Mycoplasma pneumoniae.
[0027] In some embodiments of the methods described above, the
subject is a human. In some embodiments of the methods described
above, the subject is a human with cystic fibrosis. In some
embodiments of the methods described above, the subject is a human
with pneumonia, a chronic obstructive pulmonary disease, or
sinusitis, or a human being mechanically ventilatated.
[0028] In another embodiment, a pharmaceutical composition is
provided that includes a simple liquid fluoroquinolone
antimicrobial formulation (e.g. soluble fluoroquinolone with
non-encapsulating water soluble excipients) as described above
having an osmolality from about 200 mOsmol/kg to about 1250
mOsmol/kg. In one such embodiment, the solution has a permeant ion
concentration from about 30 mM to about 300 mM. In one embodiment,
the osmolality is from about 250 mOsmol/kg to about 1050 mOsmol/kg.
In one embodiment, the osmolality is from prefereably from about
350 mOsmol/kg and about 750 mOsmol/kg and most preferably
approximately 300 mOsmol/kg.
[0029] In another embodiment, a pharmaceutical composition is
provided that includes a simple liquid fluoroquinolone
antimicrobial formulation having a permeant ion concentration
between from about 30 mM to about 300 mM and preferably between
from about 50 mM to 200 mM. In one such embodiment, one or more
permeant ions in the composition are selected from the group
consisting of chloride and bromide.
[0030] In another embodiment, a pharmaceutical composition is
provided that includes a complex liquid fluoroquinolone
antimicrobial formulation (e.g. fluoroquinolone encapsulated or
complexed with water soluble excipients such as lipids, liposomes,
cyclodextrins, microencapsulations, and emulsions) as described
above having a solution osmolality from about 200 mOsmol/kg to
about 1250 mOsmol/kg. In one such embodiment, the solution has a
permeant ion concentration from about 30 mM to about 300 mM. In one
embodiment, the osmolality is from about 250 mOsmol/kg to about
1050 mOsmol/kg. In one embodiment, the osmolality is from
preferably from about 350 mOsmol/kg and about 750 mOsmol/kg and
most preferably approximately 300 mOsmol/kg.
[0031] In another embodiment, a pharmaceutical composition is
provided that includes a complex liquid fluoroquinolone
antimicrobial formulation having a permeant ion concentration from
about 30 mM to about 300 mM. In one such embodiment, one or more
permeant ions in the composition are selected from the group
consisting of chloride and bromide.
[0032] In another embodiment, a pharmaceutical composition is
provided that includes a complex liquid fluoroquinolone
antimicrobial formulation having a permeant ion concentration from
about 50 mM to about 200 mM. In one such embodiment, one or more
permeant ions in the composition are selected from the group
consisting of chloride and bromide.
[0033] In another embodiment, a pharmaceutical composition is
provided that includes a complex liquid fluoroquinolone
antimicrobial formulation (e.g. fluoroquinolone as a low water
soluble stable nanosuspension alone or in co-crystal/co-precipitate
complexes, or mixtures with low solubility lipids, such as lipid
nanosuspensions) as described above having a solution osmolality
from about 200 mOsmol/kg to about 1250 mOsmol/kg. In one such
embodiment, the solution has a permeant ion concentration from
about 30 mM to about 300 mM. In one embodiment, the osmolality is
from about 250 mOsmol/kg to about 1050 mOsmol/kg. In one
embodiment, the osmolality is from prefereably from about 350
mOsmol/kg and about 750 mOsmol/kg and most preferably approximately
300 mOsmol/kg.
[0034] In another embodiment, a pharmaceutical composition is
provided that includes a complex suspension fluoroquinolone
antimicrobial formulation having a permeant ion concentration from
about 30 mM to about 300 mM. In one such embodiment, one or more
permeant ions in the composition are selected from the group
consisting of chloride and bromide.
[0035] In another embodiment, a pharmaceutical composition is
provided that includes a complex suspension fluoroquinolone
antimicrobial formulation having a permeant ion concentration from
about 50 mM to about 200 mM. In one such embodiment, one or more
permeant ions in the composition are selected from the group
consisting of chloride and bromide.
[0036] In another embodiment, a pharmaceutical composition is
provided that includes a taste-masking agent. By non-limiting
example a taste-masking agent may include a sugar, a divalent or
trivalent cation that complexes with a fluoroquinolone, optimized
osmolality, and/or an optimized permeant ion concentration.
[0037] In another embodiment, a pharmaceutical composition is
provided that includes a simple dry powder fluoroquinolone
antimicrobial compound (e.g. fluoroquinolone alone in dry powder
form with or without a blending agent such as lactose).
[0038] In another embodiment, a pharmaceutical composition is
provided that includes a complex dry powder fluoroquinolone
antimicrobial formulation (e.g. fluoroquinolone in
co-crystal/co-precipitate/spray dried complex or mixture with low
water soluble excipients/salts in dry powder form with or without a
blending agent such as lactose).
[0039] In another embodiment, a system is provided for
administering a fluoroquinolone antimicrobial that includes a
container comprising a solution of a fluoroquinolone antimicrobial
and a nebulizer physically coupled or co-packaged with the
container and adapted to produce an aerosol of the solution having
a particle size from about 2 microns to about 5 microns mean mass
aerodynamic diameter and a particle size geometric standard
deviation of less than or equal to about 2.5 microns mean mass
aerodynamic diameter. In one embodiment, the particle size
geometric standard deviation is less than or equal to about 2.0
microns. In one embodiment, the particle size geometric standard
deviation is less than or equal to about 1.8 microns.
[0040] In another embodiment, a system is provided for
administering a fluoroquinolone antimicrobial that includes a
container comprising a dry powder of a fluoroquinolone
antimicrobial and a dry powder inhaler coupled to the container and
adapted to produce a dispersed dry powder aerosol having a particle
size from about 2 microns to about 5 microns mean mass aerodynamic
and a particle size standard deviation of less than or equal to
about 3.0 microns. In one embodiment, the particle size standard
deviation is less than or equal to about 2.5 microns. In one
embodiment, the particle size standard deviation is less than or
equal to about 2.0 microns.
[0041] In another embodiment, a kit is provided that includes a
container comprising a pharmaceutical formulation comprising a
quinolone antimicrobial agent and an aerosolizer adapted to
aerosolize the pharmaceutical formulation and deliver it to the
lower respiratory tract and pulmonary compartment following
intraoral administration. The formulation may also be delivered as
a dry powder or through a metered-dose inhaler.
[0042] In another embodiment, a kit is provided that includes a
container comprising a pharmaceutical formulation comprising a
quinolone antimicrobial agent and an aerosolizer adapted to
aerosolize the pharmaceutical formulation and deliver it to nasal
cavity following intranasal administration. The formulation may
also be delivered as a dry powder or through a metered-dose
inhaler.
[0043] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the invention, as
claimed.
DESCRIPTION OF FIGURES
[0044] FIG. 1 is a graph showing the dose: MIC relationship of
fluoroquinolones and other antibiotics to bacterial killing.
[0045] FIG. 2 is a graph showing ciprofloxacin serum concentrations
following oral dosing in both CF patients vs healthy controls.
[0046] FIG. 3 is a graph showing ciprofloxacin sputum and serum
concentrations following oral dosing.
[0047] FIG. 4A is a graph showing Levofloxacin time-kill affects on
logarithmic PAM1020 cells.
[0048] FIG. 4B is a graph showing Levofloxacin time-kill affects on
logarithmic PAM1032 cells.
[0049] FIG. 5A is a graph showing Levofloxacin time-kill affects on
stationary phase PAM1020 cells.
[0050] FIG. 5B is a graph showing Levofloxacin time-kill affects on
stationary phase PAM1032 cells.
[0051] FIG. 6A is a graph showing PAM 1020 re-growth following a 10
minute Levofloxacin exposure.
[0052] FIG. 6B is a graph showing PAM 1020 re-growth following a
160 minute Levofloxacin exposure.
[0053] FIG. 6C is a graph showing PAM 1032 re-growth following a 10
minute Levofloxacin exposure.
[0054] FIG. 6D is a graph showing PAM 1032 re-growth following a
160 minute Levofloxacin exposure.
[0055] FIG. 7A is a graph showing Levofloxacin time-kill affects on
late-logarithmic PAM 1020 cells under oxygen limiting
conditions.
[0056] FIG. 7B is a graph showing Levofloxacin time-kill affects on
late-logarithmic PAM 1032 cells under oxygen limiting
conditions.
[0057] FIG. 8A is a graph showing Levofloxacin killing kinetics of
PAM1032 in Meuller-Hinton broth (MHB).
[0058] FIG. 8B is a graph showing Levofloxacin killing kinetics of
PAM1032 in cystic fibrosis sputum.
[0059] FIG. 9 is a graph showing levofloxacin killing affects on
Pseudomonas biofilms.
[0060] FIG. 10 is a graph showing the bactericidal effects of
levofloxacin with a Cmax of 1000 .mu.g/ml and a 10 minute half-life
in a hollow fiber model.
[0061] FIG. 11 is a graph showing the bactericidal effects of
levofloxacin with a Cmax of 600 .mu.g/ml and a 10 minute half-life
in a hollow fiber model.
[0062] FIG. 12 is a graph relating the micronization pressure used
to micronized dry powder levofloxacin vs. mean Levofloxacin dry
powder particle size.
[0063] FIGS. 13A and 13B are graphs showing the DSC profile of
micronized and pre-micronized dry powder Levofloxacin,
respectively.
[0064] FIG. 14A is a graph showing SEM photomicrographs of
pre-micronized dry powder Levofloxacin.
[0065] FIG. 14B is a graph showing SEM photomicrographs of
micronized dry powder Levofloxacin.
[0066] FIGS. 15A and 15B are graphs showing X-ray diffraction of
pre-micronized and micronized dry powder Levofloxacin,
respectively.
[0067] FIG. 16 is a graph showing the pH solubility profile of
Levofloxacin by acid titration.
[0068] FIG. 17 is a graph measuring pH while titrating Levofloxacin
with HCl.
[0069] FIG. 18 is a graph showing the Vt[OH] vs. Vt of
Levofloxacin.
[0070] FIG. 19 is a graph measuring pH while titrating Levofloxacin
with NaOH.
[0071] FIG. 20 is a graph measuring dpH/dV vs volume of NaOH
titrant (Vt) for titration of Levofloxacin.
[0072] FIG. 21 is a graph measuring the absorbance of a
Levofloxacin solution at 257 nm vs pH.
[0073] FIGS. 22A, 22B, 22C, and 22D depict graphs showing DSC scans
of pamoic acid, Levofloxacin, Levofloxacin pamoic acid
co-crystallized precipitate, and Levofloxacin-pamoic acid physical
mixture, respectively.
[0074] FIGS. 23A, 23B, 23C, and 23D depict graphs showing FTIR
spectra of pamoic acid, Levofloxacin, Levofloxacin Pamoic Acid
Co-Crystallized Precipitate, and Levofloxacin-Pamoic Acid Physical
Mixture, respectively.
[0075] FIGS. 24A and 24B depict graphs showing DSC scans of
xinafoic acid, and Levofloxacin xinafoic acid co-crystallized
precipitate, respectively.
[0076] FIGS. 25A and 25B depict graphs showing FTIR spectra of
xinafoic acid and Levofloxacin xinafoate co-crystals,
respectively.
[0077] FIGS. 26A, 26B and 26C depict graphs showing DSC scans of
stearic acid, Levofloxacin stearic acid co-crystallized
precipitate, and a physical mixture of Levofloxacin and stearic
acid, respectively.
[0078] FIGS. 27A, 27B, and 27C depict graphs showing FTIR spectra
of stearic acid, Levofloxacin stearic acid co-crystallized
precipitate, and a physical mixture of Levofloxacin and stearic
acid, respectively.
[0079] FIGS. 28A, 28B, 28C, 28D, and 28E depict graphs showing DSC
scans of oleic acid, Levofloxacin oleic acid co-crystallized
precipitate, physical mixture of Levofloxacin and oleic acid
(50:50), physical mixture of Levofloxacin and oleic acid (10:90),
and physical mixture of Levofloxacin and oleic acid (90:10),
respectively.
[0080] FIGS. 29A, 29B, and 29C depict graphs showing FTIR spectra
of oleic Acid, Levofloxacin oleic acid co-crystallized precipitate,
Levofloxacin oleic acid co-crystallized precipitate as compared to
an equimolar physical mixture of levofloxacin and oleic acid,
respectively.
[0081] FIG. 30 is a graph showing the kinetic solubility of the
co-crystallized precipitate of Levofloxacin with oleic acid at room
temperature, 40.degree. C., and equimolar physical mixture at
40.degree. C.
[0082] FIG. 31 is a graph showing the dissolution profile of
Levofloxacin xinafoate.
[0083] FIG. 32 is a graph showing the dissolution profile of
Levofloxacin xinafoate focused on the period between two and ten
minutes.
[0084] FIG. 33 is a graph showing the dissolution profile of
Levofloxacin xinafoate focused on the period between ten and thirty
minutes.
[0085] FIG. 34 is a graph showing the dissolution profile of
Levofloxacin base.
[0086] FIG. 35 is a graph showing the dissolution profile of
Levofloxacin pamoate.
[0087] FIG. 36 is a graph showing the dissolution profile of
Levofloxacin pamoate focused on the period between two and ten
minutes.
[0088] FIG. 37 is a graph showing the dissolution profile of
Levofloxacin pamoate focused on the period between ten and sixty
minutes.
[0089] FIG. 38 is a graph showing the dissolution profile of
Levofloxacin stearate.
[0090] FIG. 39 is a graph showing the dissolution profile of
Levofloxacin stearate focused on the period between two and ten
minutes.
[0091] FIG. 40 is a graph showing the dissolution profile of
Levofloxacin stearate focused on the period between ten and thirty
minutes.
[0092] FIG. 41 is a graph showing the complexation of Levofloxacin
with divalent and trivalent cations.
[0093] FIG. 42 is a graph showing the dual titration complexation
of Levofloxacin with Mg2+.
[0094] FIG. 43 is a graph showing the dual titration complexation
of Levofloxacin with Fe2+.
[0095] FIG. 44 is a graph showing the dual titration complexation
of Levofloxacin with Ca2+.
[0096] FIG. 45 is a graph showing the dual titration complexation
of Levofloxacin with Zn2+.
[0097] FIGS. 46A and 46B are graphs showing Levofloxacin complexed
with Ca2+ vs. free Levofloxacin where n=1, and where n=2,
respectively.
[0098] FIGS. 47A and 47B are graphs showing Levofloxacin complexed
with Mg2+ vs. free Levofloxacin where n=1, and where n=2,
respectively.
[0099] FIGS. 48A and 48B are graphs showing Levofloxacin complexed
with Fe2+ vs. free Levofloxacin where n=1, and where n=2,
respectively.
[0100] FIGS. 49A and 49B are graphs showing Levofloxacin complexed
with Zn2+ vs. free Levofloxacin where n=1, and where n=2,
respectively.
[0101] FIG. 50 is a graph showing the solubility of Levofloxacin in
the presence of Mg2+.
[0102] FIG. 51 is a graph showing the solubility of Levofloxacin in
the presence of Mg2+ at constant ionic strength.
[0103] FIG. 52 is a graph showing complexation of Levofloxacin with
Fe2+ as measured by spectrofluorometry.
[0104] FIG. 53 is a graph showing complexation of Levofloxacin with
Zn2+ as measured by spectrofluorometry.
DETAILED DESCRIPTION
[0105] Many of the problems associated with antimicrobial-resistant
pathogens could be alleviated if the concentration of the
antimicrobial could be safely increased at the site of infection.
For example, pulmonary infections may be treated by administration
of the antimicrobial agent directly, at high concentrations
directly to the site of infection without incurring large systemic
concentrations of the antimcirobial. Accordingly, some embodiments
disclosed herein are improved methods for delivering drug
compositions to treat pulmonary bacterial infections. More
specifically, as described herein, it has been discovered that
aerosol levofloxacin and other fluoroquinolones can be safely
delivered by inhalation at levels sufficient to kill susceptible
bacterial infections, to decrease the frequencey of antimicrobial
resistance and to increase efficacy against resistant pulmonary
infections.
DEFINITIONS
[0106] The term "administration" or "administering" refers to a
method of giving a dosage of an antimicrobial pharmaceutical
composition to a vertebrate. The preferred method of administration
can vary depending on various factors, e.g., the components of the
pharmaceutical composition, the site of the potential or actual
bacterial infection, the microbe involved, and the severity of an
actual microbial infection.
[0107] A "carrier" or "excipient" is a compound or material used to
facilitate administration of the compound, for example, to increase
the solubility of the compound. Solid carriers include, e.g.,
starch, lactose, dicalcium phosphate, sucrose, and kaolin. Liquid
carriers include, e.g., sterile water, saline, buffers, non-ionic
surfactants, and edible oils such as oil, peanut and sesame oils.
In addition, various adjuvants such as are commonly used in the art
may be included. These and other such compounds are described in
the literature, e.g., in the Merck Index, Merck & Company,
Rahway, N.J. Considerations for the inclusion of various components
in pharmaceutical compositions are described, e.g., in Gilman et
al. (Eds.) (1990); Goodman and Gilman's: The Pharmacological Basis
of Therapeutics, 8th Ed., Pergamon Press.
[0108] A "diagnostic" as used herein is a compound, method, system,
or device that assists in the identification and characterization
of a health or disease state. The diagnostic can be used in
standard assays as is known in the art.
[0109] The term "mammal" is used in its usual biological sense.
Thus, it specifically includes humans, cattle, horses, dogs, and
cats, but also includes many other species.
[0110] The term "microbial infection" refers to the undesired
proliferation or presence of invasion of pathogenic microbes in a
host organism. This includes the excessive growth of microbes that
are normally present in or on the body of a mammal or other
organism. More generally, a microbial infection can be any
situation in which the presence of a microbial population(s) is
damaging to a host mammal. Thus, a microbial infection exists when
excessive numbers of a microbial population are present in or on a
mammal's body, or when the effects of the presence of a microbial
population(s) is damaging the cells or other tissue of a
mammal.
[0111] The term "pharmaceutically acceptable carrier" or
"pharmaceutically acceptable excipient" includes any and all
solvents, dispersion media, coatings, antibacterial and antifungal
agents, isotonic and absorption delaying agents and the like. The
use of such media and agents for pharmaceutically active substances
is well known in the art. Except insofar as any conventional media
or agent is incompatible with the active ingredient, its use in the
therapeutic compositions is contemplated. Supplementary active
ingredients can also be incorporated into the compositions.
[0112] The term "pharmaceutically acceptable salt" refers to salts
that retain the biological effectiveness and properties of the
compounds of this invention and, which are not biologically or
otherwise undesirable. In many cases, the compounds of this
invention are capable of forming acid and/or base salts by virtue
of the presence of amino and/or carboxyl groups or groups similar
thereto. Pharmaceutically acceptable acid addition salts can be
formed with inorganic acids and organic acids. Inorganic acids from
which salts can be derived include, for example, hydrochloric acid,
hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and
the like. Organic acids from which salts can be derived include,
for example, acetic acid, propionic acid, naphtoic acid, oleic
acid, palmitic acid, pamoic (emboic) acid, stearic acid, glycolic
acid, pyruvic acid, oxalic acid, maleic acid, malonic acid,
succinic acid, fumaric acid, tartaric acid, citric acid, ascorbic
acid, glucoheptonic acid, glucuronic acid, lactic acid, lactobioic
acid, tartaric acid, benzoic acid, cinnamic acid, mandelic acid,
methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid,
salicylic acid, and the like. Pharmaceutically acceptable base
addition salts can be formed with inorganic and organic bases.
Inorganic bases from which salts can be derived include, for
example, sodium, potassium, lithium, ammonium, calcium, magnesium,
iron, zinc, copper, manganese, aluminum, and the like; particularly
preferred are the ammonium, potassium, sodium, calcium and
magnesium salts. Organic bases from which salts can be derived
include, for example, primary, secondary, and tertiary amines,
substituted amines including naturally occurring substituted
amines, cyclic amines, basic ion exchange resins, and the like,
specifically such as isopropylamine, trimethylamine, diethylamine,
triethylamine, tripropylamine, histidine, arginine, lysine,
benethamine, N-methyl-glucamine, and ethanolamine. Other acids
include dodecylsufuric acid, naphthalene-1,5-disulfonic acid,
naphthalene-2-sulfonic acid, and saccharin.
[0113] "Solvate" refers to the compound formed by the interaction
of a solvent and fluoroquinolone antimicrobial, a metabolite, or
salt thereof. Suitable solvates are pharmaceutically acceptable
solvates including hydrates.
[0114] In the context of the response of a microbe, such as a
bacterium, to an antimicrobial agent, the term "susceptibility"
refers to the sensitivity of the microbe for the presence of the
antimicrobial agent. So, to increase the susceptibility means that
the microbe will be inhibited by a lower concentration of the
antimicrobial agent in the medium surrounding the microbial cells.
This is equivalent to saying that the microbe is more sensitive to
the antimicrobial agent. In most cases the minimum inhibitory
concentration (MIC) of that antimicrobial agent will have been
reduced.
[0115] By "therapeutically effective amount" or "pharmaceutically
effective amount" is meant a fluoroquinolone antimicrobial agent,
as disclosed for this invention, which has a therapeutic effect.
The doses of fluoroquinolone antimicrobial agent which are useful
in treatment are therapeutically effective amounts. Thus, as used
herein, a therapeutically effective amount means those amounts of
fluoroquinolone antimicrobial agent which produce the desired
therapeutic effect as judged by clinical trial results and/or model
animal infection studies. In particular embodiments, the
fluoroquinolone antimicrobial agent are administered in a
predetermined dose, and thus a therapeutically effective amount
would be an amount of the dose administered. This amount and the
amount of the fluoroquinolone antimicrobial agent can be routinely
determined by one of skill in the art, and will vary, depending on
several factors, such as the particular microbial strain involved.
This amount can further depend upon the patient's height, weight,
sex, age and medical history. For prophylactic treatments, a
therapeutically effective amount is that amount which would be
effective to prevent a microbial infection.
[0116] A "therapeutic effect" relieves, to some extent, one or more
of the symptoms of the infection, and includes curing an infection.
"Curing" means that the symptoms of active infection are
eliminated, including the total or substantial elimination of
excessive members of viable microbe of those involved in the
infection to a point at or below the threshold of detection by
traditional measurements. However, certain long-term or permanent
effects of the infection may exist even after a cure is obtained
(such as extensive tissue damage). As used herein, a "therapeutic
effect" is defined as a statistically significant reduction in
bacterial load in a host, emergence of resistance, or improvement
in infection symptoms as measured by human clinical results or
animal studies.
[0117] "Treat," "treatment," or "treating," as used herein refers
to administering a pharmaceutical composition for prophylactic
and/or therapeutic purposes. The term "prophylactic treatment"
refers to treating a patient who is not yet infected, but who is
susceptible to, or otherwise at risk of, a particular infection.
The term "therapeutic treatment" refers to administering treatment
to a patient already suffering from an infection. Thus, in
preferred embodiments, treating is the administration to a mammal
(either for therapeutic or prophylactic purposes) of
therapeutically effective amounts of a fluoroquinolone
antimicrobial agent.
[0118] Pharmacokinetics (PK) is concerned with the time course of
antimicrobial concentration in the body. Pharmacodynamics (PD) is
concerned with the relationship between pharmacokinetics and the
antimicrobial efficacy in vivo. PK/PD parameters correlate
antimicrobial exposure with antimicrobial activity. The rate of
killing by antimicrobial is dependent on antimicrobial mode of
action and is determined by either the length of time necessary to
kill (time-dependent) or the effect of increasing concentrations
(concentration-dependent). Accordingly, to predict the therapeutic
efficacy of antimicrobials with diverse mechanisms of action
different PK/PD parameters may be used.
[0119] "AUC/MIC ratio" is one example of a PK/PD parameter. AUC is
defined as the area under the plasma or site-of-infection
concentration-time curve of an antimicrobial agent in vivo (in
animal or human). AUC/MIC ratio is determined by dividing the
24-hour-AUC for an individual antimicrobial by the MIC for the same
antimicrobial determined in vitro. Activity of antimicrobials with
the dose-dependent killing (such as fluoroquinolones) is well
predicted by the magnitude of the AUC/MIC ratio.
[0120] "Cmax:MIC" ratio is another PK:PD parameter. It describes
the maximum drug concentration in plasma or tissue relative to the
MIC. Fluoroquinolones and aminoglycosides are examples where
Cmax:MIC may predict in vivo bacterial killing where resitance can
be suppressed.
[0121] "Time above MIC" (T>MIC) is another PK/PD parameter. It
is expressed a percentage of a dosage interval in which the plasma
or site-of-infection level exceeds the MIC. Activity of
antimicrobials with the time-dependent killing (such as
beta-lactams or oxazolidinones) is well predicted by the magnitude
of the T>MIC ratio.
[0122] The term "dosing interval" refers to the time between
administrations of the two sequential doses of a pharmaceutical's
during multiple dosing regimens. For example, in the case of
ciprofloxacin, which is administered twice daily (traditional
regimen of 400 mg b.i.d) and levofloxacin, which is administered
once a day (500 mg or 750 mg q.d.), the dosing intervals are 12
hours and 24 hours, respectively.
[0123] As used herein, the "peak period" of a pharmaceutical's in
vivo concentration is defined as that time of the pharmaceutical
dosing interval when the pharmaceutical concentration is not less
than 50% of its maximum plasma or site-of-infection concentration.
In some embodiments, "peak period" is used to describe an interval
of antimicrobial dosing.
[0124] The "respirable delivered dose" is the amount of drug
inhaled during the inspiratory phase of the breath simulator that
is equal to or less than 5 microns using a simulator programmed to
the European Standard pattern of 15 breaths per minute, with an
inspiration to expiration ratio of 1:1.
[0125] Advantages of Inhaled Aerosol and Topical (Non-Oral)
Fluoroquinolone Delivery
[0126] The antibiotic rate of killing is dependent upon antibiotic
mode of action and is determined by either the length of time
necessary for the antibiotic to kill (time-dependent) or the effect
of increasing the antibiotic concentration
(concentration-dependent). Fluoroquinolones are characterized by
concentration-dependent, time-kill activity where a therapeutic
effect requires a high local peak concentration above the MICs of
the infecting pathogen.
[0127] Fluoroquinolone efficacy in humans, animals and in vitro
models of infection is linked to AUC:MIC ratio and Cmax:MIC ratio.
Given the prior uncertainty of the pharmacokinetics of
fluoroquinolones in pulmonary tissue, a number of in vitro studies
have been conducted to determine if high doses of levofloxacin with
extremely short half-lives (as predicted from a rat and human PK
model) result in bacterial killing superior to that seen under
conditions with more prolonged residence times. In these studies,
levofloxacin concentrations that were 0.018-fold-1024-fold the MIC
were evaluated in a standard kill-curve and in vitro hollow fiber
assay. In both of these assays, high concentrations of levofloxacin
were rapidly bactericidal and reached their maximum level of
killing in 10-20 minutes. This level of killing was sustained
whether levofloxacin was maintained at that level or given a
half-life of 10 minutes. Accordingly, high doses and rapid delivery
of specially formulated levofloxacin, such as a rapidly delivered
20-50 mg respirable deposited aerosol levofloxacin dose (which will
produce initial ELF concentrations of 800-1600 ug/mL) is rapidly
bactericidal for susceptible organisms and resistant organisms with
MICs up to 32 ug/ml. It is expected that these unique antimicrobial
properties of fluoroquinolones will also translate to topical
administrations, including, but not limited to infections or
prophylaxis of the skin, eye, ear, rectum, vagina, or urinary
tract.
[0128] To measure the efficacy of different delivery models, AUC
shape-enhancing levofloxacin formulations were prepared and
measured in vivo in comparison to non-AUC shape-enhancing
levofloxacin formulations and other antibiotics using both rat PK
and mouse efficacy following intratracheal administration. As was
previously shown in a rat system, there were differences among
drugs in pulmonary pharmacokinetics, with some agents showing lower
AUCs (e.g., levofloxacin), while others such as gemifloxacin or
tobramycin show higher concentrations resulting from slower
pulmonary clearance. Studies in a single dose mouse model of
infection with aerosol doses have shown variable efficacy among the
compounds. Referring to FIG. 1, analysis of the data by dividing
the aerosolized dose by the MIC indicated a strong correlation
between Dose:MIC ratio and bactericidal activity (R2=0.89). These
data suggest that the initial bactericidal activity in this model
is not affected by the pulmonary clearance of the drug. Although
pulmonary clearances have not been estimated in mice,
transformation of dose to AUC using scaled rat values would be
expected to degrade the relationship. Therefore, this data suggests
that optimizing the AUC shape for levofloxacin may not be necessary
for aerosol levofloxacin to be effective in treating respiratory
tract and pulmonary infections.
[0129] Recent investigations with fluoroquinolones resulted in
development of the concept of a "mutant selection window" (MSW) for
bacterial resistance arising during therapy. This concept assists
in identifying a concentration range where mutants are selected
more frequently in vitro and in vivo. The lower boundary of the
window is the lowest concentration that kills the majority of
infecting cells (approximated by the MIC), while the upper boundary
of the window is the drug concentration that blocks the growth of
the least susceptible first-step mutant. Above the upper boundary
concentration the growth of the infecting bacteria requires the
presence of at least two resistance mutations. This upper boundary
is designated the mutant prevention concentration (MPC). The values
of MPC vary depending on bacteria and fluoroquinolone, and may be
10- to 20-fold higher than the MIC. Several modeling studies have
demonstrated that the longer the drug concentration exceeds the MPC
at the site of infection, the more effectively the treatment will
prevent resistance development. Conversely, the longer the
antibiotic concentration stays within the MSW, the higher the
probability to select resistant mutants. Importantly, the currently
approved dosing regimen for oral or intravenous levofloxacin has
placed this antibiotic within the MSW for more than 20% of the
dosing interval for such pathogens as P. aeruginosa (Pa) and S.
pneumonia. Accordingly, a high level of levofloxacin resistance is
reported for both of these pathogens.
[0130] Therefore, in one embodiment, the concentration of
levofloxacin at the site of infection is increased by delivering it
directly to the lung using inhalation therapy, thereby decreasing
the amount of time levofloxacin is in the MSW. Such a therapeutic
approach achieves broader coverage of pathogens (including
levofloxacin resistant strains), prevents further resistance
development, and results in shorter courses of levofloxacin
therapy.
[0131] Pharmacokinetics of Orally Adminsitered Fluoroquinolones in
Non-CF and CF Populations
[0132] Sputum Concentrations in CF Patients
[0133] The pharmacokinetics of ciprofloxacin has been extensively
studied in CF patients after oral administration. In fact, it has
been demonstrated that the serum PK profile of ciprofloxacin is
very similar in CF patients to healthy volunteers (FIG. 2).
[0134] Moreover, the sputum vs time profile of ciprofloxacin is
very similar to its serum profile after oral administration (FIG.
3). After a 750 mg oral dose, peak concentrations of .about.4.2
.mu.g/ml and .about.3.5 .mu.g/ml were achieved for serum and
sputum, respectively. Serum and sputum drug concentrations peaked
at 1.5 and 4 hours, respectively. While the total amount of
ciprofloxacin into sputum is high relative to serum concentrations,
the absolute concentrations are low relative to MICs of target
organisms such as Pa. This data is consistant with poor clinical
outcome due to resistance development to these low drug
concentrations.
[0135] While data for levofloxacin intrapulmonary pharmacokinetics
in cystic fibrosis are not available, data on the closely-related
ofloxacin were published in the 1980's and 1990s. Ofloxacin is
comprised of a racemic mixture of the dextro-(microbiologically
inactive) and levo-rotatory (levofloxacin-microbiologically
active). Studies have shown that the pharmacokinetic properties of
the 2 components are similar. In comparative studies with
ciprofloxacin, ofloxacin had a longer half-life and higher
distribution into sputum (79% vs 21%) than ciprofloxacin.
[0136] Lung Epithelial Lining Fluid
[0137] More recent emphasis on the use and development of
fluoroquinolones in community acquired gram-positive infections has
focused on intrapulmonary pharmacokinetic studies in lung
epithelial lining fluid (ELF). Although the relevance of drug
distribution into this fluid is not clear in the setting of cystic
fibrosis, insights in the drug pharmacology can be obtained from
these studies. Levofloxacin penetrates well into lung tissues. Lung
tissue concentrations are generally 2- to 5-fold higher than plasma
concentrations. Several recent studies (summarized in Table 1)
demonstrated that ELF concentrations of levofloxacin in healthy
subjects following an oral dose of 750 mg reach a maximum
concentration around 20 .mu.g/mL. Similar peak concentrations are
expected in the sputum of CF patients after oral or IV
administration of 750 mg of levofloxacin. In contrast,
ciprofloxacin penetrates lung tissues much less efficiently than
levofloxacin. Based upon studies of the mutant selection window
(MSW), these ELF fluoroquinolone drug levels are insufficient to
achieve the required mutant prevention concentration of 10- to
20-fold the MIC for the infecting organism.
TABLE-US-00001 TABLE 1 Concentration of Levofloxacin in Epithelial
Linking Fluid in Man ELF Drug Concentration (.mu.g/ml) Drug Dose
Route 0.5 hr 1 hr 2 hr 4 hr 6 hr 12 hr 24 hr levofloxacin 500 mg IV
11 2.5 1.24 levofloxacin 500 mg oral 9.9 6.5 0.7 levofloxacin 500
mg oral 9.94 6.46 0.7 levofloxacin 500 mg oral 4.74 10.8 9 10.9 9.6
levofloxacin 750 mg IV 12.94 6.04 1.73 levofloxacin 750 mg oral
22.1 9.2 1.5 levofloxacin 750 mg oral 22.13 9.19 1.55 ciprofloxacin
500 mg oral 1.9 0.4
[0138] Quinolones
[0139] Non-limiting examples of quinolones for use as described
herein include amifloxacin, cinoxacin, ciprofloxacin, enoxacin,
fleroxacin, flumequine, lomefloxacin, nalidixic acid, norfloxacin,
ofloxacin, levofloxacin, lomefloxacin, oxolinic acid, pefloxacin,
rosoxacin, temafloxacin, tosufloxacin, sparfloxacin, clinafloxacin,
gatifloxacin, moxifloxacin; gemifloxacin; garenoxacin;
olamufloxacin, clinofloxacin, trovafloxacin, balofloxacin,
prulifloxacin, moxifloxacin, gemifloxacin, rufloxacin, sitafloxacin
(Sato, K, et al., 1992, Antimicrob Agents Chemother. 37:1491-98,
which is incorporated herein by reference in its entirety),
marbofloxacin, orbifloxacin, sarafloxacin, danofloxacin,
difloxacin, enrofloxacin,TG-873870, DX-619, DW-276, ABT-492,
DV-7751a (Tanaka, M, et al., 1992, Antimicrob. Agents Chemother.
37:2212-18), and F-1061 (Kurosaka et al., Interscience Conference
on Antimicrobial Agents and Chemotherapy, 2003, 43rd:Chicago, which
is incorporated herein by reference in its entirety).
[0140] Methods of Treatment or Prophylaxis
[0141] In some embodiments, a method is provided for treating a
microbial infection in an animal, specifically including in a
mammal, by treating an animal suffering from such an infection with
a fluoroquinolone antimicrobial. In some embodiments,
fluoroquinolone antimicrobials may be administered following
aerosol formation and inhalation. Thus, this method of treatment is
especially appropriate for the treatment of pulmonary infections
involving microbial strains that are difficult to treat using an
antimicrobial agent delivered parenterally due to the need for high
parenteral dose levels (which can cause undesirable side effects),
or due to lack of any clinically effective antimicrobial agents. In
one such embodiment, this method may be used to administer a
fluoroquinolone antimicrobial directly to the site of infection.
Such a method may reduce systemic exposure and maximizes the amount
of antimicrobial agent to the site of microbial infection. This
method is also appropriate for treating infections involving
microbes that are susceptible to fluoroquinolone antimicrobials as
a way of reducing the frequency of selection of resistant microbes.
This method is also appropriate for treating infections involving
microbes that are otherwise resistant to fluoroquinolone
antimicrobials as a way of increasing the amount of antimicrobial
at the site of microbial infection. A subject may be identified as
infected with bacteria that are capable of developing resistance by
diagnosing the subject as having symptoms that are characteristic
of a bacterial infection with a bacteria species known to have
resistant strains or a with a bacteria that is a member of group
that are known to have resistant strains. Alternatively, the
bacteria may be cultured and identified as a species known to have
resistant strains or a bacteria that is a member of group that are
known to have resistant strains.
[0142] In some embodiments, the aerosol fluoroquinolone
antimicrobial agent is administered at a level sufficient to
overcome the emergence resistance in bacteria or increase killing
efficiency such that resistance does not have the opportunity to
develop.
[0143] In some embodiments, the aerosol fluoroquinolone therapy may
be administered as a treatment or prophylaxis in combination or
alternating therapeutic sequence with other aerosol, oral or
parenteral antibiotics. By non-limiting example this may include
aerosol tobramycin and/or other aminoglycoside, aerosol aztreonam
and/or other beta or mono-bactam, aerosol ciprofloxacin and/or
other fluoroquinolones, aerosol azithromycin and/or other
macrolides or ketolides, tetracycline and/or other tetracyclines,
quinupristin and/or other streptogramins, linezolid and/or other
oxazolidinones, vancomycin and/or other glycopeptides, and
chloramphenicol and/or other phenicols, and colisitin and/or other
polymyxins.
[0144] Pharmaceutical Compositions
[0145] For purposes of the method described herein, a
fluoroquinolone antimicrobial agent may be administered using an
inhaler. In some embodiments, a fluoroquinolone antimicrobial
disclosed herein is produced as a pharmaceutical composition
suitable for aerosol formation, good taste, storage stability, and
patient safety and tolerability.
[0146] In some embodiments, the isoform content of the manufactured
fluoroquinolone may be optimized for tolerability, antimicrobial
activity and stability.
[0147] Administration
[0148] The fluoroquinolone antimicrobials disclosed herein can be
administered at a therapeutically effective dosage, e.g., a dosage
sufficient to provide treatment for the disease states previously
described. While optimum human dosage levels have yet to be
determined for aerosol delivery, generally a daily aerosol dose of
levofloxacin (and for most fluoroquinolone antimicrobial agents
described herein) is from about 0.1 to 10 mg/kg of body weight,
preferably about 0.20 to 5.0 mg/kg of body weight, and most
preferably about 0.4 to 4.0 mg/kg of body weight. Thus, for
administration to a 70 kg person, the dosage range would be about
7.0 to 700.0 mg per day, preferably about 14.0 to 350.0 mg per day,
and most preferably about 28.0 to 280.0 mg per day. The amount of
active compound administered will, of course, be dependent on the
subject and disease state being treated, the severity of the
affliction, the manner and schedule of administration, and the
judgment of the prescribing physician; for example, a likely dose
range for aerosol administration of levofloxacin would be about 20
to 400 mg per day.
[0149] Administration of the fluoroquinolone antimicrobial agents
disclosed herein or the pharmaceutically acceptable salts thereof
can be via any of the accepted modes of administration for agents
that serve similar utilities including, but not limited to, aerosol
inhalation.
[0150] Pharmaceutically acceptable compositions include solid,
semi-solid, liquid and aerosol dosage forms, such as, e.g.,
powders, liquids, suspensions, complexations, liposomes,
particulates, or the like. Preferably, the compositions are
provided in unit dosage forms suitable for single administration of
a precise dose. The unit dosage form can also be assembled and
packaged together to provide a patient with a weekly or monthly
supply and can also incorporate other compounds such as saline,
taste masking agents, pharmaceutical excipients, and other active
ingredients or carriers.
[0151] The fluoroquinolone antimicrobial agent can be administered
either alone or more typically in combination with a conventional
pharmaceutical carrier, excipient or the like (e.g., mannitol,
lactose, starch, magnesium stearate, sodium saccharine, talcum,
cellulose, sodium crosscarmellose, glucose, gelatin, sucrose,
magnesium carbonate, magnesium chloride, magnesium sulfate, calcium
chloride, lactose, sucrose, glucose and the like). If desired, the
pharmaceutical composition can also contain minor amounts of
nontoxic auxiliary substances such as wetting agents, emulsifying
agents, solubilizing agents, pH buffering agents and the like
(e.g., sodium acetate, sodium citrate, cyclodextrin derivatives,
sorbitan monolaurate, triethanolamine acetate, triethanolamine
oleate, and the like). Generally, depending on the intended mode of
administration, the pharmaceutical formulation will contain about
0.005% to 95%, preferably about 0.5% to 50% by weight of a compound
of the invention. Actual methods of preparing such dosage forms are
known, or will be apparent, to those skilled in this art; for
example, see Remington's Pharmaceutical Sciences, Mack Publishing
Company, Easton, Pa.
[0152] In one preferred embodiment, the compositions will take the
form of a unit dosage form such as vial containing a liquid, solid
to be suspended, dry powder, lyophilisate, or other composition and
thus the composition may contain, along with the active ingredient,
a diluent such as lactose, sucrose, dicalcium phosphate, or the
like; a lubricant such as magnesium stearate or the like; and a
binder such as starch, gum acacia, polyvinylpyrrolidine, gelatin,
cellulose, cellulose derivatives or the like.
[0153] Liquid pharmaceutically administrable compositions can, for
example, be prepared by dissolving, dispersing, etc. an active
compound as defined above and optional pharmaceutical adjuvants in
a carrier (e.g., water, saline, aqueous dextrose, glycerol,
glycols, ethanol or the like) to form a solution or suspension.
Solutions to be aerosolized can be prepared in conventional forms,
either as liquid solutions or suspensions, as emulsions, or in
solid forms suitable for dissolution or suspension in liquid prior
to aerosol production and inhalation. The percentage of active
compound contained in such aerosol compositions is highly dependent
on the specific nature thereof, as well as the activity of the
compound and the needs of the subject. However, percentages of
active ingredient of 0.01% to 90% in solution are employable, and
will be higher if the composition is a solid, which will be
subsequently diluted to the above percentages. In some embodiments,
the composition will comprise 1.0%-50.0% of the active agent in
solution.
[0154] Fluoroquinolone formulations can be separated into two
groups; those of simple formulation and complex formulations
providing taste-masking properties, improved tolerability and/or an
AUC shape-enhancing formulation. Simple formulations can be further
separated into three groups. 1. Simple formulations may include
water-based liquid formulations for nebulization. By non-limiting
example water-based liquid formulations may consist of
fluoroquinolone alone or with non-encapsulating water soluble
excipients. 2. Simple formulations may also include organic-based
liquid formulations for nebulization or meter-dose inhaler. By
non-limiting example organic-based liquid formulations may consist
of fluoroquinolone or with non-encapsulating organic soluble
excipients. 3. Simple formulations may also include dry powder
formulations for administration with a dry powder inhaler. By
non-limiting example dry powder formulations may consist of
fluoroquinolone alone or with either water soluble or organic
soluble non-encapsulating excipients with or without a blending
agent such as lactose. Complex formulations can be further
separated into five groups. 1. Complex formulations may include
water-based liquid formulations for nebulization. By non-limiting
example water-based liquid complex formulations may consist of
fluoroquinolone encapsulated or complexed with water-soluble
excipients such as lipids, liposomes, cyclodextrins,
microencapsulations, and emulsions. 2. Complex formulations may
also include organic-based liquid formulations for nebulization or
meter-dose inhaler. By non-limiting example organic-based liquid
complex formulations may consist of fluoroquinolone encapsulated or
complexed with organic-soluble excipients such as lipids,
microencapsulations, and reverse-phase water-based emulsions. 3.
Complex formulations may also include low-solubility, water-based
liquid formulations for nebulization. By non-limiting example
low-solubility, water-based liquid complex formulations may consist
of fluoroquinolone as a low-water soluble, stable nanosuspension
alone or in co-crystal/co-precipitate excipient complexes, or
mixtures with low solubility lipids, such as lipid nanosuspensions.
4. Complex formulations may also include low-solubility,
organic-based liquid formulations for nebulization or meter-dose
inhaler. By non-limiting example low-solubility, organic-based
liquid complex formulations may consist of fluoroquinolone as a
low-organic soluble, stable nanosuspension alone or in
co-crystal/co-precipitate excipient complexes, or mixtures with low
solubility lipids, such as lipid nanosuspensions. 5. Complex
formulations may also include dry powder formulations for
administration using a dry powder inhaler. By non-limiting example,
complex dry powder formulations may consist of fluoroquinolone in
co-crystal/co-precipitate/spray dried complex or mixture with
low-water soluble excipients/salts in dry powder form with or
without a blending agent such as lactose. Specific methods for
simple and complex formulation preparation are described
herein.
[0155] Aerosol Delivery
[0156] Fluoroquinolone antimicrobial agents as described herein,
are preferably directly administered as an aerosol to a site of
infection in the respiratory tract. In some embodiments, aerosol
delivery is used to treat an infection in the lungs, such as a
Pseudomonas lung infection.
[0157] Several device technologies exist to deliver either dry
powder or liquid aerosolized products. Dry powder formulations
generally require less time for drug administration, yet longer and
more expensive development efforts. Conversely, liquid formulations
have historically suffered from longer administration times, yet
have the advantage of shorter and less expensive development
efforts. The fluoroquinolone antimicrobial agents disclosed herein
range in solubility, are generally stable and have a range of
tastes. In one such embodiment, the fluoroquinolone antimicrobial
levofloxacin is water soluble at neutral pH, is stable in aqueous
solution and has limited to no taste.
[0158] Accordingly, in one embodiment, a particular formulation of
fluoroquinolone antimicrobial agent disclosed herein is combined
with a particular aerosolizing device to provide an aerosol for
inhalation that is optimized for maximum drug deposition at a site
of infection and maximal tolerability. Factors that can be
optimized include solution or solid particle formulation, rate of
delivery, and particle size and distribution produced by the
aerosolizing device.
[0159] Particle Size and Distribution
[0160] Generally, inhaled particles are subject to deposition by
one of two mechanisms: impaction, which usually predominates for
larger particles, and sedimentation, which is prevalent for smaller
particles. Impaction occurs when the momentum of an inhaled
particle is large enough that the particle does not follow the air
stream and encounters a physiological surface. In contrast,
sedimentation occurs primarily in the deep lung when very small
particles which have traveled with the inhaled air stream encounter
physiological surfaces as a result of random diffusion within the
air stream.
[0161] For pulmonary administration, the upper airways are avoided
in favor of the middle and lower airways. Pulmonary drug delivery
may be accomplished by inhalation of an aerosol through the mouth
and throat. Particles having a mass median aerodynamic diameter
(MMAD) of greater than about 5 microns generally do not reach the
lung; instead, they tend to impact the back of the throat and are
swallowed and possibly orally absorbed. Particles having diameters
of about 2 to about 5 microns are small enough to reach the upper-
to mid-pulmonary region (conducting airways), but are too large to
reach the alveoli. Smaller particles, i.e., about 0.5 to about 2
microns, are capable of reaching the alveolar region. Particles
having diameters smaller than about 0.5 microns can also be
deposited in the alveolar region by sedimentation, although very
small particles may be exhaled. Measures of particle size can be
referred to as volumetric mean diameter (VIVID), mass median
diameter (MMD), or MMAD. These measurements may be made by
impaction (MMD and MMAD) or by laser (VMD). For liquid particles,
VIVID, MMD and MMAD may be the same if environmental conditions are
maintained, e.g. standard humidity. However, if humidity is not
maintained, MMD and MMAD determinations will be smaller than VIVID
due to dehydration during impactor measurements. For the purposes
of this description, VIVID, MMD and MMAD measurements are
considered to be under standard conditions such that descriptions
of VIVID, MMD and MMAD will be comparable. Similarly, dry powder
particle size determinations in MMD, and MMAD are also considered
comparable.
[0162] In some embodiments, the particle size of the aerosol is
optimized to maximize fluoroquinolone antimicrobial agent
deposition at the site of infection and to maximize tolerability.
Aerosol particle size may be expressed in terms of the mass median
aerodynamic diameter (MMAD). Large particles (e.g., MMAD >5
.mu.m) may deposit in the upper airway because they are too large
to navigate the curvature of the upper airway. Small particles
(e.g., MMAD <2 .mu.m) may be poorly deposited in the lower
airways and thus become exhaled, providing additional opportunity
for upper airway deposition. Hence, intolerability (e.g., cough and
bronchospasm) may occur from upper airway deposition from both
inhalation impaction of large particles and settling of small
particles during repeated inhalation and expiration. Thus, in one
embodiment, an optimum particle size is used (e.g., MMAD=2-5 .mu.m)
in order to maximize deposition at a mid-lung site of infection and
to minimize intoleratiblity associated with upper airway
deposition. Moreover, generation of a defined particle size with
limited geometric standard deviation (GSD) may optimize deposition
and tolerability. Narrow GSD limits the number of particles outside
the desired MMAD size range. In one embodiment, an aerosol
containing one or more compounds disclosed herein is provided
having a MMAD from about 2 microns to about 5 microns with a GSD of
less than or equal to about 2.5 microns. In another embodiment, an
aerosol having an MMAD from about 2.8 microns to about 4.3 microns
with a GSD less than or equal to 2 microns is provided. In another
embodiment, an aerosol having an MMAD from about 2.5 microns to
about 4.5 microns with a GSD less than or equal to 1.8 microns is
provided.
[0163] Fluoroquinolone antimicrobial agents disclosed herein
intended for respiratory delivery (for either systemic or local
distribution) can be administered as aqueous formulations, as
suspensions or solutions in halogenated hydrocarbon propellants, or
as dry powders. Aqueous formulations may be aerosolized by liquid
nebulizers employing either hydraulic or ultrasonic atomization.
Propellant-based systems may use suitable pressurized metered-dose
inhalers (pMDIs). Dry powders may use dry powder inhaler devices
(DPIs), which are capable of dispersing the drug substance
effectively. A desired particle size and distribution may be
obtained by choosing an appropriate device.
[0164] Liquid Nebulizer
[0165] In one embodiment, a nebulizer is selected on the basis of
allowing the formation of an aerosol of a fluoroquinolone
antimicrobial agent disclosed herein having an MMAD predominantly
between about 2 to about 5 microns. In one embodiment, the
delivered amount of fluoroquinolone antimicrobial agent provides a
therapeutic effect for respiratory infections.
[0166] Previously, two types of nebulizers, jet and ultrasonic,
have been shown to be able to produce and deliver aerosol particles
having sizes between 2 and 4 um. These particle sizes have been
shown as being optimal for treatment of pulmonary bacterial
infection cause by gram-negative bacteria such as Pseudomonas
aeruginosa, Escherichia coli, Enterobacter species, Klebsiella
pneumoniae, K. oxytoca, Proteus mirabilis, Pseudomonas aeruginosa,
Serratia marcescens, Haemophilus influenzae, Burkholderia cepacia,
Stenotrophomonas maltophilia, Alcaligenes xylosoxidans, and
multidrug resistant Pseudomonas aeruginosa. However, unless a
specially formulated solution is used, these nebulizers typically
need larger volumes to administer sufficient amount of drug to
obtain a therapeutic effect. A jet nebulizer utilizes air pressure
breakage of an aqueous solution into aerosol droplets. An
ultrasonic nebulizer utilizes shearing of the aqueous solution by a
piezoelectric crystal. Typically, however, the jet nebulizers are
only about 10% efficient under clinical conditions, while the
ultrasonic nebulizer is only about 5% efficient. The amount of
pharmaceutical deposited and absorbed in the lungs is thus a
fraction of the 10% in spite of the large amounts of the drug
placed in the nebulizer.
[0167] Accordingly, in one embodiment, a vibrating mesh nebulizer
is used to deliver an aerosol of the fluoroquinolone antimicrobial
agent disclosed herein. A vibrating mesh nebulizer consists of a
liquid storage container in fluid contact with a diaphragm and
inhalation and exhalation valves. In one embodiment, about 1 to
about 5 ml of the fluoroquinolone antimicrobial agent is placed in
the storage container and the aerosol generator is engaged
producing atomized aerosol of particle sizes selectively between
about 1 and about 5 um.
[0168] By non-limiting example, a fluoroquinolone antimicrobial
agent disclosed herein is placed in a liquid nebulization inhaler
and prepared in dosages to deliver from about 7 to about 700 mg
from a dosing solution of about 1 to about 5 ml, preferably from
about 14 to about 350 mg in about 1 to about 5 ml, and most
preferably from about 28 to about 280 mg in about 1 to about 5 ml
with MMAD particles sizes between about 2 to about 5 um being
produced.
[0169] By non-limiting example, a nebulized fluoroquinolone
antimicrobial may be administered in the described respirable
delivered dose in less than about 20 min, preferably less than
about 10 min, more preferably less than about 7 min, more
preferably less than about 5 min, more preferably less than about 3
min, and in some cases most preferable if less than about 2
min.
[0170] By non-limiting example, in other circumstances, a nebulized
fluoroquinolone antimicrobial may achieve improved tolerability
and/or exhibit an AUC shape-enhancing characteristic when
administered over longer periods of time. Under these conditions,
the described respirable delivered dose in more than about 2 min,
preferably more than about 3 min, more preferably more than about 5
min, more preferably more than about 7 min, more preferably more
than about 10 min, and in some cases most preferable from about 10
to about 20 min.
[0171] For aqueous and other non-pressurized liquid systems, a
variety of nebulizers (including small volume nebulizers) are
available to aerosolize the formulations. Compressor-driven
nebulizers incorporate jet technology and use compressed air to
generate the liquid aerosol. Such devices are commercially
available from, for example, Healthdyne Technologies, Inc.;
Invacare, Inc.; Mountain Medical Equipment, Inc.; Pari Respiratory,
Inc.; Mada Medical, Inc.; Puritan-Bennet; Schuco, Inc., DeVilbiss
Health Care, Inc.; and Hospitak, Inc. Ultrasonic nebulizers rely on
mechanical energy in the form of vibration of a piezoelectric
crystal to generate respirable liquid droplets and are commercially
available from, for example, Omron Heathcare, Inc. and DeVilbiss
Health Care, Inc. Vibrating mesh nebulizers rely upon either
piezoelectric or mechanical pulses to respirable liquid droplets
generate. Other examples of nebulizers for use with fluoroquinolone
antimicrobial agents described herein are described in U.S. Pat.
Nos. 4,268,460; 4,253,468; 4,046,146; 3,826,255; 4,649,911;
4,510,929; 4,624,251; 5,164,740; 5,586,550; 5,758,637; 6,644,304;
6,338,443; 5,906,202; 5,934,272; 5,960,792; 5,971,951; 6,070,575;
6,192,876; 6,230,706; 6,349,719; 6,367,470; 6,543,442; 6,584,971;
6,601,581; 4,263,907; 5,709,202; 5,823,179; 6,192,876; 6,644,304;
5,549,102; 6,083,922; 6,161,536; 6,264,922; 6,557,549; and
6,612,303 all of which are hereby incorporated by reference in
their entirety. Commercial examples of nebulizers that can be used
with the fluoroquinolone antimicrobial agents described herein
include Respirgard II.RTM., Aeroneb.RTM., Aeroneb.RTM. Pro, and
Aeroneb.RTM. Go produced by Aerogen; AERx.RTM. and AERx Essence.TM.
produced by Aradigm; Porta-Neb.RTM., Freeway Freedom.TM.,
Sidestream-Ventstream and I-neb produced by Respironics, Inc.; and
PAM LC-Plus.RTM., PAM LC-Star.RTM., and e-Flow.sup.7m produced by
PAM, GmbH. By further non-limiting example, U.S. Pat. No.
6,196,219, is hereby incorporated by reference in its entirety.
[0172] In some embodiments, the drug solution is formed prior to
use of the nebulizer by a patient. In other embodiments, the drug
is stored in the nebulizer in solid form. In this case, the
solution is mixed upon activation of the nebulizer, such as
described in U.S. Pat. No. 6,427,682 and PCT Publication No. WO
03/035030, both of which are hereby incorporated by reference in
their entirety. In these nebulizers, the solid drug, optionally
combined with excipients to form a solid composition, is stored in
a separate compartment from a liquid solvent.
[0173] The liquid solvent is capable of dissolving the solid
composition to form a liquid composition, which can be aerosolized
and inhaled. Such capability is, among other factors, a function of
the selected amount and, potentially, the composition of the
liquid. To allow easy handling and reproducible dosing, the sterile
aqueous liquid may be able to dissolve the solid composition within
a short period of time, possibly under gentle shaking. In some
embodiments, the final liquid is ready to use after no longer than
about 30 seconds. In some cases, the solid composition is dissolved
within about 20 seconds, and advantageously, within about 10
seconds. As used herein, the terms "dissolve(d)", "dissolving", and
"dissolution" refer to the disintegration of the solid composition
and the release, i.e. the dissolution, of the active compound. As a
result of dissolving the solid composition with the liquid solvent
a liquid composition is formed in which the active compound is
contained in the dissolved state. As used herein, the active
compound is in the dissolved state when at least about 90 wt. % are
dissolved, and more preferably when at least about 95 wt. % are
dissolved.
[0174] With regard to basic separated-compartment nebulizer design,
it primarily depends on the specific application whether it is more
useful to accommodate the aqueous liquid and the solid composition
within separate chambers of the same container or primary package,
or whether they should be provided in separate containers. If
separate containers are used, these are provided as a set within
the same secondary package. The use of separate containers is
especially preferred for nebulizers containing two or more doses of
the active compound. There is no limit to the total number of
containers provided in a multi-dose kit. In one embodiment, the
solid composition is provided as unit doses within multiple
containers or within multiple chambers of a container, whereas the
liquid solvent is provided within one chamber or container. In this
case, a favorable design provides the liquid in a metered-dose
dispenser, which may consist of a glass or plastic bottle closed
with a dispensing device, such as a mechanical pump for metering
the liquid. For instance, one actuation of the pumping mechanism
may dispense the exact amount of liquid for dissolving one dose
unit of the solid composition.
[0175] In another embodiment for multiple-dose
separated-compartment nebulizers, both the solid composition and
the liquid solvent are provided as matched unit doses within
multiple containers or within multiple chambers of a container. For
instance, two-chambered containers can be used to hold one unit of
the solid composition in one of the chambers and one unit of liquid
in the other. As used herein, one unit is defined by the amount of
drug present in the solid composition, which is one unit dose. Such
two-chambered containers may, however, also be used advantageously
for nebulizers containing only one single drug dose.
[0176] In one embodiment of a separated-compartment nebulizer, a
blister pack having two blisters is used, the blisters representing
the chambers for containing the solid composition and the liquid
solvent in matched quantities for preparing a dose unit of the
final liquid composition. As used herein, a blister pack represents
a thermoformed or pressure-formed primary packaging unit, most
likely comprising a polymeric packaging material that optionally
includes a metal foil, such as aluminum. The blister pack may be
shaped to allow easy dispensing of the contents. For instance, one
side of the pack may be tapered or have a tapered portion or region
through which the content is dispensable into another vessel upon
opening the blister pack at the tapered end. The tapered end may
represent a tip.
[0177] In some embodiments, the two chambers of the blister pack
are connected by a channel, the channel being adapted to direct
fluid from the blister containing the liquid solvent to the blister
containing the solid composition. During storage, the channel is
closed with a seal. In this sense, a seal is any structure that
prevents the liquid solvent from contacting the solid composition.
The seal is preferably breakable or removable; breaking or removing
the seal when the nebulizer is to be used will allow the liquid
solvent to enter the other chamber and dissolve the solid
composition. The dissolution process may be improved by shaking the
blister pack. Thus, the final liquid composition for inhalation is
obtained, the liquid being present in one or both of the chambers
of the pack connected by the channel, depending on how the pack is
held.
[0178] According to another embodiment, one of the chambers,
preferably the one that is closer to the tapered portion of the
blister pack, communicates with a second channel, the channel
extending from the chamber to a distal position of the tapered
portion. During storage, this second channel does not communicate
with the outside of the pack but is closed in an air-tight fashion.
Optionally, the distal end of the second channel is closed by a
breakable or removable cap or closure, which may e.g. be a
twist-off cap, a break-off cap, or a cut-off cap.
[0179] In one embodiment, a vial or container having two
compartments is used, the compartment representing the chambers for
containing the solid composition and the liquid solvent in matched
quantities for preparing a dose unit of the final liquid
composition. The liquid composition and a second liquid solvent may
be contained in matched quantities for preparing a dose unit of the
final liquid composition (by non-limiting example in cases where
two soluble excipients or the fluoroquinolone and excipient are
unstable for storage, yet desired in the same mixture for
administration.
[0180] In some embodiments, the two compartments are physically
separated but in fluid communication such as when so the vial or
container are connected by a channel or breakable barrier, the
channel or breakable barrier being adapted to direct fluid between
the two compartments to enable mixing prior to administration.
During storage, the channel is closed with a seal or the breakable
barrier intact. In this sense, a seal is any structure that
prevents mixing of contents in the two compartments. The seal is
preferably breakable or removable; breaking or removing the seal
when the nebulizer is to be used will allow the liquid solvent to
enter the other chamber and dissolve the solid composition or in
the case of two liquids permit mixing. The dissolution or mixing
process may be improved by shaking the container. Thus, the final
liquid composition for inhalation is obtained, the liquid being
present in one or both of the chambers of the pack connected by the
channel or breakable barrier, depending on how the pack is
held.
[0181] The solid composition itself can be provided in various
different types of dosage forms, depending on the physicochemical
properties of the drug, the desired dissolution rate, cost
considerations, and other criteria. In one of the embodiments, the
solid composition is a single unit. This implies that one unit dose
of the drug is comprised in a single, physically shaped solid form
or article. In other words, the solid composition is coherent,
which is in contrast to a multiple unit dosage form, in which the
units are incoherent.
[0182] Examples of single units which may be used as dosage forms
for the solid composition include tablets, such as compressed
tablets, film-like units, foil-like units, wafers, lyophilized
matrix units, and the like. In a preferred embodiment, the solid
composition is a highly porous lyophilized form. Such
lyophilizates, sometimes also called wafers or lyophilized tablets,
are particularly useful for their rapid disintegration, which also
enables the rapid dissolution of the active compound.
[0183] On the other hand, for some applications the solid
composition may also be formed as a multiple unit dosage form as
defined above. Examples of multiple units are powders, granules,
microparticles, pellets, beads, lyophilized powders, and the like.
In one embodiment, the solid composition is a lyophilized powder.
Such a dispersed lyophilized system comprises a multitude of powder
particles, and due to the lyophilization process used in the
formation of the powder, each particle has an irregular, porous
microstructure through which the powder is capable of absorbing
water very rapidly, resulting in quick dissolution.
[0184] Another type of multiparticulate system which is also
capable of achieving rapid drug dissolution is that of powders,
granules, or pellets from water-soluble excipients which are coated
with the drug, so that the drug is located at the outer surface of
the individual particles. In this type of system, the water-soluble
low molecular weight excipient is useful for preparing the cores of
such coated particles, which can be subsequently coated with a
coating composition comprising the drug and, preferably, one or
more additional excipients, such as a binder, a pore former, a
saccharide, a sugar alcohol, a film-forming polymer, a plasticizer,
or other excipients used in pharmaceutical coating
compositions.
[0185] In another embodiment, the solid composition resembles a
coating layer that is coated on multiple units made of insoluble
material. Examples of insoluble units include beads made of glass,
polymers, metals, and mineral salts. Again, the desired effect is
primarily rapid disintegration of the coating layer and quick drug
dissolution, which is achieved by providing the solid composition
in a physical form that has a particularly high surface-to-volume
ratio. Typically, the coating composition will, in addition to the
drug and the water-soluble low molecular weight excipient, comprise
one or more excipients, such as those mentioned above for coating
soluble particles, or any other excipient known to be useful in
pharmaceutical coating compositions.
[0186] To achieve the desired effects, it may be useful to
incorporate more than one water-soluble low molecular weight
excipient into the solid composition. For instance, one excipient
may be selected for its drug carrier and diluent capability, while
another excipient may be selected to adjust the pH. If the final
liquid composition needs to be buffered, two excipients that
together form a buffer system may be selected.
[0187] In one embodiment, the liquid to be used in a
separated-compartment nebulizer is an aqueous liquid, which is
herein defined as a liquid whose major component is water. The
liquid does not necessarily consist of water only; however, in one
embodiment it is purified water. In another embodiment, the liquid
contains other components or substances, preferably other liquid
components, but possibly also dissolved solids. Liquid components
other than water which may be useful include propylene glycol,
glycerol, and polyethylene glycol. One of the reasons to
incorporate a solid compound as a solute is that such a compound is
desirable in the final liquid composition, but is incompatible with
the solid composition or with a component thereof, such as the
active ingredient.
[0188] Another desirable characteristic for the liquid solvent is
that it is sterile. An aqueous liquid would be subject to the risk
of considerable microbiological contamination and growth if no
measures were taken to ensure sterility. In order to provide a
substantially sterile liquid, an effective amount of an acceptable
antimicrobial agent or preservative can be incorporated or the
liquid can be sterilized prior to providing it and to seal it with
an air-tight seal. In one embodiment, the liquid is a sterilized
liquid free of preservatives and provided in an appropriate
air-tight container. However, according to another embodiment in
which the nebulizer contains multiple doses of the active compound,
the liquid may be supplied in a multiple-dose container, such as a
metered-dose dispenser, and may require a preservative to prevent
microbial contamination after the first use.
[0189] Meter Dose Inhaler (MDI)
[0190] A propellant driven inhaler (pMDI) releases a metered dose
of medicine upon each actuation. The medicine is formulated as a
suspension or solution of a drug substance in a suitable propellant
such as a halogenated hydrocarbon. pMDIs are described in, for
example, Newman, S. P., Aerosols and the Lung, Clarke et al., eds.,
pp. 197-224 (Butterworths, London, England, 1984).
[0191] In some embodiments, the particle size of the drug substance
in an MDI may be optimally chosen. In some embodiments, the
particles of active ingredient have diameters of less than about 50
microns. In some embodiments, the particles have diameters of less
than about 10 microns. In some embodiments, the particles have
diameters of from about 1 micron to about 5 microns. In some
embodiments, the particles have diameters of less than about 1
micron. In one advantageous embodiment, the particles have
diameters of from about 2 microns to about 5 microns.
[0192] The propellants for use with the MDIs may be any propellants
known in the art. Examples of propellants include
chlorofluorocarbons (CFCs) such as dichlorodifluoromethane,
trichlorofluorometbane, and dichlorotetrafluoroethane;
hydrofluoroalkanes (HFAs); and carbon dioxide. It may be
advantageous to use HFAs instead of CFCs due to the environmental
concerns associated with the use of CFCs. Examples of medicinal
aerosol preparations containing HFAs are presented in U.S. Pat.
Nos. 6,585,958; 2,868,691 and 3,014,844, all of which are hereby
incorporated by reference in their entirety. In some embodiments, a
co-solvent is mixed with the propellant to facilitate dissolution
or suspension of the drug substance.
[0193] In some embodiments, the propellant and active ingredient
are contained in separate containers, such as described in U.S.
Pat. No. 4,534,345, which is hereby incorporated by reference in
its entirety.
[0194] In some embodiments, the MDI used herein is activated by a
patient pushing a lever, button, or other actuator. In other
embodiments, the release of the aerosol is breath activated such
that, after initially arming the unit, the active compound aerosol
is released once the patient begins to inhale, such as described in
U.S. Pat. Nos. 6,672,304; 5,404,871; 5,347,998; 5,284,133;
5,217,004; 5,119,806; 5,060,643; 4,664,107; 4,648,393; 3,789,843;
3,732,864; 3,636,949; 3,598,294; 3,565,070; 3,456,646; 3,456,645;
and 3,456,644, each of which is hereby incorporated by reference in
its entirety. Such a system enables more of the active compound to
get into the lungs of the patient. Another mechanism to help a
patient get adequate dosage with the active ingredient may include
a valve mechanism that allows a patient to use more than one breath
to inhale the drug, such as described in U.S. Pat. Nos. 4,470,412
and 5,385,140, both of which are hereby incorporated by reference
in their entirety.
[0195] Additional examples of MDIs known in the art and suitable
for use herein include U.S. Pat. Nos. 6,435,177; 6,585,958;
5,642,730; 6,223,746; 4,955,371; 5,404,871; 5,364,838; and
6,523,536, all of which are hereby incorporated by reference in
their entirety.
[0196] Dry Powder Inhaler (DPI)
[0197] There are two major designs of dry powder inhalers. One
design is the metering device in which a reservoir for the drug is
placed within the device and the patient adds a dose of the drug
into the inhalation chamber. The second is a factory-metered device
in which each individual dose has been manufactured in a separate
container. Both systems depend upon the formulation of drug into
small particles of mass median diameters from about 1 to about 5
um, and usually involve co-formulation with larger excipient
particles (typically 100 um diameter lactose particles). Drug
powder is placed into the inhalation chamber (either by device
metering or by breakage of a factory-metered dosage) and the
inspiratory flow of the patient accelerates the powder out of the
device and into the oral cavity. Non-laminar flow characteristics
of the powder path cause the excipient-drug aggregates to
decompose, and the mass of the large excipient particles causes
their impaction at the back of the throat, while the smaller drug
particles are deposited deep in the lungs.
[0198] As with liquid nebulization and MDIs, particle size of the
fluoroquinolone antimicrobial agent aerosol formulation may be
optimized. If the particle size is larger than about 5 um MMAD then
the particles are deposited in upper airways. If the particle size
of the aerosol is smaller than about 1 um then it is delivered into
the alveoli and may get transferred into the systemic blood
circulation.
[0199] By non-limiting example, in dry powder inhalers, the
fluoroquinolone antimicrobial agents disclosed herein are prepared
in dosages to deliver from about 7 to about 700 mg from a dosing
solution of about 1 to about 5 ml, preferably from about 14 to
about 350 mg in about 1 to about 5 ml, and most preferably from
about 28 to about 280 mg in about 1 to about 5 ml with MMAD
particles sizes between about 2 to about 5 um being produced.
[0200] In some embodiments, a dry powder inhaler (DPI) is used to
dispense the fluoroquinolone antimicrobial agents described herein.
DPIs contain the drug substance in fine dry particle form.
Typically, inhalation by a patient causes the dry particles to form
an aerosol cloud that is drawn into the patient's lungs. The fine
dry drug particles may be produced by any technique known in the
art. Some well-known techniques include use of a jet mill or other
comminution equipment, precipitation from saturated or super
saturated solutions, spray drying, in situ micronization (Hovione),
or supercritical fluid methods. Typical powder formulations include
production of spherical pellets or adhesive mixtures. In adhesive
mixtures, the drug particles are attached to larger carrier
particles, such as lactose monohydrate of size about 50 to about
100 microns in diameter. The larger carrier particles increase the
aerodynamic forces on the carrier/drug agglomerates to improve
aerosol formation. Turbulence and/or mechanical devices break the
agglomerates into their constituent parts. The smaller drug
particles are then drawn into the lungs while the larger carrier
particles deposit in the mouth or throat. Some examples of adhesive
mixtures are described in U.S. Pat. No. 5,478,578 and PCT
Publication Nos. WO 95/11666, WO 87/05213, WO 96/23485, and WO
97/03649, all of which are incorporated by reference in their
entirety. Additional excipients may also be included with the drug
substance.
[0201] There are three common types of DPIs, all of which may be
used with the fluoroquinolone antimicrobial agents described
herein. In a single-dose DPI, a capsule containing one dose of dry
drug substance/excipients is loaded into the inhaler. Upon
activation, the capsule is breached, allowing the dry powder to be
dispersed and inhaled using a dry powder inhaler. To dispense
additional doses, the old capsule must be removed and an additional
capsule loaded. Examples of single-dose DPIs are described in U.S.
Pat. Nos. 3,807,400; 3,906,950; 3,991,761; and 4,013,075, all of
which are hereby incorporated by reference in their entirety. In a
multiple unit dose DPI, a package containing multiple single dose
compartments is provided. For example, the package may comprise a
blister pack, where each blister compartment contains one dose.
Each dose can be dispensed upon breach of a blister compartment.
Any of several arrangements of compartments in the package can be
used. For example, rotary or strip arrangements are common.
Examples of multiple unit does DPIs are described in EPO Patent
Application Publication Nos. 0211595A2, 0455463A1, and 0467172A1,
all of which are hereby incorporated by reference in their
entirety. In a multi-dose DPI, a single reservoir of dry powder is
used. Mechanisms are provided that measure out single dose amounts
from the reservoir to be aerosolized and inhaled, such as described
in U.S. Pat. Nos. 5,829,434; 5,437,270; 2,587,215; 5,113,855;
5,840,279; 4,688,218; 4,667,668; 5,033,463; and 4,805,811 and PCT
Publication No. WO 92/09322, all of which are hereby incorporated
by reference in their entirety.
[0202] In some embodiments, auxiliary energy in addition to or
other than a patient's inhalation may be provided to facilitate
operation of a DPI. For example, pressurized air may be provided to
aid in powder de-agglomeration, such as described in U.S. Pat. Nos.
3,906,950; 5,113,855; 5,388,572; 6,029,662 and PCT Publication Nos.
WO 93/12831, WO 90/07351, and WO 99/62495, all of which are hereby
incorporated by reference in their entirety. Electrically driven
impellers may also be provided, such as described in U.S. Pat. Nos.
3,948,264; 3,971,377; 4,147,166; 6,006,747 and PCT Publication No.
WO 98/03217, all of which are hereby incorporated by reference in
their entirety. Another mechanism is an electrically powered
tapping piston, such as described in PCT Publication No. WO
90/13327, which is hereby incorporated by reference in its
entirety. Other DPIs use a vibrator, such as described in U.S. Pat.
Nos. 5,694,920 and 6,026,809, both of which are hereby incorporated
by reference in their entirety. Finally, a scraper system may be
employed, such as described in PCT Publication No. WO 93/24165,
which is hereby incorporated by reference in its entirety.
[0203] Additional examples of DPIs for use herein are described in
U.S. Pat. Nos. 4,811,731; 5,113,855; 5,840,279; 3,507,277;
3,669,113; 3,635,219; 3,991,761; 4,353,365; 4,889,144, 4,907,538;
5,829,434; 6,681,768; 6,561,186; 5,918,594; 6,003,512; 5,775,320;
5,740,794; and 6,626,173, all of which are hereby incorporated by
reference in their entirety.
[0204] In some embodiments, a spacer or chamber may be used with
any of the inhalers described herein to increase the amount of drug
substance that gets absorbed by the patient, such as is described
in U.S. Pat. Nos. 4,470,412; 4,790,305; 4,926,852; 5,012,803;
5,040,527; 5,024,467; 5,816,240; 5,027,806; and 6,026,807, all of
which are hereby incorporated by reference in their entirety. For
example, a spacer may delay the time from aerosol production to the
time when the aerosol enters a patient's mouth. Such a delay may
improve synchronization between the patient's inhalation and the
aerosol production. A mask may also be incorporated for infants or
other patients that have difficulty using the traditional
mouthpiece, such as is described in U.S. Pat. Nos. 4,809,692;
4,832,015; 5,012,804; 5,427,089; 5,645,049; and 5,988,160, all of
which are hereby incorporated by reference in their entirety.
[0205] Dry powder inhalers (DPIs), which involve deaggregation and
aerosolization of dry powders, normally rely upon a burst of
inspired air that is drawn through the unit to deliver a drug
dosage. Such devices are described in, for example, U.S. Pat. No.
4,807,814, which is directed to a pneumatic powder ejector having a
suction stage and an injection stage; SU 628930 (Abstract),
describing a hand-held powder disperser having an axial air flow
tube; Fox et al., Powder and Bulk Engineering, pages 33-36 (March
1988), describing a venturi eductor having an axial air inlet tube
upstream of a venturi restriction; EP 347 779, describing a
hand-held powder disperser having a collapsible expansion chamber,
and U.S. Pat. No. 5,785,049, directed to dry powder delivery
devices for drugs.
[0206] Solution/Dispersion Formulations
[0207] In one embodiment, aqueous formulations containing soluble
or nanoparticulate drug particles are provided. For aqueous aerosol
formulations, the drug may be present at a concentration of about 1
mg/mL up to about 700 mg/mL. Such formulations provide effective
delivery to appropriate areas of the lung, with the more
concentrated aerosol formulations having the additional advantage
of enabling large quantities of drug substance to be delivered to
the lung in a very short period of time. In one embodiment, a
formulation is optimized to provide a well tolerated formulation.
Accordingly, in one embodiment, fluoroquinolone antimicrobial
agents disclosed herein are formulated to have good taste, pH from
about 5.5 to about 7, osmolarity from about 200 to about 1250
mOsmol/kg, permeant ion concentration from about 30 to about 300
mM.
[0208] In one embodiment, the solution or diluent used for
preparation of aerosol formulations has a pH range from about 4.5
to about 7.5, preferably from about 5.5 to about 7.0. This pH range
improves tolerability. When the aerosol is either acidic or basic,
it can cause bronchospasm and cough. Although the safe range of pH
is relative and some patients may tolerate a mildly acidic aerosol,
while others will experience bronchospasm. Any aerosol with a pH of
less than about 4.5 typically induces bronchospasm. Aerosols with a
pH from about 4.5 to about 5.5 will cause bronchospasm
occasionally. Any aerosol having pH greater than about 7.5 may have
low tolerability because body tissues are generally unable to
buffer alkaline aerosols. Aerosols with controlled pH below about
4.5 and over about 7.5 typically result in lung irritation
accompanied by severe bronchospasm cough and inflammatory
reactions. For these reasons as well as for the avoidance of
bronchospasm, cough or inflammation in patients, the optimum pH for
the aerosol formulation was determined to be between about pH5.5 to
about pH 7.0. Consequently, in one embodiment, aerosol formulations
for use as described herein are adjusted to pH between about 4.5
and about 7.5 with preferred pH range from about about 5.5 to about
7.5. Most preferred pH range is from about 5.5 to about 7.5.
[0209] By non-limiting example, compositions may also include a
buffer or a pH adjusting agent, typically a salt prepared from an
organic acid or base. Representative buffers include organic acid
salts of citric acid, ascorbic acid, gluconic acid, carbonic acid,
tartaric acid, succinic acid, acetic acid, or phthalic acid, Tris,
tromethamine, hydrochloride, or phosphate buffers.
[0210] Many patients have increased sensitivity to various chemical
tastes, including bitter, salt, sweet, metallic sensations. To
create well-tolerated drug products, by non-limiting example taste
masking may be accomplished through the addition of taste-masking
excipients, adjusted osmolality, and sweeteners.
[0211] Many patients have increased sensitivity to various chemical
agents and have high incidence of bronchospastic, asthmatic or
other coughing incidents. Their airways are particularly sensitive
to hypotonic or hypertonic and acidic or alkaline conditions and to
the presence of any permanent ion, such as chloride. Any imbalance
in these conditions or a presence of chloride above certain value
leads to bronchospastic or inflammatory events and/or cough which
greatly impair treatment with inhalable formulations. Both these
conditions prevent efficient delivery of aerosolized drugs into the
endobronchial space.
[0212] In some embodiments, the osmolality of aqueous solutions of
the fluoroquinolone antimicrobial agent disclosed herein are
adjusted by providing excipients. In some cases, a certain amount
of chloride or another anion is needed for successful and
efficacious delivery of aerosolized antibiotic. However, it has
been discovered that such amounts are lower than amounts provided
and typically used for aerosols of other compounds.
[0213] Bronchospasm or cough reflexes do not respond to the same
osmolality of the diluent for aerosolization. However, they can be
sufficiently controlled and/or suppressed when the osmolality of
the diluent is in a certain range. A preferred solution for
aerosolization of therapeutic compounds which is safe and tolerated
has a total osmolality from about 200 to about 1250 mOsmol/kg with
a range of chloride concentration of from about 30 mM to about 300
mM and preferably from about 50 mM to about 150 mM. This osmolality
controls bronchospasm, the chloride concentration, as a permeant
anion, controls cough. Because they are both permeant ions, both
bromine or iodine anions may be substituted for chloride. In
addition, bicarbonate may substituted for chloride ion.
[0214] By non-limiting example, the formulation for an aerosol
fluoroquinolone antimicrobial agent may comprise from about 7 to
about 700 mg, preferably from about 14 to about 300 mg, or most
preferably from about 28 to about 280 mg fluoroquinolone
antimicrobial agent per about 1 to about 5 ml of dilute saline
(between 1/10 to 1/1 normal saline). Accordingly, the concentration
of a levofloxacin solution may be greater than about 25 mg/ml,
greater than about 35 mg/ml and is preferably greater than about 40
mg/ml, and is as high or greater than 50/ml.
[0215] In one embodiment, solution osmolality is from about 100
mOsmol/kg to about 600 mOsmol/kg. In various other embodiments, the
solution osmolality is from about 2000 mOsmol/kg to about 1250
mOsmol/kg; from about 250 mOsmol/kg to about 1050 mOsmol/kg; and
from about 350 mOsmol/kg to about 750 mOsmol/kg.
[0216] In one embodiments, permeant ion concentration is from about
25 mM to about 400 mM. In various other embodiments, permeant ion
concentration is from about 30 mM to about 300 mM; from about 40 mM
to about 200 mM; and from about 50 mM to about 150 mM.
[0217] Solid Particle Formulations
[0218] In some embodiments, solid drug nanoparticles are provided
for use in generating dry aerosols or for generating nanoparticles
in liquid suspension. Powders comprising nanoparticulate drug can
be made by spray-drying aqueous dispersions of a nanoparticulate
drug and a surface modifier to form a dry powder which consists of
aggregated drug nanoparticles. In one embodiment, the aggregates
can have a size of about 1 to about 2 microns which is suitable for
deep lung delivery. The aggregate particle size can be increased to
target alternative delivery sites, such as the upper bronchial
region or nasal mucosa by increasing the concentration of drug in
the spray-dried dispersion or by increasing the droplet size
generated by the spray dryer.
[0219] Alternatively, an aqueous dispersion of drug and surface
modifier can contain a dissolved diluent such as lactose or
mannitol which, when spray dried, forms respirable diluent
particles, each of which contains at least one embedded drug
nanoparticle and surface modifier. The diluent particles with
embedded drug can have a particle size of about 1 to about 2
microns, suitable for deep lung delivery. In addition, the diluent
particle size can be increased to target alternate delivery sites,
such as the upper bronchial region or nasal mucosa by increasing
the concentration of dissolved diluent in the aqueous dispersion
prior to spray drying, or by increasing the droplet size generated
by the spray dryer.
[0220] Spray-dried powders can be used in DPIs or pMDIs, either
alone or combined with freeze-dried nanoparticulate powder. In
addition, spray-dried powders containing drug nanoparticles can be
reconstituted and used in either jet or ultrasonic nebulizers to
generate aqueous dispersions having respirable droplet sizes, where
each droplet contains at least one drug nanoparticle. Concentrated
nanoparticulate dispersions may also be used in these aspects of
the invention.
[0221] Nanoparticulate drug dispersions can also be freeze-dried to
obtain powders suitable for nasal or pulmonary delivery. Such
powders may contain aggregated nanoparticulate drug particles
having a surface modifier. Such aggregates may have sizes within a
respirable range, e.g., about 2 to about 5 microns MMAD.
[0222] Freeze dried powders of the appropriate particle size can
also be obtained by freeze drying aqueous dispersions of drug and
surface modifier, which additionally contain a dissolved diluent
such as lactose or mannitol. In these instances the freeze dried
powders consist of respirable particles of diluent, each of which
contains at least one embedded drug nanoparticle.
[0223] Freeze-dried powders can be used in DPIs or pMDIs, either
alone or combined with spray-dried nanoparticulate powder. In
addition, freeze-dried powders containing drug nanoparticles can be
reconstituted and used in either jet or ultrasonic nebulizers to
generate aqueous dispersions that have respirable droplet sizes,
where each droplet contains at least one drug nanoparticle.
[0224] One embodiment of the invention is directed to a process and
composition for propellant-based systems comprising nanoparticulate
drug particles and a surface modifier. Such formulations may be
prepared by wet milling the coarse drug substance and surface
modifier in liquid propellant, either at ambient pressure or under
high pressure conditions. Alternatively, dry powders containing
drug nanoparticles may be prepared by spray-drying or freeze-drying
aqueous dispersions of drug nanoparticles and the resultant powders
dispersed into suitable propellants for use in conventional pMDIs.
Such nanoparticulate pMDI formulations can be used for either nasal
or pulmonary delivery. For pulmonary administration, such
formulations afford increased delivery to the deep lung regions
because of the small (e.g., about 1 to about 2 microns MMAD)
particle sizes available from these methods. Concentrated aerosol
formulations can also be employed in pMDIs.
[0225] Another embodiment is directed to dry powders which contain
nanoparticulate compositions for pulmonary or nasal delivery. The
powders may consist of respirable aggregates of nanoparticulate
drug particles, or of respirable particles of a diluent which
contains at least one embedded drug nanoparticle. Powders
containing nanoparticulate drug particles can be prepared from
aqueous dispersions of nanoparticles by removing the water via
spray-drying or lyophilization (freeze drying). Spray-drying is
less time consuming and less expensive than freeze-drying, and
therefore more cost-effective. However, certain drugs, such as
biologicals benefit from lyophilization rather than spray-drying in
making dry powder formulations.
[0226] Conventional micronized drug particles used in dry powder
aerosol delivery having partcticle diameters of from about 2 to
about 5 microns MMAD are often difficult to meter and disperse in
small quantities because of the electrostatic cohesive forces
inherent in such powders. These difficulties can lead to loss of
drug substance to the delivery device as well as incomplete powder
dispersion and sub-optimal delivery to the lung. Many drug
compounds, particularly proteins and peptides, are intended for
deep lung delivery and systemic absorption. Since the average
particle sizes of conventionally prepared dry powders are usually
in the range of from about 2 to about 5 microns MMAD, the fraction
of material which actually reaches the alveolar region may be quite
small. Thus, delivery of micronized dry powders to the lung,
especially the alveolar region, is generally very inefficient
because of the properties of the powders themselves.
[0227] The dry powder aerosols which contain nanoparticulate drugs
can be made smaller than comparable micronized drug substance and,
therefore, are appropriate for efficient delivery to the deep lung.
Moreover, aggregates of nanoparticulate drugs are spherical in
geometry and have good flow properties, thereby aiding in dose
metering and deposition of the administered composition in the lung
or nasal cavities.
[0228] Dry nanoparticulate compositions can be used in both DPIs
and pMDIs. As used herein, "dry" refers to a composition having
less than about 5% water.
[0229] In one embodiment, compositions are provided containing
nanoparticles which have an effective average particle size of less
than about 1000 nm, more preferably less than about 400 nm, less
than about 300 nm, less than about 250 nm, or less than about 200
nm, as measured by light-scattering methods. By "an effective
average particle size of less than about 1000 nm" it is meant that
at least 50% of the drug particles have a weight average particle
size of less than about 1000 nm when measured by light scattering
techniques. Preferably, at least 70% of the drug particles have an
average particle size of less than about 1000 nm, more preferably
at least 90% of the drug particles have an average particle size of
less than about 1000 nm, and even more preferably at least about
95% of the particles have a weight average particle size of less
than about 1000 nm.
[0230] For aqueous aerosol formulations, the nanoparticulate agent
may be present at a concentration of about 5.0 mg/mL up to about
700 mg/mL. For dry powder aerosol formulations, the nanoparticulate
agent may be present at a concentration of about 5.0 mg/g up to
about 1000 mg/g, depending on the desired drug dosage. Concentrated
nanoparticulate aerosols, defined as containing a nanoparticulate
drug at a concentration of about 5.0 mg/mL up to about 700 mg/mL
for aqueous aerosol formulations, and about 5.0 mg/g up to about
1000 mg/g for dry powder aerosol formulations, are specifically
provided. Such formulations provide effective delivery to
appropriate areas of the lung or nasal cavities in short
administration times, ie., less than about 3-15 seconds per dose as
compared to administration times of up to 4 to 20 minutes as found
in conventional pulmonary nebulizer therapies.
[0231] Nanoparticulate drug compositions for aerosol administration
can be made by, for example, (1) nebulizing a dispersion of a
nanoparticulate drug, obtained by either grinding or precipitation;
(2) aerosolizing a dry powder of aggregates of nanoparticulate drug
and surface modifier (the aerosolized composition may additionally
contain a diluent); or (3) aerosolizing a suspension of
nanoparticulate drug or drug aggregates in a non-aqueous
propellant. The aggregates of nanoparticulate drug and surface
modifier, which may additionally contain a diluent, can be made in
a non-pressurized or a pressurized non-aqueous system. Concentrated
aerosol formulations may also be made via such methods.
[0232] Milling of aqueous drug to obtain nanoparticulate drug may
be performed by dispersing drug particles in a liquid dispersion
medium and applying mechanical means in the presence of grinding
media to reduce the particle size of the drug to the desired
effective average particle size. The particles can be reduced in
size in the presence of one or more surface modifiers.
Alternatively, the particles can be contacted with one or more
surface modifiers after attrition. Other compounds, such as a
diluent, can be added to the drug/surface modifier composition
during the size reduction process. Dispersions can be manufactured
continuously or in a batch mode.
[0233] Another method of forming nanoparticle dispersion is by
microprecipitation. This is a method of preparing stable
dispersions of drugs in the presence of one or more surface
modifiers and one or more colloid stability enhancing surface
active agents free of any trace toxic solvents or solubilized heavy
metal impurities. Such a method comprises, for example, (1)
dissolving the drug in a suitable solvent with mixing; (2) adding
the formulation from step (1) with mixing to a solution comprising
at least one surface modifier to form a clear solution; and (3)
precipitating the formulation from step (2) with mixing using an
appropriate nonsolvent. The method can be followed by removal of
any formed salt, if present, by dialysis or diafiltration and
concentration of the dispersion by conventional means. The
resultant nanoparticulate drug dispersion can be utilized in liquid
nebulizers or processed to form a dry powder for use in a DPI or
pMDI.
[0234] In a non-aqueous, non-pressurized milling system, a
non-aqueous liquid having a vapor pressure of about 1 atm or less
at room temperature and in which the drug substance is essentially
insoluble may be used as a wet milling medium to make a
nanoparticulate drug composition. In such a process, a slurry of
drug and surface modifier may be milled in the non-aqueous medium
to generate nanoparticulate drug particles. Examples of suitable
non-aqueous media include ethanol, trichloromonofluoromethane,
(CFC-11), and dichlorotetafluoroethane (CFC-114). An advantage of
using CFC-11 is that it can be handled at only marginally cool room
temperatures, whereas CFC-114 requires more controlled conditions
to avoid evaporation. Upon completion of milling the liquid medium
may be removed and recovered under vacuum or heating, resulting in
a dry nanoparticulate composition. The dry composition may then be
filled into a suitable container and charged with a final
propellant. Exemplary final product propellants, which ideally do
not contain chlorinated hydrocarbons, include HFA-134a
(tetrafluoroethane) and HFA-227 (heptafluoropropane). While
non-chlorinated propellants may be preferred for environmental
reasons, chlorinated propellants may also be used in this aspect of
the invention.
[0235] In a non-aqueous, pressurized milling system, a non-aqueous
liquid medium having a vapor pressure significantly greater than 1
atm at room temperature may be used in the milling process to make
nanoparticulate drug compositions. If the milling medium is a
suitable halogenated hydrocarbon propellant, the resultant
dispersion may be filled directly into a suitable pMDI container.
Alternately, the milling medium can be removed and recovered under
vacuum or heating to yield a dry nanoparticulate composition. This
composition can then be filled into an appropriate container and
charged with a suitable propellant for use in a pMDI.
[0236] Spray drying is a process used to obtain a powder containing
nanoparticulate drug particles following particle size reduction of
the drug in a liquid medium. In general, spray-drying may be used
when the liquid medium has a vapor pressure of less than about 1
atm at room temperature. A spray-dryer is a device which allows for
liquid evaporation and drug powder collection. A liquid sample,
either a solution or suspension, is fed into a spray nozzle. The
nozzle generates droplets of the sample within a range of about 20
to about 100 .mu.m in diameter which are then transported by a
carrier gas into a drying chamber. The carrier gas temperature is
typically from about 80 to about 200.degree. C. The droplets are
subjected to rapid liquid evaporation, leaving behind dry particles
which are collected in a special reservoir beneath a cyclone
apparatus.
[0237] If the liquid sample consists of an aqueous dispersion of
nanoparticles and surface modifier, the collected product will
consist of spherical aggregates of the nanoparticulate drug
particles. If the liquid sample consists of an aqueous dispersion
of nanoparticles in which an inert diluent material was dissolved
(such as lactose or mannitol), the collected product will consist
of diluent (e.g., lactose or mannitol) particles which contain
embedded nanoparticulate drug particles. The final size of the
collected product can be controlled and depends on the
concentration of nanoparticulate drug and/or diluent in the liquid
sample, as well as the droplet size produced by the spray-dryer
nozzle. Collected products may be used in conventional DPIs for
pulmonary or nasal delivery, dispersed in propellants for use in
pMDIs, or the particles may be reconstituted in water for use in
nebulizers.
[0238] In some instances it may be desirable to add an inert
carrier to the spray-dried material to improve the metering
properties of the final product. This may especially be the case
when the spray dried powder is very small (less than about 5 .mu.m)
or when the intended dose is extremely small, whereby dose metering
becomes difficult. In general, such carrier particles (also known
as bulking agents) are too large to be delivered to the lung and
simply impact the mouth and throat and are swallowed. Such carriers
typically consist of sugars such as lactose, mannitol, or
trehalose. Other inert materials, including polysaccharides and
cellulosics, may also be useful as carriers.
[0239] Spray-dried powders containing nanoparticulate drug
particles may used in conventional DPIs, dispersed in propellants
for use in pMDIs, or reconstituted in a liquid medium for use with
nebulizers.
[0240] For compounds that are denatured or destabilized by heat,
such as compounds having a low melting point (i.e., about 70 to
about 150.degree. C.), or for example, biologics, sublimation is
preferred over evaporation to obtain a dry powder nanoparticulate
drug composition. This is because sublimation avoids the high
process temperatures associated with spray-drying. In addition,
sublimation, also known as freeze-drying or lyophilization, can
increase the shelf stability of drug compounds, particularly for
biological products. Freeze-dried particles can also be
reconstituted and used in nebulizers. Aggregates of freeze-dried
nanoparticulate drug particles can be blended with either dry
powder intermediates or used alone in DPIs and pMDIs for either
nasal or pulmonary delivery.
[0241] Sublimation involves freezing the product and subjecting the
sample to strong vacuum conditions. This allows for the formed ice
to be transformed directly from a solid state to a vapor state.
Such a process is highly efficient and, therefore, provides greater
yields than spray-drying. The resultant freeze-dried product
contains drug and modifier(s). The drug is typically present in an
aggregated state and can be used for inhalation alone (either
pulmonary or nasal), in conjunction with diluent materials
(lactose, mannitol, etc.), in DPIs or pMDIs, or reconstituted for
use in a nebulizer.
[0242] Liposomal Compositions
[0243] In some embodiments, fluoroquinolone antimicrobial agents
disclosed herein may be formulated into liposome particles, which
can then be aerosolized for inhaled delivery. Lipids which are
useful in the present invention can be any of a variety of lipids
including both neutral lipids and charged lipids. Carrier systems
having desirable properties can be prepared using appropriate
combinations of lipids, targeting groups and circulation enhancers.
Additionally, the compositions provided herein can be in the form
of liposomes or lipid particles, preferably lipid particles. As
used herein, the term "lipid particle" refers to a lipid bilayer
carrier which "coats" a nucleic acid and has little or no aqueous
interior. More particularly, the term is used to describe a
self-assembling lipid bilayer carrier in which a portion of the
interior layer comprises cationic lipids which form ionic bonds or
ion-pairs with negative charges on the nucleic acid (e.g., a
plasmid phosphodiester backbone). The interior layer can also
comprise neutral or fusogenic lipids and, in some embodiments,
negatively charged lipids. The outer layer of the particle will
typically comprise mixtures of lipids oriented in a tail-to-tail
fashion (as in liposomes) with the hydrophobic tails of the
interior layer. The polar head groups present on the lipids of the
outer layer will form the external surface of the particle.
[0244] Liposomal bioactive agents can be designed to have a
sustained therapeutic effect or lower toxicity allowing less
frequent administration and an enhanced therapeutic index.
Liposomes are composed of bilayers that entrap the desired
pharmaceutical. These can be configured as multilamellar vesicles
of concentric bilayers with the pharmaceutical trapped within
either the lipid of the different layers or the aqueous space
between the layers.
[0245] By non-limiting example, lipids used in the compositions may
be synthetic, semi-synthetic or naturally-occurring lipids,
including phospholipids, tocopherols, steroids, fatty acids,
glycoproteins such as albumin, negatively-charged lipids and
cationic lipids. Phosholipids include egg phosphatidylcholine
(EPC), egg phosphatidylglycerol (EPG), egg phosphatidylinositol
(EPI), egg phosphatidylserine (EPS), phosphatidylethanolamine
(EPE), and egg phosphatidic acid (EPA); the soya counterparts, soy
phosphatidylcholine (SPC); SPG, SPS, SPI, SPE, and SPA; the
hydrogenated egg and soya counterparts (e.g., HEPC, HSPC), other
phospholipids made up of ester linkages of fatty acids in the 2 and
3 of glycerol positions containing chains of 12 to 26 carbon atoms
and different head groups in the 1 position of glycerol that
include choline, glycerol, inositol, serine, ethanolamine, as well
as the corresponding phosphatidic acids. The chains on these fatty
acids can be saturated or unsaturated, and the phospholipid can be
made up of fatty acids of different chain lengths and different
degrees of unsaturation. In particular, the compositions of the
formulations can include dipalmitoylphosphatidylcholine (DPPC), a
major constituent of naturally-occurring lung surfactant as well as
dioleoylphosphatidylcholine (DOPC) and dioleoylphosphatidylglycerol
(DOPG). Other examples include dimyristoylphosphatidycholine (DMPC)
and dimyristoylphosphatidylglycerol (DMPG)
dipalmitoylphosphatidcholine (DPPC) and
dipalmitoylphosphatidylglycerol (DPPG)
distearoylphosphatidylcholine (DSPC) and di
stearoylphosphatidylglycerol (DSPG), diol
eylphosphatidylethanolamine (DOPE) and mixed phospholipids like
palmitoylstearoylphosphatidylcholine (PSPC) and
palmitoylstearoylphosphatidylglycerol (PSPG), and single acylated
phospholipids like mono-oleoyl-phosphatidylethanolamine (MOPE).
[0246] In a preferred embodiment, PEG-modified lipids are
incorporated into the compositions of the present invention as the
aggregation-preventing agent. The use of a PEG-modified lipid
positions bulky PEG groups on the surface of the liposome or lipid
carrier and prevents binding of DNA to the outside of the carrier
(thereby inhibiting cross-linking and aggregation of the lipid
carrier). The use of a PEG-ceramide is often preferred and has the
additional advantages of stabilizing membrane bilayers and
lengthening circulation lifetimes. Additionally, PEG-ceramides can
be prepared with different lipid tail lengths to control the
lifetime of the PEG-ceramide in the lipid bilayer. In this manner,
"programmable" release can be accomplished which results in the
control of lipid carrier fusion. For example, PEG-ceramides having
C.sub.20-acyl groups attached to the ceramide moiety will diffuse
out of a lipid bilayer carrier with a half-life of 22 hours.
PEG-ceramides having C.sub.14- and C.sub.8-acyl groups will diffuse
out of the same carrier with half-lives of 10 minutes and less than
1 minute, respectively. As a result, selection of lipid tail length
provides a composition in which the bilayer becomes destabilized
(and thus fusogenic) at a known rate. Though less preferred, other
PEG-lipids or lipid-polyoxyethylene conjugates are useful in the
present compositions. Examples of suitable PEG-modified lipids
include PEG-modified phosphatidylethanolamine and phosphatidic
acid, PEG-modified diacylglycerols and dialkylglycerols,
PEG-modified dialkylamines and PEG-modified
1,2-diacyloxypropan-3-amines. Particularly preferred are
PEG-ceramide conjugates (e.g., PEG-Cer-C.sub.8, PEG-Cer-C.sub.14 or
PEG-Cer-C.sub.20) which are described in U.S. Pat. No. 5,820,873,
incorporated herein by reference.
[0247] The compositions of the present invention can be prepared to
provide liposome compositions which are about 50 nm to about 400 nm
in diameter. One with skill in the art will understand that the
size of the compositions can be larger or smaller depending upon
the volume which is encapsulated. Thus, for larger volumes, the
size distribution will typically be from about 80 nm to about 300
nm.
[0248] Surface Modifiers
[0249] Fluoroquinolone antimicrobial agents disclosed herein may be
prepared in a pharmaceutical composition with suitable surface
modifiers which may be selected from known organic and inorganic
pharmaceutical excipients. Such excipients include low molecular
weight oligomers, polymers, surfactants and natural products.
Preferred surface modifiers include nonionic and ionic surfactants.
Two or more surface modifiers can be used in combination.
[0250] Representative examples of surface modifiers include cetyl
pyridinium chloride, gelatin, casein, lecithin (phosphatides),
dextran, glycerol, gum acacia, cholesterol, tragacanth, stearic
acid, benzalkonium chloride, calcium stearate, glycerol
monostearate, cetostearyl alcohol, cetomacrogol emulsifying wax,
sorbitan esters, polyoxyethylene alkyl ethers (e.g., macrogol
ethers such as cetomacrogol 1000), polyoxyethylene castor oil
derivatives, polyoxyethylene sorbitan fatty acid esters (e.g., the
commercially available Tweens.RTM., such as e.g., Tween 20.RTM.,
and Tween 80.RTM., (ICI Specialty Chemicals)); polyethylene glycols
(e.g., Carbowaxs 3350.RTM., and 1450.RTM., and Carbopol 934.RTM.,
(Union Carbide)), dodecyl trimethyl ammonium bromide,
polyoxyethylenestearates, colloidal silicon dioxide, phosphates,
sodium dodecyl sulfate, carboxymethylcellulose calcium,
hydroxypropyl cellulose (HPC, HPC-SL, and HPC-L), hydroxypropyl
methylcellulose (HPMC), carboxymethylcellulose sodium,
methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose,
hydroxypropylmethyl-cellulose phthalate, noncrystalline cellulose,
magnesium aluminum silicate, triethanolamine, polyvinyl alcohol
(PVA), polyvinylpyrrolidone (PVP),
4-(1,1,3,3-tetaamethylbutyl)-phenol polymer with ethylene oxide and
formaldehyde (also known as tyloxapol, superione, and triton),
poloxamers (e.g., Pluronics F68.RTM., and F108.RTM., which are
block copolymers of ethylene oxide and propylene oxide);
poloxamnines (e.g., Tetronic 908.RTM., also known as Poloxamine
908.RTM., which is a tetrafunctional block copolymer derived from
sequential addition of propylene oxide and ethylene oxide to
ethylenediamine (BASF Wyandotte Corporation, Parsippany, N.J.)); a
charged phospholipid such as dimyristoyl phophatidyl glycerol,
dioctylsulfosuccinate (DOSS); Tetronic 1508.RTM.; (T-1508) (BASF
Wyandotte Corporation), dialkylesters of sodium sulfosuccinic acid
(e.g., Aerosol OT.RTM., which is a dioctyl ester of sodium
sulfosuccinic acid (American Cyanamid)); Duponol P.RTM., which is a
sodium lauryl sulfate (DuPont); Tritons X-200.RTM., which is an
alkyl aryl polyether sulfonate (Rohm and Haas); Crodestas
F-110.RTM., which is a mixture of sucrose stearate and sucrose
distearate (Croda Inc.); p-isononylphenoxypoly-(glycidol), also
known as Olin-Log.RTM., or Surfactant 10-G.RTM., (Olin Chemicals,
Stamford, Conn.); Crodestas SL-40.RTM., (Croda, Inc.); and SA9OHCO,
which is C.sub.18H.sub.37CH.sub.2(CON(CH.sub.3)--CH.sub.2
(CHOH).sub.4(CH.sub.2 OH).sub.2 (Eastman Kodak Co.);
decanoyl-N-methylglucamide; n-decyl-beta-D-glucopyranoside;
n-decyl-beta-D-maltopyranoside; n-dodecyl-beta-D-glucopyranoside;
n-dodecyl-beta-D-maltoside; heptanoyl-N-methylglucamide;
n-heptyl-beta-D-glucopyranoside; n-heptyl-beta-D-thioglucoside;
n-hexyl-beta-D-glucopyranoside; nonanoyl-N-methylglucamide;
n-noyl-beta-D-glucopyranoside; octanoyl-N-methylglucarmide;
n-octyl-beta-D-glucopyranoside; octyl-beta-D-thioglucopyranoside;
and the like. Tyloxapol is a particularly preferred surface
modifier for the pulmonary or intranasal delivery of steroids, even
more so for nebulization therapies.
[0251] Examples of surfactants for use in the solutions disclosed
herein include, but are not limited to, ammonium laureth sulfate,
cetamine oxide, cetrimonium chloride, cetyl alcohol, cetyl
myristate, cetyl palmitate, cocamide DEA, cocamidopropyl betaine,
cocamidopropylamine oxide, cocamide MEA, DEA lauryl sulfate,
di-stearyl phthalic acid amide, dicetyl dimethyl ammonium chloride,
dipalmitoylethyl hydroxethylmonium, disodium laureth
sulfosuccinate, di(hydrogenated) tallow phthalic acid, glyceryl
dilaurate, glyceryl distearate, glyceryl oleate, glyceryl stearate,
isopropyl myristate nf, isopropyl palmitate nf, lauramide DEA,
lauramide MEA, lauramide oxide, myristamine oxide, octyl
isononanoate, octyl palmitate, octyldodecyl neopentanoate,
olealkonium chloride, PEG-2 stearate, PEG-32 glyceryl
caprylate/caprate, PEG-32 glyceryl stearate, PEG-4 and PEG-150
stearate & distearate, PEG-4 to PEG-150 laurate &
dilaurate, PEG-4 to PEG-150 oleate & dioleate, PEG-7 glyceryl
cocoate, PEG-8 beeswax, propylene glycol stearate, sodium C14-16
olefin sulfonate, sodium lauryl sulfoacetate, sodium lauryl
sulphate, sodium trideceth sulfate, stearalkonium chloride,
stearamide oxide, TEA-dodecylbenzene sulfonate, TEA lauryl
sulfate.
[0252] Most of these surface modifiers are known pharmaceutical
excipients and are described in detail in the Handbook of
Pharmaceutical Excipients, published jointly by the American
Pharmaceutical Association and The Pharmaceutical Society of Great
Britain (The Pharmaceutical Press, 1986), specifically incorporated
by reference. The surface modifiers are commercially available
and/or can be prepared by techniques known in the art. The relative
amount of drug and surface modifier can vary widely and the optimal
amount of the surface modifier can depend upon, for example, the
particular drug and surface modifier selected, the critical micelle
concentration of the surface modifier if it forms micelles, the
hydrophilic-lipophilic-balance (HLB) of the surface modifier, the
melting point of the surface modifier, the water solubility of the
surface modifier and/or drug, the surface tension of water
solutions of the surface modifier, etc.
[0253] In the present invention, the optimal ratio of drug to
surface modifier is .about.0.1% to .about.99.9% fluoroquinolone
antimicrobial agent, more preferably about 10% to about 90%.
[0254] Microspheres
[0255] Microspheres can be used for pulmonary delivery of
fluoroquinolones by first adding an appropriate amount of drug
compound to be solubilzed in water. For example, an aqueous
levofloxacin solution may be dispersed in methylene chloride
containing a predetermined amount (0.1-1% w/v) of
poly(DL-lactide-co-glycolide) (PLGA) by probe sonication for 1-3
min on an ice bath. Separately, levofloxacin will be solubilized in
methylene chloride containing PLGA (0.1-1% w/v). The resulting
water-in-oil primary emulsion or the polymer/drug solution will be
dispersed in an aqueous continuous phase consisting of 1-2%
polyvinyl alcohol (previously cooled to 4.degree. C.) by probe
sonication for 3-5 min on an ice bath. The resulting emulsion will
be stirred continuously for 2-4 hours at room temperature to
evaporate methylene chloride. Microparticles thus formed will be
separated from the continuous phase by centrifuging at 8000-10000
rpm for 5-10 min. Sedimented particles will be washed thrice with
distilled water and freeze dried. Freeze-dried levofloxacin
microparticles will be stored at -20.degree. C.
[0256] By non-limiting example, a spray drying approach will be
employed to prepare levofloxacin microspheres. An appropriate
amount of levofloxacin will be solubilized in methylene chloride
containing PLGA (0.1-1%). This solution will be spray dried to
obtain the microspheres.
[0257] By non-limiting example, levofloxacin microparticles will be
characterized for size distribution (requirement: 90%<5 .mu.m,
95%<10 .mu.m), shape, drug loading efficiency and drug release
using appropriate techniques and methods.
[0258] By non-limiting example, this approach may also be used to
sequester and improve the water solubililty of solid, AUC
shape-enhancing formulations, such as low-solubility levofloxacin
salt forms for nanoparticle-based formulations.
[0259] A certain amount of fluoroquinolone can be first dissolved
in the minimal quantity of ethanol 96% necessary to maintain the
fluoroquinolnoe in solution when diluted with water from 96 to 75%.
This solution can then be diluted with water to obtain a 75%
ethanol solution and then a certain amount of paracetamol can be
added to obtain the following w/w drug/polymer ratios: 1:2, 1:1,
2:1, 3:1, 4:1, 6:1, 9:1, and 19:1. These final solutions are
spray-dried under the following conditions: feed rate, 15 mL/min;
inlet temperature, 110.degree. C.; outlet temperature, 85.degree.
C.; pressure 4 bar and throughput of drying air, 35 m3/hr. Powder
is then collected and stored under vacuum in a dessiccator.
[0260] Solid Lipid Particles
[0261] Preparation of fluoroquinolone solid lipid particles may
involve dissolving the drug in a lipid melt (phospholipids such as
phophatidyl choline and phosphatidyl serine) maintained at least at
the melting temperature of the lipid, followed by dispersion of the
drug-containing melt in a hot aqueous surfactant solution
(typically 1-5% w/v) maintained at least at the melting
temeperature of the lipid. The coarse dispersion will be
homogenized for 1-10 min using a Microfluidizer.RTM. to obtain a
nanoemulsion. Cooling the nanoemulsion to a temperature between
4-25.degree. C. will re-solidify the lipid, leading to formation of
solid lipid nanoparticles. Optimization of formulation parameters
(type of lipid matrix, surfactant concentration and production
parameters) will be performed so as to achieve a prolonged drug
delivery. By non-limiting example, this approach may also be used
to sequester and improve the water solubililty of solid, AUC
shape-enhancing formulations, such as low-solubility levofloxacin
salt forms for nanoparticle-based formulations.
[0262] Melt-Extrusion AUC Shape-Enhancing Formulation
[0263] Melt-Extrusion AUC shape-enhancing fluoroquinolone
formulations may be preparation by dissolving the drugs in micelles
by adding surfactants or preparing micro-emulsion, forming
inclusion complexes with other molecules such as cyclodextrins,
forming nanoparticles of the drugs, or embedding the amorphous
drugs in a polymer matrix. Embedding the drug homogeneously in a
polymer matrix produces a solid dispersion. Solid dispersions can
be prepared in two ways: the solvent method and the hot melt
method. The solvent method uses an organic solvent wherein the drug
and appropriate polymer are dissolved and then (spray) dried. The
major drawbacks of this method are the use of organic solvents and
the batch mode production process. The hot melt method uses heat in
order to disperse or dissolve the drug in an appropriate polymer.
The melt-extrusion process is an optimized version of the hot melt
method. The advantage of the melt-extrusion approach is lack of
organic solvent and continuous production process. As the
melt-extrusion is a novel pharmaceutical technique, the literature
dealing with it is limited. The technical set-up involves a mixture
and extrusion of fluoroquinolone, hydroxypropyl-b-cyclodextrin
(HP-b-CD), and hydroxypropylmethylcellulose (HPMC), in order to, by
non-limiting example create a AUC shape-enhancing formulation of
levofloxacin or other fluoroquinlone. Cyclodextrin is a
toroidal-shaped molecule with hydroxyl groups on the outer surface
and a cavity in the center. Cyclodextrin sequesters the drug by
forming an inclusion complex. The complex formation between
cyclodextrins and drugs has been investigated extensively. It is
known that water-soluble polymer interacts with cyclodextrin and
drug in the course of complex formation to form a stabilized
complex of drug and cyclodextrin co-complexed with the polymer.
This complex is more stable than the classic cyclodextrin-drug
complex. As one example, HPMC is water soluble; hence using this
polymer with HP-b-CD in the melt is expected to create an aqueous
soluble AUC shape-enhancing formulation. By non-limiting example,
this approach may also be used to sequester and improve the water
solubililty of solid, AUC shape-enhancing formulations, such as
low-solubility levofloxacin salt forms for nanoparticle-based
formulations.
[0264] Co-Precipitates
[0265] Co-precipitate fluoroquinolone formulations may be prepared
by formation of co-precipitates with pharmacologically inert,
polymeric materials. It has been demonstrated that the formation of
molecular solid dispersions or co-precipitates to create an AUC
shape-enhancing formulations with various water-soluble polymers
can significantly slow their in vitro dissolution rates and/or in
vivo absorption. In preparing powdered products, grinding is
generally used for reducing particle size, since the dissolution
rate is strongly affected by particle size. Moreover, a strong
force (such as grinding) may increase the surface energy and cause
distortion of the crystal lattice as well as reducing particle
size. Co-grinding drug with hydroxypropylmethylcellulose,
b-cyclodextrin, chitin and chitosan, crystalline cellulose, and
gelatine, may enhance the dissolution properties such that AUC
shape-enhancement is obtained for otherwise readily bioavailable
fluoroquinolones. By non-limiting example, this approach may also
be used to sequester and improve the water solubility of solid, AUC
shape-enhancing formulations, such as low-solubility levofloxacin
salt forms for nanoparticle-based formulations.
[0266] Dispersion-Enhancing Peptides
[0267] Compositions may include one or more di- or tripeptides
containing two or more leucine residues. By further non-limiting
example, U.S. Pat. No. 6,835,372 disclosing dispersion-enhancing
peptides, is hereby incorporated by reference in its entirety. This
patent describes the discovery that di-leucyl-containing dipeptides
(e.g., dileucine) and tripeptides are superior in their ability to
increase the dispersibility of powdered composition.
[0268] In another embodiment, highly dispersible particles
including an amino acid are administered. Hydrophobic amino acids
are preferred. Suitable amino acids include naturally occurring and
non-naturally occurring hydrophobic amino acids. Some naturally
occurring hydrophobic amino acids, including but not limited to,
non-naturally occurring amino acids include, for example,
beta-amino acids. Both D, L and racemic configurations of
hydrophobic amino acids can be employed. Suitable hydrophobic amino
acids can also include amino acid analogs. As used herein, an amino
acid analog includes the D or L configuration of an amino acid
having the following formula: --NH--CHR--CO--, wherein R is an
aliphatic group, a substituted aliphatic group, a benzyl group, a
substituted benzyl group, an aromatic group or a substituted
aromatic group and wherein R does not correspond to the side chain
of a naturally-occurring amino acid. As used herein, aliphatic
groups include straight chained, branched or cyclic C1-C8
hydrocarbons which are completely saturated, which contain one or
two heteroatoms such as nitrogen, oxygen or sulfur and/or which
contain one or more units of desaturation. Aromatic groups include
carbocyclic aromatic groups such as phenyl and naphthyl and
heterocyclic aromatic groups such as imidazolyl, indolyl, thienyl,
furanyl, pyridyl, pyranyl, oxazolyl, benzothienyl, benzofuranyl,
quinolinyl, isoquinolinyl and acridintyl.
[0269] Suitable substituents on an aliphatic, aromatic or benzyl
group include --OH, halogen (--Br,--Cl,--I and --F), --O(aliphatic,
substituted aliphatic, benzyl, substituted benzyl, aryl or
substituted aryl group),--CN, --NO.sub.2, --COOH, --NH.sub.2,
--NH(aliphatic group, substituted aliphatic, benzyl, substituted
benzyl, aryl or substituted aryl group), --N(aliphatic group,
substituted aliphatic, benzyl, substituted benzyl, aryl or
substituted aryl group).sub.2, --COO(aliphatic group, substituted
aliphatic, benzyl, substituted benzyl, aryl or substituted aryl
group), --CONH.sub.2, --CONH(aliphatic, substituted aliphatic
group, benzyl, substituted benzyl, aryl or substituted aryl
group)), --SH, --S(aliphatic, substituted aliphatic, benzyl,
substituted benzyl, aromatic or substituted aromatic group) and
--NH--C(.dbd.NH)--NH.sub.2. A substituted benzylic or aromatic
group can also have an aliphatic or substituted aliphatic group as
a substituent. A substituted aliphatic group can also have a
benzyl, substituted benzyl, aryl or substituted aryl group as a
substituent. A substituted aliphatic, substituted aromatic or
substituted benzyl group can have one or more substituents.
Modifying an amino acid substituent can increase, for example, the
lypophilicity or hydrophobicity of natural amino acids which are
hydrophilic.
[0270] A number of the suitable amino acids, amino acids analogs
and salts thereof can be obtained commercially. Others can be
synthesized by methods known in the art.
[0271] Hydrophobicity is generally defined with respect to the
partition of an amino acid between a nonpolar solvent and water.
Hydrophobic amino acids are those acids which show a preference for
the nonpolar solvent. Relative hydrophobicity of amino acids can be
expressed on a hydrophobicity scale on which glycine has the value
0.5. On such a scale, amino acids which have a preference for water
have values below 0.5 and those that have a preference for nonpolar
solvents have a value above 0.5. As used herein, the term
hydrophobic amino acid refers to an amino acid that, on the
hydrophobicity scale, has a value greater or equal to 0.5, in other
words, has a tendency to partition in the nonpolar acid which is at
least equal to that of glycine.
[0272] Examples of amino acids which can be employed include, but
are not limited to: glycine, proline, alanine, cysteine,
methionine, valine, leucine, tyosine, isoleucine, phenylalanine,
tryptophan. Preferred hydrophobic amino acids include leucine,
isoleucine, alanine, valine, phenylalanine and glycine.
Combinations of hydrophobic amino acids can also be employed.
Furthermore, combinations of hydrophobic and hydrophilic
(preferentially partitioning in water) amino acids, where the
overall combination is hydrophobic, can also be employed.
[0273] The amino acid can be present in the particles of the
invention in an amount of at least 10 weight %. Preferably, the
amino acid can be present in the particles in an amount ranging
from about 20 to about 80 weight %. The salt of a hydrophobic amino
acid can be present in the particles of the invention in an amount
of at least 10 weight percent. Preferably, the amino acid salt is
present in the particles in an amount ranging from about 20 to
about 80 weight %. In preferred embodiments the particles have a
tap density of less than about 0.4 g/cm.sup.3.
[0274] Methods of forming and delivering particles which include an
amino acid are described in U.S. Pat. No. 6,586,008, entitled Use
of Simple Amino Acids to Form Porous Particles During Spray Drying,
the teachings of which are incorporated herein by reference in
their entirety.
[0275] Proteins/Amino Acids
[0276] Protein excipients may include albumins such as human serum
albumin (HSA), recombinant human albumin (rHA), gelatin, casein,
hemoglobin, and the like. Suitable amino acids (outside of the
dileucyl-peptides of the invention), which may also function in a
buffering capacity, include alanine, glycine, arginine, betaine,
histidine, glutamic acid, aspartic acid, cysteine, lysine, leucine,
isoleucine, valine, methionine, phenylalanine, aspartame, tyrosine,
tryptophan, and the like. Preferred are amino acids and
polypeptides that function as dispersing agents. Amino acids
falling into this category include hydrophobic amino acids such as
leucine, valine, isoleucine, tryptophan, alanine, methionine,
phenylalanine, tyrosine, histidine, and proline.
Dispersibility-enhancing peptide excipients include dimers,
trimers, tetramers, and pentamers comprising one or more
hydrophobic amino acid components such as those described
above.
[0277] Carbohydrates
[0278] By non-limiting example, carbohydrate excipients may include
monosaccharides such as fructose, maltose, galactose, glucose,
D-mannose, sorbose, and the like; disaccharides, such as lactose,
sucrose, trehalose, cellobiose, and the like; polysaccharides, such
as raffinose, melezitose, maltodextrins, dextrans, starches, and
the like; and alditols, such as mannitol, xylitol, maltitol,
lactitol, xylitol sorbitol (glucitol), pyranosyl sorbitol,
myoinositol, isomalt, trehalose and the like.
[0279] Polymers
[0280] By non-limiting example, compositions may also include
polymeric excipients/additives, e.g., polyvinylpyrrolidones,
derivatized celluloses such as hydroxymethylcellulose, hydroxyethyl
cellulose, and hydroxypropylmethylcellulose, Ficolls (a polymeric
sugar), hydroxyethylstarch, dextrates (by non-limiting example
cyclodextrins may include, 2-hydroxypropyl-beta-cyclodextrin,
2-hydroxypropyl-gamma-cyclodextrin, randomly methylated
beta-cyclodextrin, dimethyl-alpha-cyclodextrin,
dimethyl-beta-cyclodextrin, maltosyl-alpha-cyclodextrin,
glucosyl-1-alpha-cyclodextrin, glucosyl-2-alpha-cyclodextrin,
alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin, and
sulfobutylether-b eta-cyclodextrin), polyethylene glycols, and
pectin may also be used.
[0281] Highly dispersible particles administered comprise a
bioactive agent and a biocompatible, and preferably biodegradable
polymer, copolymer, or blend. The polymers may be tailored to
optimize different characteristics of the particle including: i)
interactions between the agent to be delivered and the polymer to
provide stabilization of the agent and retention of activity upon
delivery; ii) rate of polymer degradation and, thereby, rate of
drug release profiles; iii) surface characteristics and targeting
capabilities via chemical modification; and iv) particle
porosity.
[0282] Surface eroding polymers such as polyanhydrides may be used
to form the particles. For example, polyanhydrides such as
poly[(p-carboxyphenoxy)hexane anhydride] (PCPH) may be used.
Biodegradable polyanhydrides are described in U.S. Pat. No.
4,857,311. Bulk eroding polymers such as those based on polyesters
including poly(hydroxy acids) also can be used. For example,
polyglycolic acid (PGA), polylactic acid (PLA), or copolymers
thereof may be used to form the particles. The polyester may also
have a charged or functionalizable group, such as an amino acid. In
a preferred embodiment, particles with controlled release
properties can be formed of poly(D,L-lactic acid) and/or
poly(DL-lactic-co-glycolic acid) ("PLGA") which incorporate a
surfactant such as dipalmitoyl phosphatidylcholine (DPPC).
[0283] Other polymers include polyamides, polycarbonates,
polyalkylenes such as polyethylene, polypropylene, poly(ethylene
glycol), poly(ethylene oxide), poly(ethylene terephthalate), poly
vinyl compounds such as polyvinyl alcohols, polyvinyl ethers, and
polyvinyl esters, polymers of acrylic and methacrylic acids,
celluloses and other polysaccharides, and peptides or proteins, or
copolymers or blends thereof. Polymers may be selected with or
modified to have the appropriate stability and degradation rates in
vivo for different controlled drug delivery applications.
[0284] Highly dispersible particles can be formed from
functionalized polyester graft copolymers, as described in Hrkach
et al., Macromolecules, 28: 4736-4739 (1995); and Hrkach et al.,
"Poly(L-Lactic acid-co-amino acid) Graft Copolymers: A Class of
Functional Biodegradable Biomaterials" in Hydrogels and
Biodegradable Polymers for Bioapplications, ACS Symposium Series
No. 627, Raphael M, Ottenbrite et al., Eds., American Chemical
Society, Chapter 8, pp. 93-101, 1996.
[0285] In a preferred embodiment of the invention, highly
dispersible particles including a bioactive agent and a
phospholipid are administered. Examples of suitable phospholipids
include, among others, phosphatidylcholines,
phosphatidylethanolamines, phosphatidylglycerols,
phosphatidylserines, phosphatidylinositols and combinations
thereof. Specific examples of phospholipids include but are not
limited to phosphatidylcholines dipalmitoyl phosphatidylcholine
(DPPC), dipalmitoyl phosphatidylethanolamine (DPPE), distearoyl
phosphatidyicholine (DSPC), dipalmitoyl phosphatidyl glycerol
(DPPG) or any combination thereof. Other phospholipids are known to
those skilled in the art. In a preferred embodiment, the
phospholipids are endogenous to the lung.
[0286] The phospholipid, can be present in the particles in an
amount ranging from about 0 to about 90 weight %. More commonly it
can be present in the particles in an amount ranging from about 10
to about 60 weight %.
[0287] In another embodiment of the invention, the phospholipids or
combinations thereof are selected to impart controlled release
properties to the highly dispersible particles. The phase
transition temperature of a specific phospholipid can be below,
around or above the physiological body temperature of a patient.
Preferred phase transition temperatures range from 30 degrees C. to
50 degrees C. (e.g., within +/-10 degrees of the normal body
temperature of patient). By selecting phospholipids or combinations
of phospholipids according to their phase transition temperature,
the particles can be tailored to have controlled release
properties. For example, by administering particles which include a
phospholipid or combination of phospholipids which have a phase
transition temperature higher than the patient's body temperature,
the release of dopamine precursor, agonist or any combination of
precursors and/or agonists can be slowed down. On the other hand,
rapid release can be obtained by including in the particles
phospholipids having lower transition temperatures.
[0288] Taste Masking, Flavor, Other
[0289] By non-limiting example, compositions may further include
flavoring agents, taste-masking agents, inorganic salts (e.g.,
sodium chloride), antimicrobial agents (e.g., benzalkonium
chloride), sweeteners, antioxidants, antistatic agents, surfactants
(e.g., polysorbates such as "TWEEN 20" and "TWEEN 80"), sorbitan
esters, saccharin, cyclodextrins, lipids (e.g., phospholipids such
as lecithin and other phosphatidylcholines,
phosphatidylethanolamines), fatty acids and fatty esters, steroids
(e.g., cholesterol), and chelating agents (e.g., EDTA, zinc and
other such suitable cations). Other pharmaceutical excipients
and/or additives suitable for use in the compositions according to
the invention are listed in "Remington: The Science & Practice
of Pharmacy", 19th ed., Williams & Williams, (1995), and in the
"Physician's Desk Reference", 52nd ed., Medical Economics,
Montvale, N.J. (1998).
[0290] By non-limiting example, classes of taste-masking agents for
fluoroquinolone formulation include the addition of flavorings,
sweeteners, and other various coating strategies. By non-limiting
examples these may be chosen from sugars such as sucrose, dextrose,
and lactose), carboxylic acids, salts such as magnesium and calcium
(non-specific or chelation-based fluoroquinolone taste masking),
menthol, amino acids or amino acid derivatives such as arginine,
lysine, and monosodioum glutamate, and synthetic flavor oils and
flavoring aeromatics and/or natural oils, extracts from plants,
leaves, flowers, fruits, etc. and combinations thereof. These may
include cinnamon oils, oil of wintergreen, peppermint oils, clover
oil, bay oil, anise oil, eucalyptus, vanilla, citrus oil such as
lemon oil, orange oil, grape and grapefruit oil, fruit essences
including apple, peach, pear, strawberry, raspberry, cherry, plum,
pineapple, apricot, etc. Additional sweeteners include sucrose,
dextrose, aspartame (Nutrasweet.RTM.), acesulfame-K, sucrolose and
saccharin, organic acids (by non-limiting example citric acid and
aspartic acid). Such flavors may be present at about 0.05 to about
4 percent. Another approach to improve or mask the taste of
unpleasant inhaled drugs is to decrease the drugs solubility, e.g.
drugs must dissolve to interact with taste receptors. Hence, to
deliver solid forms of the drug may avoid the taste response and
acquire the desired improved taste affect. Non-limiting methods to
decrease fluoroquinolone solubility are described in this document,
e.g. salt forms of levofloxacin or gemifloxacin with xinafoic acid,
oleic acid, stearic acid and pamoic acid. Additional
co-precipitating agents include dihydropyridines and a polymer such
as polyvinyl pyrrolidone. Moreover, taste-masking may be
accomplished by creation of lipopilic vesicles. Additional coating
or capping agents include dextrates (by non-limiting example
cyclodextrins may include, 2-hydroxypropyl-beta-cyclodextrin,
2-hydroxypropyl-gamma-cyclodextrin, randomly methylated
beta-cyclodextrin, dimethyl-alpha-cyclodextrin,
dimethyl-beta-cyclodextrin,malto syl-alp ha-cyclo dextrin,
glucosyl-1-alpha-cyclodextrin, glucosyl-2-alpha-cyclodextrin,
alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin, and
sulfobutylether-beta-cyclodextrin), modified celluloses such as
ethyl cellulose, methyl cellulose, hydroxypropyl cellulose,
hydroxyl propyl methyl cellulose, polyalkylene glycols,
polyalkylene oxides, sugars and sugar alcohols, waxes, shellacs,
acrylics and mixtures thereof. By non-limiting example, other
methods to deliver non-dissolved forms of fluoroquinolones are to
administer the drug alone or in simple, non-solubilty affecting
formulation as a crystalline micronized, dry powder, spray-dried,
and nanosuspension formulation. However, an alternative method is
to include taste-modifying agents. These include taste-masking
substance that is mixd with, coated onto or otherwise combined with
the fluoroquinolone active medicament. However, this addition may
also serve to improve the taste of another chosen drug product
addition, e.g. a mucolytic agent. Non-limiting examples of such
substances include acid phospholipids, lysophospholipid, tocopherol
polyethyleneglycol succinate, and embonic acid (pamoate). Many of
these agents can be used alone or in combination with
fluoroquinolones for aerosol administration.
[0291] Mucolytic Agents
[0292] Methods to produce formulations that combine agents to
reduce sputum viscosity during aerosol treatment with a
fluoroquinolone include the following. These agents can be prepared
in fixed combination or be administered in succession with aerosol
fluoroquinolone therapy.
[0293] The most commonly prescribed agent is N-acetylcysteine
(NAC), which depolymerizes mucus in vitro by breaking disulphide
bridges between macromolecules. It is assumed that such reduction
of sputum tenacity facilitates its removal from the respiratory
tract. In addition, NAC may act as an oxygen radical scavenger. NAC
can be taken either orally or by inhalation. Differences between
these two methods of administration have not been formally studied.
After oral administration, NAC is reduced to cysteine, a precursor
of the antioxidant glutathione, in the liver and intestine. The
antioxidant properties could be useful in preventing decline of
lung function in cystic fibrosis (CF). Nebulized NAC is commonly
prescribed to patients with CF, in particular in continental
Europe, in order to improve expectoration of sputum by reducing its
tenacity. The ultimate goal of this is to slow down the decline of
lung function in CF.
[0294] L-lysine-N-acetylcysteinate (ACC) or Nacystelyn (NAL) is a
novel mucoactive agent possessing mucolytic, antioxidant, and
anti-inflammatory properties. Chemically, it is a salt of ACC. This
drug appears to present an activity superior to its parent molecule
ACC because of a synergistic mucolytic activity of L-lysine and
ACC. Furthermore, it's almost neutral pH (6.2) allows its
administration in the lungs with a very low incidence of
bronchospasm, which is not the case for the acidic ACC (pH 2.2).
NALis difficult to formulate in an inhaled form because the
required lung dose is very high (approximately 2 mg) and the
micronized drug is sticky and cohesive and it is thus problematic
to produce a redispersable formulation. NAL was first developed as
a chlorofluorocarbon (CFC) containing metered-dose inhaler (MDI)
because this form was the easiest and the fastest to develop to
begin the preclinical and the first clinical studies. NAL MDI
delivered 2 mg per puff, from which approximately 10% was able to
reach the lungs in healthy volunteers. One major inconvenience of
this formulation was patient compliance because as many as 12 puffs
were necessary to obtain the required dose. Furthermore, the
progressive removal of CFC gases from medicinal products combined
with the problems of coordination met in a large proportion of the
patient population (12) have led to the development of a new
galenical form of NAL. A dry powder inhaler (DPI) formulation was
chosen to resolve the problems of compliance with MDIs and to
combine it with an optimal, reproducible, and comfortable way to
administer the drug to the widest possible patient population,
including young children.
[0295] The DPI formulation of NAL involved the use of a
nonconventional lactose (usually reserved for direct compression of
tablets), namely, a roller-dried (RD) anhydrous (3-lactose. When
tested in vitro with a monodose DPI device, this powder formulation
produces a fine particle fraction (FPF) of at least 30% of the
nominal dose, namely three times higher than that with MDIs. This
approach may be used in combination with a fluoroquinolone
antibiotic for either co-administration or fixed combination
administration antibiotic therapy.
[0296] In addition to mucolytic activity, excessive neutrophil
elastase activity within airways of cystic fibrosis (CF) patients
results in progressive lung damage. Disruption of disulfide bonds
on elastase by reducing agents may modify its enzymatic activity.
Three naturally occurring dithiol reducing systems were examined
for their effects on elastase activity: 1) Escherichia coli
thioredoxin (Trx) system, 2) recombinant human thioredoxin (rhTrx)
system, and 3) dihydrolipoic acid (DHLA). The Trx systems consisted
of Trx, Trx reductase, and NADPH. As shown by spectrophotometric
assay of elastase activity, the two Trx systems and DHLA inhibited
purified human neutrophil elastase as well as the elastolytic
activity present in the soluble phase (sol) of CF sputum. Removal
of any of the three Trx system constituents prevented inhibition.
Compared with the monothiols N-acetylcysteine and reduced
glutathione, the dithiols displayed greater elastase inhibition. To
streamline Trx as an investigational tool, a stable reduced form of
rhTrx was synthesized and used as a single component. Reduced rhTrx
inhibited purified elastase and CF sputum sol elastase without
NADPH or Trx reductase. Because Trx and DHLA have mucolytic
effects, we investigated changes in elastase activity after
mucolytic treatment. Unprocessed CF sputum was directly treated
with reduced rhTrx, the Trx system, DHLA, or DNase. The Trx system
and DHLA did not increase elastase activity, whereas reduced rhTrx
treatment increased sol elastase activity by 60%. By contrast, the
elastase activity after DNase treatment increased by 190%. The
ability of Trx and DHLA to limit elastase activity combined with
their mucolytic effects makes these compounds potential therapies
for CF.
[0297] In addition, bundles of F-actin and DNA present in the
sputum of cystic fibrosis (CF) patients but absent from normal
airway fluid contribute to the altered viscoelastic properties of
sputum that inhibit clearance of infected airway fluid and
exacerbate the pathology of CF. One approach to alter these adverse
properties is to remove these filamentous aggregates using DNase to
enzymatically depolymerize DNA to constituent monomers and gelsolin
to sever F-actin to small fragments. The high densities of negative
surface charge on DNA and F-actin suggest that the bundles of these
filaments, which alone exhibit a strong electrostatic repulsion,
may be stabilized by multivalent cations such as histones,
antimicrobial peptides, and other positively charged molecules
prevalent in airway fluid. Furthermore, As a matter-a-fact, it has
been observed that bundles of DNA or F-actin formed after addition
of histone H1 or lysozyme are efficiently dissolved by soluble
multivalent anions such as polymeric aspartate or glutamate.
Addition of poly-aspartate or poly-glutamate also disperses DNA and
actin-containing bundles in CF sputum and lowers the elastic moduli
of these samples to levels comparable to those obtained after
treatment with DNase I or gelsolin. Addition of poly-aspartic acid
also increased DNase activity when added to samples containing DNA
bundles formed with histone H1. When added to CF sputum,
poly-aspartic acid significantly reduced the growth of bacteria,
suggesting activation of endogenous antibacterial factors. These
findings suggest that soluble multivalent anions have potential
alone or in combination with other mucolytic agents to selectively
dissociate the large bundles of charged biopolymers that form in CF
sputum.
[0298] Hence, NAC, unfractionated heparin, reduced glutathione,
dithiols, Trx, DHLA, other monothiols, DNAse, dornase alfa,
hypertonic formulations (e.g. osmolalities greater than about 350
mOsmol/kg), multivalent anions such as polymeric aspartate or
glutamate, glycosidases and other examples listed above can be
combined with fluoroquinolone antibiotics and other mucolytic
agents for aerosol administration to improve antibacterial activity
through better distribution from reduced sputum viscosity, and
improved clinical outcome through improved pulmonary function (from
improved sputum mobility and mucociliary clearance) and decreased
lung tissue damage from the immune inflammatory response.
EXAMPLES
[0299] The following examples serve to more fully describe the
manner of using the above-described invention, as well as to set
forth the best modes contemplated for carrying out various aspects
of the invention. It is understood that these examples in no way
serve to limit the true scope of this invention, but rather are
presented for illustrative purposes. All references cited herein
are incorporated by reference in their entirety.
Example 1
High Local Concentration with Short Duration Aerosol
Fluoroquinolone Exposure
[0300] Aerosol administration of fluoroquinolones such as
levofloxacin produces high concentrations in the epithelial lining
fluid (ELF) of rats and humans. However, this dose has been
observed to rapidly decline following administration.
[0301] In order to determine if short duration, high concentrations
of levofloxacin could be effective in treatment of P. aeruginosa
(PA), studies were conducted to measure their bactericidal activity
on various strains of this organism which were grown at different
conditions. Those were chosen based on what is known about
conditions and growth of PA in a cystic fibrosis (CF) lung. Four
isogenic strains of P. aeruginosa were used for these experiments
(Table 2).
TABLE-US-00002 TABLE 2 Strains of PA Used in Time-Kill Experiments
Levofloxacin MIC Strain Genotype (ug/ml) PAM1020 Wt 0.25 PAM1032
nalB 1
[0302] PAM1020 is the parent wild-type strain, PAM1032 contains
nalB mutation which results in increased levofloxacin resistance
due to overexpression of the MexAB-OprM efflux pump which can
extrude levofloxacin out of cells.
[0303] Experiment 1. Activity of Levofloxacin Against Exponentially
Grown Cells.
[0304] Methods
[0305] Inoculum Preparation
[0306] Strains were grown aerobically overnight in Mueller-Hinton
Broth (MHB) at 35.degree. C. Next, cultures were diluted 1:1000
into 100 ml of fresh MHB and grown to OD.sub.600.about.0.3 to reach
CFU/ml .about.10.sup.8. 10 ml of this culture was moved to 50 ml
flasks, each containing 10 ml of pre-warmed MHB broth with
appropriate concentrations of levofloxacin (2.times. as compared to
the exposure concentrations).
[0307] Exposure
[0308] All strains were treated for 10 min., 20 min., 40 min., 80
min. and 160 minutes. The following concentrations of levofloxacin
(ug/ml) were used for the exposure of PAM1020 and PAM1032: 16, 32,
64, 128 and 256. All strains were treated at each concentration for
10 min., 20 min., 40 min., 80 min. and 160 minutes.
[0309] Determination of Viable Cell Numbers
[0310] At appropriate times, 1 ml of each exposure culture was
centrifuged for 2 minutes, the pellet was washed twice with 1 ml of
drug-free MHB, and re-suspended in 1 ml of MHB. The viable cell
numbers were enumerated by plating serially diluted samples (in
duplicates) on MHB plates by the drop (10 ul) plating method. The
limit of detection was 100 CFU/ml. Killing is reported as the log
reduction calculated relative to cell count at the time of
initiation of antibiotic exposure. Relative antibiotic
concentrations (relative to MIC of the corresponding strains) are
used. Cell numbers at initiation of antibiotic exposure are shown
in Table 3.
TABLE-US-00003 TABLE 3 Bacterial Numbers at Time of Initial
Bacterial Exposure Strain CFU/ml PAM1020 4.03E+07 PAM1032
5.60E+07
[0311] Results
[0312] For the most susceptible strain, PAM1020, maximum killing
(5.5 log decrease in viable cell counts) was achieved after
incubation for 10 minutes with the concentration of levofloxacin
corresponding to 256-fold MIC (64 ug/ml tested). 5-logs of killing
were achieved already with the lowest concentration tested (16
ug/ml or 64-fold MIC) (FIG. 4A). For the strain PAM1032, as long as
the concentration above 128-fold the MIC (128 ug/ml) was reached,
10 minute of exposure was sufficient to result in maximum killing
(more than 5 logs). At short duration exposures (10 or 20 minutes),
less killing was observed at concentrations below 128-fold of MICs.
At longer exposure times, concentration corresponding to 16-fold
MICs and above resulted in similar maximum killing (FIG. 4B). These
results inducate that logarithmic cells of P. aeruginosa are
efficiently killed after short duration exposures to high
concentrations of levofloxacin.
[0313] Experiment 2. Activity of Levofloxacin Against Stationary
Phase Cells
[0314] Methods
[0315] Inoculum Preparation
[0316] Strains were grown aerobically overnight in Mueller-Hinton
Broth (MHB) at 35.degree. C. (350 ml total). The spent medium was
obtained after centrifugation of overnight cultures and filtering
the supernatant. Cultures were diluted to OD=0.3 into spent medium.
The same medium was also used to prepare antibiotic concentrations
(the same as in Experiment 1).
[0317] Exposure
[0318] Antibiotic concentrations, time of exposure as determination
of viable cell counts were the same as in Experiment 1.
[0319] Results
[0320] Cell numbers at initiation of antibiotic exposure are shown
in Table 4.
TABLE-US-00004 TABLE 4 Bacterial Numbers at Time of Initial
Bacterial Exposure Strain CFU/ml PAM1020 8.0E+08 PAM1032
8.50E+08
[0321] For stationary phase cells of PAM1020, maximum killing was
observed at the lowest concentration corresponding to 64-fold above
MIC (16 ug/ml) and the shortest duration of exposure, 10 minutes
(FIG. 5A). However, PAM1032 demonstrated clear dose-dependent
killing with the maximum killing (4 logs) at concentrations 64 the
MIC at a short exposure time. Extending the exposure times did not
result in larger extent of killing. However, lower concentrations
of drug were required to achieve the same killing at longer
exposure times (FIG. 5B).
[0322] Next, we have compared the re-growth of PAM1020 and PAM1032
after either 10 minutes or 160 minutes of treatment with various
concentrations of levofloxacin. After the corresponding treatments,
cells were washed twice with antibiotic-free medium. 150 .mu.l of
cells was placed into 96-well plate and the growth was continuously
monitored at A.sub.660 using SpectraMax (Molecular Devices). The
results are shown in FIGS. 6A-6D.
[0323] The results demonstrate that the re-growth of both strains
was observed at approximately the same time whether cells were
treated with high concentrations of levofloxacin for 10 minutes or
160 minutes. These results further support the efficiency of short
duration treatment with high concentrations of levofloxacin.
[0324] Experiment 3. Activity of Levofloxacin Against Cells Grown
Under Oxygen-Limiting Conditions.
[0325] Methods
[0326] Inoculum Preparation
[0327] Overnight cultures were grown aerobically overnight in
Mueller-Hinton Broth and next diluted 1:10000 in MHB which filled
growth flasks to the very top. Cultures were grown without shaking
to OD.about.0.3 at 37.degree. C. Under these conditions an average
of .about.20 hours was required to reach an OD=0.3 as compared to
.about.5 hours under aerated conditions (50 ml of medium in 250 ml
flasks, vigorous shaking). Upon analysis, it appeared that an
OD=0.3 corresponded to a late-logarithmic phase of growth. Other
than decreased aeration, antibiotic concentration, time of
exposure, and determination of viable cell counts were the same as
in Experiments 1 and 2.
[0328] Results
[0329] Cell numbers at initiation of antibiotic exposure are shown
in Table 5.
TABLE-US-00005 TABLE 5 Bacterial Numbers at Time of Initial
Bacterial Exposure Strain CFU/ml PAM1020 7.5E+07 PAM1032
8.5E+07
[0330] In the case of PAM1020 near maximum killing (4 logs vs 4.5
logs observed under normal aeration) was achieved after exposure
with the lowest concentration of levofloxacin for the shortest
duration of time (10 minutes) (FIG. 7A). In the case of PAM1032
dose-dependent killing was observed for 10 minutes or 20 minutes of
exposure with the highest killing observed at concentrations
corresponding to 128 to 256-fold the MIC. Slightly stronger (less
than 1 log difference) killing was observed for longer exposure
intervals (FIG. 7B). These data indicate that under conditions of
oxygen limitation cells which are at the late logarithmic phase of
growth are efficiently killed after short duration of exposure with
high concentrations of levofloxacin.
[0331] Experiment 4. Activity of Levofloxacin Against PAM1032 CF
Sputum.
[0332] Methods
[0333] Cells of strain PAM1032 (MIC=1 ug/ml) were grown to OD=1
(late-exponential/early stationary phase of growth) in MHB and next
concentrated 10-fold in 10-fold concentrated MHB. 10 ul of cells
were then added to 90 ul of sputum or water in 96-well round bottom
plates, restoring MHB to its original concentration. Quantitation
plates were pre-warmed for 5 minutes at 37.degree. C. and different
concentrations of levofloxacin (512 ug/ml, 128 ug/ml, 32 ug/ml, 8
ug/ml, 2 ug/ml, and 0.5 ug/ml) were added. At appropriate times, 10
ul of each treatment culture was diluted 100-fold in MHB to
minimize the carryover of levofloxacin. Viable cell numbers were
enumerated by plating serially diluted samples on MHB plates by the
drop (10 ul) plating method. The limit of detection was 10.sup.4
CFU/ml. Killing is reported as the percentage of the starting
inoculum survived after the levofloxacin treatment. Results are
shown in FIGS. 8A and 8B.
[0334] Results
[0335] The results indicate that while sputum slightly affected the
degree of killing by levofloxacin, rapid and extensive (up to five
orders of magnitude) killing by levofloxacin in sputum was still
observed after short duration of treatment at high concentrations
of antibiotic.
[0336] Experiment 4. Activity of Levofloxacin Against Colony
Biofilms of PAM1032.
[0337] Methods
[0338] Biofilm Preparation
[0339] Colony biofilms were grown on polycarbonate membrane filters
(diameter, 25 mm; Poretics, Livermore, Calif.) resting on MHB
plates. Overnight culture of PAM1032 was diluted to OD=0.3, and
then diluted 1:100 in fresh MHB. 5 ul of this culture was spotted
on the membrane filter. Bacteria were incubated at 37.degree. C.
for 48 hours (mature biofilms).
[0340] Exposure
[0341] After growth filters were placed into tubes containing 3 ml
saline or saline and levofloxacin at 128 ug/ml and 1024 ug/ml. Each
tube was treated for 10 minutes and 80 minutes. At about 5 min.
before incubation time elapsed, tubes were vigorously vortexed (A)
or sonicated and vortexed (B) to detach cells. 1 ml of each
exposure culture was centrifuged for 2 minutes, the pellet was
washed twice with 1 ml of drug-free MHB, and re-suspended in 1 ml
of MHB. The viable cell numbers were enumerated by plating serially
diluted samples (in duplicates) on MHB plates by the drop (10 ul)
plating method. Results are shown in FIG. 9.
[0342] Results
[0343] The data demonstrate that maximum killing (.about.2 logs) is
obtained after 10 min with the lowest concentration of levofloxacin
tested (128-fold MIC). No additional killing was observed at the
higher levofloxacin concentration. These data indicate that colony
biofilms are more resistant to killing as compared to logarithmic
or stationary phase cells. However, the maximum observed
bactericidal activity against biofilms (99% under these conditions)
was achieved after 10 minutes of levofloxacin exposure.
[0344] Experiment 5. Simulated Short-Term, Rapid Aerosol
Administration, Delivering High Concentration Drug Exposure in in
vitro Pharmacodynamic Model.
[0345] In vitro pharmacodynamic models of infection allow for
exposure of a growing bacterial inoculum to changing concentrations
of drug as would occur in vivo. The strength of this approach is
that the serum concentration vs. time profile of a drug in man can
be simulated in the laboratory in vitro to determine the optimal
exposure profile (i.e., dose and dosing interval) for a drug and
target pathogen.
[0346] The following report describes experiments designed to
determine the Cmax and AUC that will provide maximum bactericidal
effects after an aerosol dose of a fluoroquinolone.
[0347] Material and Methods
[0348] In Vitro Pharmacodynamic Model of Infection
[0349] The in vitro pharmacodynamic model consists of a central
(analogous "serum" compartment) and peripheral ("extravascular")
compartment. The peripheral compartments consist of artificial
capillary units (Unisyn, Hopkinton, Mass.) arranged in series with
the central compartment. Each capillary unit has a bundle of small
semi-permeable fibers with a molecular size retention of ca. 10,000
MW to allow passage of nutrients but not bacteria. The entire
system is set up in a dry heat incubator adjusted to 37.degree.
C.
[0350] Both the central and peripheral compartments were filled
with Mueller-Hinton broth. Each peripheral compartment (capillary
unit and tubing) contained ca. 23 ml of growth medium.
[0351] Bacteria were introduced into the peripheral chamber of the
model and allowed to grow for 2 hours prior to the first "dose" of
drug. Drug doses were administered into the central compartment and
pumped to peripheral chambers by a peristaltic pump. Concentrations
in the model declined according to first order elimination
(half-life) by dilution of the central compartment with drug free
medium introduced by an additional peristaltic pump adjusted to the
desired clearance.
[0352] Samples (0.3 ml) were collected from peripheral compartments
at various intervals for determination of drug and bacterial
concentrations. Samples were collected from the peripheral
compartments and assayed for drug concentrations by HPLC.
[0353] Bacterial Test Strains
[0354] Pseudomonas aeruginosa PAM1032 and PAM1582. The MICs of
these strains to levofloxacin were 1.0 and 32 ug/ml,
respectively.
[0355] Inocolum Preparation
[0356] Strains were grown aerobically overnight in Mueller-Hinton
Broth (MHB) at 35.degree. C. and subcultured to fresh MHB and
reincubated at 35.degree. C. for 2 hours. After 2 hours, the
inoculum was further diluted 1:1000 to a final concentration of
approx. 1.0.times.106 CFU/ml. Of the resulting dilution, 2.3 ml was
injected into each peripheral chamber of the hollow-fiber
bioreacters (Unisyn, Hopkinton, Mass.).
[0357] Pharmacokinetics
[0358] The half-life of levofloxacin was adjusted to be 10 minutes
to be equivalent to that observed following aerosol delivery of
levofloxacin to the pulmonary compartment of man. The targeted Cmax
was 1000 and 600 ug/ml over two experiments.
[0359] Results
[0360] As targeted, the model exhibited a levofloxacin half-life of
10 minutes and the Cmax of 1000 ug/ml for Experiment 5. By
comparison, Experiment 6 was modified to achieve the same half-life
as Experiment 5, but with a targeted Cmax of 600 .mu.g/ml.
[0361] The bactericidal effects of these two regimens correlated
with the Cmax. In Experiment 5 with a Cmax of 1000 ug/ml, the
maximum bactericidal effect was observed as a 5 log reduction in
bacterial counts within 10 minutes with PAM1032 and a 4 log
reduction in bacterial counts within 20 minutes with PAM1582 and no
re-growth observed over the remaining 2 hours of the experiment
(FIG. 10). In contrast, while the Cmax of 600 ug/ml used in
Experiment 6 maintained the 5-log reduction in bacterial counts for
PAM1032, albeit taking 30 min instead of 10 min observed in
Experiment 1, only a 3-log reduction in bacterial counts was
observed for PAM1582 after 45 min (FIG. 11). Moreover, PAM1582
exhibited initial re-growth before the end of the 2 hour
experimental window.
[0362] Conclusions
[0363] Levofloxacin can produce up to a 99.9999% bacterial
reduction with a Cmax of both 600 and 1000 ug/ml against a strain
with an MIC of 1 ug/ml. However, maximal bactericidal activity
requires 3.times. more time at a Cmax of 600 ug/ml. Levofloxacin
can also produce up to 99.99% bacterial reduction with a Cmax of
both 600 ug/ml against a strain with an MIC of 32 ug/ml. However,
the time to reach the maximum effect is 45 minutes. In contrast,
levofloxacin can produce up to 99.999% bacterial reduction of this
resistant strain with a Cmax of 1000 ug/ml and the time to maximum
effect is reduced to 20 minutes. From these results, extremely
high, but short duration exposures of levofloxacin produce rapid
and sustained bacterial killing in both flask and hollow fiber
models. Taken together, the above results indicate that achieving
an initial 800 ug/ml levofloxacin or other fluoroquinolone human
ELF or sputum concentration is sufficient to achieve the above
antibiotic affects for the MIC99 population as represented by
PAM1582 (MIC of 32 ug/ml).
Example 2
Determination of the Aerosol Properties of Antibacterial
Fluoroquinolones
[0364] Introduction
[0365] Objective. The purpose of these studies was to evaluate the
ability to formulate and deliver by nebulization a variety of
fluoroquinolones for treatment of pulmonary bacterial infections by
aerosol administration. The fluoroquinolones evaluated are shown in
Table 6.
TABLE-US-00006 TABLE 6 Fluoroquinolones Tested SP MSSA MRSA Pa
Fluoro- MIC.sub.90 MIC.sub.90 MIC.sub.90 MIC.sub.90 quinolone
(ug/mL) (ug/mL) (ug/mL) (ug/mL) Approval Status Ciprofloxacin 2 1
64 8 Approved Gemifloxacin 0.06 0.06 2 8 Approved Levofloxacin 2
0.5 16 8 Approved Marbofloxacin 2 2 ND 8 Veterinary Gatifloxacin
0.5 0.125 4 16 Approved Ofloxacin 2 1 >32 16 Approved
Tosufloxacin 0.5 0.125 >16 16 Japan Lomefloxacin 16 2 >32 32
Approved Moxifloxacin 0.25 0.125 2 32 Approved Sparfloxacin 0.5
0.125 16 32 Withdrawn Orbifloxacin 2 2 ND >32 Veterinary
Pefloxacin 32 2 >32 >32 Europe Trovafloxacin 0.25 0.06 8
>32 Withdrawn
[0366] These fluoroquinolones were chosen based on their
availability, approval status and antimicrobial properties. All
tested fluoroquinolones are either currently approved in the United
States or have been approved but later withdrawn due to various
adverse reactions. In addition, several fluoroquinolones, which are
in use for veterinary applications, have also been evaluated. Among
bacterial pathogens responsible for respiratory tract infections,
Pseudomonas aeruginosa (Pa) and methicillin resistant
Staphylococcus aureus (MRSA) are the most refractory to treatment
with fluoroquinolones. Streptocossus pneumonia (Sp) is probably the
most important pathogen responsible for respiratory tract
infections and numerous reports demonstrate high rates of
fluoroquinolone resistance in these bacteria. MIC.sub.90 for Pa
ranges from 4 ug/ml to 32 ug/ml and from 2 ug/ml to >32 ug/ml
for Pa and MRSA, respectively. Ciprofloxacin, levofloxacin,
gemifloxacin and gatifloxacin vs gemifloxacin and moxifloxacin are
the most potent against Pa and MRSA, respectively.
[0367] Table 7 contains a list of additional fluoroquinolones for
potential evaluation. The most microbiologically interesting
compounds in the list are clinafloxacin and olamufloxacin, which
were discontinued due to adverse reactions, and sitofloxacin, which
is in Phase III clinical trials.
TABLE-US-00007 TABLE 7 Fluoroquinolones for Potential Evaluation Sp
Sa MRSA Pa Fluoro- MIC.sub.90 MIC.sub.90 MIC.sub.90 MIC.sub.90
quinolone (ug/mL) (ug/mL) (ug/mL) (ug/mL) Market Status
Clinafloxacin 0.06 0.06 2 4 Discontinued Sitafloxacin 0.06 0.125 4
8 Phase III Olamufloxacin 0.06 1 2 16 Discontinued Norfloxacin 16 1
>4 16 Approved Prulifloxacin 1 0.25 32 16 Phase III Danofloxacin
NA 0.125 NA >16 Veterinary Enrofloxacin 1 0.125 8 >16
Veterinary Sarafloxacin NA 0.25 >16 >16 Veterinary
Balofloxacin 0.5 0.25 8 32 Korea Fleroxacin 8 1 >4 32 Europe
Difloxacin 2 0.5 NA 32 Veterinary Rufloxacin 32 2 64 32 Europe,
China Enoxacin 16 1 >4 >32 Withdrawn Garenoxacin 0.06 0.06 8
>32 Phase III Grepafloxacin 0.5 0.125 32 >32 Withdrawn
Pazufloxacin 4 0.5 >16 >32 Japan
[0368] The fluoroquinolones in these two tables represent one field
of options for an aerosol fluroquinolone candidate. Several potent
fluoroquinolones such as DX-619 and DW-286, which are at the early
stage of clinical development, might also be of interest for future
studies.
[0369] Specific physico-chemical considerations for nebulization
include aqueous solubility, viscosity and surface tension. The
aqueous solubility of the drug should advantageously be sufficient
to meet or exceed the minimal dosing requirement. The loading drug
concentration also affects delivery time. Longer delivery times may
be commercially unacceptable or lead to poor patient compliance.
Although longer delivery times may in effect modify the AUC shape,
by non-limiting example, the PARI eFlow device has been discovered
to administer 4 ml of aqueous levofloxacin in less than 5 min.
Moreover, using such an efficient device, high concentration
levofloxacin may be able to deliver the effective doses described
herein in a timeframe further enabling the rapid administration,
high concentration drug requirements needed for optimal
fluoroquinolone therapy.
[0370] In the case of fluoroquinolones, pH directly affects
solubility. In general, solubility decreases significantly with
increase in pH in the range 1.5 to 6.5. Because pH also affects
patient tolerability (see below), the optimal choice of
fluoroquinolone for pulmonary delivery via aerosol has certain
solubility and pH levels.
[0371] For the purpose of this feasibility study, the target
solubility was set at 10 mg/mL or higher at a pH of 4.5 or greater,
based on calculations of therapeutic dose and the delivery metrics
for available nebulizers. In order to be above the mutant
prevention concentration (MPC), peak concentration of
fluoroquinolone after aerosol administration advantageously reaches
about 100 ug/ml to about 1000 ug/ml at the site of infection,
pending the MIC of the infecting organism. Based on these
considerations, the minimal dose to be in this therapeutically
relevant range was projected to be at least about 30-40 mg
Respirable Delivered Dose (RDD). Given the relative half-life of
levofloxacin in the human lung, the practical achievement of this
dose by nebulization may be obtained with a loading dose of at
least about 100 mg in a volume of about 2 mL (about 50 mg/mL) in a
high-efficiency vibrating-mesh device operating at its maximum
performance efficiency delivering this dose in less than 4 min. A
standard ultrasonic or jet nebulizer may require a loading dose of
at least about 400 mg in a volume of about 5 mL (about 80 mg/mL).
However, the rate of administration by these less efficient devices
may not be sufficient to achieve high local concentration with
short duration exposure. Similar efficacious doses may also be
achieved by administration of levofloxacin as a dry powder, where
the rapid solubility properties of levofloxacin may permit a quick
dissolution resulting in these desired soluble drug concentrations.
However, alternative concentrations or alteration of the
fluoroquinolone AUC shape profile may be desirable.
[0372] Alternatively, although aqueous solubility is important, it
is reasonable to predict a formulation utilizing particle or
complexation technology to enable nebulization of less soluble
fluoroquinolones. Unfortunately, more intricate formulations
increase both the complexity and cost of drug development, and in
the case of jet and ultrasonic nebulizers, a significant reduction
in efficiency of delivery, and limit the ability to introduce other
design elements into a final drug product.
[0373] In addition to drug solubility, for vibrating mesh devices
nebulization is also sensitive to the surface tension of the drug
formulation. Therefore, in one embodiment, the surface tension is
adjusted during formulation by modifying drug concentration,
excipient concentration and/or the addition of surfactant.
[0374] In addition to factors that affect efficient nebulization,
other factors may be considered for patient tolerability and
compliance. By non-limiting example, these factors may include
osmolality, pH and taste. Osmolality affects acute tolerability in
the respiratory tract and can be optimized for most drugs during
formulation. Similarly, the pH of an aerosol also contributes to
tolerability, yet only negatively when the formulation pH is less
than 4.5. Therefore, because pH directly contributes to
fluoroquinolone solubility, fluoroquinolones that require a pH less
than 4.5 for solubility are likely to be poorly tolerated. Finally,
fluoroquinolone taste can affect good patient compliance.
Fluoroquinolones are known generally to be associated with an
unpleasant, sometimes very intense taste. While there are
technologies available that may mask poor drug taste, these
technologies increase development complexity and cost, and may not
be totally effective in the case of fluoroquinolones. Thus, similar
to pH, taste may be considered in identifying a fluoroquinolone
suitable for nebulization.
[0375] Preparation and Characterization of the Test Solutions
[0376] Antibiotics were purchased from one of several sources as
shown in Table 8.
TABLE-US-00008 TABLE 8 Preparation of Fluoroquinolone Test
Solutions Fluoro- Volume No. quinolone Source.sup.a Purity.sup.b
Amount H.sub.2O Final Conc. 1 Gatifloxacin LKT 99.6 8.7 mg 0.87 mL
10 mg/mL 2 Gemifloxacin LG 99.6 9.5 mg 0.95 mL 10 mg/mL 3
Levofloxacin LKT 99.2 10.3 mg 1.03 mL 10 mg/mL 4 Moxifloxacin LKT
99.5 12.5 mg 1.25 mL 10 mg/mL 5 Ciprofloxacin LKT 99.3 19.5 mg 1.95
mL 10 mg/mL 6 Ofloxacin LKT 99.1 11.7 mg 1.17 mL 10 mg/mL 7
Lomefloxacin MPI NA 17.0 mg 1.70 mL 10 mg/mL 8 Marbofloxacin
Vetoquino NA 4.8 mg 0.48 mL 10 mg/mL 9 Orbifloxacin MPI NA 4.2 mg
0.42 mL 10 mg/mL 10 Pefloxacin MPI NA 15.0 mg 1.50 mL 10 mg/mL 11
Sparfloxacin MPI NA 14.5 mg 1.45 mL 10 mg/mL 12 Tosufloxacin MPI NA
15.2 mg 1.52 mL 10 mg/mL 13 Trovafloxacin MPI NA 2.0 mg 0.20 mL 10
mg/mL .sup.aLKT: LKT Laboratories. LG: LG Chem. NA. Source
unavailable. .sup.bPurity of material tested. Described as GAR) or
in percent API. c. 25 mg/ml solution
[0377] A 2 to 20 mg sample of each antibiotic was weighed into
sterile plastic tubes and brought up with a volume of sterile water
to make a 10 mg/mL solution or suspension of the antibiotic.
Samples were incubated for approximately 10 minutes at room
temperature with occasional mixing, prior to further handling.
[0378] Following the incubation period, the antibiotic solutions
were observed for their visible appearance, with results as shown
in Table 9.
[0379] Five of the fluoroquinolones tested were visibly soluble,
and either colorless, or a shade of yellow. Eight were visibly
insoluble, appearing either cloudy (fine particulate), opaque
(dense fine to medium particulate), or turbid (thick, large
particulate slurry), in all cases with a visible sediment. The pH
of these initial solutions were determined, and ranged from 3.5 to
7.0. The insoluble solutions were titrated with 1N HCl to the point
of visible solubility, and the pH of the solubilized solution
determined. In three cases, marbofloxacin, sparfloxacin and
tosufloxacin, solubility was not reached by pH 1.5, and further
addition of acid was stopped. With the exception of ofloxacin, the
pH of these titrated solutions was in the range of 1.5 to 3.0.
TABLE-US-00009 TABLE 9 Fluoroquinolone Solution Characteristics
After pH Adjustment 1N Initial Solution HCl No. Fluoroquinolone
Appearance pH (uL) Appearance.sup.a pH 1 Gatifloxacin white,
cloudy, visible 7.0 5 slight yellow color, 3.0 sediment
transparent, no sediment 2 Gemifloxacin colorless, transparent, no
4.7 NR -- sediment 3 Levofloxacin slight yellow color, 4.7 NR --
transparent, no sediment 4 Moxifloxacin bright yellow color, 4.7 NR
-- transparent, no sediment 5 Ciprofloxacin white, opaque (very
dense), 5.5 60 colorless, transparent, no 2.0 visible sediment
sediment 6 Ofloxacin cloudy, visible sediment 6.5 10 slightly
yellow color, 5.2 transparent, no sediment 7 Lomefloxacin cloudy,
visible sediment 4.2 -- transparent, no sediment, -- after 10 min.
at rm. temp. 8 Marbofloxacin white, very turbid, visible 6.5 40
white, turbid, visible 1.5 sediment sediment 9 Orbifloxacin white,
cloudy, visible 20 colorless, transparent, no 1.7 sediment sediment
10 Pefloxacin colorless, transparent, no 4.5 NR -- precipitate 11
Sparfloxacin bright yellow, turbid, visible 5.0 20 bright yellow,
densely 1.5 sediment turbid, visible sediment 12 Tosufloxacin
white, turbid, visible 3.5 20 white, cloudy, less turbid, 1.5
sediment visible sediment 13 Trovafloxacin colorless, slightly
cloudy, no 4.2 NR -- sediment .sup.aNR: pH adjustment not required.
Fluoroquinolone was solution at a pH >4 in the initial
solution.
[0380] After the pH adjustment, and following a further 10 minute
incubation period with occasional mixing, the final appearance of
the solutions was determined, just prior to the aerosol
tolerability and taste test. Results are shown in Table 10.
TABLE-US-00010 TABLE 10 Appearance of Fluoroquinolone Final
Solution No. Fluoroquinolone pH Solubility Color Sediment
Opaqueness 1 Gatifloxacin 3.0 + C none none to very slight 2
Gemifloxacin + C none none to very slight 3 Levofloxacin 4.7 + VLY
none none 4 Moxifloxacin 4.7 + Y +/- none 5 Ciprofloxacin 2.0 + C
none none 6 Ofloxacin 5.2 + LY +/- none 7 Lomefloxacin 4.2 + C +/-
none to very slight 8 Marbofloxacin 1.5 -- W ++ ++ 9 Orbifloxacin
1.7 + C none slight 10 Pefloxacin 4.5 + C none slight 11
Sparfloxacin 1.5 --- DY +++ ++++ 12 Tosufloxacin 1.5 -- W ++ +++ 13
Trovafloxacin 4.2 + C + slight Y = yellow; LY = light yellow; VYL =
very light yellow; DY = dark yellow; C = colorless; W = white.
[0381] The compounds exhibiting preferred solubility for solutions
suitable for delivery by inhalation (10 mg/mL at a pH of 4.5 or
above), were levofloxacin, gemifloxacin, moxifloxacin, ofloxacin
and pefloxacin. Levofloxacin, ofloxacin and moxifloxacin exhibited
the best solubility/pH characteristics.
[0382] Taste and Tolerability Evaluation
[0383] Two evaluations were done to determine the suitability of
the fluoroquinolone solutions with respect to taste and
tolerability.
[0384] First, in an oral taste test the taste of a 20 uL portion of
test sample was determined in a single, healthy human volunteer by
placing the material directly onto the center front part of the
tongue. Taste was then monitored over a 1 minute period. This test
was performed on the initial solutions prepared as well as the
final solutions following pH adjustment. Data are shown in Table
11.
TABLE-US-00011 TABLE 11 Oral Fluoroquinolone Taste Test Fluoro- No.
quinolone Initial Solution Final Solution 1 Gatifloxacin moderate
bitter unpleasant strong bitter taste, slightly aromatic unpleasant
almond-like taste, strong aftertaste 2 Gemifloxacin very bitter
unpleasant taste not performed with strong aftertaste, all the way
into throat 3 Levofloxacin slight chemical taste, not performed
slightly bitter, slight almond-like taste 4 Moxifloxacin moderate
bitter-sweet not performed unpleasant taste, slightly aromatic 5
Ciprofloxacin sweet almond-like taste very strong bitter taste all
the way into the throat 6 Ofloxacin bitter unpleasant, moderate
bitter almond-like taste unpleasant, almond-like taste 7
Lomefloxacin moderate to strong not performed almond-like taste,
not very unpleasant 8 Marbofloxacin bitter unpleasant moderate to
strong almond-like taste bitter unpleasant almond-like taste 9
Orbifloxacin strong unpleasant taste very strong, very unpleasant
bitter taste 10 Pefloxacin strong bitter unpleasant not performed
almond-like taste 11 Sparfloxacin slight taste strong almond-like
taste 12 Tosufloxacin mild to moderate strong almond-like
almond-like taste taste 13 Trovafloxacin very strong bitter not
done unpleasant almond-like taste, strong aftertaste
[0385] Lowering of the pH generally had the effect of enhancing the
taste properties of the solution. Gatifloxacin, gemifloxacin,
ciprofloxacin, orbifloxacin and trovafloxacin were the least
desirable in taste testing. Of the fluoroquinolones tested,
Levofloxacin was the only fluoroquinolone that was tolerable with
respect to taste, at the concentration tested. Lomefloxacin had a
moderately strong almond-like taste, and the taste was slightly
unpleasant.
[0386] In the second test, the tolerability and taste of a small
aerosol sample from a 0.5 ml aliquot of the test formulation was
determined in a single healthy human volunteer, following
nebulization in a PART eFlow nebulizer (Table 12).
TABLE-US-00012 TABLE 12 Aerosol Fluoroquinolone Tolerability and
Taste Test Fluoro- No. quinolone Aerosol Tolerability and Taste 1
Gatifloxacin moderate bitter unpleasant taste, mild cough sensation
2 Gemifloxacin strong unpleasant bitter taste, strong aftertaste,
mild cough sensation 3 Levofloxacin chemical taste, somewhat
bitter, mild cough sensation 4 Moxifloxacin moderate bitter
unpleasant taste, some cough, strong bitter aftertaste 5
Ciprofloxacin very strong, bitter unpleasant taste, immediate
coughing 6 Ofloxacin bitter chemical taste, mild cough sensation 7
Lomefloxacin chemical taste, somewhat bitter, mild cough sensation
8 Marbofloxacin too insoluble to test 9 Orbifloxacin very acidic,
strong bitter unpleasant taste, strong cough 10 Pefloxacin chemical
taste, some cough 11 Sparfloxacin too insoluble to test 12
Tosufloxacin too insoluble to test 13 Trovafloxacin bitter
unpleasant taste, no cough or cough sensation, no aftertaste
[0387] In the case of orbifloxacin, marbofloxacin and
trovafloxacin, smaller portions were tested, due to solubility
limitations. In a calibration experiment, the inhaler produced an
aerosol output of 4.1 microns VIVID, with a geometric standard
deviation (GSD) of 1.64 micron VIVID. In addition to these
measurements, the inhaler produced a fine particle dose (FPD) of
54.9% (percent of emitted dose in particles less than 5 microns).
The tolerability and taste of the drug during a very brief
administration period and for a period of 10 minutes post
administration were monitored. Tolerability parameters were of the
following types: (i) cough, cough sensation, or sneezing (ii)
irritation, burning or tightness of throat, (ii) irritation or
runniness in nasal passages or eyes, (iii) irritation, burning or
tightness of the lungs or shortness of breadth, and (iv) dizziness,
headache, nausea or other systemic effects.
[0388] Marbofloxacin, sparfloxacin and tosufloxacin were too
insoluble to evaluate in this test. For the remaining
fluoroquinolones tested, no tolerability effects were observed
during or after aerosol exposure in categories ii, iii or iv
(above). Gatifloxacin, moxifloxacin ciprofloxacin, orbifloxacin and
pefloxacin were all associated with cough. In the case of
ciprofloxacin and orbifloxacin this may have been associated with
the low-pH of the solution. Of the fluoroquinolones tested,
Levofloxacin at 10 mg/ml had the best taste characteristics.
Ofloxacin, lomefloxacin and pefloxacin had a more discernible taste
than levofloxacin, which were also acceptable during the short
course of administration.
[0389] Summary and Conclusions from the Fluoroquinolone Taste
Test
[0390] Of the thirteen flouroquinolones tested in this study,
levofloxacin had preferred physical-chemical properties for aerosol
administration and a demonstration of best acute tolerability of
the fluoroquinolones tested (Table 13). Levofloxacin is also
recognized as having one of the best antimicrobial profiles for
respiratory pathogens and has the highest in vivo efficacy,
comparable to ciprofloxacin, for treatment of Pseudomonas
aeruginosa infections.
TABLE-US-00013 TABLE 13 Overall Suitability for Nebulization
Fluoro- Overall No. quinolone Assessment Score Limitation 1
Gatifloxacin poor solubility and pH, moderately strong --
Solubility, Taste bitter aerosol taste 2 Gemifloxacin sufficient
solubility and pH, strong bitter --- Taste aerosol taste, strong
aftertaste 3 Levofloxacin excellent solubility and pH, chemical +
Taste aerosol taste, somewhat bitter 4 Moxifloxacin sufficient
solubility and pH, moderately -- Taste, strong bitter aerosol
taste, strong aftertaste Pa Activity 5 Ciprofloxacin poor
solubility and pH, very strong bitter --- Solubility, Taste aerosol
taste, coughing 6 Ofloxacin minimally acceptable solubility and pH,
-/+ Taste bitter chemical aerosol taste 7 Lomefloxacin minimally
acceptable solubility and pH, -/+ Pa Activity chemical aerosol
taste, strong liquid taste 8 Marbofloxacin very poor solubility
even at low pH, --- Solubility unable to test 9 Orbifloxacin very
poor solubility even at low pH, --- Solubility, strong bitter
unpleasant aerosol taste, Taste, Activity strong cough 10
Pefloxacin sufficient solubility and pH, aerosol -/+ Pa Activity
chemical taste, strong unpleasant liquid taste 11 Sparfloxacin very
poor solubility even at low pH, --- Solubility, unable to test Pa
Activity 12 Tosufloxacin very poor solubility even at low pH, ---
Solubility unable to test 13 Trovafloxacin moderate solubility and
pH, bitter aerosol -- Taste, taste Pa Activity
[0391] Ofloxacin, lomefloxacin and pefloxacin exhibited lower
solubility and stronger taste at 10 mg/mL than levofloxacin.
Ofloxacin is 2-fold less potent that levofloxacin, and lomefloxacin
and pefloxacin are 4-fold less potent. Higher concentrations of
these antibiotics have the preferred potency and administration
times under 15 minutes.
[0392] In a separate study, conducted in a similar manner,
norfloxacin was tested and found to have a solubility, taste and
potency profile very similar to gatifloxacin, with the exception of
significantly less activity against the gram-positive
pathogens.
[0393] Taste Testing of Aerosol Salt Formulations of Levofloxacin
and Gemifloxacin
[0394] Based on the results of the above studies, levofloxacin, and
its racemate ofloxacin, as well as gemifloxacin, and to a lesser
extent gatifloxacin and norfloxacin are amenable to aerosol
administration for pulmonary antibacterial treatment. To further
test the taste and acute tolerability (cough sensation and cough)
properties of levofloxacin and gemifloxacin, several formulations
were prepared with different organic and inorganic acids and tested
in the manner described above. Solutions were prepared by first
adding 500 mg levofloxacin to 10 ml of water or adding 500 mg of
gemifloxacin to 20 ml of saline (due to solubility limitations),
titrating the pH to .about.6.5 with HCl or organic acid, then
adjusting the osmolality of levofloxacin containing solutions to
.about.300 mOsmol/kg with sodium chloride. The formulations tested
are shown in Table 14.
TABLE-US-00014 TABLE 14 Levofloxacin and Gemifloxacin Formulations
Osmo- Conc lality Fluoro- (mg/ (mOsm/ quinolone Acid mL) pH kg)
Levofloxacin HC1 50 6.5 181 Levofloxacin Acetic 50 6.41 273
Levofloxacin Citric 50 6.45 286 Levofloxacin Lactic 50 6.42 286
Levofloxacin Ascorbic 50 6.50 278 Levofloxacin Tartaric 50 6.35 286
Gemifloxacin HC1 25 5.6 330 Gemifloxacin Citric 25 5.7 363
Gemifloxacin Ascorbic 25 5.9 347
[0395] These formulations were tested by a total of three healthy
human volunteers in the same manner as described above, at a
levofloxacin concentration of 50 mg/mL, and a gemifloxacin
concentration of 25 mg/mL, in a carefully controlled, head-to-head,
fully blinded test. Results are shown in Table 15 and 16.
TABLE-US-00015 TABLE 15 Aerosol Taste and Tolerability of
Levofloxacin Formulation at 50 mg/mL. Taster Acid 1 2 3 HC1
Moderate bitter Bitter taste, cough Bitter taste taste sensation
Acetic Acid Very acidic taste Strong acidic taste, Acidic taste,
cough sensation after taste Citric Acid Mild after taste, Mild
taste, sweet Mild after taste slightly sweet Lactic Acid Strong
bitter taste, Mild taste, after Bitter, mild aftertaste taste,
slight cough after taste Ascorbic Mild taste, slight Mild taste
Little taste or Acid acidity after-taste Tartaric Acid Very bitter,
strong Strong bitter taste, Bitter taste after taste bitter after
taste
TABLE-US-00016 TABLE 16 Taste and Tolerability of Gemofloxacin
Formulatons at 25 mg/mL. Taster Acid 1 2 3 Hydrochloric Metallic
taste, Slight bitter taste Bitter taste, Acid strong after taste
slightly metallic Citric Acid Slightly sweet Mild cough, slightly
Very mild taste, bitter no after taste Ascorbic Mild taste Cough,
mild bitter Slightly bitter, Acid after taste mild after taste
[0396] These results demonstrate that hydrochloric acid, citric
acid and ascorbic acid formulations of levofloxacin have superior
taste and tolerability compared to the acetic acid, lactic acid and
tartaric acid formulations of levofloxacin. Furthermore, these
levofloxacin formulations have superior taste and tolerability over
the equivalent gemifloxacin formulations. With respect to
gemifloxacin, the citric acid formulation had superior taste and
tolerability compared to the HCl and ascorbic acid formulations of
gemifloxacin, and with further formulation refinement, would be
amenable to aerosol administration.
[0397] Taste Testing of Additional Aerosol Levofloxacin
Formulations
[0398] To further test the taste and tolerability properties of
additional levofloxacin excipient combinations in a systematic
manner, a series of formulations were prepared and tested. The
formulations are listed in Table 17. They included sugars, salts,
sweeteners and other excipients prepared by mixing levofloxacin
with water, adding the excipients listed in Table 17, and titrating
if necessary to the desired pH with dilute HCl, Osmolality was not
optimized for these studies. However, osmolality was determined
using an Advanced Instruments Model 3250 Osmometer. This
measurement, made on 250 .mu.L of sample, relies on freezing point
depression to determine osmolality.
[0399] These formulations were tested in a total of three healthy
human volunteers in a series of tests (A-G) in the same manner as
described above, in a carefully controlled, head-to-head, fully
blinded manner. All tests were performed in a fully blinded
fashion. Results of the tests (Tables 19-25) are described below.
The following scoring system was used (Table 18).
[0400] Test A: Taste Testing of Sweeteners, Divalent Metal Salts,
and Surface Active Agents.
[0401] This test included sweeteners, calcium and magnesium salts,
and surface active agents (i.e., glycerin and PS-80). As shown in
Table 17, formulations containing the sweeteners shown are mildly
bitter and have metallic taste. The artificial sweeteners appeared
to produce a bitter taste that is distinct from the bitterness
otherwise observed. Most significantly, the formulation containing
CaCl.sub.2 had the most improved taste relative to control
(MgCl.sub.2 was not tested in this experiment) (Table 19).
[0402] Test B: Taste Testing of Mono- and Disaccharides in the
Presence of Calcium Chloride.
[0403] All of the formulzations screened in this experiment were
well tolerated and tasted better than the control sample.
Formulations containing both the calcium salt and sugar performed
better than either one alone, suggesting that these compounds
improve taste through different mechanisms. Of these formulations,
5% CaCl.sub.2+7.5% glucose performed best. Note that the lactose is
present at a lower concentration than the other sugars (Table
20).
TABLE-US-00017 TABLE 17 Levofloxacin Formulations Containing
Various Excipients Osmo- Conc lality Fluoro- (mg/ (mOsm/ quinolone
mL) Excipients pH kg) Levofloxacin 50 Control A (0.225% NaC1) 6.50
180 Levofloxacin 50 Aspartame (0.1%) 6.49 175 Levofloxacin 50
Sucrulose (0.1%) 6.49 178 Levofloxacin 50 Glucose (5%) 6.5 380
Levofloxacin 50 Sucrose (7.5%); NaCl (0.225%) 6.51 329 Levofloxacin
50 Glycerin (5%) 6.48 880 Levofloxacin 50 PS-80 (0.1%) 6.51 189
Levofloxacin 50 CaCl.sub.2 (5%) 6.10 784 Levofloxacin 50 MgSO.sub.4
(5%) 6.41 73 Levofloxacin 50 Control - B-E (0.225% NaC1) 6.51 182
Levofloxacin 50 CaCl.sub.2 (5%) 6.1 735 Levofloxacin 50 CaCl.sub.2
(5%), Sucrose (7.5%) 6.10 958 Levofloxacin 50 CaCl.sub.2 (5%),
Glucose (7.5%) 6.10 1174 Levofloxacin 50 CaCl.sub.2 (5%), Glucose
(7.5%) 5.25 1246 Levofloxacin 50 CaCl.sub.2 (5%), Lactose (5%) 6.07
864 Levofloxacin 50 MgCl.sub.2 (5%) 5.90 600 Levofloxacin 50
MgCl.sub.2 (5%), Sucrose (7.5%) 5.98 815 Levofloxacin 50 MgCl.sub.2
(5%), Glucose (7.5%) 5.98 999 Levofloxacin 50 MgCl.sub.2 (5%),
Glucose (7.5%) 5.04 1035 Levofloxacin 50 MgCl.sub.2(5%), Lactose
(5%) 5.96 697 Levofloxacin 50 MgSO.sub.4(5%), Sucrose (7.5%) 6.20
433 Levofloxacin 50 MgSO.sub.4(5%), Glucose (7.5%) 6.21 625
Levofloxacin 50 MgSO.sub.4(5%), Glucose (7.5%) 5.40 660
Levofloxacin 50 MgSO.sub.4(5%), Lactose (5%) 6.18 387 Levofloxacin
50 Control F- G (0.45% NaC1) 6.5 221 Levofloxacin 50 Glucose (5%)
6.5 376 Levofloxacin 50 Sucrose (5%) 6.5 240 Levofloxacin 50
Lactose (5%) 6.62 241 Levofloxacin 50 Lactose (2.5%) 6.55 170
Levofloxacin 50 CaCl.sub.2 (5%) 6.10 735 Levofloxacin 50 CaCl.sub.2
(5%), Lactose (5%) 6.21 1037 Levofloxacin 50 CaCl.sub.2 (2.5%),
Lactose (5%) 6.36 565 Levofloxacin 50 CaCl.sub.2 (2.5%), Lactose
(2.5%) 6.41 370 Levofloxacin 50 CaCl.sub.2 (1.25%), Lactose (2.5%)
6.64 227 Levofloxacin 50 CaCl.sub.2 (0.625%), Lactose (2.5%) 6.06
163
TABLE-US-00018 TABLE 18 Taste Test Scoring System. Score Taste
Tolerability 1 Comparable to saline No cough sensation, no cough
1.25 Slightly more taste than saline Slight cough sensation, no
cough 1.5 Mild bitter/metallic taste Cough sensation, slight cough
1.75 Between 1.5 and 2 -- 2 Moderate bitter/metallic taste Cough
sensation, moderate cough 2.25 Between 2 and 2.5 -- 2.5 Strong
bitter/metallic taste -- 2.75 Between 2.5 and 3 -- 3 Very strong
bitter/metallic taste Cough sensation and strong cough 4 Very
strong bitter/metallic taste Cough sensation, strong cough and
other unacceptable taste and other irritation
TABLE-US-00019 TABLE 19 Taste and Tolerability of Levofloxacin
Formulations Containing Sweetners, Divalent Metal Salts, and
Surface Active Agents Taster 1 2 3 Median Excipients Taste Tol.
Taste Tol. Taste Tol. Taste Tol. Aspartame (0.1%) 2 1.25 2 1 2 1 2
1 Sucrulose (0.1%) 2 1 1.75 1 2 1 2 1 Sucrose (7.5%); NaCl (0.225%)
2 1 2.25 1 2 1 2 1 Glucose (5%) 1.5 2 2.5 1 2 1 2 1 Glycerin (5%)
2.25 1 2.25 1 2.5 1 2.3 1 PS-80 (0.1%) 1.75 1 2.25 1 2.5 1 2.3 1
CaCl.sub.2 (5%) 1.25 1 1.5 1.5 2 1 1.5 1 MgS0.sub.4 (5%) 1.5 1.5
2.5 2.5 2.5 1 2.5 1.5 Control-A (0.225% NaCl) 3 1 3 1 2.5 1 3 1
TABLE-US-00020 TABLE 20 Taste and Tolerability of Levofloxacin
CaCl.sub.2 Formualations Taster 1 2 3 Median Excipients Taste Tol.
Taste Tol. Taste Tol. Taste Tol. CaCl.sub.2 (5%) 1.75 1 2 1 2.75 1
2 1 Sucrose (5%) 2 1 2 1 2 1 2 1 CaCl2 (5%).sub.2, Sucrose (7.5%)
1.75 1 1.75 1 1.5 1 1.8 1 CaCl.sub.2(5%), Glucose (7.5%) 1.5 1 1.5
1 2 1 1.5 1 CaCl.sub.2(5%), Lactose (5%) 1 1 1.75 1 2 1 1.8 1
Control B-E (0.225% NaCl) 3 1 2.5 1 3 1 3 1
[0404] Test C: Taste Testing of Mono- and Disaccharides in the
Presence of Magnesium Chloride.
[0405] As above, all of the formulations screened in this
experiment were well tolerated and tasted better than the control
sample. Formulations containing both the magnesium salt and lactose
appeared to perform slightly better than either one alone. This
experiment confirms that combining divalent metal salts and simple
sugars are effective at improving taste (Table 21).
TABLE-US-00021 TABLE 21 Taste and Tolerability of Levofloxacin
MgCl.sub.2 Formulations Taster 1 2 3 Median Excipients Taste Tol.
Taste Tol. Taste Tol. Taste Tol. MgCl.sub.2 (5%) 1.5 1 -- -- 1.75 1
1.6 1 MgCl.sub.2 (5%), Sucrose (7.5%) 1.5 1 1.75 1 2 1 1.8 1
MgCl.sub.2(5%), Glucose (7.5%) 1.25 1 2.25 1 2 1 2 1 MgCl.sub.2
(5%), Lactose (5%) 1 1 1.5 1 1.5 1 1.5 1 Control B-E (0.225% NaC1)
2.25 1 -- -- 2.75 1 2.5 1
[0406] Test D: Taste Testing of Mono- and Disaccharides in the
Presence of Magnesium Sulfate.
[0407] As with calcium and magnesium chloride, formulations
containing magnesium sulfate and glucose, sucrose or lactose tasted
better than the control sample. This experiment reconfirms that
combining divalent metal salts and simple sugars improve taste
(Table 22).
TABLE-US-00022 TABLE 22 Taste and Tolerability of Levofloxacin
MgSO.sub.4 Formulations Taster 1 2 3 Median Excipients Taste Tol.
Taste Tol. Taste Tol. Taste Tol. MgSO.sub.4, Sucrose 1.5 2 1.5 1.25
1.5 1 1.5 1.3 MgSO.sub.4, Glucose 1.5 2.75 2 2.5 1.5 1.5 1.5 2.5
MgSO.sub.4, Lactose 1.25 2.25 1.75 1.25 1.75 1 1.8 1.3 Control B-E
(0.225% NaC1) 2.25 1 -- -- 3 1 2.6 1
[0408] Test E: Taste Testing of Divalent Metal Salts in the
Presence of Glucose at Low and High pH.
[0409] In this experiment, the effect of glucose in combination
with each of the three divalent cation salts on taste and
tolerability was tested at low (.ltoreq.5.5) and high (.gtoreq.6.0)
pH. Small but consistent improvements in taste were observed at the
higher pH (Table 23).
TABLE-US-00023 TABLE 23 Taste and Tolerability of Levofloxacin
CaCl2 Formulations at Low Versus High pH Taster 1 2 3 Median
Excipients Taste Tol. Taste Tol. Taste Tol. Taste Tol. CaCl.sub.2
(5%), Glucose (7.5%), pH6.1 1 1 1.5 1 2 1 1.5 1 CaCl.sub.2 (5%),
Glucose (7.5%), pH 5.5 1.25 1 1.75 1 2.5 1 1.8 1 MgCl.sub.2 (5%),
Glucose (7.5%), pH 6.0 1.25 1 2 1 2 1 2 1 MgCl.sub.2 (5%), Glucose
(7.5%), pH 5.0 1.75 1 1.75 1 1.5 1 1.8 1 MgSO.sub.4 (5%), Glucose
(7.5%), pH 6.2 1.25 2.25 2.25 1.75 1.5 1 1.5 1.8 MgSO.sub.4 (5%),
Glucose (7.5%), pH 5.4 1.5 1.75 1.75 1.5 2 1 1.8 1.5 Control B-E
(0.225% NaC1) 2 1 -- --
[0410] Test F. Taste Testing of Mono- and Disaccharides.
[0411] All of the formulations screened in this experiment were
well tolerated and tasted better than the control sample. All three
sugars at 5% were better than the control, lactose at 2.5% tasted
better than the control, but not as good as at 5%. This experiment
reconfirms that simple sugars improve taste (Table 24).
TABLE-US-00024 TABLE 24 Taste and Tolerability of Levofloxacin
Sugar Formulations Taster 1 3 Median Excipients Taste Tol. Taste
Tol. Taste Tol. Glucose (5%) 1.5 1.5 2 1 1.8 1.3 Sucrose (5%) 1.5
1.5 1.5 1 1.5 1.3 Lactose (5%) 1.75 1.25 2 1 1.9 1.1 Lactose (2.5%)
2.25 1.5 2 1 2.1 1.3 Control F-G (0.45% NaC1) 2.5 1 2.5 1 2.5 1
[0412] Test G. Taste and Tolerability of Levofloxacin CaCl2
Formulations in the Presence of Lactose.
[0413] In this experiment, levofloxacin was formulated with varying
concentrations of calcium chloride and lactose (Table 25). As noted
through this series of experiments, all formulations containing
divalent metal salts and sugar were improved with respect to taste
and tolerability relative to the control formulation. Most
importantly, 5% calcium chloride or 2.5% calcium chloride in the
presence of 5% lactose were most effective at decreasing
levofloxacin bitterness. Further decreases in the concentration of
these excipients were less effective.
TABLE-US-00025 TABLE 25 Taste and Tolerability of Levofloxacin
CaCl2 Formulations in the Presence of Lactose Taster 1 3 Median
Excipients Taste Tol. Taste Tol. Taste Tol. CaCl.sub.2 (5%) 1.25 1
1.5 1 1.4 1 CaCl.sub.2 (5%), Lactose (5%) 1.25 1 2 1 1.6 1
CaCl.sub.2 (2.5%), Lactose (5%) 1.25 1 2 1 1.6 1 CaCl.sub.2 (2.5%),
Lactose (2.5%) 1.5 1 2.5 1 2 1 CaCl.sub.2 (1.25%), Lactose 1.75 1 2
1 1.9 1 (2.5%) CaCl.sub.2 (0.625%), Lactose 1.75 1.25 2 1 1.9 1.1
(2.5%) Control F-G (0.45% NaC1) 3 1 2.5 1 2.8 1
Example 3
Aerosol Levofloxacin Characterization in PARI LC Plus Jet
Nebulizer
[0414] The following studies describe the potential for aerosolized
delivery of levofloxacin to be administered to a patient via a jet
nebulizer. To accomplish this task, a simple levofloxacin
formulation was prepared and the aerosol was characterized in a jet
nebulizer. The results of these studies are shown in the summary
below.
[0415] Levofloxacin inhalation solution (55 mg/ml) was evaluated
using a PART LC Plus Air Jet Nebulizer with ProNeb Compressor. The
emitted dose, particle size distribution and fine particle fraction
were measured by cascade impaction using a Marple Miller Impactor.
The above-mentioned parameters were used for evaluating the in
vitro performance of aerosolized medications.
[0416] Marple Miller Study
[0417] Objective.
[0418] To determine the particle size distribution and estimate the
amount of drug that a patient is likely to inhale (respirable
fraction). A secondary objective was to estimate emitted dose,
which is the amount of levofloxacin that exited the nebulizer.
[0419] Methods.
[0420] Formulation: 55 mg/ml levofloxacin, 120 mM chloride, 70 mM
sodium, pH 6.7. Formulation established from maximum solubility
permitting a 300 mg dosage in 6 ml and neutral pH. 5.5 ml of
levofloxacin formulation was added to a PART LC Plus Air-Jet
Nebulizer with ProNeb Compressor. The nebulizer cup contained a
total of 302 mg of levofloxacin. The nebulizer was connected inline
with a Marple Miller Impactor (MMI), which was run with an airflow
rate of 60 l/min. Each nebulizer (n=2) was run to dryness (no
aerosol produced as judged by visual inspection for 15 minutes.
Following aerosolization, the MMI was disassembled and levofloxacin
was quantitatively extracted with mobile phase (90/10 ACN:water)
from the USP entry port, each of the impactor collection cups
(stages) and the glass fiber filter. Any remaining formulation in
the nebulizer after aerosolization (cup and mouthpiece) was also
quantified.
[0421] Results
[0422] As shown in Table 26, the total average amount recovered
from the MMI experiments was 170.2 mg. The expected recovery was
302 mg. This represents a total recovery of .about.57%, which does
not meet the generally accepted specifications for impaction-based
studies (85%-115% total recovery). This difference was found to be
due to non-specific adherence of levofloxacin to the LC Plus
nebulizer device. The average percent of drug exiting the nebulizer
in fine particles was .about.72%. Thus, the respirable emitted dose
was 89.7 mg. Assuming that .about.50% is not inhaled during normal
tidal breathing, a total of -40 mg may be deposited in the lung
with this 300 mg dose. However, given the slow administration time
with this device, competition with pulmonary clearance would likely
prevent the accumulation of sufficient levofloxacin to meet the
required minimal concentration for "rapid administration, high
concentration" dosing needed for maximum fluoroquinolone
antimicrobial activity and resistance prevention.
TABLE-US-00026 TABLE 26 Marple Miller Impactor Data Set B A + B
Percent of Total A Amount of Drug Amount Drug Exiting Emitted A
Remaining in of Drug Nebulizer in Fine Dose Nebulizer Cup Recovered
Particle Fraction Sample ID (mg) (mg) (mg) (% < 5 um) Levo
134.70 45.00 179.70 73.5 Run 1 Levo 114.40 46.30 160.70 70.4 Run 2
Average 124.6 45.7 170.2 72.0
Example 4
Animal Models and Evaluation of Fluoroquinolones and
Fluoroquinolone Formulations
[0423] Pharmocokinetic Model
[0424] Six rats per study are given a single slow bolus intravenous
dose of 10 mg/kg via the lateral tail vein or are given a single
microspray aerosol dose of 10 mg/kg using a microspray aerosol
generation device (PennCentury, Philadelphia, Pa.). Blood samples
are taken at various times over 3 hours to determine the plasma
pharmacokinetic parameters. Two rats are sacrificed at 0.5, 1.5 and
3 hours after dosing to determine lung, broncheoalveolar lavage
(BAL), and epithelial lining fluid (ELF) levels. The plasma and
tissue concentrations are determined by an HPLC method and the data
are then fit using WinNonlin. Data are shown in Table 27.
TABLE-US-00027 TABLE 27 Pharmacokinetic Modeling ELF Dose Serum AUC
F, % from Drug Route (mg/kg) AUC (0-inf) Serum t1/2 (0.5-3 h) Lung
vs. IV Levofloxacin IV 10 3.8 0.5 10.5 NA Levofloxacin IT 10 3.28
0.4 12.07 86% Ciprofloxacin IV 10 2.56 0.53 ND NA Ciprofloxacin IT
3.3 0.8 0.93 194 82% Clinafloxacin IT 10 3.2 0.74 30.8 Gatifloxacin
IV 10 5.31 1.06 5.32 Gatifloxacin IT 10 5.83 1.13 54.7 100%
Norfloxacin IV 10 4.65 1.21 3.27 Norfloxacin IT 10 4.46 1.13 41.7
100% Gemifloxacin IV 8 4.54 1.04 3.72 Gemifloxacin IT 10 5.86 1.68
536.5 86% Tobramycin IV 10 15.7 0.5 27.6 NA Tobramycin IT 10 13.82
1.0 5152.0 81%
[0425] Efficacy Model
[0426] P. aeruginosa strain PAM 1723 is grown in Mueller-Hinton
Broth (MHB) at 35.degree. C. under constant aeration, after 16
hours, the inoculum is sub-cultured into fresh MHB and allowed to
regrow at 35.degree. C., under constant aeration, for 4 hours. The
inoculum is adjusted to ca. 5.times.10.sup.6 CFU/ml by correlation
of absorbance at 600 nm with predetermined plate counts. Male CFW
mice (4-6 weeks old, N=4/group) are made neutropenic by the
intraperitoneal injection of 150 mg/kg cyclophosphamide (Cytoxan,
Mead Johnson, Princeton, N.J.) on days 1 and 4. On day 5, mice are
infected by an intratracheal instillation of 0.05 ml of inoculum
while under isoflurane anesthesia (5% isoflurane in oxygen running
at 4 L/min). Two hours after infection, mice are given either
intraperitoneal or intratracheal doses of each fluoroquinolone at a
dose of 25 mg/kg. Mice are sacrificed 1 and 4 hours after
treatment, their lungs removed, homogenized and plated to determine
colony counts. Data are shown in Table 28.
TABLE-US-00028 TABLE 28 Efficacy Modeling Dose DeltaLOG DeltaLOG
Drug Route.sup.a (mg/kg) CPU 1 hr.sup.b CPU 4 hr.sup.b Levofloxacin
IP 25 -1.00 -0.52 Levofloxacin IT 25 -1.97 -1.28 Gemifloxacin IP 25
-0.28 -0.32 Gemifloxacin IT 25 -2.45 -1.81 Levofloxacin IP 25 -1.40
-1.14 Levofloxacin IT 25 -2.48 -1.45 Gemifloxacin IP 25 -0.74 -0.71
Gemifloxacin IT 25 -3.20 -2.28 Clinafloxacin IP 25 -1.32 -1.33
Clinafloxacin IT 25 -2.86 -2.47 Tobramycin IP 5 -0.70 0.29
Tobramycin IT 5 -1.59 -0.94 Ciprofloxacin IP 25 -1.59 -0.41
Ciprofloxacin IT 25 -2.32 -1.45 Gatifloxacin IP 25 -0.34 -0.02
Gatifloxacin IT 25 -1.48 -2.11 Clinafloxacin IP 10 -0.96 -1.39
Clinafloxacin IT 10 -2.71 -2.40 Sparfloxacin IP 25 -0.85 0.09
Sparfloxacin IT 25 -1.56 -0.81 Tosufloxacin IP 25 0.00 1.33
Tosufloxacin IT 25 -0.48 -0.24 .sup.aRoute of drug administration
.sup.bTime post-drug administration
[0427] In rat pharmacokinetic studies, aerosol administration of
fluoroquinolones results in increased ELF AUCs from 0.5-3 hours for
all fluoroquinolones tested, as well as tobramycin, suggesting that
the aerosol route of administration will produce increased efficacy
against lung infections.
[0428] In a mouse lung infection model, the increased efficacy,
suggested by the pharmacokinetic studies rats, was confirmed. For
all fluoroquinolones tested, the aerosol route of administration
(intratracheal, or IT), produced larger reductions in bacterial
counts than the intraperitoneal (IP) route of administration,
suggesting that observed increased efficacy was due to high local
concentrations produced by direct aerosol administration.
Example 5
Aerosol Levofloxacin Characterization in the PART eFlow
Nebulizer
[0429] Laser Particle Sizing
[0430] Device performance was characterized by measuring the size
of the particles emitted. By non-limiting example, particle sizing
of emitted aerosol of Levofloxacin solution may be conducted with a
Malvern Spraytec particle sizer under the following conditions.
Ambient conditions are controlled to maintain a room temperature of
between 23.0.degree. C. and 24.0.degree. C. and relative humidity
of 42% to 45%. Levofloxacin at 25 mg/ml was loaded into 2 PART
eFlow Nebulizers fitted with the "40" nebulizing heads. Software
for the Malvern Spraytec particle sizer is programmed to calculate
the following information. A) Volume Mean Diameter (VIVID), the
volume mean of the particles passing across the beam of the laser.
B) Geometric Standard Deviation (GSD), diameter 84.sup.th
percentile/diameter 50.sup.th percentile. C) % of particles
.ltoreq.5 microns, the percent of the number of particles less than
5 microns or % of particle >1 micron and <7 microns, the
percent of the number of particles between 1 and 7 microns.
[0431] The device was loaded with 2 ml Levofloxacin at 25 mg/ml.
The mouthpiece of the device was positioned with the tip of the
mouthpiece 2 cm from the center of the beam on the x axis and as
close to the optical lens of the laser as possible on the y axis.
Ambient conditioned, bias flow was provided through the nebulizer
in an amount to obtain a total nebulizer flow of 20 LPM. Ambient
conditioned, bias flow was provided through the nebulizer in an
amount to obtain a total nebulizer flow of 20 LPM. The nebulizer
was turned on and allowed to run continuously for 1 minute prior to
measuring. The measurement sequence was begun after 1 minute and
measurements are made continuously for 1 minute in 1 second
intervals. At the end of the measurement phase, these 60 records
are averaged for VIVID, GSD and %.ltoreq.5 micron and %>1 and
<7 micron. Finally, the nebulizer was weighed for determination
of output rate.
[0432] Breath Simulation Studies
[0433] Device performance was measured under conditions similar to
natural inhalation by using a breath simulator PART Compas breath
Simulator programmed to use the European Standard pattern of 15
breaths per minute with an inspiration to expiration ratio of 1:1.
Such measurements was performed under ambient conditions that can
be controlled to maintain a room temperature of between
23.0.degree. C. and 24.0.degree. C. and relative humidity of 42% to
45%. For this experiment, the PART eFlow device was loaded with 4
ml Levofloxacin solution at 25 mg/ml.
[0434] Breathing simulation was commenced, and the nebulizers
begun. The devices were allowed to run continuously until
nebulization ceases. The duration is timed from the beginning of
nebulization. Following nebulization, the inspiratory and
expiratory filters were individually washed in a known amount of
solvent (dH.sub.2O). The nebulizer cup is also washed individually.
For quantitation, the individual washings were assayed via
spectrophotometry at a wavelength of 290 nanometers and the
resultant concentration converted to content. Using this
quantitative data, the following analysis was made. A) Inspired
dose (ID), the total amount of drug assayed from the inspiratory
filter. B) Residual dose (RD), the amount of drug assayed from the
nebulizer at the end of nebulization. C) Fine Particle Dose (FPD),
the ID multiplied by the respirable fraction (for example, %
particles .ltoreq.5 microns VIVID depending on the method used to
determine the size of the particles emitted from the selected
device). D) Duration, time from the beginning to the end of
nebulization. E) Respirable Delivered Dose (RDD), % ID that is, for
example, .ltoreq.5 microns VIVID.
[0435] The results in Table 29 indicate that a 100 mg dose of
levofloxacin likely deposits .about.34 mg fluoroquinolone in the
pulmonary compartment in .about.4 min using the PART eFlow device
(Table 29) compared to the 300 mg dose from the PAR LC Plus device
delivering an equivalent dose in >15 min. From the "rapid
administration, high concentration" dosing and delivery model
described herein, while the 15 min delivery time from the LC Plus
will likely fail, a 4 min administration time fo 35-40 mg
levofloxacin may meet the criteria for maximum fluoroquinolone
activity. However, increasing the drug concentration to enable more
rapid administration (e.g. 50 mg/ml in a 2 ml dosing delivering
35-40 mg levofloxacin in .about.2 min) will more likely meet these
minimal requirements. Moreover, shorter administration times will
improve patient dosing compliance. In addition, it should be noted
that hypotonic solutions of levofloxacin at concentrations greatere
than 10 mg/ml are poorly tolerated for inhalation.
TABLE-US-00029 TABLE 29 Levofloxacin Aerosol Properties (100 mg
Loading Dose) Duration Residual Inspired FPD (%) RDD (mg) VMD GSD
Osmo (minutes) Dose Dose .ltoreq.5u 1-7u .ltoreq.5u 1-7u um um
mOs/kg 3.9 .+-. 0.1 24.8 .+-. 3.4 61.1 .+-. 1.6 54.9 73.8 33.5 45.1
4.7 1.6 67 .+-. 1.0
Example 6
Tolerability of Aerosol Levofloxacin in a Healthy Human Subject
[0436] Methods
[0437] In a single subject, healthy volunteer the feasibility of
delivering levofloxacin as an aerosol was established using either
an Aerogen Clinical vibrating mesh device creating a 3.4 micron
volumetric mean diameter (VIVID) particle, or .about.2 micron MMAD
(hereinafter "Aerogen Small"), or using a PARI eFlow nebulizer
producing a .about.4.7 micron VIVID particle (hereinafter "PARI
Large"). Levofloxacin was tested at a concentration of 4.25 mg/mL
or 18.75 mg/mL at doses of 10 mg, 35 mg and 55 mg, in isotonic
solution.
[0438] Results
[0439] In the first test, 6 mL of the 4.25 mg/mL solution was
inhaled using the Aerogen Small nebulizer. The estimated RDD based
on separate in vitro device characterization studies using breath
simulation was estimated to be 10 mg. Delivery time was 22 minutes.
No discernable adverse effects were observed in the throat, airway
or lungs, during or after administration, including cough sensation
or cough, and there was only a slight chemical taste during and
after administration. No adverse effects or taste were observed
over a 30 minute monitoring period following drug administration.
At this low concentration and dose, and slow rate of
administration, levofloxacin was well tolerated.
[0440] In the second test, 4 ml of the 18.75 mg/mL solution was
inhaled using the Aerogen Small nebulizer. The estimated RDD based
on separate in vitro device characterization studies using a breath
simulator was 35 mg. Delivery time for administration of the drug
was 14 minutes. Despite the increased dose, the acute tolerability
was very comparable to the first test both during and after
administration. The taste, which was stronger, was the solution had
a more the bitter/metallic chemical taste characteristic of
levofloxacin. The taste was most discernible for a period of a few
minutes after the end of administration, again a characteristic of
levofloxacin.
[0441] In the third test, 4 mL of the 18.75 mg/mL solution was
inhaled using the PARI Large device. The estimated RDD based on
separate in vitro device characterization studies was .about.55 mg
(using the <5 microns FPD definition). Delivery time for
administration of the drug was .about.5 minutes. Despite the
significantly increased particle size and delivery rate for drug
compared to test 2, no adverse effects in the throat, airway or
lungs, other than the acute effects of taste noted above, were
experienced, including cough sensation or coughing, throughout the
dosing period and for a 30 minute observation period following
delivery of the dose. Urinary recovery of the drug, which is an
accurate measure of exposure, confirms that the projected
respirable dose of approximately 55 mg was successfully
delivered.
[0442] These results demonstrate the feasibility of aerosol
delivery of levofloxacin in a human subject at the intermediate
concentrations tested, and suggest that higher concentrations and
doses, properly formulated for tolerability and taste are
achievable.
Example 7
Levofloxacin Micronization
[0443] Dry powder levofloxacin base may be micronized for high
local concentration exposure therapy, taste-masking or AUC
shape-enhanced delivery of levofloxacin using dry powder pulmonary
administration. Other approaches currently being investigated
include spray-dry and in situ micronization techniques. This
approach may also be used with other fluoroquinolone antibiotics
including, without limitation ofloxacin, lomefloxacin, pefloxacin,
ciprofloxacin, gatifloxacin, gemifloxacin, moxifloxacin,
tosufloxacin, pazufloxacin, rufloxacin, fleroxacin, balofloxacin,
sparfloxacin, trovafloxacin, enoxacin, norfloxacin, clinafloxacin,
grepafloxacin, sitafloxacin, marbofloxacin, orbifloxacin,
sarafloxacin, danofloxacin, difloxacin, enrofloxacin, garenoxacin,
prulifloxacin, olamufloxacin, DX-619, TG-873870 and DW-276.
[0444] Description
[0445] To characterize the feasibility of micronizing levofloxacin
base, the following studies were performed.
[0446] Micronization
[0447] Levofloxacin drug powder was micronized using a jet mill.
Following micronization the drug powder was collected in two
fractions, one between 5-6 micron and a finer fraction.
[0448] Powder Characterization
[0449] The drug was characterized for particle size and particle
size distribution, before and after milling using laser diffraction
technology. Any changes in the physical form of the drug were
evaluated by Differential Scanning calorimetery (DSC) and X-Ray
diffraction ( )M)). Particle morphology was studied using Scanning
Electron Microscopy (SEM). The equilibrium moisture content of the
drug powder before and after micronization was determined by
Thermogravimetric Analysis (TGA) or Karl Fischer. Any degradation
of the drug substance during micronization was evaluated by HPLC.
The separation conditions were used to determine if any new peaks
are formed after micronization.
[0450] Micronization
[0451] Experimental Methodology
[0452] Two batches of Levofloxacin were micronized using a jet mill
(Glen Mills). Method development was performed to determine the
micronization pressure required to achieve the required size
fractions between a) 5-6 micron and b) 2-3 micron. The particle
size of levofloxacin was determined by Sympatec HELOS laser
diffraction particle size analyzer.
[0453] Results
[0454] FIG. 12 shows the plot of mean particle diameter (X50) Vs
micronization pressure. The first batch of Levofloxacin showed a
mean particle diameter of 10.6 micron before micronization. From
the plot it is seen that particle size decreased as the
micronization pressure increased. A pressure of about 120 psi was
required to achieve a size of 2.5 micron. With the second batch of
levofloxacin, having a mean particle size of 12.99 micron before
micronization, a pressure of 30 psi was required to achieve a
particle size of 5.2 micron.
[0455] Powder Characterization
[0456] Differential Scanning calorimetry
[0457] Experimental Methodology
[0458] Differential Scanning calorimetry of pre-micronized as well
as micronized levofloxacin (mean particle size 2.5 micron) was
performed using TA Instrument DSC Q1000. 1-2 mg of each sample was
weighed into pan, sealed and heated at 10.degree. C./min from
25.degree. C. to 300.degree. C. under nitrogen.
[0459] Results
[0460] The DSC profiles of the pre-micronized and micronized
levofloxacin are shown as FIGS. 13A and 13B. There was no
difference in the DSC profiles of micronized compared to
pre-micronized levofloxacin.
[0461] Experimental Methodology
[0462] The powders (micronized and pre-micronized) were adhered to
double-sided carbon tabs on aluminum stubs, which were then coated
with gold-palladium. Photomicrographs were taken of several
different areas of the powder on the stub using a Scanning electron
microscope.
[0463] Results
[0464] Representative Scanning electron micrographs of the
pre-micronized and micronized levofloxacin are shown in FIGS. 14A
and 14B. Crystals of levofloxacin are plate like before
micronization. This shape is retained after micronization.
[0465] Experimental Methodology
[0466] A thin layer of powder sample was mounted on a zero
background plate in an XRD sample holder. Each sample was analyzed
using a Scintag XDS 2000 Diffractometer under the following
conditions: Excitation source: Copper K a X-rays; Scan rate:
1.degree. per minute; Voltage: 40 KV; Curent: 35 mA.
[0467] Results
[0468] The X-ray diffraction plots of pre-micronized and micronized
Levofloxacin are shown as FIGS. 15A and 15B. Intensity of
diffracted peak at 9.degree. is reduced after micronization. These
results are in accordance to those reported in the literature for
micronization of olanzapine (Stephenson G. A. The Rigaku Journal,
22 (2005): 2-15). The reduction in the relative intensities of the
diffracted peaks might be due to formation of new faces to a
crystal. The most developed face after micronization would be the
one for which the intensity is maximally reduced.
[0469] Experimental Methodology
[0470] 15-25 mg of micronized and pre-micronized levofloxacin
samples were dissolved in methanol (having predetermined moisture
content) and the moisture content in the samples were determined by
Aquastar 3000 Coulometric Karl Fisher Titrator.
[0471] Results
[0472] The results of Karl Fisher analysis are shown in Table
30.
TABLE-US-00030 TABLE 30 Moisture Content of Pre- and
Post-Micronized Levofloxacin Moisture content (%) Pre- micronized
6.16 Post- micronized 5.42
Example 8
Preformulation of Levofloxacin Base
[0473] The goal of this study was to characterize levofloxacin base
to understand the physico-chemical capabilities and restrictions of
levofloxacin base for various formulation approaches. The purpose
of this study was to characterize the physicochemical properties of
levofloxacin base.
[0474] Preformulation
[0475] pH-Solubility Studies
[0476] The solubility of levofloxacin was determined as a function
of pH. Buffers were first prepared in the pH range 2-10. Small
aliquots of each buffer (.about.200-250 .mu.L) were saturated with
drug and agitated to achieve equilibrium solubility. The samples
were then becentrifuged and the supernatant analyzed for dissolved
drug by UV or HPLC. The buffers used in this study were shown to
affect the solubility result (because different buffer counter-ions
can form different levo salt forms in solution). Hence,
pH-solubility will also be assessed in the absence of buffers (via
titration).
[0477] pKa Determination
[0478] The pKa of levofloxacin was determined by titrimetry.
Obtained pKa values were confirmed by UV spectrophotometry. This
information was used to aid in salt selection for levofloxacin and
to determine the charge on levofloxacin under the pH conditions in
the lung.
[0479] Preformulation for Liquid System
[0480] The feasibility of a liquid formulation was investigated
using (a) solubility and (b) surface tension as baseline parameters
for formulation in saline alone.
[0481] Preformulation Studies on Levofloxacin
[0482] HPLC Method Transfer
[0483] Experimental Methodology
[0484] A HPLC method was used to evaluate the linearity, accuracy
and precision of the levofloxacin assay. The column used was a
50.times.4.6 mm, Onyx Monolithic C18 (Phenomenex) at 30o C. The
mobile phase consisted of 85% of 0.1% TFA in water and 15% 0.1% TFA
acetonitrile. The flow rate was adjusted to 3 ml/min. Samples were
injected into the chromatographic system and the effluent monitored
at 277 nm.
[0485] Results
[0486] The retention time for levofloxacin was approximately 0.82
min. The assay was found to be linear over a range of 5-15
.mu.g/ml, with a correlation coefficient of 1.000. RSD (relative
standard deviation) was less than 0.5% and accuracy was within
98-102%.
[0487] pH-Solubility Studies
[0488] By Titration
[0489] Experimental Methodology
[0490] A saturated solution of levofloxacin in 0.1 N HCl was
titrated with NaOH. After each addition of the base, the solution
was shaken by vortexing. An aliquot of the sample solution was
removed, centrifuged and the supernatant analyzed by UV
spectroscopy at 288 nm. The same solution was back titrated with
HCl.
[0491] Results
[0492] The pH-solubility profile of levofloxacin is shown in FIG.
16. By titrimetery levofloxacin exhibited a solubility of 25.4
mg/ml at pH 7.3. However contrary to the results of the shaking
experiments, the solubility by titrimetry decreased below pH 6.5
which can be attributed to the common ion effect. Since a solution
of levofloxacin was prepared in HCl, a hydrochloride salt of
levofloxacin would have formed in solution. Further addition of
chloride ions in the form of hydrochloric acid would suppress the
solubility of the hydrochloride salt.
[0493] pKa Determination
[0494] By Titrimetery
[0495] Experimental Methodology
[0496] A solution of levofloxacin (18 mg/g) was prepared in water
(18.45 mg/g). The initial pH of the solution was 7.36. This
solution was titrated with 1 N HCl. Measured aliquots of HCl were
added and the pH recorded after each addition. Titration was
continued till a pH of 1.
[0497] In order to determine the acidic pKa, a solution of
levofloxacin (18.38 mg/g) was prepared in 0.1 N HCl. The initial pH
of the solution was 1.32. The solution was titrated with I N NaOH.
Titration was continued till a pH of 6.55.
[0498] Results
[0499] FIG. 17 shows a plot of pH Vs volume of titrant added for
the titration of levofloxacin with HCL. This data was fit into the
following equation: V.sub.t [OH]=K.sub.b. V.sub.ep K.sub.b.
V.sub.t, where V.sub.t=Volume of titrant added; V.sub.ep volume of
titrant added till the equivalance point; [OH.sup.-]=hydroxide ion
concentration=Kw/[H.sup.+]; [H.sup.+]=hydronium ion
concentration=10.sup.-pH.
[0500] A plot of V.sub.t [OH.sup.-] Vs V.sub.t gave a straight line
(FIG. 18). Data shown is from the pre-equivalence point region.
From the slope we get: Slope: K.sub.b=2.09.times.10.sup.-8;
pK.sub.b=-log K.sub.b=7.7; pK.sub.a 14-pK.sub.b=6.3.
[0501] FIG. 19 shows a plot of pH Vs volume of titrant added for
the titration of levofloxacin with NaOH. Acidic pKa was difficult
to calculate because it was quite low (<2.0). However, a rough
approximation of pKa can be made as the pH at half the equivalence
point. From the plot dpH/dV vs volume of titrant (V.sub.t) (FIG.
20), the equivalence point is at 250 IA. The pH at half the
equivalence point (i.e. when V.sub.t=125 .mu.l) is 1.6. So the
acidic pKa .about.1.6.
[0502] By UV Spectroscopy
[0503] Experimental Methodology
[0504] Dilute solutions of levofloxacin (0.013 mg/ml) were prepared
in several buffers. The buffers used were HCL (pH 1,2), acetate (pH
4,5), phosphate (pH 6,7,8) and borate (9,10). The levofloxacin
solutions were analyzed by UV spectroscopy at 257 nm.
[0505] Results
[0506] A plot of pH Vs Absorbance of the levofloxacin solution at
257 nm is shown as FIG. 21. This data was fitted into a modified
Henderson Hasselbach equation:
Abs.sub.observed=Abs.sub.HA[H.sup.+]+Abs.sub.A.
[H.sup.+]Ka+[H.sup.+]Ka+[H.sup.+], where
Abs.sub.observed=Absorbance of levofloxacin solution;
Abs.sub.HA=Absorbance of levofloxacin solution pH 1.2;
Abs.sub.A-=Absorbance of levofloxacin solution at pH 7.8;
[H.sup.+]=hydronium ion concentration=10.sup.-pH. The fitted
equation provided an estimate of pKa=5.91.
Example 9
Levofloxacin Salt Formation
[0507] The goal of this study was to prepare various salt forms of
levofloxacin that may gain AUC shape-enhancement properties through
decreased solubility and/or dissolution. These benefits may alter
the pharmacodynamic properties of levofloxacin following pulmonary
administration using nanoparticle suspension or dry powder
inhalation. These formulations may be optimized to prolong the
release of levofloxacin from decreased solubility salt forms. These
properties may also be incorporated into other fluoroquinolone
antibiotics including, without limitation gemifloxacin,
gatifloxacin, norfloxacin, tosufloxacin, sitafloxacin sarafloxacin,
prulifloxacin, and pazufloxacin. Studies are underway to
characterize various salt forms and co-preciptates of gemifloxacin
for taste masking, AUC shape-enhancement, nanoparticle suspension
and dry powder inhalation administration. Other approaches
currently being investigated include spray-dry and in situ
micronization techniques.
[0508] For suspension and powder formulations, a specific salt form
can provide important physical and chemical characteristics that
may have impacts on the product performance. For a AUC
shape-enhancing formulation, the objective of salt selection was to
decrease the solubility and/or reduce the dissolution rate of
levofloxacin. The acid counterions can be selected by:
[0509] Manipulation of melting point: An increase in melting point
is usually accompanied by a reduction in salt solubility. Salts
formed from planar, high melting aromatic acids generally yield
crystalline salts of high melting point.
[0510] Manipulation of hydrophobicity: Salts formed with
hydrophobic conjugate acids are hydrophobic and difficult to wet,
and may ultimately lead to prolonged dissolution.
[0511] Examples of acids have been selected for salt preparation
are listed as follows: a) Pamoic acid (embonic acid); b)
2-naphthalene sulfonic acid (napsylic acid); c) Oleic acid; d)
Xinafoic acid; e) Stearic acid; f) Lauryl Sulfonate (estolate).
[0512] Other factors considered include salt surface properties,
polymorph and chemical stability.
[0513] Description
[0514] The objective of the study was to prepare salt forms of
levofloxacin in order to reduce its solubility and/or dissolution
rate. The goal was to: (a) make levofloxacin less soluble through
salt formation with suitable excipient(s); (b) prepare salt forms
of levofloxacin that will have a lower solubility and/or
dissolution rate than the free base. To accomplish these tasks,
efforts were concentrated on preparing salts at the basic site of
the molecule (pKa .about.6.8).
[0515] Pamoic acid (mp=280.degree. C.) and napsylic acid
(mp=125.degree. C.) possess planar, hydrophobic structures that
were expected to provide hydrophobic character to the salt. The
high melting point of pamoic acid may yield a high melting
crystalline salt form. Oleic acid was chosen primarily because it
is approved for lung delivery. It has a low melting point
(4.degree. C.) which may not satisfy the condition under (1),
however it was hoped that the long aliphatic chain may impart
sufficient hydrophobicity to decrease solubility. Xinafoic acid
(mp=195.degree. C.) was also selected for salt formation as it also
possess planar, hydrophobic structures that is expected to provide
hydrophobic character to the salt. The rationale for choosing
stearic acid and lauryl sulfonate (estolate) was similar to oleic
acid, only their lung toxicities are unknown. Estolate is approved
for oral delivery (erythromycin estolate has approximately
1/12.sup.th the solubility of the free base, and is formulated as
an oral suspension).
[0516] Salt Formation
[0517] In general, levofloxacin base and the acid were dissolved in
a suitable volatile, organic solvent (1:1 molar ratio), and stirred
at room temperature. Any crystallized product formed was filtered,
dried, and characterized. Characterization would consist of DSC,
FTIR, and elemental analysis.
[0518] Formation and Characterization of Co-Crystals of
Levofloxacin with Pamoic Acid
[0519] Experimental Methodology
[0520] Formation of Co-Crystals of Levofloxacin with Pamoic
Acid
[0521] 0.31 g (0.8 mM) of pamoic acid was dissolved by stirring in
100 ml of tetrahydrofuran (THF). To this, 0.30 g (0.8 mM) of
levofloxacin was added, dissolved by stirring and the resulting
solution refluxed for 2.5 hrs. The suspension formed was cooled to
room temperature, filtered and the precipitate obtained was dried
in vacuum at about 70.degree. C. for 3 hours.
[0522] Characterization
[0523] Thermal analysis. Thermal analysis of (a) pamoic acid (b)
levofloxacin (c) levofloxacin pamoate co-crystallized precipitate
(d) physical mixture of pamoic acid and levofloxacin was performed
using a Differential Scanning calorimeter (TA Instrument DSC
Q1000). 2-5 mg of each sample was weighed into pan, sealed and
heated at 10.degree. C./min from 25.degree. C. to 300.degree. C.
under nitrogen.
[0524] Fourier transform Infrared (FT-IR) spectroscopy. FT-IR
spectroscopy of (a) pamoic acid (b) levofloxacin (c) levofloxacin
pamoate co-crystallized precipitate (d) physical mixture of pamoic
acid and levofloxacin was carried out using a FTIR spectrometer
(Model IRPrestige-21, Shimadzu).
[0525] Saturation solubility. Saturation solubility of levofloxacin
and levofloxacin pamoic acid co-crystallized precipitate was
determined by equilibrating excess amount of solid with water. The
suspensions were adjusted to pH's 4, 5, 6 and 7 with HCL, shaken,
centrifuged and the supernatant analyzed by UV spectroscopy at 288
nm.
[0526] Results
[0527] Thermal analysis. DSC scans of (a) pamoic acid (b)
levofloxacin (c) levofloxacin pamoate co-crystal precipitate (d)
physical mixture of pamoic acid and levofloxacin are shown as FIGS.
22A, 22B, 22C, and 22D. Pamoic acid and levofloxacin show sharp
endotherms at 330.degree. C. and 239.degree. C., respectively,
which most likely would be due to the melting of pamoic acid and
levofloxacin, respectively. The DSC profile of levofloxacin pamoate
co-crystals showed one major endotherm at 210.degree. C., while a
1:1 molar admixture of levofloxacin and pamoic acid displayed broad
endotherms at 129.degree. C. and 220.degree. C.
[0528] FTIR. FTIR spectra obtained from (a) pamoic acid (b)
levofloxacin (c) levofloxacin pamoate co-crystallized precipitate
(d) physical mixture of pamoic acid and levofloxacin are displayed
as FIGS. 23A, 23B, 23C, and 23D. The high intensity absorption
bands at 1650 cm.sup.-1 in the FTIR spectra of pamoic acid, which
is due to the stretching of C=0 group is greatly reduced in the co
crystal.
[0529] Saturation solubility. Table 31 displays the saturation
solubility data of levofloxacin and levofloxacin pamoate at
different pH's. Solubility was determined in water, since buffer
acids have an effect on the solubility of levofloxacin. However
after shaking levofloxacin or salt solutions in water, the pH
shifted, especially the levofloxacin solution at pH 5 shifted to pH
1.6. As the solution at pH 5 is between the two pKa's of
levofloxacin (.about.1.6 and .about.6), such a solution will have a
lower buffer capacity and hence the pH shift. Solutions at pH's
near the pKa's of the drug have a high buffer capacity and resist
pH changes. Solubility of levofloxacin pamoate was considerably
less than that of levofloxacin at all pH's.
TABLE-US-00031 TABLE 31 Saturation Solubility Data of Levofloxacin
and Levofloxacin Pamoate. Levofloxacin pH before shaking 3.97 5.06
5.96 pH after shaking 4.21 1.63 5.70 Solubility (mg/ml) 158.28
225.04 297.20 Levofloxacin pH before shaking 4.06 4.98 5.98 7.00
pamoate pH after shaking 5.63 6.30 6.66 7.32 Solubility (mg/ml)
0.34 0.29 0.24 0.44
[0530] Interpretation
[0531] Since the co-crystallized precipitate of levofloxacin
pamoate has a different melting point and FTIR spectra from that of
levofloxacin, pamoic acid or their physical mixture, it is possible
that the equimolar complex of the levofloxacin with pamoic acid
might be the salt levofloxacin pamoate, having a considerably less
solubility than levofloxacin.
[0532] Formation and Characterization of Co-Crystals of
Levofloxacin with Xinafoic Acid
[0533] Experimental Methodology
[0534] Formation of of Co-Crystals of Levofloxacin with Xinafoic
Acid
[0535] 1.004 g (2.7 mM) of levofloxacin was dissolved by refluxing
in 80 ml ethyl acetate. To this, 0.51 g (2.7 mM) of xinafoic acid
dissolved in 35 ml of ethyl acetate was added and the solution
cooled overnight under stirring conditions to ambient temperature.
The suspension obtained was filtered, and the precipitate dried
under vacuum at 75.degree. C. for about 3.5 hours.
[0536] Characterization
[0537] Thermal analysis. Thermal analysis of (a) xinafoic acid (b)
levofloxacin xinafoate co-crystallized precipitate was performed
using a Differential Scanning calorimeter (TA Instrument DSC
Q1000). 2-5 mg of each sample was weighed into pan, sealed and
heated at 10.degree. C./min from 25.degree. C. to 300.degree. C.
under nitrogen.
[0538] Fourier transform Infrared (FT-IR) spectroscopy. FT-IR
spectroscopy of (a) xinafoic acid (b) levofloxacin xinafoate
co-crystallized precipitate was carried out using a FTIR
spectrometer (Model IRPrestige-21, Shimadzu).
[0539] Saturation solubility. Saturation solubility of levofloxacin
xinafoic acid co-crystallized precipitate was determined by
equilibrating excess amount of solid with water. The suspensions
were adjusted to pH's 4, 5, 6 and 7 with HCL, shaken, centrifuged
and the supernatant analyzed by UV spectroscopy at 288 nm.
[0540] Results
[0541] Thermal analysis. DSC profiles of (a) xinafoic acid (b)
levofloxacin xinafoate co-crystallized precipitate are shown as
FIGS. 24A and 24B. Levofloxacin xinafoate co-crystallized
precipitate exhibits a melting endotherm at 196.degree. C., which
is different than that of xinafoic acid (216.degree. C.) and
levofloxacin (239.degree. C.).
[0542] FTIR. FTIR spectra obtained from (a) xinafoic acid (b)
levofloxacin xinafoate co-crystallized precipitate are displayed as
FIGS. 25A and 25B. The FTIR spectrum of the co crystal exhibit
transmittance minima's at wave numbers different from that of
xinafoic acid and levofloxacin.
[0543] Saturation solubility. Table 32 shows the saturation
solubility data of levofloxacin xinafoate at different pH's.
Solubility of the xinafoate salt was intermediate between that of
the levofloxacin base and levofloxacin pamoate co crystal.
TABLE-US-00032 TABLE 32 Saturation Solubility Data of Levofloxacin
Xinafoate Co-Crystal Levofloxacin pH before shaking 4.05 4.94 6.00
6.95 xinafoate pH after shaking 4.78 5.37 6.30 7.17 Solubility
(mg/ml) 21.69 12.95 4.59 5.95
[0544] Interpretation
[0545] The co-crystallized precipitate of levofloxacin pamoate has
a different melting point and FTIR spectra than that of
levofloxacin and xinafoic acid, suggesting a possible formation of
a levofloxacin xinafoate salt. This salt has intermediate
solubility between levofloxacin and levofloxacin pamoate.
[0546] Formation and Characterization of Co-Crystals of
Levofloxacin with Stearic Acid
[0547] Experimental Methodology
[0548] Formation of Co-Crystals of Levofloxacin with Stearic
Acid
[0549] 0.77 g (2.07 mM) of stearic acid was dissolved by heating
and sonication in 40 ml of methanol. To this, 1.00 g (2.07 mM) of
levofloxacin dissolved in 60 ml of methanol was added. The
resulting solution was heated at 55.degree. C. for about 15
minutes, followed by cooling to room temperature and then at
-20.degree. C. The suspension obtained was filtered.
[0550] Characterization
[0551] Thermal analysis. Thermal analysis of (a) stearic acid (b)
levofloxacin stearate co-crystallized precipitate (c) physical
mixture of stearic acid and levofloxacin was performed using a
Differential Scanning calorimeter (TA Instrument DSC Q1000). 2-5 mg
of each sample was weighed into pan, sealed and heated at
10.degree. C./min from 25.degree. C. to 250.degree. C. under
nitrogen.
[0552] Fourier transform Infrared (FT-IR) spectroscopy, FT-IR
spectroscopy of (a) stearic acid (b) levofloxacin stearic acid
co-crystallized precipitate (d) physical mixture of stearic acid
and levofloxacin was carried out using a FTIR spectrometer (Model
IRPrestige-21, Shimadzu).
[0553] Saturation solubility. Saturation solubility of levofloxacin
and levofloxacin stearic acid co-crystallized precipitate was
determined by equilibrating excess amount of solid with water. The
suspensions were adjusted to pH's 4, 5, 6 and 7 with HCL, shaken,
centrifuged and the supernatant analyzed by UV spectroscopy at 288
nm.
[0554] Results
[0555] Thermal analysis. DSC scans of (a) stearic acid (b)
levofloxacin stearate co-crystal precipitate (d) physical mixture
of stearic acid and levofloxacin are shown as FIGS. 26A, 26B and
26C. Stearic acid and levofloxacin show sharp endotherms at
76.4.degree. C. and 239.degree. C., respectively, which most likely
would be due to the melting of stearic acid and levofloxacin,
respectively. The DSC profile of levofloxacin stearic acid
co-crystals showed two sharp endotherms at 88.03.degree. C. and
138.54.degree. C. and minor endotherms at 231.degree. C. and
242.72.degree. C. The minor endotherms might be due to melting of
trace quantities of residual levofloxacin in the original sample. A
1:1 molar admixture of levofloxacin and stearic acid displayed
endotherms at 68.87.degree. C., 134.43.degree. C. and
240.74.degree. C. and minor endotherms at 79.73.degree. C. and
86.74.degree. C.
[0556] FTIR. FTIR spectra obtained from (a) stearic acid (b)
levofloxacin stearic acid co-crystallized precipitate (c) physical
mixture of stearic acid and levofloxacin are displayed as FIGS.
27A, 27B, and 27C. The C=0 stretch band is seen at 1700, 1705 and
1721 cm.sup.-1 in stearic acid, co-crystallized precipitate and
physical mixture, respectively.
[0557] Saturation solubility. Table 33 shows the saturation
solubility data of levofloxacin stearic acid co-crystals at
different pH's.
TABLE-US-00033 TABLE 33 Saturation Solubility Data of Levofloxacin
Stearic Acid Co-Crystals Levofloxacin pH before shaking 4.05 5.02
6.01 6.96 stearate pH after shaking 3.36 5.05 6.02 6.98
Solubility(mg/ml) 0.86 1.30 2.20 1.64
[0558] Interpretation
[0559] The DSC profile of levofloxacin stearic acid co-crystal
precipitate shows two endotherms. One of these endotherms might be
due to melting of the cocrystals. The nature of the second
endotherm has to be investigated. Since the levofloxacin stearic
acid co-crystal precipitate has a solubility values lower than of
levofloxacin, it is possible that the precipitate might be the
salt, levofloxacin stearate salt.
[0560] Formation and Characterization of Co-Crystals of
Levofloxacin with Oleic Acid
[0561] Experimental Methodology
[0562] Formation of Co-Crystals of Levofloxacin with Oleic Acid
[0563] 0.78 g (2.76 mM) of oleic acid was dissolved in 10 ml
chloroform. To this, 1.025 (2.76 mM) of levofloxacin dissolved in
10 ml of chloroform was added. The resulting solution was mixed
thoroughly and evaporated at 40.degree. C.
[0564] Characterization
[0565] Thermal analysis. Thermal analysis of (a) oleic acid (b)
levofloxacin oleate co-crystal precipitate (c) physical mixture of
oleic acid and levofloxacin (50:50) (d) physical mixture of oleic
acid and levofloxacin (10:90) and (e) physical mixture of oleic
acid and levofloxacin (90:10) was performed using a Differential
Scanning calorimeter (TA Instrument DSC Q1000). 2-5 mg of each
sample was weighed into pan, sealed and heated at 1.degree. C./min
or 10.degree. C./min from 25.degree. C. to 250.degree. C. under
nitrogen.
[0566] Fourier transform Infrared (FT-IR) spectroscopy. FT-IR
spectroscopy of (a) oleic acid (b) levofloxacin oleic acid
co-crystallized precipitate (d) physical mixture of oleic acid and
levofloxacin was carried out using a FTIR spectrometer (Model
IRPrestige-21, Shimadzu).
[0567] Kinetic solubility determination. Levofloxacin oleate
co-crystallized precipitate (50 mg) was suspended in 2 ml of water.
The suspension was adjusted to pH 7 with HCL and shaken. The
solubility of these co-crystals was determined at various time
intervals. This study was performed at room temperature and at
40.degree. C. The kinetic solubility of an equimolar physical
mixture of levofloxacin and oleic acid was also performed and
compared to that of the co-crystals at 40.degree. C.
[0568] Results
[0569] Thermal analysis. DSC scans of (a) oleic acid (b)
levofloxacin oleate co-crystal precipitate (c) physical mixture of
oleic acid and levofloxacin (50:50) (d) physical mixture of oleic
acid and levofloxacin (10:90) and (e) physical mixture of oleic
acid and levofloxacin (90:10) are shown as FIGS. 28A, 28B, 28C,
28D, and 28E. Oleic acid thermogram shows endotherms at
-6.15.degree. C. and 13.05.degree. C. The endotherm at
-6.15.degree. C. corresponds to gamma-alpha oleic acid phase
transition (Crowley K. J, 1999). Levofloxacin oleate
co-crystallized precipitate shows endotherm at 127.69.degree. C.,
while an equimolar physical mixture of levofloxacin with oleic acid
shows endotherms at 123.69.degree. C., 179.35.degree. C. and
224.degree. C. The equimolar physical mixture is showing an
endotherm which is close to melting point of the co-crystals,
suggesting a possible reaction between oleic acid and levofloxacin
in the solid state. To investigate this phenomenon, DSC on physical
mixtures of levofloxacin and oleic acid (90:10) and (10:90) were
performed. Physical mixture of levofloxacin and oleic acid (10:90)
shows major endotherm at 10.33.degree. C. (possible melting of
oleic acid) and at 281.degree. C. It does not show endotherm near
the melting point of co-crystals. A levofloxacin oleic acid (90:10)
physical mixture shows no melting endotherm at 10.degree. C. for
oleic acid. It exhibits endotherms at 79.77.degree. C. and at
128.degree. C. (close to the melting point of the co-crystals),
suggesting a possible reaction of levofloxacin and oleic in
presence of high amounts of levofloxacin.
[0570] FTIR.
[0571] The FTIR spectra of oleic acid shows a C=0 stretch intense
peak at 1710 cm-1 and O--H in-plane and out-of-plane bands at 1462
and 937 cm-1, respectively.
[0572] The high intensity absorption bands at 1710 cm.sup.-1 in the
FTIR spectra of oleic acid, which is due to the stretching of C=0
group is slightly reduced in the co crystal. The O--H in plane and
out of plane bands at 1462 and 937 cm-1 in the oleic acid are
absent in the co-crystal. Also the FTIR spectrum of the physical
mixture is different from that of the salt (FIGS. 29A, 29B, and
29C).
[0573] Kinetic Solubility Determinations
[0574] FIG. 30 displays the data for the kinetic solubility
experiments performed with the co-crystallized precipitate at room
temperature and at 40.degree. C. The solubility of the co-crystals
at room temperature is about 0.9 mg/ml, which remains constant
throughout the period of the study. At 40.degree. C., the
solubility increased from 1.17 mg/ml at 15 minutes to 1.86 mg/ml at
4 hrs which remained almost constant till 24 hrs. The solubility
profile of the equimolar physical mixture at 40.degree. C. looks
different from that of the co-crystals. The physical mixture has a
higher solubility (9.16 mg/ml at 24 hrs) as compared to the
co-crystals (1.89 mg/ml at 24 hrs).
[0575] Interpretation
[0576] The DSC data of the equimolar physical mixture exhibits an
endotherm near the melting endotherm of the co-crystallized
precipitate. However the FTIR and solubility data of the
co-crystals is different than that of physical mixture, with the
co-crystals having a low saturation solubility. The saturation
solubility of the co-crystals is 0.9 mg/ml temperature as opposed
to 25 mg/ml for levofloxacin base.
[0577] However the levofloxacin oleate salt is waxy in nature which
might be difficult to grind/micronize and thereby formulate. It is
reported that the tacky and deformable properties of a wax-like
drug fatty acid salt, propranolol oleate made particle size
reduction difficult (Crowley. J., et al, International journal of
Pharmaceutics, 2000, 211 (1-2): 9-17.
[0578] Dissolution Rate Studies
[0579] Levofloxacin Xinafoate
[0580] Experimental Methodology
[0581] 50 mg of the levofloxacin xinafoate salt was suspended in a
dissolution bath containing 500 ml of pH 7.4 Tris buffer at
37.degree. C. and rotated by means of paddles at 100 rpm. 5 ml
samples were removed at periodic time intervals and replaced with
same volume of plain buffer.
[0582] Results
[0583] The dissolution profile of levofloxacin xinafoate is shown
as FIG. 31. It is seen that the dissolution rate of levofloxacin
xinafoate in the earlier stages of 2-10 minutes is faster than that
seen from 10-30 minutes. When levofloxacin xinafoate is added to
the dissolution media, it gets dispersed as a fine powder, and the
dissolution from these fine particles is faster, approximately 1.24
mg/min (FIG. 32). With time, the powder gets agglomerated and moves
in a vortex created by the paddle, thereby decreasing the
dissolution rate to 0.28 mg/min (FIG. 33).
[0584] Levofloxacin
[0585] Experimental Methodology
[0586] 200 mg of levofloxacin was suspended in a dissolution bath
containing 500 ml of pH 7.4 Tris buffer at 37.degree. C. and
rotated by means of paddles at 100 rpm. 5 ml samples were removed
at periodic time intervals and replaced with same volume of plain
buffer.
[0587] Results
[0588] The dissolution profile of levofloxacin is shown as FIG. 34.
As levofloxacin has a higher solubility than the salts its
dissolution rate is very fast. With levofloxacin too, the earlier
dissolution was from finely dispersed particles and hence a faster
dissolution rate. In the later stages the particles agglomerated
and reduced its dissolution rate.
[0589] Levofloxacin Pamoate
[0590] Experimental Methodology
[0591] 10 mg of the levofloxacin pamoate salt was suspended in a
dissolution bath containing 500 ml of pH 7.4 Tris buffer at
37.degree. C. and rotated by means of paddles at 100 rpm. 5 ml
samples were removed at periodic time intervals (2, 5, 10, 15, 20,
25, 30, 45, 60, 120, 240, 1320 and 1440 minutes) and replaced with
same volume of plain buffer. The study was performed in
duplicate.
[0592] Results
[0593] The dissolution profile of levofloxacin pamoate is shown as
FIG. 35. It is seen that the dissolution rate of levofloxacin
pamoate in the earlier stages of 2-10 minutes is faster than that
seen from 10-60 minutes. When levofloxacin pamoate, is added to the
dissolution media, it gets dispersed as a fine powder, and the
dissolution from these fine particles is faster, approximately
0.146 mg/min (FIG. 36). With time, the powder gets agglomerated and
moves in a vortex created by the paddle, thereby decreasing the
dissolution rate to 0.0331 mg/min (FIG. 37).
[0594] Levofloxacin Stearate
[0595] Experimental Methodology
[0596] 25 mg of the levofloxacin stearate salt was suspended in a
dissolution bath containing 500 ml of pH 7.4 Tris buffer at
37.degree. C. and rotated by means of paddles at 100 rpm. 5 ml
samples were removed at periodic time intervals (2, 5, 10, 15, 20,
25, 30, 45, 60, 120, 240, 1320 and 1440 minutes) and replaced with
same volume of plain buffer.
[0597] Results
[0598] The dissolution profile of levofloxacin stearate is shown as
FIG. 38. It is seen that the dissolution rate of levofloxacin
stearate in the earlier stages of 2-10 minutes is 0.499 mg/min
(FIG. 39) which is faster than that seen from 10-30 minutes (0.161
mg/min) (FIG. 40).
[0599] Dissolution of levofloxacin and salts was carried out with
quantities such that the concentration of the dissolved solute in
the dissolution bath never reached more than 10% of its saturation
solubility. This was done in an attempt to maintain sink
conditions.
[0600] Pending the dissolution rate of these and other salt forms
and co-precipitates, these AUC shape-enhancement forms of
levofloxacin, gemifloxacin and other fluoroquinolone antibiotics
these forms may be best suited for nanoparticle suspension
(solubilities <100 ug/ml, slow dissolution rates) or micron-size
dry powders (solubilities >100 ug/ml, quicker dissolution rate
than that best for nanosuspension. The nanoparticle suspensions may
be administered by nebulization using jet, ultrasonic, or vibrating
mesh technologies, while dry powder formulations may be
administered using either active or passive dry powder
inhalers.
Example 11
Levofloxacin Solid Lipid Nanoparticles
[0601] The goal of this study was to prepare solid lipid
nanoparticles of levofloxacin to obtain AUC shape-enhancing
properties through decreased solubility and dissolution. These
benefits may enhance the pharmacodynamic properties of levofloxacin
following pulmonary administration using nanoparticle suspension or
dry powder inhalation formulations. These formulations are being
optimized to prolong the release of levofloxacin from decreased
solubility salt forms. These properties may also be incorporated
into other fluoroquinolone antibiotics including, without
limitation gemifloxacin, gatifloxacin, norfloxacin, tosufloxacin,
sitafloxacin sarafloxacin, prulifloxacin, and pazufloxacin. Studies
are also underway to characterize various lipid nanoparticle forms
of gemifloxacin for taste masking, AUC shape-enhancement,
nanoparticle suspension and dry powder inhalation administration.
Other approaches for solid lipid nanoparticle currently being
investigated include spray-dry and in situ micronization
techniques.
[0602] Preformulation Studies
[0603] Partitioning of each compound (including levofloxacin salts
and metal cation complexes) into 1-octanol were determined at
different relevant pH values. Partitioning as a function of time
may also be evaluated to determine whether dissociation of
levofloxacin occurs (from both salts and complexes), and in the
case of salts, also to determine if selective partitioning of the
fatty acid component occurs over time. Compound(s) with significant
partitioning (log P>2.0) was evaluated for their solubility in
various lipid melts. Additionally, partitioning of a lipophilic
fluoroquinolne (if available) is also being studied, and its
solubility in different lipid melts will be evaluated. A lipid in
which drug is sufficiently soluble will be selected for formulation
of solid lipid nanoparticles. A prerequisite to obtain a sufficient
loading capacity of the drug in solid lipid nanoparticles was a
high solubility of drug in the lipid melt.
[0604] Formulation of Solid Lipid Nanoparticles
[0605] Formulation of solid lipid nanoparticles typically involves
dissolving the drug in a lipid melt, followed by dispersion of the
drug-containing melt in a hot aqueous surfactant solution. The
coarse dispersion is homogenized using a Microfluidizer.RTM. to
obtain a nanoemulsion. Cooling the nanoemulsion to room temperature
will re-solidify the lipid, leading to formation of solid lipid
nanoparticles. Optimization of formulation parameters (type of
lipid matrix, surfactant concentration and production parameters)
will be performed so as to achieve a prolonged drug delivery.
[0606] Characterization of Solid Lipid Nanoparticles
[0607] The nanoparticles are being characterized for size and zeta
potential using a Dynamic Light Scattering instrument while Laser
diffraction will be used for the detection of large
microparticles.
[0608] Upun completion of the synthesis, differential scanning
calorimetric studies will be performed to investigate any possible
modifications induced in the physical form of the lipid.
[0609] In vitro drug release testing will be done using appropriate
methodology."
Example 12
Levofloxacin Metal Ion Complexes
[0610] The goal of this study was to prepare levofloxacin of
various chelate salt forms to obtain gain taste-masking properties,
AUC shape-enhancing properties through changes in solubility,
dissolution and/or bioavailability. These benefits may enhance the
pharmacodynamic properties of levofloxacin following pulmonary
administration using nanoparticle suspension, dry powder inhalation
or simple liquid formulations. These formulations may be optimized
to create AUC shape-enhancing formulations of levofloxacin from
altered solubility, or slow-release or low bioavailability
chelates. These properties may also be incorporated into other
fluoroquinolone antibiotics including, without limitation
gemifloxacin, gatifloxacin, norfloxacin, tosufloxacin, sitafloxacin
sarafloxacin, prulifloxacin, and pazufloxacin. Studies are also
underway to characterize various and chelate forms of gemifloxacin
for taste masking, AUC shape-enhancement, nanoparticle suspension
and dry powder inhalation administration.
[0611] Preparation of Levofloxacin-Metal Ion Complexes
[0612] Preliminary Studies
[0613] A mixture of levofloxacin and a salt of a given cation was
solubilized in deionized water and titrated with sodium hydroxide.
The titration curve was compared against one obtained for
levofloxacin alone to assess formation of levofloxacin-metal
complex as described in Physical Pharmacy (4th Edition) by Alfred
Martin (pp 261-263). Salts of various metal cations (e.g. Ca2+,
Mg2+, etc) were then evaluated to identify suitable candidate(s)
for subsequent evaluations. Different molar ratios of cations and
levofloxacin were also evaluated.
[0614] Preparation of Complexes
[0615] Levofloxacin solutions were titrated against aqueous
solutions of selected metal salts. Titrations were carried out at a
constant pH. Formation of complexes were monitored by different
methods including titrimetry, spectrofluorometry, solubility, etc.
as applicable. The end point of the complexation reaction depended
on the method adopted.
[0616] Characterization of Levofloxacin Complexes
[0617] Levofloxacin-metal cation complexes were characterized for
stoichiometry, formation constants and dissociation kinetics using
appropriate methodology.
[0618] Goals
[0619] To formulate and characterize levofloxacin complexes with
metal cations (di- and tri-valent).
[0620] Assessment of Complexation
[0621] Preliminary investigations suggested that levofloxacin forms
soluble complexes with metal cations. As a result, evaluation of
the complexation process by precipitation was not possible. Other
approaches that were attempted are described below.
[0622] Titrimetry
[0623] This approach was based on the assumption that the
carboxylic acid moiety of levofloxacin is involved in complex
formation with a given metal cation and that complexation results
in the release of a proton from levofloxacin. The concentration of
released protons would thus be proportional to the extent of
complexation (depending on the binding constant) and the
stoichiometry of the complex (Physical Pharmacy: 4.sup.th Edition
by Alfred Martin; pp-261-263).
[0624] Experimental Methodology
[0625] About 0.35 mmoles of levofloxacin (in 16 mL of deionized
water) were titrated with 6N NaOH in the presence and absence of
salt of a metal cation (equimolar). Levofloxacin solutions were
acidified to pH values less than 2.0 with 6N HCl prior to titration
with NaOH. Salts of metal cations used include calcium chloride,
magnesium chloride, ferrous chloride, zinc chloride, aluminum
sulfate and aluminum chloride.
[0626] Results
[0627] As shown in FIG. 41, titrations performed in the presence of
metal cations resulted in a positive shift of the titration curves
as compared to the one obtained with levofloxacin alone suggesting
that additional NaOH (titrant) is required to obtain a specific pH
of the solution in the presence of metal cation. The magnitude of
the shift in titration curve at any point would represent moles of
proton released due to complexation and hence moles of complexed
levofloxacin.
[0628] Extent of complexation (binding and/or stoichiometry)
appears to increase in the order
Ca.sup.+<Mg.sup.2+<Zn.sup.2+=Fe.sup.2+<Al.sup.3+, which is
in reasonable agreement with existing literature.
[0629] Note: It was noted from the literature that aluminum
chloride and aluminum sulfate have acid-like properties and would
lower the pH of aqueous solutions. Consequently, the titration
curves obtained with A1C13 and Al2(504)3 may not provide conclusive
information on complexation with levofloxacin.
[0630] Dual Titration
[0631] In this approach levofloxacin solution was titrated with a
solution of a given metal cation to observe a drop in pH presumably
due to release of protons through complexation. This was followed
by addition of NaOH to revert back to the initial pH of the
levofloxacin solution (prior to addition of solution of cation).
This enables determination of the fraction of levofloxacin in the
complexed form at a given pH.
[0632] Experimental Methodology
[0633] About 1.55-1.72 mmoles of levofloxacin were solubilized in
deionized water and the resulting solution was acidified with 6N
HCl to the desired initial pH. This acidified levofloxacin solution
was titrated with a known volume of concentrated solution of a
given metal cation (Ca.sup.2+, Mg.sup.2+, Fe2.sup.+ and Zn.sup.2+).
The change in pH was neutralized (to the initial pH) by the
addition of 6N NaOH and volume of NaOH solution added was recorded.
Addition of solution of metal cation followed by neutralization
with NaOH was continued until further addition of solution of metal
cation failed to result in pH change of the levofloxacin solution,
which would indicate endpoint of complexation. The cumulative
amounts of metal cation added were plotted against cumulative
amounts of NaOH required to neutralize the change in pH (FIGS.
42-45).
[0634] Results
[0635] From FIGS. 42-45, the plateau regions were extrapolated to
obtain total amount of NaOH required to neutralize the change in pH
due to complexation. These values also represent the amounts of
levofloxacin in the complexed form (assuming that complexation of
levofloxacin results in an equimolar release of protons). Amounts
of levofloxacin in the complexed form with Ca.sup.2+, Mg.sup.2+,
Fe.sup.2+ and Zn.sup.2+ are 0.8, 1.0, 1.3 and 1.1 mmoles,
respectively. These represent 46.5, 64.5, 77.8 and 64.5%
complexation for Ca.sup.2+, mg.sup.2+, Fe.sup.2+ and Zn.sup.2+,
respectively. It should be noted that % complexation would depend
on the total concentrations of levofloxacin.
[0636] The binding constants as well as the stoichiometry of
complexation for the levofloxacin complexes with the metal cations
were determined as follows: M+nA 4MA.sub.nK.sub.b, where M, A and
MA.sub.n represent the metal cation, levofloxacin and the complex,
respectively. K.sub.b would be the equilibrium binding constant.
The above reaction assumes that `n` moles of levofloxacin react
with one mole of metal to yield one mole of complex.
[0637] Equation 1 is K.sub.b=[MA.sub.n]/{[M][A].sup.n} (units
M.sup.-n), where [MA.sub.n] is the concentration of complex formed;
[M] and [A] are the concentrations of the unbound metal and unbound
levofloxacin, respectively.
[0638] Rearranging Eq.1; Equation 2 is
[MA.sub.n]/[A].sup.n=K.sub.b*[M], where
[A]=[A].sub.Total-[A].sub.bound=[A].sub.Total [NaOH].sub.used;
[M]=[M].sub.Total [M].sub.bound=[M].sub.Total[Na0H].sub.used/n; and
[MA.sub.n]=[A].sub.bound/n=[NaOH]/.sub.used/n.
[0639] Note: [NaOH].sub.used the concentration of sodium hydroxide
used at any given point to neutralize the change in pH caused by
the addition of metal cation (presumably due to complexation).
[0640] Equation 2 can be modified to obtain Equation 3, which is:
[A].sub.bound[A].sub.n=nK.sub.b*[M]. It is inferred from Equation 3
that a plot of [M] versus [A].sub.bound[A].sub.n would result in a
straight line with a slope of nK.sub.b when, n=1, for a 1:1
complex; n=2, for a 2:1 complex; n=3, for a 3:1 complex etc.
[0641] Shown below in FIGS. 46A-46B, 47A-47B, 48A-48B, and 49A-49B
are these plots for Ca.sup.2+, Mg.sup.2+, Fe.sup.2+ and Zn.sup.2+,
respectively.
[0642] As shown in FIGS. 46A-46B, 47A-47B, 48A-48B, and 49A-49B,
for each of the cations evaluated a plot of [A]bound/[A]n versus
nK.sub.b*[M] was linear when n=2 (for Ca.sup.2+ n=2 resulted in a
better fit than n=1). These results suggest that levofloxacin
complexes with Ca.sup.2+, Mg.sup.2+, Fe.sup.2+ and Zn.sup.2+ are
formed with a stoichiometry of 2 moles of drug per mole of cation
(2:1).
[0643] Using n=2, the binding constants for the above complexes can
be determined from the slopes of the respective linear plots.
[0644] The binding constants for 2:1 complexes represented as log
(K.sub.b) are as follows: Ca.sup.2+=2.75, Mg.sup.2+=3.69,
Zn.sup.2+=4.44, Fe.sup.2+=4.54.
[0645] Solubility
[0646] This method allows for a relatively simple way of
determining the stoichiometry of complexation. The approach
involved evaluation of solubility of the drug (levofloxacin) in the
presence of increasing concentrations of complexation agent (a
given metal cation). The total solubility of the drug
(complexed+uncomplexed) was expected to increase linearly owing to
complexation and to reach a plateau corresponding to the saturation
solubility of both the drug and the complex. Determination of the
stoichiometry from such a solubility curve was explained in detail
elsewhere (Physical Pharmacy: 4.sup.th Edition by Alfred Martin; pp
265).
[0647] Experimental Methodology
[0648] Excess quantities of levofloxacin (amounts were recorded)
were agitated, in the presence of increasing concentrations of
MgCl.sub.2, with 25 mM IVIES buffer (pH 5.99) using a vortex mixer.
The samples were then filtered and the filtrate was diluted
appropriately and analyzed spectrophotometrically to determine
levofloxacin concentrations (FIG. 50).
[0649] Results
[0650] As shown in FIG. 50, the solubility of levofloxacin did
increase with increasing MgCl2 concentrations. However, beyond the
plateau solubility (.about.650 mM levofloxacin), further increase
in solubility was observed, which is not consistent with the
expected profile. This was attributed to the effect of ionic
strength on levofloxacin solubility. It is important to note that
the final pH of all the solutions were constant, albeit greater
than 5.99 (final pH .about.7.0).
[0651] Subsequently, the experiment was repeated at a constant
ionic strength of .about.1.0M (adjusted with NaCl) and with 0.5M
MES buffer (pH 5.99) to enhance the buffer capacity of the solution
(FIG. 51).
[0652] Spectrofluorometry
[0653] This approach was adopted to evaluate levofloxacin
complexation based on existing literature evidence that the
complexation process is associated with a change in the
fluoroquinolone fluorescence properties. By monitoring the change
in fluorescence emission of levofloxacin in the presence of
different concentrations of a given metal cation it was possible to
determine the binding constant of complexation as well as the
stoichiometry.
[0654] Experimental Methodology
[0655] The fluorescence emission of levofloxacin was evaluated at
excitation and emission wavelengths of 298 nm and 498 nm,
respectively. Studies were conducted at two different pH values
i.e. 5.0 (acetate) and 9.0 (histidine). A series of solutions
containing a constant levofloxacin concentration but increasing
concentrations of a given cation were analyzed for fluorescence
emission due to levofloxacin. Metal salts studied included
CaCl.sub.2, MgCl.sub.2, FeCl.sub.2, ZnCl.sub.2 and
Al.sub.2(SO.sub.4).sub.3.
[0656] Results
TABLE-US-00034 TABLE 34 Fluorescence Characteristics of
Levofloxacin in the Presence of Cations Fluorescence of
levofloxacin Cation pH 5.0 pH 9.0 Results Comments Ca.sup.2+ Change
not Change not N/A -- significant significant mg.sup.2+ Change not
Change not N/A -- significant significant Fe.sup.2+ Decrease in N/A
FIG. 3.12 FeCl.sub.2 insoluble emission with (pH 5.0) at pH 9.0
increasing Fe.sup.2+ Zn.sup.2+ Change not Increase in FIG. 3.13 --
significant emission with (pH 9.0) increasing Zn.sup.2+ Al.sup.3+
Change not N/A N/A Al.sub.2(SO.sub.4).sub.3 significant Insoluable
at pH 9.0
[0657] As shown in Table 34, significant data were obtained only
for Fe.sup.2+ and Zn.sup.2+. For the remaining cations, the
relative concentrations of levofloxacin and the cation need to be
further optimized to observe a specific trend in change in
levofloxacin fluorescence.
[0658] The influence of increasing concentrations of Fe2+ and Zn2+
on levofloxacin fluorescence emission are shown in FIGS. 52 and 53,
respective.
[0659] As described above, both Fe.sup.2+ and Zn.sup.2+ appear to
form 2:1 complexes with levofloxacin; however, their influence on
levofloxacin fluorescence are dissimilar (FIGS. 52 and 53). The
exact reason for this is unclear at this point.
[0660] Samples of Levofloxacin Complexes
[0661] Seven samples of levofloxacin complexes were evaluated in
vivo for efficacy and pharmacokinetics. Details of the samples
tested are shown in Table 35 below.
TABLE-US-00035 TABLE 35 Molar Ratios of Levofloxacin Complexes
Molar Total Final pH ratio Levofloxacin of the Sample identifier
Cation used (mg/mL) solution NB-049-001-06-066A Mg.sup.2+ 1:1 40.2
6.24 NB-049-001-06-066B Fe.sup.2+ 1:1 40.1 6.30 NB-049-001-06-066C
Mg.sup.2+ 1:1 202 5.98 NB-049-001-06-081A Ca.sup.2+ 1:1 40.1 6.53
NB-049-001-06-081B Ca.sup.2+ 1:1 201 6.04 NB-049-001-06-081C
Zn.sup.2+ 1:1 40 6.33 NB-049-001-06-081D Zn.sup.2+ 1:1 200 5.69
[0662] Conclusions and Next Steps
[0663] Results obtained from our dual titration studies suggest
that levofloxacin forms 2:1 complexes with all the divalent metal
cations. The binding constants (log K.sub.b) for complexation with
Ca.sup.2+, Mg.sup.2+, Fe.sup.2+ and Zn.sup.2+ are 2.75, 3.69, 4.44
and 4.54, respectively.
Example 13
Levofloxacin and Gemifloxacin Formulations with Organic Acids
[0664] Experimental Methodology
[0665] Levofloxacin solution was prepared by dissolving either 50
or 100 mg levofloxacin base in 15-20 ml water. The initial pH of
levofloxacin solution in water was about 7.3. The pH of the
solution was adjusted with about 10% solution of acid prepared in
water. The following acids were used to adjust the pH of the
levofloxacin solution: acetic acid, ascorbic acid, citric, lactic,
tartaric and propionic acid. After making up the volume of the
solution to approximately 90% of the final volume, the osmolality
of the solution was measured and adjusted to 300 mOsm/kg with about
20% solution of sodium chloride prepared in water After pH and
osmolality adjustment, the volume of the solution was made up to
about 25 ml with water and its surface tension measured. The pH and
osmolality were measured after making up the volume and are
reported in Table 36. (The exact quantities of levofloxacin
weighed, acid required to adjust pH, sodium chloride to adjust
osmolality and final volume of solutions are listed in Table 36).
The content of levofloxacin in the solutions was determined by
HPLC.
TABLE-US-00036 TABLE 36 Formulations of Levofloxacin with Organic
Acids 9.94% Measured acetic 19.7% Final Vol Final Wt of acid Acetic
NaC1 of Levo osmolality Surface Levo used acid used NaC1 solution
conc (mOsm/ tension used (g) (ml) used(g) (ml) used (g) (ml)
(mg/ml) kg) Final pH (mN/m) 1.253 1.05 0.104 0.681 0.134 25.105
49.9 312 6.48 63.2 2.501 2.05 0.204 0.326 0.064 25.935 96.4 300
6.53 62.5 9.99% Measured ascorbic 19.7% Final Vol Final Wt of acid
ascorbic NaC1 of Levo osmolality Surface Levo used acid used NaC1
solution conc (mOsm/ tension used (g) (ml) used(g) (ml) used (g)
(ml) (mg/ml) kg) Final pH (mN/m) 1.253 3.400 0.339 0.550 0.108
25.135 49.8 297 6.40 64.4 2.505 7.400 0.739 0.300 0.059 25.135 99.7
298 6.47 62.5 10.05% Measured citric 21.54% Final Vol Final Wt of
acid citric NaC1 of Levo osmolality Surface Levo used acid used
NaC1 solution conc (mOsm/ tension used (g) (ml) used(g) (ml) used
(g) (ml) (mg/ml) kg) Final pH (mN/m) 1.251 1.25 0.126 1.005 0.216
25.12 49.8 299 6.54 61.5 2.498 2.6 0.261 0.918 0.198 25.82 96.7 301
6.53 61.4 10% Measured lactic 21.54% Final Vol Final Wt of acid
Lactic NaC1 of Levo osmolality Surface Levo used acid used NaC1
solution conc (mOsm/ tension used (g) (ml) used (g) (ml) used (g)
(ml) (mg/ml) kg) Final pH (mN/m) 1.258 2.1 0.21 0.745 0.160 25.135
50.1 297 6.54 59.4 2.497 4.2 0.42 0.392 0.084 25.605 97.5 301 6.63
57.5 10% Measured tartaric 21.54% Final Vol Final Wt of acid
Tartaric NaC1 of Levo osmolality Surface Levo used acid used NaC1
solution conc (mOsm/ tension used (g) (ml) used (g) (ml) used (g)
(ml) (mg/ml) kg) Final pH (mN/m) 1.252 1.55 0.155 0.948 0.204
25.180 49.7 298 6.51 61.5 Measured 9.79% 21.54% Final Vol Final Wt
of propionic propionic NaC1 of Levo osmolality Surface Levo acid
used acid used used NaC1 solution conc (mOsm/ Final tension used
(g) (ml) (g) (ml) used (g) (ml) (mg/ml) kg) pH (mN/m) 1.25281 1.310
0.128 0.737 0.159 25.045 50.02 298 6.50 58.1 2.51342 2.610 0.256
0.310 0.067 25.030 100.42 297 6.57 52.0
[0666] Results
[0667] The details about the levofloxacin formulations with organic
acids are shown in Table 36. The results of HPLC are shown in Table
37.
TABLE-US-00037 TABLE 37 Theoretical and Measured Concentrations of
Levofloxacin in the Formulations Theoretical Measured Conc.
Concentration Acid (mg/mL) (mg/mi) by HPLC acetic acid 50.05 51.45
acetic acid 99.9 102.32 citric acid 49.91 50.31 citric acid 99.86
102.99 L-ascorbic acid 49.95 50.01 L-ascorbic acid 100 102.49
lactic acid 50.05 50.07 lactic acid 97.54 95.27 tartaric acid 49.74
51.07
[0668] When tartaric acid was used to adjust the pH of the 100
mg/ml levofloxacin solution, a precipitate was formed.
[0669] Note: Solutions with acetic acid, citric acid and ascorbic
acid were remade for HPLC analysis and hence the theoretical
concentration for these solutions in Table 36 and Table 37 are
different.
[0670] Gemofloxacin Formulations with Organic Bases
[0671] Experimental Methodology and Results
[0672] Gemofloxacin Formulation with Sodium Ascorbate
[0673] 50.30 mg of Gemifloxacin mesylate (equivalent to 40.37 mg
Gemifloxacin) was added to 1.5 ml water. The resulting solution was
cloudy. It was filtered through a 0.45 micron filter. 1.3 ml of
solution was obtained after filtering having a pH of 4.28. The pH
of this solution was adjusted to 5.48 with 400 uL of a 10% solution
of sodium ascorbate prepared in water (Quantity of base required to
adjust pH=0.04 g). The osmolality of this solution was 308 mOsm/kg,
hence sodium chloride was not used to adjust osmolality. The final
volume of the solution was 1.7 ml. Theoretical concentration of
gemifloxacin in this formulation would be 20.59 mg/ml. Theoretical
concentration=Theoretical quantity of gemifloxacin in filtered
solution (in this case 35 mg Gemifloxacin in filtered 1.3 mL)/Final
volume of solution (in this case 1.7 mL).
[0674] Gemifloxacin Formulation with Sodium Lactate
[0675] 50.05 mg of Gemifloxacin mesylate (equivalent to 40.17 mg
Gemifloxacin) was added to 1.8 ml water. The resulting solution was
cloudy. It was filtered through a 0.45 micron filter. 1.52 ml of
solution was obtained after filtering having a pH of 4.21. The pH
of this solution was adjusted to 5.42 with 180 uL of a 20% solution
of sodium lactate prepared in water (Quantity of base required to
adjust pH=0.036 g). The osmolality of this solution was 478
mOsm/kg. The final volume of the solution was 1.7 ml. Theoretical
concentration of gemifloxacin in this formulation would be 19.95
mg/ml.
[0676] Gemofloxacin Formulation with Sodium Acetate
[0677] 50.47 mg of Gemifloxacin mesylate (equivalent to 40.50 mg
Gemifloxacin) was added to 2.0 ml water. The resulting solution was
cloudy. It was filtered through a 0.45 micron filter. 1.77 ml of
solution was obtained after filtering having a pH of 4.40. The pH
of this solution was adjusted to 5.40 with 50 uL of a 10% solution
of sodium acetate prepared in water (Quantity of base required to
adjust pH=0.005 g). The osmolality of this solution was 192
mOsm/kg. The osmolality of this solution was adjusted to 295
mOsm/kg using 28 uL of 20% solution of sodium chloride prepared in
water.
[0678] Gemofloxacin Formulation with Sodium Propionate
[0679] 50.00 mg of Gemifloxacin mesylate (equivalent to 40.13 mg
Gemifloxacin) was added to 1.9 ml water. The resulting solution was
cloudy. It was filtered through a 0.45 micron filter. 1.39 ml of
solution was obtained after filtering having a pH of 4.32. The pH
of this solution was adjusted to 5.50 with 30 uL of a 20% solution
of sodium propionate prepared in water (Quantity of base required
to adjust pH=0.006 g). The osmolality of this solution was 183
mOsm/kg. The osmolality of this solution was adjusted to 296
mOsm/kg using 25 uL of 22% solution of sodium chloride prepared in
water. This solution was remade with osmolality adjustment to 237
m0 sm/Kg
[0680] Gemifloxacin Formulation with Sodium Citrate
[0681] 49.92 mg of Gemifloxacin mesylate (equivalent to 40.06 mg
Gemifloxacin) was added to 1.9 ml water. The resulting solution was
cloudy. It was filtered through a 0.45 micron filter. 1.63 ml of
solution was obtained after filtering having a pH of 4.20. The pH
of this solution was adjusted to 5.39 with 15 uL of a 20% solution
of sodium citrate prepared in water (Quantity of base required to
adjust pH=0.003 g).
Example 14
Microspheres of Levofloxacin
[0682] The goal of this study was to prepare various microsphere
forms of levofloxacin that may gain taste-masking, and AUC
shape-enhancing properties through decreased solubility and/or
dissolution. These benefits may enhance the pharmacodynamic
properties of levofloxacin following pulmonary administration using
either nanoparticle suspension or dry powder inhalation. These
formulations are being optimized to prolong the release of
levofloxacin from decreased solubility or dissolution forms. These
properties may also be incorporated into other fluoroquinolone
antibiotics including, without limitation gemifloxacin,
gatifloxacin, norfloxacin, tosufloxacin, sitafloxacin sarafloxacin,
prulifloxacin, and pazufloxacin. Studies are underway to
characterize micorspheres of gemifloxacin for taste masking, AUC
shape-enhancement, nanoparticle suspension and dry powder
inhalation administration. Other approaches for dry powder
administration currently being investigated include spray-dry and
in situ micronization techniques.
[0683] Preformulation for Levofloxacin
[0684] Preformulation Studes
[0685] Preformulation studies were performed to determine the
solubility of levofloxacin and polymers in various solvents which
are expected to be used during processing.
[0686] Preparation of Microspheres
[0687] A spray drying technique is being used to formulate polymer
microparticles loaded with levofloxacin. Formulation of
microspheres will typically involve dissolving the drug and polymer
in a suitable solvent. The solution is being spray dried using a
spray dryer to evaporate the solvent, thereby entrapping the drug
in a polymer matrix. Optimization of formulation parameters (drug:
polymer ratio, polymer solution concentration and production
parameters) is being performed to achieve a desired micro particle
size, optimum drug loading and in vitro drug release.
[0688] Characterization of Microspheres
[0689] The microparticles will be characterized for their
morphology using SEM while microscopy or a suitable technique
(Laser diffraction) will be used for estimating their size.
[0690] Drug loading will be determined by extracting the drug from
the microspheres in a suitable solvent and analyzing the extract by
UV/HPLC.
[0691] Drug release from the microspheres will be carried out using
a USP dissolution apparatus.
Example 15
Inhalation Toxicology in Rats
[0692] In a 4 day non-GLP ascending dose study of aerosolized
levofloxacin in male and female Sprague-Dawley rats, a 25 mg/ml
solution of levofloxacin was administered for one hour on day one
and a 50 mg/ml solution of levofloxacin was administered for two
hours per day on days 2 thru 4. No clinical signs of toxicity were
observed during the treatment period. Necropsy 24 hours after
administration of the last dose did not show any findings.
[0693] In a GLP study of aerosolized levofloxacin in male and
female Sprague-Dawley rats, aerosolized levofloxacin was
administered daily with an average dose of 6.92 mg/kg/day to the
males and 10.04 mg/kg/day for the females over 4 days using a
nose-only aerosol delivery device. Total exposures were 29 and 42
mg/kg for males and females, respectively over the study period.
Each dose was delivered over 2 hours daily. The dose for this study
was chosen based on the maximum solubility of levofloxacin that
could be administered in the device over 2 hours. No clinical signs
of toxicity were observed, and all animals survived during the 4
day treatment period. Necropsy of animals after administration of
the last dose did not show any findings.
[0694] In a 28-day GLP study in Sprague-Dawley rats, animals were
randomized to 3 dose levels of aerosolized levofloxacin or saline.
Additional recovery groups using the vehicle control and the
highest dose were also treated and observed for a 14 day recovery
period following the last dose. Average aerosolized levofloxacin
doses were 1.49, 3.63, and 7.29 mg/kg/day for male rats, and 2.20,
5.35, and 11.01 mg/kg/day in female rats. The total exposures over
the 28-day treatment period ranged between 41.7 and 204.1 mg/kg for
males and 61.6 and 308.3 mg/kg for females. Each dose was delivered
over 2 hours daily. No dose related clinical signs of toxicity were
observed, and all animals survived during the 28 day treatment
period. Necropsy of animals after administration of the last dose
showed a dose related squamous cell hyperplasia of the larynx which
declined in severity during a 14 day recovery period.
* * * * *