U.S. patent application number 10/158387 was filed with the patent office on 2003-07-10 for liquid crystal forms of cyclosporin.
Invention is credited to Bennett, David B., Cabot, Kirsten M., Foster, Linda C., Lechuga-Ballesteros, David, Patton, John S., Tan, Trixie K..
Application Number | 20030130176 10/158387 |
Document ID | / |
Family ID | 22125639 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030130176 |
Kind Code |
A1 |
Bennett, David B. ; et
al. |
July 10, 2003 |
Liquid crystal forms of cyclosporin
Abstract
This invention relates to novel, liquid crystal forms of the
cyclic peptide cyclosporin and to novel powder formulations of
cyclosporin prepared using this novel liquid crystal form of the
drug. Methods for preparing and using these formulations are also
provided. In particular, the present invention relates to
dispersible spray dried particles of cyclosporin suitable for
pulmonary delivery.
Inventors: |
Bennett, David B.; (San
Jose, CA) ; Cabot, Kirsten M.; (San Francisco,
CA) ; Foster, Linda C.; (Sunnyvale, CA) ;
Lechuga-Ballesteros, David; (Santa Clara, CA) ;
Patton, John S.; (Portola Valley, CA) ; Tan, Trixie
K.; (Daly City, CA) |
Correspondence
Address: |
INHALE THERAPEUTIC SYSTEMS, INC
150 INDUSTRIAL ROAD
SAN CARLOS
CA
94070
US
|
Family ID: |
22125639 |
Appl. No.: |
10/158387 |
Filed: |
May 29, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10158387 |
May 29, 2002 |
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09248416 |
Feb 11, 1999 |
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6413547 |
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60075422 |
Feb 20, 1998 |
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Current U.S.
Class: |
514/772.4 ;
514/20.5; 514/21.1 |
Current CPC
Class: |
A61P 37/06 20180101;
A61K 9/1688 20130101; A61K 9/1274 20130101; Y10S 514/951 20130101;
A61K 38/13 20130101; A61P 11/00 20180101; A61P 11/06 20180101; A61P
29/00 20180101; A61K 9/0075 20130101; Y10S 514/886 20130101 |
Class at
Publication: |
514/9 |
International
Class: |
A61K 038/13 |
Claims
It is claimed:
1. Cyclosporin in liquid crystal form.
2. The cyclosporin of claim 1 wherein the cyclosporin is
cyclosporin A.
3. The cyclosporin of claim 1 which shows sharp peaks by small
angle X-ray scattering.
4. The cyclosporin of claim 1 which is in dispersible powder
form.
5. The cyclosporin of claim 1 for use as an immunosuppressive,
anti-inflammatory, or anti-asthmatic agent.
6. The cyclosporin of claim 1 which is prepared by spray drying
from a solvent.
7. A composition for pulmonary delivery comprising liquid crystal
cyclosporin in respirable powder particles.
8. The composition of claim 7 wherein the cyclosporin is
cyclosporin A.
9. The composition of claim 7 which is dispersible.
10. The composition of claim 7 which further comprises a
pharmaceutically acceptable excipient or carrier.
11. The composition of claim 7 which is prepared by spray
drying.
12. The composition of claim 7 wherein the cyclosporin comprises at
least about 40% by weight of the composition.
13. The composition of claim 7 wherein the particles in the powder
have a particle size range between 0.1 and 15 .mu.m MMD.
14. The composition of claim 7 wherein the particles have an MMAD
of less than about 5 .mu.m.
15. The composition of claim 7 which has a delivered dose
efficiency of at least about 30%.
16. A method for preparing the composition of claim 7 comprising:
a) mixing cyclosporin with a solvent to form a solution or
suspension; and b) spray drying the mixture formed in step a) under
conditions which provide a respirable powder.
17. The method of claim 16 further comprising the step of adding a
pharmaceutically acceptable excipient or carrier prior to spray
drying.
18. The method of claim 17 wherein said solvent comprises a
solution of less than 50% water.
19. The method of claim 16 wherein the solvent is selected from the
group consisting of ethanol, acetone, acetonitrile, isopropanol and
methanol.
20. A method of treating or preventing a condition in a subject
which may be prevented or alleviated by cyclosporin, the method
comprising pulmonary administration of a therapeutically effective
amount of the composition of claim 7 to a subject susceptible to or
suffering from the condition.
21. The method of claim 20 wherein the condition is selected from
the group consisting of asthma, transplant rejection, sarcoidosis,
chronic inflammatory lung disease, chronic obstructive pulmonary
disease, emphysema, primary and secondary pulmonary hypertension,
cystic fibrosis, lung infections, rheumatoid arthritis and
idiopathic pulmonary fibrosis.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a liquid crystal form of the
cyclic peptide cyclosporin and to powder formulations of
cyclosporin prepared using this novel liquid crystal form of the
drug. Methods for preparing and using these formulations are also
provided. In particular, the present invention relates to
dispersible spray dried particles of cyclosporin suitable for
pulmonary delivery.
BACKGROUND OF THE INVENTION
[0002] The cyclosporins are a group of non-polar oligopeptides with
immunosuppressant activity. Cyclosporin A, also known as
cyclosporine, is the major known cyclosporin, with the structure of
cyclosporins B through I also being known (The Merck Index, Twelfth
Edition, 464-465 (1996)). A number of synthetic cyclosporin
analogs, have been prepared. (Id.)
[0003] Cyclosporin A is an orally active immunosuppressive drug
that has been used for immune suppression since the mid-1980's
(Guzman et al., J. of Pharm Sci, 82:5) 496-506 (1993)). It has
become the mainstay of organ transplant therapy as prophylaxis
against organ rejection. The original cyclosporine product for this
use, Sandimmune by Sandoz, is formulated in corn oil and designed
for oral delivery, however, bioavailability from the
gastrointestinal tract tends to be low and somewhat erratic. (Id.)
Recently, Sandoz has begun marketing an improved proprietary oral
formulation (Neoral) that is claimed to be more reliable than the
original (Med. Ad. News, Feb. 1996, 7-10). Cyclosponn A causes
kidney and liver toxicity at high doses when delivered orally and
tolerability must always be monitored along with clinical
assessments of rejection (Physician's Desk Reference. 52.sup.nd Ed,
1891-1901 (1998)).
[0004] In order to avoid the complications associated with oral
delivery, and, in particular, to prevent lung transplant rejection,
it may be desirable to deliver cyclosporin directly to the lungs.
In fact, nebulized cyclosporin A appears to be efficacious in
preventing lung transplant rejection using aerosolized liquid
ethanol and polyethylene glycol cyclosporine formulations
(Burckart, et al., Inhalation Delivery of Therapeutic Peptides and
Proteins, Marcel Dekker, NY, pp 281-299 (1997)). Nebulized
cyclosporin A also appears to lower oral cortico-steroid dependency
in asthma (Morley, et al., Ciclosporin Form for Pulmonary
Administration, European Patent Application No. 92104426.9 (1992)).
Liposomal cyclosporin has also been administered as an aerosol
using a nebulizer (Waldrep, et al., Cyclosporin A Liposome Aerosol:
Particle Size and Calculatated Respiratory Deposition. Intl. J.
Pharm. 97:205-212 (1993)). The aim of such formulations has been to
decrease toxicity compared to conventional oral formulations and to
provide an alternative to nebulized solutions containing
cosolvents.
[0005] Nebulized solution delivery of cyclosporin suffers from
limited drug solubility in aqueous based vehicles. Further, there
are safety concerns surrounding nebulization of organic vehicles.
Delivery of nebulized solutions and suspensions both suffer from
low drug delivery efficiency from commercial nebulizers.
Aerosolization of cyclosporin A (CsA) with MDI's would involve a
solution of CsA in propellant(s) (chlorofluorocarbon or
non-chlorofluorocarbon propellants) or the use of finely divided
CsA suspended in propellant(s). Poor drug delivery efficiency and
low drug-carrying payload capacity make MDI's an inconvenient means
of aerosol delivery for human dosing regimens that may require 1 mg
to 20 mg of CsA delivered per day to the lung.
[0006] In view of the difficulty of delivering a solution of
cyclosporin by inhalation, it may be desirable to deliver
cyclosporin as a dry powder. The ability to deliver pharmaceutical
compositions as dry powders, however, is problematic in certain
respects. The dosage of many pharmaceutical compositions is often
critical, so it is desirable that dry powder delivery systems be
able to accurately, precisely and reliably deliver the intended
amount of drug. It is also essential that dry powders for pulmonary
delivery be readily dispersible in order to assure adequate
distribution and systemic absorption. Because CsA can cause
gingivitis, it is important that oropharyngeal deposition be
minimized.
SUMMARY OF THE INVENTION
[0007] The present invention provides a novel liquid crystal form
of cyclosporin not previously known. This novel form is
thermotropic liquid crystal cyclosporin. It has unexpectedly been
found that spray drying organic solutions containing cyclosporin,
in particular cyclosporin A (CsA), under specific conditions,
results in this novel form of cyclosporin. Spray drying of organic
solutions containing cyclosporin produces powders where the
particulate cyclosporin exhibits a lack of 3-dimensional (3-d)
order as determined by powder X-ray diffraction (PXRD) and also
exhibits 2-d order when analyzed by small angle X-ray scattering
(SAXS). Further, it exhibits a phase change from solid to liquid
over a narrow temperature range with a step-wise change in heat
capacity, i.e., a glass transition-like melt. This form of
cyclosporin is liquid crystal cyclosporin. The process conditions
for spray drying may be varied within certain limits to achieve
very narrow particle size distributions that make the powders
especially suitable for efficient delivery by oral inhalation.
These powders have high delivery efficiency when aerosolized with a
dry powder inhaler and have demonstrated physical, chemical, and
aerosol stability over prolonged periods of high temperature and
high humidity.
[0008] In one aspect the invention provides liquid crystal
cyclosporin. In particular, the liquid crystal form of cyclosporin
A is provided.
[0009] In another aspect the invention provides dispersible powder
formulations of liquid crystal cyclosporin for pulmonary delivery.
In particular, cyclosporin-based dispersible powder formulations
which are spray dried from cyclosporin and, optionally, excipient,
in a solvent are provided, as are methods for making these
formulations. Spray dried cyclosporin A powders are specifically
provided.
[0010] In a further aspect the invention provides methods for
treating a subject suffering from or subject to a condition which
may be alleviated or prevented by the administration of cyclosporin
comprising administering the dispersible powder cyclosporin
formulations described above. In particular, methods to alleviate
or prevent lung diseases or conditions which affect the lung are
provided. Cyclosporin may be used as an anti-inflammatory,
immunosuppressive or anti-asthmatic agent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIGS. 1A through 1C illustrate the difference in X-ray
powder diffraction patterns between two of the known crystalline
forms of cyclosporine (non-solvated orthorhombic (FIG. 1A) and
dihydrate tetragonal (FIG. 1B)) and the novel thermotropic liquid
crystal form of cyclosporine provided by the present invention
(FIG. 1C).
[0012] FIG. 2A illustrates a representative open pan differential
scanning calorimetry (DSC) tracing and FIG. 2B illustrates a
representative closed pan DSC tracing for the thermotropic liquid
crystal form of cyclosporine of the present invention.
[0013] FIG. 3 presents the small angle X-ray scattering data for
orthorhombic and tetragonal crystalline cyclosporine and for spray
dried liquid crystal cyclosporine at 10, 80 and 150.degree. C.
[0014] FIG. 4 presents the dielectric analysis (DEA) of a
thermotropic liquid crystal CsA formulation according to the
present invention.
[0015] FIGS. 5A, 5B and 5C illustrate HPLC analysis of spray dried
cyclosporin A at accelerated storage conditions of 110.degree. C.
for 196 hours, 140.degree. C. for 50 hours and 210.degree. C. for
10 minutes, respectively.
[0016] FIGS. 6A, 6B and 6C demonstrate that spray dried cyclosporin
A powder stored for 10 months at 40.degree. C. and 75% relative
humidity that showed no appreciable degradation based on HPLC
analysis.
[0017] FIG. 7 demonstrates that spray dried cyclosporin A powders
stored at room temperature for 15 months that showed no appreciable
degradation based on HPLC analysis.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention is based at least in part on the
discovery of a novel, thermotropic liquid crystal form of
cyclosporin, particularly cyclosporin A. This liquid crystal form
of cyclosporin may be formulated as a dispersible powder by spray
drying from organic solvents. The cyclosporin-based compositions
are suitable for pulmonary delivery due to their dispersibility
characteristics. The compositions of the invention are readily
aerosolized and presented to the deep lung of a host when delivered
by a dry powder inhaler. The powder formulations of the present
invention retain stability, are readily dispersible for pulmonary
delivery and allow for unit dose packaging.
[0019] The invention consists, in part, of compositions comprising
cyclosporin in dispersible powder formulations. The use of
particles of a certain size range allows for delivery of
cyclosporin to the alveolar area of the lungs (i.e., to the deep
lung). Optionally, the powder formulations of the present invention
may contain stabilizers and excipients such as buffer salts,
sugars, tonicifiers, preservatives and anti-oxidants. The
compositions of the present invention are useful in pulmonary dry
powder drug delivery systems, including but not limited to those
disclosed in U.S. Pat. No. 5,458.135 and International Patent
Publication WO96/09085.
[0020] The solid state forms of CsA that have previously been
reported are described in Table 1.
1TABLE 1 Solid State Forms of Cyclosporin A Melting Unit Cell
Dimensions Crystal Range Space (.ANG.) System Solvation (.degree.
C.) Group a b c Reference tetragonal dihydrate 140-150 P4.sub.1
13.837 13.387 41.242 1, 2 tetragonal non-solvated nr P4.sub.1 nr nr
nr 3 orthorhombic di-(di-isopropyl ether) .about.150
P2.sub.12.sub.12.sub.1 12.5 22.9 23.4 1 orthorhombic non-solvated
180-195 P2.sub.12.sub.12.sub.1 12.7 15.7 36.3 1, 3 orthorhombic
monohydrate nr P2.sub.12.sub.12.sub.1 12.5 22.9 28.4 4 amorphous
n/a n/a n/a n/a n/a n/a 3 nr = not reported n/a = not
applicable
[0021] References
[0022] 1. Giron, et al., Orthorhombic Ciclosporin Crystals, UK
Patent Application No. 8829556.3 (1988).
[0023] 2. Loosli, et al., The Conformation of Cyclosporin A in the
Crystal and in Solution, Helvetica Chemica Acta, 68:682-704
(1985).
[0024] 3. Matha, et al., The Story of the Czech Cyclosporin A, 28
pp.
[0025] 4. Knott, et al., Neutron Structure of the Immunosuppressant
Cyclosporin-A, Acta Cryst., C46:1528-1533 (1990).
[0026] Tetragonal and orthorhombic crystal forms of CsA exhibit
high melting points and have characteristic sharp diffraction peaks
when analyzed by PXRD and are birefringent to polarized light.
Amorphous materials, unlike liquid crystals, have no peaks by SAXS
and are not birefringent to polarized light. Liquid crystals show a
distinct melt over a narrow temperature range unlike amorphous
glasses which show no such melt. An amorphous form of CsA has been
mentioned without report of its physicochemical properties (Morley,
et al., European Patent Application No. 92104426.9 (1992)).
[0027] We have discovered that CsA powders prepared by organic
solvent spray drying can be designed such that they are not of the
orthorhombic or tetragonal crystal forms. Indeed, no sharp
diffraction peaks indicative of 3-dimensional order are observed by
PXRD of the spray dried powders (FIG. 1C). However, the spray dried
powders do exhibit 2-dimensional order when analyzed by SAXS,
indicative of a liquid crystal form (FIG. 3).
[0028] Furthermore, the CsA powders prepared by organic solvent
spray drying also demonstrated a distinct endotherm between
0-75.degree. C. when analyzed by differential scanning calorimetry
(DSC) at 10.degree./min in an open pan (FIG. 2A). Since the
physical nature of the powders does not change (not a melt) through
that temperature range and because the endotherm is absent in the
closed pan DSC trace (FIG. 2B), the transition is believed to be
due to solvent evaporation. A melt occurs beginning at about
120.degree. C. when analyzed by hotstage microscopy at
2.degree./minute. The DSC thermogram at the same heating rate shows
a step-wise change in heat capacity (Cp) (a Tg-like transition) at
that temperature. Typically, 3-d ordered crystals do not exhibit a
step-wise Cp change going from solid to liquid. Furthermore,
dielectric analysis is consistent with DSC results and confirms
that the transition observed at .about.120.degree. C. is a second
order transition, as it is demonstrated by the observed frequency
dependency.
[0029] A. Definitions
[0030] As used herein the following terms have the following
meanings:
[0031] The terms "dispersibility" or "dispersible" mean a dry
powder having a moisture and/or residual solvent content of less
than about 10% by weight (% w), usually below about 5% w and
preferably less than about 3% w and often less than about 1% w; a
particle size of between 0.1 and 15 .mu.m, often between 0.2 .mu.m
and 10 .mu.m, usually about 0.4 to 5 .mu.m mass median diameter
(MMD), preferably about 1 to 4 .mu.m MMD and most preferably 1 to 2
.mu.m MMD; a delivered dose of greater than about 30%, usually
greater than about 40%, preferably greater than about 50% and most
preferably greater than about 60%; and an aerosol particle size
distribution of about 1-5 .mu.m mass median aerodynamic diameter
(MMAD), usually about 1.5-4.5 .mu.m MMAD and preferably about
1.5-4.0 .mu.m MMAD, or with at least about 40% (preferably at least
about 50%) of the particles less than about 3.3 .mu.m in
diameter.
[0032] The term "cyclosporin" means any of the group of non-polar
cyclic oligopeptides with immunosuppressant activity and includes
known cyclosporins A through I. In particular, this term includes
cyclosporin A, also known as cyclosporine. Synthetically produced,
naturally-derived or purified and recombinantly produced moieties
are included, as are analogs, derivatives, agonists, antagonists
and pharmaceutically acceptable salts of any of these. The term
also includes cyclosporins which have D-amino acids, modified,
derivatized or non-naturally occurring amino acids in the D- or
L-configuration and/or peptomimetic or prodrug units as part of
their structure.
[0033] A thermotropic liquid crystal is a state of matter distinct
from the amorphous and 3-dimensional crystalline states and
characterized by the existence of long range order in one (nematic)
or two (smectic) dimensions in the absence of solvent. An amorphous
phase lacks long-range order and a 3-dimensional crystalline phase
contains 3-dimensional long-range order.
[0034] The term "powder" means a composition that consists of
finely dispersed solid particles that are free flowing and capable
of being readily dispersed in an inhalation device and subsequently
inhaled by a subject so that the particles reach the spaces of the
deep lung to permit deposition in the alveoli. Thus, the powder is
said to be "respirable."
[0035] The terms "pharmaceutical excipient" or "additive" mean
compounds which stabilize cyclosporin and/or improve powder aerosol
performance and stability. The types of excipients useful in the
present invention include buffer salts, sugars, tonicifiers,
preservatives and anti-oxidants, and the like.
[0036] The term "physically stable" or "physical stability" intends
a composition that does not show a change in phase over time. The
term "chemically stable" or "chemical stability" means that the
composition shows less than 10% and, preferably, less than 5% total
degradation in 2 years at room temperature at the storage
conditions specified. "Aerosol stability" means that the aerosol
composition shows no statistical change in delivered dose
efficiency with time.
[0037] The term "subject" includes any human or animal species in
need of cyclosporin for treatment or prophylaxis of conditions for
which pulmonary delivery of cyclosporin would be efficacious.
[0038] B. Compositions:
[0039] The present invention is drawn to liquid crystal forms of
cyclosporin and to dispersible cyclospoin-containing powder
compositions suitable for pulmonary delivery formed by spray drying
from organic solvents. The dispersible powder compositions comprise
a therapeutically effective amount of cyclosporin, optionally in
combination with a pharmaceutically acceptable carrier or
excipient.
[0040] Spray drying is a process that utilizes high temperatures
and high-carrier gas flow rates to rapidly evaporate solvents from
an atomized solution that contains dissolved solutes. The solvent
evaporates to leave a solid particle. The size of the particle is
dependent upon the conditions of the spray drying process (e.g.,
solids content of solution, pressure of atomization gas, design of
atomizer nozzle and design of cyclone collector). Control of
particle size and particle size distribution is important for
efficient inhalation delivery to the airways and the deep lung. The
mass median diameter (MMD) of the particles should preferably be
between 1 and 2 .mu.m, with 100% of the particles less than 15
.mu.m.
[0041] It can also be difficult to control particle size and
particle size distribution in compositions produced by spray
drying. For pulmonary delivery it is critical that the average
particle size be maintained in a respirable range and that the
amount of the composition comprising particles outside the target
size range be minimized. Moreover, it can sometimes be difficult to
achieve a desired low residual solvent and/or moisture content
required for physical and chemical stability in the final
particulate product, particularly in an economic manner. Useful
methods are disclosed, for example, in International Patent
Application No. PCT/US97/07779, the disclosure of which is
incorporated herein by reference in its entirety.
[0042] Cyclosporin, including cyclosporin A (CsA) is very
hydrophobic and is practically insoluble (<6 .mu.g/mL) in
aqueous vehicles. Organic solvents with boiling points less than
200.degree. C., preferably less than 150.degree. C., and most
preferably less than 100.degree. C. should be used to obtain
powders with low residual solvent. The preferred solvents for
making spray dried cyclosporin (including CsA) powders include, but
are not limited to, ethanol, acetone, acetonitrile, methanol,
isopropanol, and methylene chloride, either alone or in combination
or in cosolvent systems. Pharmaceutically acceptable protic
solvents with low dielectric constants are more preferred (e.g.,
ethanol is preferred over methanol).
[0043] Solvent mixtures with less than 50%, preferably less than
25%, and most preferably with 10% or less water by volume may also
be employed for spray drying cyclosporin. Use of water in the
solvent mixture allows the incorporation of water-soluble
excipients into the CsA particles, however non-aqueous systems are
preferred. Water-soluble excipients useful in the present invention
include, but are not limited to, buffer salts (e.g., citric
acid/sodium citrate), natural and synthetic sugars as bulking
agents (e.g., lactose, mannitol), tonicifiers (e.g., sodium
chloride), and preservatives and anti-oxidants (e.g., ascorbic
acid/sodium ascorbate).
[0044] Pharmaceutical excipients and/or additives generally useful
in the present invention include suitable pH adjusters or buffers
such as organic salts prepared from organic acids and bases, such
as sodium citrate, glycine, sodium tartrate, sodium lactate,
tromethamine and the like. Proteins (e.g., HSA, recombinant human
albumin (rHA), gelatin and casein), peptides (e.g., aspartame) and
amino acids (e.g., alanine, glycine, arginine, glutamic acid and
aspartic acid) which improve dispersibility of the powder may be
useful. Carbohydrates/sugars and alditols are also useful. Suitable
carbohydrate/sugar compounds include sucrose, trehalose, lactose,
raffinose, and the like. Suitable alditols include mannitol and
pyranosyl sorbitol and the like. Polymeric excipients/additives
include polyvinylpyrrolidones (PVP), Ficolls, soluble hydroxy ethyl
starch, dextrates and the like of high molecular weight. Also
useful are small amounts of pharmaceutically acceptable surfactants
such as Tweens, chelators such as EDTA and inorganic acids and
bases such as sodium phosphate and the like. Other suitable
pharmaceutical excipients and/or additives include those disclosed
in Remington, Pharmaceutical Sciences 18th ed. (1990), the
disclosure of which is incorporated herein by reference.
[0045] The temperatures employed for drying the atomized solution
droplets may range from 20 to 300.degree. C., preferably 30 to
150.degree. C., and most preferably 40 to 120.degree. C. These
temperatures are expressed as the outlet temperature of the carrier
gas. Specifically, the outlet temperature is the temperature of the
gas at the outlet of the drying chamber prior to entry into the
cyclone and collector. Correspondingly higher temperatures are
required at the point of atomization to achieve the recommended
outlet temperatures. The spray drying process may include
maintaining the powder an additional period of time at a given
temperature after the completion of cyclosporin solution feed
through the system (i.e., secondary drying). This secondary drying
may be used to reduce any residual solvent left in the powder.
[0046] A droplet size of about 4 to about 8 .mu.m diameter is
preferred in order to achieve optimal powder characteristics. Such
a droplet size may be achieved, for example, by using the
atomization method described in International Patent Application
No. PCT/US97/07779. Unless otherwise specified, atomization methods
that result in droplet sizes of 4-8 .mu.m were used in the examples
that follow.
[0047] The mass median diameter (MMD) of the powders prepared by
organic spray drying were measured by centrifugal sedimentation
with a Horiba CAPA-700 Particle Size Analyzer. A powder sample was
dispersed in a vehicle of Sedisperse W-11 (Micromeritics, Norcross,
Ga.) which was pre-saturated with cyclosporin A and filtered prior
to the addition of the powder sample. The particle size ranged from
about 0.7 to about 2.4 MMD. The size of the CsA particles was
confirmed by scanning electron microscopy; the particles were also
found to be generally spherical in shape, i.e., from smooth spheres
to dimpled, raisin-like or wrinkled.
[0048] The aerosol performance characteristics of the powders were
evaluated using the Inhale Therapeutic System's aerosol device. The
device includes an aerosol chamber and employs a volume of
compressed air to disperse the powder from an aluminum foil blister
package. The delivered dose efficiency (DDE) for each powder was
defined as the percentage of the nominal dose contained within a
blister package that exited the mouthpiece of the aerosol device
and was captured on a filter through which a vacuum was drawn (30
L/min) for 2.5 seconds following device actuation. The filter was
weighed before and after actuation of the device to determine the
mass of powder delivered past the mouthpiece. The particle size
distribution of the aerosolized powders was determined using an
Andersen cascade impactor through which a vacuum (28.3 L/min) was
pulled for 2.5 seconds.
[0049] The residual solvent and/or moisture content of the powder
particles of the present invention is usually below about 10% by
weight, preferably below about 5% w and more preferably below about
3% w. Such low solvent and/or moisture content powders are
generally physically and chemically stable during storage at room
temperature and are readily dispersible in an inhalation device to
form an aerosol.
[0050] Stability studies of spray dried cyclosporin formulations of
the present invention were performed, and showed that these
compositions retained aerosol and physical stability. In
particular, the DDE of a cyclosporin powder spray dried from
ethanol at 70.degree. C. without secondary drying was measured
immediately after preparation and found to be 48.4%. The powder was
then stored at room temperature for 10 months. The DDE was again
measured and found to be 49.5%, indicating that the powder retained
aerosol stability.
[0051] In another stability test, the DDE of cyclosporin powders
spray dried from ethanol at 70.degree. C. without secondary drying
was measured immediately after preparation and found to be about
72%. The powder was then stored at the accelerated conditions of
40.degree. C. and 75% relative humidity (RH). DDE was measured
after 8 weeks and again after 15 weeks of storage under these
conditions. Results showed that the DDE remained approximately the
same, i.e., about 75% at 8 weeks and about 74% at 15 weeks. A DSC
scan of this powder formulation done immediately after preparation
showed a melt at 118.61.degree. C., while a DSC scan of the
formulation done after 15 weeks at 40.degree. C. and 75% relative
humidity showed a melt at 119.00.degree. C. These results indicate
that no physical change of the powder occurred over this period and
the powder retained aerosol stability.
[0052] The amount of cyclosporin which constitutes a
therapeutically effective amount will vary in the composition
depending on the biological activity of the cyclosporin employed
and the amount needed in the unit dosage form. The condition to be
treated or prevented will also determine the amount of cyclosporin
required, as will the subject to which the composition is being
administered. The compositions comprise at least about 40% by
weight cyclosporin in the formulation, preferably between about 70%
to about 100% and most preferably about 90% to about 100%. The
amount of excipients and pharmaceutically acceptable additives may
be from about 0-60%, preferably from about 0-30% and most
preferably from about 0-10% by weight.
[0053] The compositions of the present invention will often be
packaged as unit doses where a therapeutically effective amount of
the cyclosporin composition is present in a unit dose receptacle,
such as a blister pack, gelatin capsule, or the like, so long as a
moisture barrier is provided.
[0054] The cyclosporin-based dry powder compositions of the present
invention may be produced by spray drying solutions or slurries of
the cyclosporin and, optionally, excipients, in a non-aqueous
solvent under conditions to provide a respirable dry powder.
Solvents may include ethanol, acetone, acetonitrile, methanol and
isopropanol, which may be readily dried. Further, the
cyclosporin-based dry powder compositions may also be produced by
evaporative drying, freeze-drying, quench from a melt,
precipitation including super-critical fluid precipitation.
[0055] C. Characterization:
[0056] It was found that, by spray drying cyclosporin from organic
solvents, a thermotropic liquid crystal form of cyclosporin is
formed. In particular, characterization of this cyclosporin form
using polarized light microscopy, showed that it was birefringent,
indicating that it was a non-amorphous form of cyclosporin.
Similarly, SAXS analysis showed the presence of sharp peaks (FIG.
3), a characteristic of non-amorphous materials.
[0057] Further characterization of this novel form of cyclosporin
by powder X-ray diffraction disclosed no sharp diffraction peaks
which would have indicated a 3-dimensional order such as that found
in crystalline structures, indicating that this was not a
3-dimensional crystalline form of cyclosporin. FIGS. 1A through 1C
show X-ray powder diffraction patterns of two crystalline forms of
cyclosporin (tetragonal and orthorhombic) and our novel spray dried
form.
[0058] Hotstage microscopy, DSC, DEA, and SAXS were used to
characterize the novel form of cyclosporin. Hotstage microscopy of
this material showed a distinct melting point which is
characteristic of both crystalline and liquid crystalline
materials. DSC showed a step-wise heat capacity change at the melt
temperature, characteristic of liquid crystalline materials. FIG.
2A shows a DSC (heating rate at 10.degree. C./min) of the liquid
crystal cyclosporin of the present invention, indicating a melting
point beginning at 122.degree. C. and which can be between
115.degree. C. and 125.degree. C. When analyzed by DEA, such
transition was found to be frequency dependent, suggesting it is
indeed a second order transition and not a true melt. The liquid
crystal state was confirmed by SAXS, which showed sharp diffraction
peaks at low diffraction angles, as characteristic of 2-dimensional
order in liquid crystals. FIG. 3 shows SAXS for spray dried
cyclosporin. The material remains a liquid crystal below the melt
(at 10.degree. C. and 80.degree. C.) and above the melt (at
150.degree. C.).
[0059] D. Pulmonary Cyclosporin
[0060] Pulmonary cyclosporin is useful for the treatment of asthma
and lung transplants but has the potential for use in many other
indications as well. Pulmonary cyclosporin may be useful to treat
sarcoidosis. Obliterative bronchiolitis (OB), the pulmonary
pathology that occurs in lung transplant rejection, also occurs in
heart and bone marrow rejection, thus there is the potential for
inhaled cyclosporin to be of use in other transplant therapies in
conjunction with oral immunosuppressants. Chronic inflammatory lung
disease, chronic obstructive pulmonary disease, emphysema, primary
and secondary pulmonary hypertension, cystic fibrosis, lung
infections or idiopathic pulmonary fibrosis (IPF) are other
pulmonary diseases that may respond to inhaled cyclosporin, since
they appear to be caused or exacerbated by an overly reactive
immune system. Further, cyclosporin may be useful to treat
pulmonary complications associated with autoimmune diseases such as
rheumatoid arthritis. The advantage of pulmonary delivery of
cyclosporin for lung disease or conditions which affect the lungs
is that the total body burden of drug can be reduced, which reduces
or eliminates systemic side effects.
[0061] According to the current invention, cyclosporin may be
delivered directly to the deep lung in dry powder form using a dry
powder delivery device. A significant requirement for such dry
powder delivery devices is efficiency. The delivered dose must be
relatively high to reduce the number of breaths required to achieve
a total dosage. The ability to achieve adequate dispersion is a
significant technical challenge that requires in part that each
unit dosage of the powder composition be readily and reliably
dispersible. Certain pulmonary delivery devices, such as those
disclosed in U.S. Pat. No. 5,458,135 and International Patent
Publication WO96/09085 (the disclosures of which are incorporated
herein by reference) are useful for pulmonary delivery of dry
powder drugs.
[0062] The disclosure of each of the publications, patents or
patent applications herein mentioned is hereby incorporated by
reference in its entirety to the same extent as if the language of
each individual publication, patent and patent application was
specifically and individually incorporated by reference.
DISCLOSURE OF THE EXAMPLES OF THE INVENTION
[0063] The following examples are not intended to limit the scope
of the invention in any manner.
[0064] Materials and Methods:
[0065] In general the following materials and methods were used in
the examples that follow unless otherwise indicated.
[0066] Materials:
[0067] Cyclosporin A, GMP grade, was obtained as a powder
crystallized from acetone (melting point 148-150.degree. C.) from
Poli Industria Chimica, S.p.A.
[0068] Sample Storage:
[0069] Spray dried powders were stored under dry atmosphere
(RH<5%).
[0070] Physical Methods:
[0071] Powder particle size distribution
[0072] The particle size distribution (PSD) of the spray dried
powder samples was measured with a Horiba CAPA-700 centrifugal
sedimentation particle size analyzer. A powder sample was dispersed
in a vehicle of Sedisperse W-11 (Micromeritics, Norcross, Ga.)
which was pre-saturated with cyclosporin A and filtered prior to
the addition of the powder sample.
[0073] Approximately 5 mg of powder was suspended in about 5 ml of
the Sedisperse and sonicated 5-10 minutes in a Lab Supplies
ultra-sonicator before analysis. The instrument was configured to
measure a particle size range of 0.4 to 10 .mu.m in diameter using
a particle density of about 1.2 g/cm.sup.3.
[0074] Powder X-ray diffraction (PXRD)
[0075] The PXRD was performed on a Siemens D-500 X-ray Diffractor.
The sample was measured at 3.degree./min (0.8 sec/0.04.degree.
step) and 0.5.degree./step, 1 sec/step respectively. The scan was
run continuously from 2.degree. to 40.degree. in 2.theta..
[0076] Small angle X-ray scattering (SAXS)
[0077] SAXS analysis was performed on a Rigaku 12KW diffractometer
equipped with a Kratky camera and a Braun 10-cm position sensitive
detector, using a copper X-ray source of 1.542 .ANG. at a scanning
rate of 0.12.degree./min in the range of 0 to 2.2.degree. in
2.theta..
[0078] Method to test birefringency
[0079] Birefringence was tested using a polarized light microscope,
Nikon Optiphot 2-Pol, equipped with a Hamamatsu camera and
controller C2400. Pictures were printed on a graphic printer
UP890MD. The powders, either dry or immersed in Sedisperse W-11 or
water, were examined under 20.times., 40.times. and 60.times.
objectives, and photomicrographs were taken through normal and
cross polarized light.
[0080] Method for hotstage microscopy
[0081] Hotstage microscopy was performed on a Nikon Optiphot 2-Pol
equipped with a Mettler Toledo FP82HT Hotstage and a Hamamatsu
camera and controller C2400. Photomicrographs were printed on a
graphic printer UP890MD. The slide was placed in the hotstage and a
representative field was found using the 40.times. objective.
Samples were heated at a rate of 2.degree. C./min from room
temperature to past the melting point. Pictures were taken when
changes were visually observed.
[0082] Method for TGA-Residual solvent
[0083] Samples were analyzed by Oneida Research Services, Inc. The
TGA was performed on a Omnitherm 1500. Samples were heated from
30-200.degree. C./min under a nitrogen atmosphere with a flow rate
of 30 ml/min. The weight loss due to drying was measured and is
presented as % weight lost.
[0084] Method for TGA-Decomposition
[0085] Samples were analyzed by Oneida Research Services, Inc. The
TGA was performed on a Omnitherm 1500 TGA. Samples were heated from
40-600.degree. C. at 10.degree./min under a nitrogen atmosphere
with a flow rate of 30 ml/min.
[0086] Differential scanning calorimetry (DSC)
[0087] The DSC scans were performed on a TA Instrument model 2920
Modulated DSC with a TA refrigerated cooling system (RCS) unit, and
pure helium gas with a flow rate of .about.120 cm.sup.3/min. The
cell flow rate was set at about 40 cm.sup.3/min. The scans were
performed at 10.degree. C./min non-modulated, with an equilibration
temperature of -30.degree. C. for 15-30 mm, followed by heating to
about 200-225.degree. C. Open and closed aluminum pans were filled
with about 2 mg-6 mg of powder (FIGS. 2A and 2B, respectively).
[0088] Dielectric analysis (DEA)
[0089] The DEA scan was performed on a TA Instrument 2970 Dielectnc
Analyzer using liquid nitrogen to cool the sample to the initial
temperature. The powder (40-45 mg) was pressed into a pellet,
1/2inch in diameter and approximately 0.3 mm thick, using a Carver
press for 40 seconds at 1 ton. Two thin layers of Teflon 25 .mu.m
and {fraction (7/16)}inch in diameter, were inserted into the
pellet die to alleviate adhesion to the die faces. Dunng the
measurement, the pellet was surrounded by a silicone gasket, ID
{fraction (9/16)}inch, OD 1{fraction (1/16)}inches thickness, 0.35
mm, to help maintain thickness during the measurement. The pellet
was also sandwiched between two layers of Teflon, 25 .mu.m thick,
to remove possible contributions from ionic conductivity.
Electrodes were fabricated from TA Instruments' sensors for sputter
coated samples and gold foil, 25 .mu.m thick, one disk {fraction
(7/16)}inch in diameter and the other {fraction (6/8)}inch in
diameter, so that only the sample contacted the foil electrodes.
Experiments were performed using a heating rate of 2.degree. C./min
from -40 to 200.degree. C. and using the following frequencies: 1
Hz, 10 Hz, 100 Hz, 1,000 Hz, 10,000 Hz, 100,000 Hz. The
permitivities measured with this method were in arbitrary units
since the data was not adjusted for the gold foil sensors; however,
this does not impact the interpretation of the results (FIG.
4).
[0090] Aerosol Methods:
[0091] Delivered dose assay
[0092] The delivered dose assay was performed to determine the
efficiency and reproducibility of pulmonary delivery of the
dispersible powder cyclosporin compositions. The aerosol
performance characteristics of the powders were evaluated using the
Inhale Therapeutic System's aerosol device, similar to devices
disclosed in WO96/09085. The device includes an aerosol chamber and
employs a volume of compressed air to disperse the powder from an
aluminum foil blister package. The delivered dose efficiency (DDE)
for each powder was defined as the percentage of the nominal dose
contained within a blister package that exited the mouthpiece of
the aerosol device and was captured on a glass fiber filter
(Gelman, 47 mm diameter) through which a vacuum was drawn (30
L/min) for 2.5 seconds following device actuation. Delivered dose
efficiency was calculated by dividing the mass of the powder
collected on the filter by the mass of the powder in the blister
pack. Each result was the average of 5-10 replicate
measurements.
[0093] Aerosol particle size distribution
[0094] The aerosol particle size distribution was obtained using an
eight stage cascade impactor (Graseby Andersen, Smyrna, Ga.). The
impactor air-flow was set to pull a vacuum of 28.3 L/min, the
calibrated flow-rate for the instrument, for 2.5 seconds. For each
run, the blister packs filled with approximately 5 mg of powder
were dispersed from the inhaler. The particle size was determined
by weighing the powder on the impactor plates and evaluating the
results on a log-probability plot. Both the mass median aerodynamic
diameter (MMAD) and the mass fraction less than 5 .mu.m were
determined from the log-probability plot.
[0095] Chemical Stability Method:
[0096] The stability-indicating HPLC method that was used is
described in Oliyai, et al., Kinetics of Acid-Catalyzed Degradation
of Cyclosporin A and its Analogs in Aqueous Solutions, Peptide and
Protein Res. 43:239-247 (1994). The method was run according to
that described, however the mobile phase ratio was adjusted
slightly to obtain the retention times for cyclosporin A and
iso-cyclosporin A.
EXAMPLE 1
Cyclosporin A Spray Dried from Ethanol at 70.degree. C. with No
Secondary Drying
[0097] Solution Preparation
[0098] 1.5 g of cyclosporin A was dissolved in 50 mL of ethanol
(200 proof, USP, NF grade from Spectrum).
[0099] Spray Drying
[0100] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer using a nitrogen atmosphere containing less than 5%
oxygen (with N.sub.2 atm<5% O.sub.2) with the following
parameters:
2 Outlet Temperature 70.degree. C. Inlet Temperature 100.degree. C.
Feed Rate 5 mL/min Atomizer Flow Rate 13 lit/min Secondary Drying
None
[0101] Powder Characterization
[0102] PXRD of the powder showed that it exhibited a double halo
with two maxima at 2.theta. equal to 8.5.degree. and 17.degree.
(FIG. 1C). The absence of sharp peaks in the diffractogram show
that the material is not a 3-dimensional crystal. Polarized light
microscopy showed the particles to be birefringent. The SEM images
appear to be rounded and highly wrinkled particles. There was no
solid state change in the formulation due to the increase in
relative humidity as shown by the DSC's of the powders exposed to
0% relative humidity and 75% relative humidity. The DSC scan showed
a large endotherm ranging from about 20.degree. C. to about
70.degree. C. with a peak maximum at 69.degree. C. The Tg-like
endotherm, which is a melt, appeared on the scan at 122.degree. C.
onset temperature. Hotstage microscopy showed the melt to be in the
range of 138-140.degree. C. The MMD of the powder sample was
determined to be 1.6 .mu.m, with 96.5% less than 5.2 .mu.m.
[0103] The DEA showed a frequency-dependent change in the
permitivity indicative of a second order transition, in the same
temperature range as determined by DSC, where the change in heat
capacity started around 125.degree. C. At the temperature range
that the large endotherm was seen in the DSC scan
(.about.20-70.degree. C.), there was no change in the permitivity,
suggesting that the endotherm is not due to a phase change but
rather to solvent evaporation.
[0104] Aerosol Characterization
[0105] The delivered dose efficiency (DDE) of the above spray dried
cyclosporin A powder was determined to be 79%.+-.4.2% (n=10). The
mass median aerodynamic diameter (MMAD) was determined to be 2.81
.mu.m, with 85% less than 5 .mu.m.
[0106] Chemical Stability
[0107] HPLC analysis showed degradation products of the spray dried
cyclosporin A under stressed conditions. FIG. 5A shows a sample
stored at 110.degree. C. for 196 hours, FIG. 5B shows a sample
stored at 140.degree. C. for 50 hours and FIG. 5C shows a sample
stored at 210.degree. C. for 10 minutes. The degradation products
for the liquid crystal cyclosporin are different than for other
reported forms of cyclosporin. (Oliyai, et al., Kinetics of
Acid-Catalyzed Degradation of Cyclosporin A and its Analogs in
Aqueous Solution, Peptide and Protein Res. 43:239-247 (1994) and
Oliyai, et al., Kinetics and Mechanism of Isomerization of
Cyclosporin A, Pharm. Res. 9(5):617-622 (1992)).
EXAMPLE 2
Cyclosporin A Spray Dried from Acetone at 88.degree. C. with
Secondary Drying
[0108] Solution Preparation
[0109] 1.5 g of cyclosporin A was dissolved in 50 mL of acetone
(HPLC grade from J. T. Baker).
[0110] Spray Drying
[0111] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm<5% O.sub.2 with the following
parameters:
3 Outlet Temperature 88.degree. C. Inlet Temperature 118.degree. C.
Feed Rate 5 mL/min Atomizer Flow Rate 13 lit/min Secondary Drying
85.degree. C./5 min
[0112] Once the solution was consumed, the outlet temperature was
maintained at 85.degree. C. for 5 min by slowly decreasing the
inlet temperature to provide secondary drying.
[0113] Powder Characterization
[0114] PXRD of the powder showed that it exhibited a double halo
with two maxima at 2.theta. equal to 8.5.degree. and 17.degree..
Polarized light microscopy showed the particles to be birefringent.
TGA analysis of the powder showed the powder to have 0.1% by weight
of residual solvent and a decomposition temperature range of
347-421.degree. C. The SEM image of the powder showed the particles
to be rounded, with slight dimples. The DSC scan showed a large
endotherm ranging from about 20.degree. C. to about 70.degree. C.
with a peak maximum at 58.degree. C. The Tg-like endotherm, which
is a melt, appeared on the scan at 121.degree. C. onset
temperature. The MMD of the powder sample was determined to be 1.19
.mu.m, with 95.8% less than 5.2 .mu.m.
[0115] Aerosol Characterization
[0116] The DDE of the above spray dried cyclosporin A powder was
determined to be 59%.+-.9% (n=10). The MMAD was determined to be
2.0 .mu.m with 84% less than 5 .mu.m.
EXAMPLE 3
Cyclosporin A Spray Dried from Ethanol at 85.degree. C. with
Secondary Drying
[0117] Solution Preparation
[0118] 1.5 g of cyclosporin A was dissolved in 50 mL of ethanol
(200 proof, USP, NF grade from Spectrum).
[0119] Spray Drying
[0120] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm<5% O, with the following
parameters:
4 Outlet Temperature 85.degree. C. Inlet Temperature 120.degree. C.
Feed Rate 5 mL/min Atomizer Flow Rate 13 lit/min Secondary Drying
85.degree. C./5 min
[0121] Once the solution was consumed, the outlet temperature was
maintained at 85.degree. C. for 5 min by slowly decreasing the
inlet temperature to provide secondary drying.
[0122] Powder Characterization
[0123] PXRD of the powder showed that it exhibited a double halo
with two maxima at 2.theta. equal to 8.5.degree. and 17.degree..
Polarized light microscopy showed the particles to be birefringent.
TGA analysis of the powder showed the powder to have 0.3% by weight
of residual solvent and a decomposition temperature range of
348-425.degree. C. The SEM image of the powder showed the particles
were raisin-like. The DSC scan showed a large endotherm ranging
from about 20.degree. C. to about 70.degree. C. with a peak maximum
at 62.degree. C. The Tg-like endotherm, which is a melt, appeared
on the scan at 122.degree. C. onset temperature. The MMD of the
powder sample was determined to be 1.27 .mu.m, with 100% less than
5.2 .mu.m.
[0124] Aerosol Characterization
[0125] The DDE of the above spray dried cyclosporin A powder was
determined to be 71.4%.+-.6% (n=10). The MMAD was determined to be
2.8 .mu.m with 86% less than 5 .mu.m.
[0126] Chemical Stability
[0127] HPLC analysis showed no appreciable degradation from samples
of the spray dried cyclosporin A powder stored at 40.degree. C. and
75% relative humidity for 10 months (see FIGS. 6A, 6B and 6C). The
powder is considered to be chemically stable over the time course
of the study. FIG. 6A is a chromatogram of the mobile phase, FIG.
6B is a chromatogram of the bulk cyclosporin A in the mobile phase
with a 25 .mu.g load. FIG. 6C is a chromatogram of the spray dried
cyclosporin A aged at 40.degree. C. and 75% relative humidity for
10 months reconstituted in the mobile phase.
EXAMPLE 4
Cyclosporin A Spray Dried from Acetonitrile at 101.degree. C. with
Secondary Drying
[0128] Solution Preparation
[0129] 1.5 g of cyclosporin A was dissolved in 50 mL of
acetonitrile (HPLC grade from Burdick and Jackson).
[0130] Spray Drying
[0131] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm<5% O.sub.2 with the following
parameters:
5 Outlet Temperature 101.degree. C. Inlet Temperature 141.degree.
C. Feed Rate 5 mL/min Atomizer Flow Rate 15 lit/min Secondary
Drying 100.degree. C./5 min
[0132] Once the solution was consumed, the outlet temperature was
maintained at 100.degree. C. for 5 min by slowly decreasing the
inlet temperature to provide secondary drying.
[0133] Powder Characterization
[0134] PXRD of the powder showed that it exhibited a double halo
with two maxima at 2.theta. equal to 8.5.degree. and 17.degree..
Polarized light microscopy showed the particles to be birefringent.
The SEM image of the powder showed the particles to be slightly
dimpled. The DSC scan showed a large endotherm ranging from about
20.degree. C. to about 70.degree. C. with a peak maximum at
69.degree. C. The Tg-like endotherm, which is a melt, appeared on
the scan at 121.degree. C. onset temperature. The MMD of the powder
sample was determined to be 1.99 .mu.m, with 99% less than 5.2
.mu.m.
[0135] Aerosol Characterization
[0136] The DDE of the above spray dried cyclosporin A powder was
determined to be 69.9%.+-.7% (n=10). The MMAD was determined to be
1.9 .mu.m with 83% less than 5 .mu.m.
EXAMPLE 5
Cyclosporin A Spray Dried from Acetone at 102-103.degree. C. with
Secondary Drying
[0137] Solution Preparation
[0138] 1.5 a of cyclosporin A was dissolved in 50 mL of acetone
(HPLC grade from J. T. Baker).
[0139] Spray Drying
[0140] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm<5% O.sub.2 with the following
parameters:
6 Outlet Temperature 102-103.degree. C. Inlet Temperature
140.degree. C. Feed Rate 5 mL/min Atomizer Flow Rate 15 lit/min
Secondary Drying 101.degree. C./5 min
[0141] Once the solution was consumed, the outlet temperature was
maintained at 101.degree. C. for 5 min by slowly decreasing the
inlet temperature to provide secondary drying.
[0142] Powder Characterization
[0143] Polarized light microscopy showed the particles to be
birefringent. The SEM image of the powder showed that the particles
looked round. The DSC scan showed a large endotherm ranging from
about 20.degree. C. to about 70.degree. C. with a peak maximum at
69.degree. C. The Tg-like endotherm, which is a melt, appeared on
the scan at 123.degree. C. onset temperature.
[0144] The MMD of the powder sample was determined to be 1.20 .mu.m
with 87.0%<5.2 .mu.m.
[0145] Aerosol Characterization
[0146] The DDE of the above spray dried cyclosporin A powder was
determined to be 63.3%.+-.7% (n=10). The MMAD was determined to be
1.8 .mu.m with 80% less than 5 .mu.m.
EXAMPLE 6
90% Cyclosporin A:10% Citrate Spray Dried from Ethanol at
85.degree. C. with Secondary Drying
[0147] Solution Preparation
[0148] 1.35 g of cyclosporin A was dissolved in 50 mL of ethanol
(200 proof, USP, NF grade from Spectrum). 150 mg of Sodium Citrate
from Sigma Chemicals was dissolved in 2.5 mL of de-ionized water.
The ethanol/cyclosporin A solution was added to the Sodium
Citrate/water solution and swirled rapidly. The resulting
suspension was processed in the Spray Dryer.
[0149] Spray Drying
[0150] A dry powder comprised of cyclosporin A and sodium citrate
(90:10) was produced by spray drying the organic solution using a
Buchi B-190 Laboratory Spray Dryer with N.sub.2 atm<5% O.sub.2
with the following parameters:
7 Outlet Temperature 85.degree. C. Inlet Temperature 120.degree. C.
Feed Rate 5 mL/min Atomizer Flow Rate 13 lit/min Secondary Drying
85.degree. C/5 min
[0151] Once the solution was consumed, the outlet temperature was
maintained at 85.degree. C. for 5 min by slowly decreasing the
inlet temperature to provide secondary drying.
[0152] Powder Characterization
[0153] PXRD of the powder showed that it exhibited a double halo
with two maxima at 2.theta. equal to 8.5.degree. and 17.degree..
The sharp diffraction peaks which stood out above the double halo
corresponded to a sodium citrate dihydrate scan. Polarized light
microscopy showed the particles to be birefringent. TGA analysis of
the powder showed the powder to have 1.3% by weight of residual
solvent and a decomposition temperature range of 288-395.degree. C.
The SEM image of the powder showed the particles appeared
raisin-like and some facetted individual citrate crystals were
observed. The DSC scan showed a large endotherm ranging from about
20.degree. C. to about 70.degree. C. with a peak maximum at
59.degree. C. The Tg-like endotherm, which is a melt, appeared on
the scan at 117.degree. C. onset temperature. The MMD of the powder
sample was determined to be 1.11 .mu.m, with 96.7% less than 5.2
.mu.m.
[0154] Aerosol Characterization
[0155] The DDE of the above spray dried cyclosporin A:citrate
(90:10) powder was determined to be 65.9%.+-.5% (n=10). The MMAD
was determined to be 3.2 .mu.m with 78% less than 5 .mu.m.
EXAMPLE 7
Cyclosporin A Spray Dried from Ethanol at 85.degree. C. Without
Secondary Drying
[0156] Solution Preparation
[0157] 1.5 g of cyclosporin A was dissolved in 50 mL of ethanol
(200 proof, USP, NF grade from Spectrum).
[0158] Spray Drying
[0159] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm<5% O.sub.2 with the following
parameters:
8 Outlet Temperature 85.degree. C. Inlet Temperature 120.degree. C.
Feed Rate 5 mL/min Atomizer Flow Rate 13 lit/min Secondary Drying
None
[0160] Powder Characterization
[0161] PXRD of the powder showed that it exhibited a double halo
with two maxima at 2.theta. equal to 8.5.degree. and 17.degree..
Polarized light microscopy showed the particles to be birefringent.
TGA analysis of the powder showed the powder to have 0.7% by weight
of residual solvent and a decomposition temperature range of
347-428.degree. C. The SEM image of the powder showed that the
particles looked raisin-like. The DSC scan showed a large endotherm
ranging from about 20.degree. C. to about 70.degree. C. with a peak
maximum at 65.degree. C. The Tg-like endotherm, which is a melt,
appeared on the scan at 122.degree. C. onset temperature. The MMD
of the powder sample was determined to be 0.9 .mu.m, with 97.6%
less than 5.2 .mu.m.
[0162] Aerosol Characterization
[0163] The DDE of the above spray dried cyclosporin A powder was
determined to be 70.8%.+-.3% (n=10). The MMAD was determined to be
2.7 .mu.m with 85% less than 5 .mu.m.
EXAMPLE 8
Cyclosporin A Spray Dried from Ethanol at 101.degree. C. with No
Secondary Drying
[0164] Solution Preparation
[0165] 1.0 g of cyclosporin A was dissolved in 33 mL of ethanol
(HPLC grade).
[0166] Spray Drying
[0167] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm<5% O.sub.2 with the following
parameters:
9 Outlet Temperature 101.degree. C. Inlet Temperature 138.degree.
C. Feed Rate 5 mL/min Atomizer Flow Rate 14.5 lit/min Secondary
Drying None
[0168] Powder Characterization
[0169] Polarized light microscopy showed the particles to be
birefringent. The SEM images showed that the particles were
slightly dimpled. The DSC scan showed a large endotherm ranging
from about 20.degree. C. to about 70.degree. C. with a peak maximum
at 68.degree. C. The Tg-like endotherm, which is a melt, appeared
on the scan at 122.degree. C. onset temperature. The MMD of the
powder sample was determined to be 2.3 .mu.m, with 86.6% less than
5.2 .mu.m. The X-ray diffraction pattern of the powder showed a
halo with two broad maxima at 2.theta. equal to .about.8.5.degree.
and .about.18.8.degree.. The small angle X-ray diffraction pattern
of the powder showed a peak at 2.theta. equal to 0.2.degree.,
indicative of 2-dimensional order.
[0170] Aerosol Characterization
[0171] The DDE of the above spray dried cyclosporin A powder was
determined to be 64%.+-.6.9% (n=7). The MMAD was determined to be
2.59 .mu.m with 75% less than 5 .mu.m.
EXAMPLE 9
[0172] Cyclosporin A Spray Dried from Acetone at 49.degree. C. with
No Secondary Drying
[0173] Solution Preparation
[0174] 1.0 g of cyclosporin A was dissolved in 33 mL of acetone
(HPLC grade).
[0175] Spray Drying
[0176] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm<5% O.sub.2 with the following
parameters:
10 Outlet Temperature 49.degree. C. Inlet Temperature 60.degree. C.
Feed Rate 5 mL/min Atomizer Flow Rate 14.5 lit/min Secondary Drying
None
[0177] Powder Characterization
[0178] Polarized light microscopy showed the particles to be
birefringent. The SEM images showed that the particles were round
and dimpled. The MMD of the powder sample was determined to be 3.5
.mu.m, with 70.3% less than 5.2 .mu.m.
[0179] Aerosol Characterization
[0180] The DDE of the above spray dried cyclosporin A powder was
determined to be 52.4%.+-.2.1% (n=7). The MMAD was determined to be
2.30 .mu.m with 63.6% less than 5 .mu.m.
EXAMPLE 10
Cyclosporin A Spray Dried from Acetone at 100.degree. C. with No
Secondary Drying
[0181] Solution Preparation
[0182] 1.0 g of cyclosporin A was dissolved in 33 mL of acetone
(HPLC grade).
[0183] Spray Drying
[0184] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm<5% O.sub.2 with the following
parameters:
11 Outlet Temperature 100.degree. C. Inlet Temperature 135.degree.
C. Feed Rate 5 mL/min Atomizer Flow Rate 14.5 lit/min Secondary
Drying None
[0185] Powder Characterization
[0186] Polarized light microscopy showed the particles to be
birefringent. The SEM images showed that the particles were round
and non-dimpled. The DSC scan showed a large endotherm ranging from
about 20.degree. C. to about 70.degree. C. with a peak maximum at
66.degree. C. The Tg-like endotherm, which is a melt, appeared on
the scan at 120.degree. C. onset temperature. The MMD of the powder
sample was determined to be 2.75 .mu.m, with 76.3% less than 5.2
.mu.m.
[0187] The X-ray diffraction pattern of the powder showed a halo
with a broad maxima at 2.theta. equal to .about.7.8.degree.. The
small angle X-ray diffraction pattern of the powder showed a peak
at 20 equal to 0.2.degree., indicative of 2-dimensional order.
[0188] Aerosol Characterization
[0189] The delivered dose efficiency (DDE) of the above spray dried
cyclosporin A powder was determined to be 57.3%.+-.3.42% (n=7). The
mass median aerodynamic diameter (MMAD) was determined to be 2.1
.mu.m with 70% less than 5 .mu.m.
EXAMPLE 11
Cyclosporin A Spray Dried from Isopropanol at 77.degree. C., No
Secondary Drying
[0190] Solution Preparation
[0191] 1.0 g of cyclosporin A was dissolved in 33 mL of isopropyl
alcohol (HPLC grade).
[0192] Spray Drying
[0193] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm <5% O.sub.2 with the following
parameters:
12 Outlet Temperature 77.degree. C. Inlet Temperature 105.degree.
C. Feed Rate 5 mL/min Atomizer Flow Rate 14.5 lit/min Secondary
Drying None
[0194] Powder Characterization
[0195] Polarized light microscopy showed the particles to be
birefringent. The SEM images showed that the particles were round
and slightly dimpled. The DSC scan showed a large endotherm ranging
from about 20.degree. C. to about 70.degree. C. with a peak maximum
at 66.degree. C. The Tg-like endotherm, which is a melt, appeared
on the scan at 122.degree. C. onset temperature. The MMD of the
powder sample was determined to be 2.22 .mu.m, with 85.7% less than
5.2 .mu.m. The X-ray diffraction pattern of the powder showed a
halo with a broad maxima at 2.theta. equal to .about.7.5.degree..
The small angle X-ray diffraction pattern of the powder showed a
peak at 2.theta. equal to 0.1.degree., indicative of 2-dimensional
order.
[0196] Aerosol Characterization
[0197] The DDE of the above spray dried cyclosporin A powder was
determined to be 69.2%.+-.2.42% (n=7). The MMAD was determined to
be 3.8 .mu.m with 97.8% less than 5 .mu.m.
EXAMPLE 12
Cyclosporin A Spray Dried from Isopropanol at 104.degree. C., No
Secondary Drying
[0198] Solution Preparation
[0199] 1.0 g of cyclosporin A was dissolved in 33 mL of isopropyl
alcohol (HPLC grade).
[0200] Spray Drying
[0201] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm <5% O.sub.2 with the following
parameters:
13 Outlet Temperature 104.degree. C. Inlet Temperature 145.degree.
C. Feed Rate 5 mL/min Atomizer Flow Rate 14.5 lit/min Secondary
Drying None
[0202] Powder Characterization
[0203] Polarized light microscopy showed the particles to be
birefringent. The SEM images showed that the particles were round
and non-dimpled. The DSC scan showed a large endotherm ranging from
about 20.degree. C. to about 70.degree. C. with a peak maximum at
66.degree. C. The Tg-like endotherm, which is a melt, appeared on
the scan at 121.degree. C. onset temperature. The MMD of the powder
sample was determined to be 2.36 .mu.m, with 89.9% less than 5.2
.mu.m. The X-ray diffraction pattern of the powder showed a halo
with two broad maxima at 2.theta. equal to .about.8.9.degree. and
.about.19.degree.. The small angle X-ray diffraction pattern of the
powder showed a peak at 2.theta. equal to 0.1.degree., indicative
of 2-dimensional order.
[0204] Aerosol Characterization
[0205] The DDE of the above spray dried cyclosporin A powder was
determined to be 67.1%.+-.2.85% (n=7). The MMAD was determined to
be 2.7 .mu.m with 76.8% less than 5 .mu.m.
EXAMPLE 13
[0206] Cyclosporin A Spray Dried from Methanol at 63.degree. C.
with No Secondary Drying
[0207] Solution Preparation
[0208] 1.0 g of cyclosporin A was dissolved in 33 mL of methanol
(HPLC grade).
[0209] Spray Drying
[0210] A dry powder comprised of cyclosporin A was produced by
spray drying the organic solution using a Buchi B-190 Laboratory
Spray Dryer with N.sub.2 atm <5% O.sub.2 with the following
parameters:
14 Outlet Temperature 63.degree. C. Inlet Temperature 88.degree. C.
Feed Rate 5 mL/min Atomizer Flow Rate 14.5 lit/min Secondary Drying
None
[0211] Powder Characterization
[0212] Polarized light microscopy showed the particles to be
birefringent. The SEM images showed that the particles were very
dimpled. The MMD of the powder sample was determined to be 2.37
.mu.m, with 90.1% less than 5.2 .mu.m. The DSC scan showed a large
endotherm ranging from about 20-70.degree. C. with a peak maximum
at 52.degree. C. The Tg-like endotherm, which is a melt, appeared
on the scan at 119.degree. C. onset temperature.
[0213] Aerosol Characterization
[0214] The DDE of the above spray dried cyclosporin A powder was
determined to be 67.2%.+-.3.43% (n=6). The MMAD was determined to
be 2.5 .mu.m with 80.7% less than 5 .mu.m.
EXAMPLE 14
[0215] The method of Example 1 was followed except that the
solution was atomized using a standard, commercially available,
Buchi nozzle. The mass mean diameter (MMD) of the droplets using
this nozzle was between 7 and 15 .mu.m.
[0216] Chemical Stability
[0217] HPLC analysis showed no appreciable degradation from the
samples of the spray dried cyclosporin A powder. FIG. 7 is a
chromatogram of the spray dried sample reconstituted in a mobile
phase after storage for 15 months at room temperature. The powder
was determined to be chemically stable over the time course of the
study.
EXAMPLE 15
Processing of Spray Dried Cyclosporin A Powder Formulations
[0218] Spray dried cyclosporin A powders were produced from various
solvents using a variety of spray drying temperatures with or
without secondary drying. Secondary drying appeared to have no
effect on particle properties.
[0219] Measurement of residual solvent showed that little solvent
was left in the particles. Lower levels of residual solvent are
preferred to minimize any possible lung irritation caused by
solvent.
[0220] The percent yield, defined as the weight of CsA-containing
powder recovered in the collector of the spray dryer divided by the
weight of CsA (and any excipient) in the solution which was spray
dried (times 100%), ranged from 22% to 78%. Yields of at least
about 20% are preferred, with higher yields being generally more
preferred, so long as other powder characteristics such as MMD and
DDE are acceptable.
[0221] The fine particle fraction (%), defined as DDE times the %
<5 .mu.m, ranged from 33.3 to 67.7%. Powders with a fine
particle fraction of at least about 25% are preferred.
[0222] Several batches of CsA powders were spray dried from ethanol
at 70.degree. C. without secondary drying. The results of these
batches is presented in Table 2.
15TABLE 2 CsA Powders Spray Dried from Ethanol at 70.degree. C.
with No Secondary Drying Fine Yield MMD DDE % Particle Trial %
.mu.m % <5 .mu.m Fraction 1 70.0 0.8 71.4 85.6 61.1 2 66.3 1.6
78.6 84.4 66.4 3 59.5 1.7 76.3 78.0 59.5
[0223] Modification of the above-described modes of carrying out
the various embodiments of this invention will be apparent to those
skilled in the art following the teachings of this invention as set
forth herein. The examples described above are not limiting, but
are merely exemplary of this invention, the scope of which is
defined by the following claims.
[0224] The disclosure of each publication, patent or patent
application mentioned in this specification is hereby incorporated
by reference to the same extent as if each individual publication,
patent or patent application were specifically and individually
indicated to be incorporated by reference.
* * * * *