U.S. patent application number 15/747032 was filed with the patent office on 2019-01-10 for drug loaded nanoresin particles.
This patent application is currently assigned to SUN PHARMA ADVANCED RESEARCH COMPANY LIMITED. The applicant listed for this patent is SUN PHARMA ADVANCED RESEARCH COMPANY LIMITED. Invention is credited to Arindam Halder, Ajay Jaysingh Khopade, Shivam Umeshkumar Upadhyay.
Application Number | 20190008772 15/747032 |
Document ID | / |
Family ID | 57884335 |
Filed Date | 2019-01-10 |
United States Patent
Application |
20190008772 |
Kind Code |
A1 |
Khopade; Ajay Jaysingh ; et
al. |
January 10, 2019 |
DRUG LOADED NANORESIN PARTICLES
Abstract
The present invention relates to nano-resin particles that are
suitable for pharmaceutical use and their use in the pharmaceutical
field. The present invention provides nano-sized resin particles
having a particle size distribution characterized in that D.sub.90
value is between 200 nanometers to 900 nanometer and D.sub.10 value
is not less than 50 nanometers, wherein the nano-resin particles
are in pure form and safe for pharmaceutical use. The present
invention further relates to pharmaceutical compositions comprising
these purified nano-resin particles and their use in the treatment
of diseases. The present invention further provides a process for
preparing purified, nano-sized resin particles that are suitable
for pharmaceutical use, the process comprising steps of: (i)
washing an ion exchange resin and suspending in an aqueous liquid,
(ii) subjecting the suspension of (i) to wet milling for a period
such that the particles have a particle size distribution
characterized in that the D90 value is between 200 nanometers to
900 nanometers and D.sub.10 value is not less than 50 nanometers,
(iii) subjecting the suspension of (ii) to purification to remove
impurities, (iv) drying the pun fled suspension to obtain
nano-resin particles in the form of dry powder.
Inventors: |
Khopade; Ajay Jaysingh;
(Baroda, IN) ; Halder; Arindam; (Baroda, IN)
; Upadhyay; Shivam Umeshkumar; (Baroda, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SUN PHARMA ADVANCED RESEARCH COMPANY LIMITED |
Mumbai |
|
IN |
|
|
Assignee: |
SUN PHARMA ADVANCED RESEARCH
COMPANY LIMITED
Mumbai
IN
|
Family ID: |
57884335 |
Appl. No.: |
15/747032 |
Filed: |
July 27, 2016 |
PCT Filed: |
July 27, 2016 |
PCT NO: |
PCT/IN2016/050253 |
371 Date: |
January 23, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 9/06 20130101; A61K
31/196 20130101; A61K 9/10 20130101; A61K 9/2018 20130101; A61K
31/519 20130101; A61K 31/498 20130101; B82Y 5/00 20130101; A61K
47/38 20130101; A61K 9/146 20130101; A61K 47/32 20130101; A61K
9/0014 20130101; A61K 31/335 20130101; A61K 31/135 20130101; A61K
31/65 20130101 |
International
Class: |
A61K 9/14 20060101
A61K009/14; A61K 31/498 20060101 A61K031/498; A61K 31/65 20060101
A61K031/65; A61K 31/335 20060101 A61K031/335; A61K 31/196 20060101
A61K031/196; A61K 31/135 20060101 A61K031/135; A61K 31/519 20060101
A61K031/519 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 27, 2015 |
IN |
2841/MUM/2015 |
Claims
1. Nano-resin particles having a particle size distribution
characterized in that the D.sub.90 value is between 200 nanometers
to 900 nanometers and D.sub.10 value is not less than 50
nanometers.
2. The nano-resin particles as claimed in claim 1, wherein the
particle size distribution is characterized in that the D.sub.50
value is between 75 nanometers to 300 nanometers.
3. The nano-resin particles as claimed in claim 1, wherein the
nano-resin particles are loaded with a drug, such that the
drug-loaded nano-resin is suitable for pharmaceutical use.
4. The nano-resin particles as claimed in claim 1, wherein the
nano-resin particles contain water extractable impurities of not
more than 1% by weight of the total resin.
5. The nano-resin particles as claimed in claim 1, wherein the
nano-resin particles contain total unknown organic impurities of
not more than 3 ppm.
6. The nano-resin particles as as claimed in claim 1, wherein the
nano-resin is an ion exchange resin selected from a cation exchange
resin or an anion exchange resin.
7. A suspension dosage form comprising drug loaded nanoresin
particles having a particle size distribution characterized in that
the D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, a suspending agent
and an aqueous vehicle, wherein the drug loaded nanoresin particles
are characterized by a property of forming reversible clusters
having a D.sub.50 value of at least 2 micrometer.
8. A process of preparing nano-resin particles having a particle
size distribution characterized in that the D.sub.90 value is
between 200 nanometers to 900 nanometer and D.sub.10 value is not
less than 50 nanometers, the process comprising steps of: i.
washing an ion exchange resin and suspending in an aqueous liquid,
ii. subjecting the suspension of (i) to wet milling for a period
such that the particles have a particle size distribution
characterized in that the D.sub.90 value is between 200 nanometers
to 900 nanometers and D.sub.10 value is not less than 50
nanometers, iii. subjecting the suspension of (ii) to purification
to remove impurities, iv. drying the purified suspension to obtain
nano-resin particles in the form of dry powder.
9. Nanoresin particles prepared by the process of claim 8.
10. A method of treating a disease, comprising administering via
dermal or oral or sublingual route of administration drug loaded
nano-resin particles having a particle size distribution
characterized in that the D.sub.90 value is between 200 nanometers
to 900 nanometers and D.sub.10 value is not less than 50
nanometers.
11. The method as claimed in claim 10, wherein the particle size
distribution is characterized in that the D.sub.50 value is between
75 nanometers to 300 nanometers.
12. The method as claimed in claim 10, wherein the nano-resin
particles contain water extractable impurities of not more than 1%
by weight of the total resin.
13. The method as claimed in claim 10, wherein the nano-resin
particles contain total unknown organic impurities of not more than
3 ppm.
14. The method claimed in claim 10, wherein the nano-resin is an
ion exchange resin selected from a cation exchange resin or an
anion exchange resin.
15. The method as claimed in claim 10, Use of wherein the drug
loaded nanoresin particles are in an aqueous suspension dosage form
comprising a suspending agent and an aqueous vehicle.
16. The method as claimed in claim 10, wherein the drug loaded
nanoresin particles are in a semisolid dosage form in an aqueous or
a non-aqueous vehicle, and the drug is delivered via dermal route
of administration.
17. The method as claimed in claim 16, wherein the semisolid dosage
form is a cream, ointment, lotion, emulsion, suspension or a gel.
Description
FIELD OF INVENTION
[0001] The present invention relates to nano-resin particles that
are suitable for pharmaceutical use and their use in the
pharmaceutical field.
BACKGROUND OF THE PRESENT INVENTION
[0002] There is plethora of prior art on the use of resins,
particularly ion exchange resin, to complex the drug to meet
various objectives such as to make a taste masking composition, to
improve chemical stability of a drug, controlling the release of
the drug etc. Ion exchange resins are commercially available, but
the average particle size is in micrometer size, such as for
example in the range of 50 to 150 microns. Till date, ion exchange
resins are known to be available only in the micrometer size range,
and not in nanometer range which may be suitable for pharmaceutical
use. This may be due to the fact that while reducing the particle
size of the ion exchange resins, the resin material tends to break
down forming impurities which raise safety concerns or toxicity
concerns such as irritation to the mucosa, skin irritation,
hypersensitivity, allergic reactions and so on. For example, the
limit for water extractable impurities for Amberlite IRP-64 is not
more than 2%. The present inventors faced with a problem of
unacceptable higher levels of water extractable impurities as high
as 3% and more than 10 ppm of organic extractable impurities, when
the resins were reduced to a particle size in the nanometer
range.
SUMMARY OF THE INVENTION
[0003] The present inventors arrived at ion exchange nano-resin
particles having average particle size range in nano-meter range
and low levels of water extractable and organic impurities. The
milled resin particles have a particle size distribution such that
the D.sub.90 value is between 200 nanometers to 900 nanometer and
D.sub.10 value is not less than 50 nanometers. This fraction of the
resin is particularly free of very fine particles such as particles
having size of less than 50 nanometers. The inventors found that
such a resin of the defined particle size distribution such that
D.sub.90 value is between 200 nanometers to 900 nanometer and
D.sub.10 value is not less than 50 nanometers, could be obtained by
a process which is less time consuming, economical and cost
effective. Lowering the content of the very fine particles that are
less than 50 nm enabled the inventors to purify the resins. It was
found by the inventors that it was extremely difficult to obtain
purified form of a resin that includes very fine particles having
D.sub.10 value of less than 50 nanometers. This was because during
the purification of the milled resins to remove the water
extractable impurities by passing through an ultrafiltration
membrane, there was a problem of clogging of the membrane because
of the presence of fine particles such as those which have D.sub.10
value of less than 50 nanometers, making the process very time
consuming and not feasible in commercial scale.
[0004] The present invention provides nano-sized resin particles
suitable for pharmaceutical use, wherein the resin particles have a
particle size distribution such that D.sub.90 value is between 200
nanometers to 900 nanometers and D.sub.10 value is not less than 50
nanometers. The purified nanoresins of the present invention
contain water extractable impurities of less than 1% by weight. The
individual unknown organic impurity is not more than 1 ppm and
total unknown organic impurities are not more than 3 ppm. Such a
purified form of the nano-resin particles of the present invention
finds applicability as efficient drug carriers, where drugs are
adsorbed onto the surface of the resin particles. These drug loaded
nano-resin particles are suitable for incorporation into
pharmaceutical dosage forms meant for topical, ophthalmic, dermal,
peripheral, oral, sublingual, nasal, otic, peripheral, rectal or
vaginal delivery.
[0005] In one aspect, the present invention provides use of a
pharmaceutical composition comprising drug loaded nano-resin
particles having a particle size distribution characterized in that
the D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, in the treatment of
a disease by delivering the drug via dermal or oral or sublingual
route of administration. The drug loaded nano-resin particles used
in the treatment of a disease by delivering the drug via dermal or
oral or sublingual route of administration contain water
extractable impurities of not more than 1% by weight of the total
resin and total unknown organic impurities of not more than 3
ppm.
[0006] In one aspect the present invention provides an aqueous
suspension dosage form comprising drug loaded nanoresin particles
having a particle size distribution characterized in that the
D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, a suspending agent
and an aqueous vehicle, and its use in the treatment of a disease
by delivering the drug via dermal or oral or sublingual route of
administration.
[0007] In another aspect, the present invention provides a
semisolid dosage form comprising drug loaded nanoresin particles
having a particle size distribution characterized in that the
D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, in an aqueous or a
non-aqueous vehicle, and its use in the treatment of a disease by
delivering the drug via dermal route of administration. The
semisolid dosage form can be in the form of a cream, ointment,
lotion, emulsion, suspension or a gel.
[0008] The present invention also provides nano-sized resin
particles suitable for pharmaceutical use, wherein the resin
particles have a particle size distribution such that D.sub.90
value is between 200 nanometers to 900 nanometers and D.sub.10
value is not less than 50 nanometers, prepared by a process
comprising steps of: [0009] i. washing an ion exchange resin and
suspending in an aqueous liquid, [0010] ii. subjecting the
suspension of (i) to wet milling for a period such that the
particles have a particle size distribution characterized in that
the D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, [0011] iii.
subjecting the suspension of (ii) to purification to remove
impurities, [0012] iv. drying the purified suspension to obtain
nano-resin particles in the form of dry powder.
[0013] The present invention further relates to a process of
preparing nano-sized resin particles having a particle size
distribution such that D.sub.90 value is between 200 nanometers to
900 nanometer and D.sub.10 value is not less than 50 nanometers,
the process comprising steps of: [0014] i. washing an ion exchange
resin and suspending in an aqueous liquid, [0015] ii. subjecting
the suspension of (i) to wet milling for a period such that the
particles have a particle size distribution characterized in that
the D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, [0016] iii.
subjecting the suspension of (ii) to purification to remove
impurities, [0017] iv. drying the purified suspension to obtain
nano-resin particles in the form of dry powder.
BRIEF DESCRIPTION OF THE FIGURES
[0018] FIG. 1 is an illustrative histogram for the nano-resin
particles of the present invention.
[0019] FIG. 2 is the histogram showing particle size distribution
of individual drug-loaded nanoresin particles in aqueous suspension
when subjected to application of shear as per Example 4 of the
specification.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The particle size is expressed in terms of particle size
distribution including values of D.sub.90, D.sub.50 and D.sub.10,
as measured by Malvern Mastersizer, which is based on laser light
diffraction technique. The particle size distribution may
alternatively be measured using other techniques such as photon
correlation spectroscopy, sedimentation field flow fractionation,
or disk centrifugation.
[0021] The water extractable impurities and organic impurities like
individual unknown impurity and total unknown organic impurities,
of the resin are the impurities that are formed during milling and
whose chemical structure is not known. Such impurities may be
determined by techniques known in the art. In one aspect, the water
extractable impurities are determined by weighing the dried water
extract of the resin. The organic impurities may be determined by
extracting the resin with an organic solvent and determining the
impurities content by weighing the dried organic extract of the
resin. It is possible to determine the impurity levels by any other
means such as HPLC, mass spectroscopy etc.
[0022] `Reversible Clusters` of drug loaded nano-resin particles,
as described herein means that the individual drug loaded nanoresin
particles when formulated into an aqueous suspension along with
suspending agents, form aggregates or agglomerates having mean size
of about 2 micrometers or greater, which upon application of mild
shear, deagglomerate or decluster into individual drug loaded
nano-resin particles. The mild shear that can cause deagglomeration
or declustering of the reversible clusters include mild shear such
as that observed upon blinking of eye or contact with aqueous
environment of mucous membranes, saliva, gastrointestinal flora,
mild rubbing or application during topical skin application and the
like.
[0023] According to one aspect of the invention, the resin is an
ion exchange resin. The ion exchange resins are covalently bound in
repeating positions on the resin chain. These charged groups
associate with other ions of opposite charge. The ion exchange
resin may be cationic or anionic in nature. Depending on whether
the mobile counter ion is a cation or an anion, it is possible to
distinguish between cationic and anionic exchange resins. The ion
exchange resins commercially available in the market have a mean
particle size in micron range such as for example between 50
microns to 150 microns. The matrix in cationic exchangers carries
ionic groups such as sulfonic, carboxylate and phosphate groups.
The matrix in anionic exchangers carries primary, secondary,
tertiary or quaternary ammonium groups. The resin matrix determines
its physical properties, its behavior towards biological
substances, and to a certain extent, its capacity.
[0024] Cationic drugs such as brimonidine have a positive charge,
so they can bind with cation exchange resins. Preferred cation
exchange resin includes sulfonic acid exchangers. In general, they
are cross-linked polystyrenes with sulfonic acid groups that have
been introduced after polymerization by treatment with sulfuric
acid or chlorosulfonic acid.
[0025] Suitable cation exchange resins that may be used in the
present invention includes, but are not limited to, sodium
polystyrene divinyl benzene sulphonate, such as marketed by Rohm
and Haas, under the trade name Amberlite.TM. IRP 69; polacrilex
resin which is derived from a porous copolymer of methacrylic acid
and divinylbenzene, such as marketed by Rohm and Haas, under the
trade name Amberlite.TM. IRP 64; polacrilin potassium, which is a
potassium salt of a cross linked polymer derived from methacrylic
acid and divinylbenzene, such as marketed by Rohm and Haas, under
the trade name Amberlite.TM. IRP 88. The resins marketed by the
company Ion Exchange India Ltd., under the tradenames such as
INDION.TM.234; INDION.TM.264; INDION.TM. 204; INDION.TM. 214 may
also be used.
[0026] In one embodiment, the preferred resin used in the present
invention is Amberlite IRP69 which is derived from a sulfonated
copolymer of styrene and divinyl benzene. Amberlite IRP-69 is a
pharmaceutical grade strong cation exchange resin and structurally
a polystyrene sulfonic acid resin cross-linked with divinyl
benzene, i.e. polystyrene divinyl benzene sulfonate. Amberlite
IRP-69 resin is available commercially from Rhom & Haas
Company. The mobile or exchangeable cation in the resin is sodium,
which can be exchanged for, or replaced by, cationic (basic)
species.
[0027] In some embodiments of the present invention, positively
charged cationic drug is bound to the negatively charged sulfonic
acid groups of the Amberlite resin.
[0028] In some embodiments of the present invention, the
ion-exchange resin is an anion exchange resin and the drug is
anionic in nature. The matrix in anionic exchange resin generally
carries primary, secondary, tertiary or quaternary ammonium groups.
Suitable anion exchange resins that may be used in the present
invention includes, but are not limited to, cholestyramine resin,
such as marketed by Rohm and Haas, under the trade name Duolite.TM.
AP143/1093; INDION.TM.860, which is a macroporous weakly basic
anion resin having a tertiary amine functionality attached to a
polymeric styrene divinyl benzene matrix; INDION.TM.GS400, which is
strong base Type II anion exchange resin, based on cross linked
polystyrene matrix with benzyl dimethyl ethanol amine functional
groups.
[0029] The present invention provides nano-resin particles having a
particle size distribution characterized in that the D.sub.90 value
is between 200 nanometers (nm or nms) to 900 nanometers (nm or
nms), such as 250, 300, 350, 400, 450, 500, 550, 600, 650, 700,
750, 800 or 850 nanometers, preferably between 250 nms to 700 nms,
more preferably between 300 nms to 500 nms. The nano-resin
particles have a D.sub.50 value between 75 nms to 300 nms, such as
80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250 or 275
nanometers, preferably between 100 nms to 250 nms, more preferably
between 120 nms to 175 nms. The nano-resin particles have a
D.sub.10 value of not less than 50 nanometers, preferably between
50 nms to 200 nms, such as 60 nms, 65 nms, 70 nms, 75 nms, 80 nms,
85 nms, 90 nms, 95 nms, 100 nms, 110 nms, 120 nms, 130 nms, 140
nms, 150 nms, 160 nms, 170 nms, 180 nms or 190 nms, more preferably
between 60 nms to 150 nms.
[0030] In one embodiment, the present invention provides nano-resin
particles having a particle size distribution characterized in that
the D.sub.90 value is between 200 nms to 900 nms, and D.sub.10
value is not less than 50 nanometers.
[0031] In one embodiment, the present invention provides nano-resin
particles having a particle size distribution characterized in that
the D.sub.90 value is between 200 nms to 900 nms, D.sub.50 value is
between 75 nms to 300 nms and D.sub.10 value is not less than 50
nanometers.
[0032] In one embodiment, the present invention provides nano-resin
particles having a particle size distribution characterized in that
the D.sub.90 value is between 250 nms to 700 nms, D.sub.50 value is
between 100 nms to 250 nms and D.sub.10 value is between 60 nms to
150 nanometers, for example, 65 nm, 70 nms, 71 nms, 72 nms, 73 nm,
74 nms, 75 nm, 80 nms, 85 nms, 90 nms, 95 nms, 100 nms, 105 nms,
110 nms, 120 nms, 130 nms, 140 nms or 150 nms.
[0033] The `drugs` according to the present invention include
therapeutically active ingredients that are capable of forming a
salt with an acid or an alkali, and includes ionizable
therapeutically active ingredients.
[0034] According to one aspect, drugs include ionizable drugs that
can form salts with acids, known as cationic drugs.
[0035] According to another aspect, drugs include ionizable drugs
that can form a salt with a base or an alkali, known as anionic
drugs.
[0036] Non limiting examples of the drugs according to the present
invention include therapeutically active agents selected from, but
not limited to antiglaucoma agents; antibiotics or anti-infective
agents; anti-allergic agents; antihistamines; analgesic agents;
anti-inflammatory agents; steroids; non-steroidal anti-inflammatory
agents; decongestant; anaesthetic agents; mydriatic agents,
analeptic agents; antiasthmatic agents; antiarthritic agents;
anticancer agents; anticholinergic agents; anticonvulsant agents;
antidepressant agents; antiemetic agents; antihelminthic agents;
antidiabetic agents; antidiarrheal agents; antihyperlipidemic
agents; antihypertensive agents; antimigraine agents;
antineoplastic agents; antiparkinsonism drugs; antipruritic agents;
antipsychotic agents; antipyretic agents; antispasmodic agents;
antitubercular agents; antiulcer agents; antiviral agents;
anxiolytic agents; anorexic agents; attention deficit disorder and
attention deficit hyperactivity disorder drugs; cardiovascular
agents including calcium channel blockers, antianginal agents,
central nervous system agents, beta-blockers and antiarrhythmic
agents; central nervous system stimulants; diuretics; genetic
materials; hormonolytics; hypnotics; hypoglycemic agents;
immunosuppressive agents; muscle relaxants; narcotic antagonists;
nicotine; nutritional agents; parasympatholytics; peptide drugs;
psychostimulants; sedatives; sialagogues, steroids; smoking
cessation agents; sympathomimetics; tranquilizers; vasodilators;
beta-agonist etc. These include drugs that are suitable for the
treatment of disorders of the eye, like antiglaucoma agents, such
as beta-blockers, carbonic anhydrase inhibitors, alpha-adrenergic
agonists, prostaglandins, parasympathomimetics and cholinesterase
inhibitors.
[0037] Non-limiting examples drugs that may be used include,
latanoprost, travoprost, bimatoprost, tafluprost, isopropyl
unoprostone, 8-isoprostaglandin-E2, timolol, levobunolol, befundol,
metipranolol, carteolol, betaxolol, levobetaxolol, timolol,
befunolol, labetalol, propranolol, metaprolol, bunalol, esmalol,
pindolol, hepunolol, metipranolol, celiprolol, azotinolol,
diacetolol, acebutolol, atenolol, isoxaprolol, brinzolamide,
dorzolamide, acetazolamide, methazolamide, dichlorophenamide,
brimonidine, dipivefrine, clonidine, p-aminoclonidine,
p-acetoamidoclonidine, apraclonidine, physostigmine, ecothiopate,
pilocarpine, demecarium, moxifloxacin, besifloxacin, gentamicin,
neomycin; erythromycin, ciprofloxacin, polymyxin B, beta-lactam
antibiotics, tetracycline, minocycline, doxycycline,
chlortetracycline, olopatadine, emedastine, azelastine, epinastine,
levocabastine, bepotastine, pheniramine, chlorpheniramine,
epinephrine, proepinephrine, norepinephrine, pyrilamine,
dextromethorphan, dexamethasone, prednisolone, amitryptilline,
ketotifen, oxymetazoline, phenylephrine, naphazoline, antazoline,
proparacaine, lidocaine, cyclopentolate, diclofenac, bromfenac,
sulfacetamide, flurbiprofen, ketorolac, lodoxamide, sulfacetamide,
methotrexate, cromolyn, pemirolast or their pharmaceutically
acceptable salts or mixtures thereof. Other drugs that can form a
complex with ion exchange resins may also be used and are within
the scope of this invention.
[0038] In one embodiment, the weight ratio of resin to drug may
range from 0.1:1 to 1:0.1, such as 0.2:1 to 1:0.2, 0.3:1 to 1:0.3,
0.4:1 to 1:0.4, 0.5:1 to 1:0.5, 0.6:1 to 1:0.6, 0.7:1 to 1:0.7,
0.8:1 to 1:0.8 or 0.9:1 to 1:0.9, more preferably from 0.3:1 to
1:0.3. In one preferred embodiment, the weight ratio between the
nano-resin particles and drug is about 1:1.
[0039] The nano-resin particles of the present invention in dried
form have water content of not more than 15% by weight, such as not
more than 14.0, 13.0, 12.0, 11.0, 10.0, 9.0, 8.0, 7.0, 6.0, 5.5,
5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.0 or 0.5%, preferably not
more than 10%, more preferably not more than 5% by weight.
[0040] The nano-resin particles of the present invention are in
purified form, suitable for pharmaceutical use. The nano-resin
particles in a purified form contain safe amounts of water
extractable impurities and organic impurities like individual
unknown impurity and total unknown organic impurities. The purified
nanoresins contain water extractable impurities of less than 1% by
weight, individual unknown organic impurity not more than 1 ppm
(parts per million) and total unknown organic impurities not more
than 3 ppm.
[0041] The purified nano-resin particles of the present invention
are safe for pharmaceutical use. The safety has been tested and
demonstrated in one of the most sensitive external tissue of the
body i.e. the ocular tissue. The nano-resin particles were used to
formulate an ophthalmic suspension of drug loaded nano-resinate
particles. The test drug was brimonidine. The ophthalmic suspension
was subjected to safety studies by daily ocular administration to
the eyes of New-Zealand White rabbits for consecutive 14 days. The
effect of various dose levels was studied, the dose levels varying
from low dose (60 .mu.L/animal/day i.e. 30 .mu.L per
eye/time.times.1 times a day) to mid dose (180 .mu.L/animal/day
i.e. 30 .mu.L per eye/time.times.3 times a day) to high dose (360
.mu.L/animal/day i.e. 30 .mu.L per eye/time.times.6 times a day).
Several safety related test parameters were evaluated,
including--Daily Clinical Signs and Mortality; Detailed Clinical
Sign Observation; Body Weights; Ophthalmoscopy and Necroscopy. The
details of these test parameters along with the results are
described below. Besides these, other parameters were also
evaluated including: clinical pathology, histology, biochemistry,
prothrombin time and urine analysis. It was observed that there
occurs no mortality in animals of any dose group. No test item
related clinical signs were observed during daily or detailed
clinical sign observations. No test item related adverse changes
noticed in body weights, percent body weight changes,
ophthalmoscopy, hematology, biochemistry, urine, absolute organ
weights and relative organ weights of males and females. In males
and females, no test item related macroscopic or microscopic
lesions were observed in any organ including eyes in any dose
group.
[0042] Another study was performed which validated the safety of
purified nano-resin particles of the present invention. This long
term study evaluated the safety of an ophthalmic suspension
comprising brimonidine loaded nano-resin particles, after multiple
daily instillation for 30 consecutive days in New Zealand white
rabbits. No test item related changes were noticed for hemodynamic
parameters in any animal during the study period. No mortality was
observed in any dose group. No test item related changes were
noticed in detailed clinical sign observations, body weights,
percent body weight changes, ophthalmoscopy, hematology and
biochemistry of animals. Therefore, based on these observations,
the ocular NOAEL (no observed adverse effect levels) of 0.35% w/v
Brimonidine tartrate ophthalmic suspension, according to one
embodiment of the present invention, was established to be about
0.33 mg/kg/day in New Zealand White Rabbits. The NOAEL for systemic
effects was also 0.33 mg/kg/day. This is about 30 times more than
the human maximum dose of brimonidine in mg/m.sup.2 basis. It is
concluded that ocular delivery of test item at 30 .mu.L/eye in both
eyes, up to maximum 6 times per day for 30 days consecutive daily
administration, did not produce any adverse effects in the eye with
no local toxicity at the site of application as well as no systemic
toxicity.
[0043] Besides this study, the present inventors also carried out
biological reactivity tests wherein the nano-resin particles of the
present invention (Example 1) were subjected to in vivo and in
vitro biological reactivity tests to determine their biological
reactivity. The in vivo biological reactivity of milled resin
extract was assessed by Intracutaneous test in New Zealand White
Rabbits as per procedure mentioned in USP <88> biological
reactivity, and it was observed that the milled nano-resin extract
complied with USP "Intracutaneous test" requirements. The in-vitro
biological reactivity of milled resin extract was assessed by
Agarose diffusion Assay in NCTC clone 929 (L cell; L-929) ATCC. No
biological reactivity of mammalian cell cultures following milled
resin extract was observed.
[0044] These safety experiments validate the safe and non-toxic
nature of the nano-resin particles of the present invention and
also supported their suitability for use in pharmaceutical dosage
forms such as ophthalmic, dermal, sublingual, buccal, peroral,
nasal, otic etc.
[0045] The present invention provides a pharmaceutical composition
comprising nano-resin particles having a particle size distribution
characterized in that the D.sub.90 value is between 200 nanometers
to 900 nanometers and D.sub.10 value is not less than 50 nanometers
and a pharmaceutically active agent.
[0046] The present invention in one aspect provides, use of a
pharmaceutical composition comprising drug loaded nano-resin
particles having a particle size distribution characterized in that
the D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers in the treatment of a
disease by delivering the drug via dermal or oral or sublingual
route of administration. The nano-resin particles are further
characterized in having D.sub.50 value between 75 nanometers to 300
nanometers. The nano-resin particles used in the pharmaceutical
compositions contain water extractable impurities of not more than
1% by weight of the total resin, and total unknown organic
impurities of not more than 3 ppm.
[0047] The present invention further provides use of a semisolid
dosage form comprising drug loaded nanoresin particles having a
particle size distribution characterized in that the D.sub.90 value
is between 200 nanometers to 900 nanometers and D.sub.10 value is
not less than 50 nanometers, in an aqueous or a non-aqueous
vehicle, in the treatment of a disease by delivering the drug via
dermal route of administration. The semisolid dosage form may be
one of a cream, an ointment, lotion, emulsion, suspension or a gel.
The semi-solid dosage forms are suitable for the treatment of
dermal disorders such as atopic dermatitis, acne, rosacea,
alopecia, impetigo, secondary skin infections, inflammatory
disorders, dermatitis, lupus erythematosus, psoriasis, plague,
keratosis, actinic keratosis, seborrheic keratosis, eczema, hives,
warts, seborrhea, shingles, scabies, skin lesions, vitiligo,
hyperhidrosis, ichthyosis, bacterial, fungal or viral infections of
the skin, etc.
[0048] In one embodiment, the dosage form is suitable for
application on scalp, for the treatment of disorders like alopecia.
Suitably in this embodiment, the drug that may be used includes
brimonidine, bromfenac, doxycycline, etc.
[0049] The present invention in one aspect provides liquid dosage
form comprising drug loaded nanoresin particles having a particle
size distribution characterized in that the D.sub.90 value is
between 200 nanometers to 900 nanometers and D.sub.10 value is not
less than 50 nanometers, in an aqueous or a non-aqueous liquid
vehicle.
[0050] The present invention in one aspect provides use of an
ophthalmic composition comprising drug loaded nanoresin particles
having a particle size distribution characterized in that the
D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, in an aqueous or a
non-aqueous vehicle, in the treatment of a disorder of the eye, by
delivering the drug via ophthalmic route of administration. The
ophthalmic composition is suitable for the treatment of diseases or
disorders of the eye. In some embodiment, the ophthalmic
composition is suitable for the treatment of glaucoma, eye
infection, conjunctivitis, ptyerigium. The ophthalmic dosage form
may be a suspension, ointment, gel or other suitable ophthalmic
compositions.
[0051] The present invention in one aspect provides use of an
aqueous suspension dosage form comprising drug loaded nanoresin
particles having a particle size distribution characterized in that
the D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, a suspending agent
and an aqueous vehicle, in the treatment of a disease by delivering
the drug via dermal or oral or sublingual route of
administration.
[0052] In one embodiment, the pharmaceutical composition is in the
form of an aqueous suspension dosage form comprising drug loaded
nanoresin particles having a particle size distribution
characterized in that the D.sub.90 value is between 200 nanometers
to 900 nanometers and D.sub.10 value is not less than 50
nanometers, a suspending agent and an aqueous vehicle, suitable for
the treatment of a disease by delivering the drug via dermal or
oral or sublingual route of administration. The suspending agent
used may be selected from an anionic polymer, a non-ionic polymer
or mixtures thereof. A cationic polymer may also be used. The
anionic polymers may be selected from the group consisting of
polymers of acrylic acid like carboxyvinyl polymer or carbomer,
also known as carbopols. Various grades of carbomers including
carbopol 934P, 974, 1342 and the like may be used in the present
invention. The polymers of acrylic acid may be present in the
aqueous suspension of the present invention in an amount ranging
from about 0.01% to 0.5% weight by volume of the suspension. Other
anionic polymers that can be used include, but are not limited to,
sodium hyaluronate; sodium carboxymethylcellulose; guargum;
chondroitin sulphate; sodium alginate. Particularly, the preferred
anionic polymers that may be used include carbopol 974P. This
anionic polymer is most preferably used in an amount of 0.1% w/v of
the suspension.
[0053] The non-ionic polymers that can be used according to the
present invention may be selected from the group consisting of
non-ionic polymers such as polyvinyl pyrrolidone, soluplus-a
polyvinyl caprolacatam-polyvinyl acetate-PEG graft co-polymer,
poloxamers, polyvinyl alcohol, polypropylene glycol, cellulose
derivatives like hydroxyethylcellulose, hydroxypropyl cellulose,
hydroxypropyl methylcellulose, methyl cellulose, ethyl cellulose
and the like. The non-ionic polymers may be present in the aqueous
suspension of the present invention in an amount ranging from about
0.1% to about 5.0% weight by volume of the suspension. The
preferred non-ionic polymers that may be used include hydroxypropyl
methylcellulose and polyvinylpyrrolidone. Various pharmaceutically
acceptable grades of hydroxypropyl methylcellulose (also known as
hypromellose or HPMC or Methocel) and polyvinylpyrrolidine (also
known as povidone or PVP or plasdone) may be used. The preferred
grades of polyvinylpyrrolidine which can be used in the suspensions
of the present invention include PVP K-30, PVP K-25, PVP K-50; PVP
K-60 and PVP K-90. It may be present in the aqueous suspension in
an amount ranging from about 0.5% to about 3.0% weight by volume of
the suspension. The most preferred grade is PVP K-90, whose 10% w/v
aqueous solution has a dynamic viscosity in the range of about
300.0 cps to about 700.0 cps at 20.degree. C., and has an
approximate molecular weight of about 1,000,000 to 1,500,000. In
preferred embodiment, polyvinylpyrrolidine PVP K-90 is used in an
amount of 1.2% w/v of the suspension. The preferred grades of
hydroxypropylmethylcellulose which may be selected to be used in
the aqueous suspensions of the present invention include, but is
not limited to METHOCEL E, (USP grade 2910/HYPROMELLOSE 2910);
METHOCEL F, (USP grade 2906/HYPROMELLOSE 2906); METHOCEL A15
(Premium LV); METHOCEL A4C (Premium); METHOCEL A15C (Premium);
METHOCEL A4M (Premium), HPMC USP Grade 1828 and the like. It may be
present in the suspension dosage form in an amount ranging from
about 0.5% to about 3.0% weight by volume of the suspension. In
most preferred embodiment, the aqueous suspension comprises
Hypromellose 2910 in an amount of 0.3% w/v. As auxiliary to the
suspending agents, the flocculation of nanoresin particles may also
be assisted by electrolytes.
[0054] The liquid dosage forms such as the aqueous suspension,
according to the present invention may comprise other
pharmaceutically acceptable excipients such as pH adjusting agents,
buffers, chelating agents, preservatives, antioxidants, one or more
osmotic agents/tonicity adjusting agents, colouring agents,
sweetners, flavouring agents, preservative adjuvants, etc. The
pharmaceutically acceptable excipients can be selected from those
provided in the text book--Remington: The Science and Practice of
Pharmacy, 22.sup.nd Edition. The excipients may be used in suitable
amounts, which can be readily determined by one of ordinary skill
in the art, so as to get compositions having desired
properties.
[0055] In one particular embodiment, the drug-loaded nano-resin
particles are formulated into a suspension dosage form along with a
suspending agent and an aqueous vehicle. When the drug particles
are loaded onto the nano-sized resin particles, and formulated into
an aqueous suspension with a suspending agent, a non-ionic polymer
and an aqueous vehicle, surprisingly the inventors found that the
drug-loaded nano-sized drug particles tend to agglomerate into a
cluster, however, upon application of a shear, these clusters
convert back into the individual drug loaded nano-sized drug
particles having a particle size distribution such that D.sub.90
value is between 200 nms to 900 nms and D.sub.10 value is not less
than 50 nms. The clusters are reversible clusters, which upon
application of shear, deagglomerate or deaggregate to form
individual drug loaded nanoresin particles. This is particularly
important as there occurs no irreversible agglomeration, which can
otherwise cause change in the particle size and impact the
stability and bioavailability of the drug.
[0056] Qualitatively, the declustering can be observed by
microscopy (Morphology G3S-ID Instrument, Make: Malvern) by
observing sheared (by smearing) and unsheared samples onto the
glass slide. Quantitatively, the D.sub.50 of the clusters can be
measured using Malvern Mastersizer before the application of shear.
Other known means for determining particle size
distribution/D.sub.50 may alternatively be used.
[0057] The suspension of clusters is subjected to shear by placing
in a sonication bath and using sonication frequency of about
33.+-.3 kHz for 5 seconds, and a sample withdrawn to measure the
particle size distribution using Malvern Mastersizer. Following
intervals of 1 minute each, the process is repeated 5 times. The
particle size distribution data before application of shear and
upon application of shear at various time intervals is presented in
Example 4, FIGS. 2-7. The particle size distribution of the
nanoresin particles may be considered as the particle size
distribution obtained after the suspension has been subjected to 5
pulses of frequency of 33.+-.3 KHz with intervals of 1 minute each,
as described above. During particle size analysis, the sonication
means of the instrument are not used.
[0058] In one aspect, the present invention thus provides a
suspension dosage form comprising drug loaded nanoresin particles
having a particle size distribution characterized in that the
D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, a suspending agent
and an aqueous vehicle, wherein the drug loaded nanoresin particles
are characterized by a property of forming reversible clusters
having a D.sub.50 value of at least 2 micrometer.
[0059] In one particular embodiment, the nano-resin particles of
the present invention are used for formulating an ophthalmic
composition. It has been observed that an ophthalmic formulation
comprising drug-loaded nanoresin particles of the present
invention, show complete drug loading and at the same time, the
drug release takes place at desired rate, which is important for an
ophthalmic formulation where the residence time in the eye is very
low. At the same time, the nano-resin particles are able to
interact with the mucin layer in the eye, which improves overall
retention and drug diffusion. This leads to enhance ocular
bioavailability and reduction in dose and frequency of
administration to achieve the desired therapeutic efficacy.
[0060] The liquid dosage forms, particularly the aqueous
suspensions according to the present invention have a viscosity
ranging from about 1 cps to 4000 cps, preferably about 5 cps to 400
cps such as 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75,
80, 85, 90, 95, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280,
300, 320, 340, 360 or 380 cps. The viscosity may be measured by
known techniques and instruments such as by Brookfield viscometer,
under standard conditions. The aqueous suspensions according to one
embodiment of the present invention, is such that it maintains its
viscosity upon topical application to the mucosal cavity such as
instillation into the eye. The viscosity does not change
substantially upon coming in contact with the mucous fluid such as
for example eye fluid that contains various ions such as sodium,
potassium, calcium, magnesium, zinc, chloride, and bicarbonate.
[0061] In another aspect, the pharmaceutical composition is a
semisolid dosage form comprising drug loaded nanoresin particles
having a particle size distribution characterized in that the
D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, in an aqueous or a
non-aqueous vehicle, suitable for the treatment of a disease by
delivering the drug via topical route of administration. The
semisolid dosage form may be one of a cream, an ointment, lotion,
emulsion, suspension, paste, liniment, hydrogel or a gel.
[0062] The semisolid dosage forms or topical compositions may
include excipients such as, but not limited to, wetting agents like
cationic, anionic or non-ionic surfactant, non-aqueous vehicles,
oils, waxes, penetration enhancing agents, antioxidants,
preservatives, viscosity modifier, anti perspirant, anti-static
agent, chelating agent, colorant, diluent, humectant, occlusive
agent, perfuming agent, sunscreen, or other agents suitable for
topical pharmaceutical compositions. Any suitable excipient/agent
in each group that is suitable for topical pharmaceutical
application may independently be used. Such suitable
pharmaceutically acceptable excipients may be selected from those
provided in the test book--Remington: The Science and Practice of
Pharmacy, 22.sup.nd Edition. The excipients may be used in suitable
amounts known, which can be readily determined by one of ordinary
skill in the art, so as to get compositions having desired
properties.
[0063] In one particular embodiment, the pharmaceutical composition
is a semisolid dosage form comprising drug loaded nanoresin
particles having a particle size distribution characterized in that
the D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, in non-aqueous
vehicle, suitable for the treatment of a disease by delivering the
drug via dermal route of administration. The semisolid dosage form
is preferably a cream or an ointment or a suspension or a gel. Such
semisolid dosage forms comprising drug incorporated in nano-resin
particles and formulated in non-aqueous vehicles are particularly
suitable for incorporating, stabilizing and delivery of drugs that
are susceptible to degradation in the presence of water or aqueous
environment. Such drugs include but are not limited to minocycline,
doxycycline, tetracycline, oxytetracycline, demeclocycline,
lymecycline, meclocycline, methacycline, rolitetracycline,
chlorotetracycline or tigecycline or pharmaceutically acceptable
salts or mixtures thereof. The semisolid dosage forms according to
this embodiment are useful in the treatment of disorders of the
skin, particularly acne, rosacea, impetigo or a skin disease caused
by bacteria.
[0064] The non-aqueous semisolid dosage form includes one or more
non-aqueous vehicles that may be selected from silicon fluids like
silicones, silicone derivatives or siloxanes, for example linear or
cyclic alkyl siloxanes, aryl siloxanes, alkylether siloxanes,
haloalkyl siloxanes, polycycloxanes, siloxane polymers, other
functionalized siloxanes and mixtures thereof; non-volatile oil
such as mineral oil, paraffin oil, castor oil, olive oil, seasom
oil, soybean oil, peanut oil, coconut oil, avocado oil, jojoba oil,
grape seed oil, jojaba oil, corn oil, cottonseed oil, white
petrolatum, white soft paraffin, shea butter, triglycerides like
labrafac, triacetin, capric/caprylic triglyeride, octyl dodecanol,
diisopropyl adipate, light mineral oil and the like and mixtures
thereof. It may further include other agents like wetting agents,
emollients, gelling agents, viscosity builders, a penetration
enhancer, an antioxidant, a preservative or other non-aqueous
pharmaceutically acceptable excipients that are suitable for
topical application. The wetting agent or surfactants may be
selected from, but not limited to silicon based surfactant,
non-ionic surfactants like Sorbitan esters (such as Span.RTM.80);
Sucrose stearic acid esters; glyceryl monostearate, glyceryl
monooleate, macrogolglycerol; hydroxy stearates (PEG 7 hydrogenated
castor oil), PEGS castor oil and the like and mixtures thereof. A
penetration enhancer may be selected form but not limited to
isopropyl myristate, isopropyl palmitate, oleic acid etc. The
antioxidant that may be used may be selected from butylated hydroxy
anisole, butylated hydroxy toluene, tocopherol succinate, propyl
gallate, tocopherol, (vitamin E), tocopherol sorbate, tocopherol
acetate, other esters of tocopherol, butylated hydroxy benzoic
acids and the like. A preservative may be selected form C.sub.12 to
C.sub.15 alkyl benzoates, alkyl p-hydxoxybenzoates, ascorbic acid,
benzalkonium chloride, sorbic acid, citric acid, benzoic acid,
benzoic acid esters of C.sub.9 to C.sub.15 alcohols, chlorocresol,
methyl paraben, propyl paraben, sodium benzoate and the like.
[0065] In some embodiments, the drug loaded nano-resin particles
are formulated into oral dosage forms. The oral dosage form may be
a solid oral or a liquid oral dosage form suitable for peroral,
sublingual or buccal delivery. The present invention in one aspect
provides use of a solid oral dosage form comprising drug loaded
nanoresin particles having a particle size distribution
characterized in that the D.sub.90 value is between 200 nanometers
to 900 nanometers and D.sub.10 value is not less than 50 nanometers
and pharmaceutically acceptable excipients. The solid oral dosage
form may be in the form of a capsule, a tablet, an ovule, a
chewable tablet, a buccal tablet, a sublingual tablet, a
quick-dissolving tablet, a mouth disintegrating tablet or granules,
an effervescent tablet, a granule, a pellet, a bead, a pill, a
sachet, a sprinkle, a film, a dry syrup, a reconstitutable solid, a
lozenge, a troche, an implant, a powder, a triturate, a platelet,
or a strip. The dosage forms are formulated using suitable
pharmaceutically acceptable excipients. The solid oral dosage forms
according to the present invention may comprise pharmaceutically
acceptable excipients suitable for oral dosage forms such as those
mentioned in the book--Remington: The Science and Practice of
Pharmacy, 22.sup.nd Edition. These include, but are not limited to
diluents, disintegrating agents, bulking agents, binders,
lubricants, glidants, colouring agent etc.
[0066] In one embodiment, the present invention provides nano-resin
particles suitable for pharmaceutical use, wherein the resin
particles have a particle size distribution such that D.sub.90
value is between 200 nanometers to 900 nanometer and D.sub.10 value
is not less than 50 nanometers, and is prepared by a process
comprising the steps of: [0067] i. washing an ion exchange resin
and suspending in an aqueous liquid, [0068] ii. subjecting the
suspension of (i) to wet milling for a period such that the
particles have a particle size distribution characterized in that
the D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, [0069] iii.
subjecting the suspension of (ii) to purification to achieve
impurities within acceptable limit, [0070] iv. drying the purified
suspension to obtain nano-resin particles in the form of dry
powder, having a water content of not more than 15%. [0071] wherein
the water extractable impurities are not more than 1% by weight of
the resin and the organic impurities are not more than 3 ppm.
[0072] In one embodiment, the nano-resin particles according to the
present invention are prepared by a process comprising the steps
of-- [0073] i. washing an ion exchange resin and suspending in an
aqueous liquid, [0074] ii. subjecting the suspension of (i) to wet
milling for a period such that the particles have a particle size
distribution characterized in that the D.sub.90 value is between
200 nanometers to 900 nanometers and D.sub.10 value is not less
than 50 nanometers, [0075] iii. subjecting the suspension of (ii)
to purification to remove the water extractable and organic
impurities, [0076] iv. drying the purified suspension to obtain
nano-resin particles in the form of dry powder.
[0077] In one preferred embodiment, the purification of the
suspension to remove the water extractable and organic impurities
is performed by diafiltration technique with the help of use of a
membrane filter having a pore size molecular weight cut off in the
range of 200 kD to 750 kD, such as 250, 300, 350, 400, 450, 500,
550, 600, 650 or 700 kD, preferably in the range of 300 kD to 600
kD.
[0078] In one specific embodiment, the step of wet milling is
performed in two steps comprising:
(a) milling the resin of step (i) using grinding medium having bead
size that range from 0.5 mm to 1.25 mm, and (b) milling the resin
of sub-step (a) using grinding medium having bead size that range
from 0.1 mm to 0.4 mm.
[0079] In one embodiment the grinding medium has a bead size in the
range approximately 0.5 mm to 1.25 mm, such as 0.6 0.7, 0.8, 0.9,
1.0, 1.1 or 1.2 mm.
[0080] In one embodiment the grinding medium has a bead size in the
range approximately 0.1 mm to 0.4 mm, such as 0.2 or 0.3 mm.
[0081] In one specific embodiment, the nano-resin particles
according to the present invention are prepared by a process
comprising the steps of-- [0082] i. washing an ion exchange resin
and suspending in an aqueous liquid, [0083] ii. subjecting the
suspension of (i) to wet milling for a period of time such that
particles have a particle size distribution characterized in that
the D.sub.90 value is between 200 nanometers to 900 nanometers and
D.sub.10 value is not less than 50 nanometers, wherein the wet
milling is performed in two sub-steps comprising (a) milling the
resin of step (i) using grinding medium having bead size that range
from 0.5 mm to 1.25 mm, and (b) milling the resin of sub-step (a)
using grinding medium having bead size that range from 0.1 mm to
0.4 mm, [0084] iii. subjecting the suspension of (ii) to
diafiltration, using a ultrafiltration membrane having a pore size
molecular weight cut off in the range of 200 kD to 750 kD, to
remove the water extractable and organic impurities, [0085] iv.
lyophilizing the suspension of (iii) to obtain free flowing
nano-resin particles in the form of dry powder.
[0086] In one aspect, the step of washing the marketed micron size
resin (step (i)) may be carried out by using a suitable organic
liquid like methanol, which leads to removal of extraneous organic
materials. For this, the resin suspension in water is taken and
methanol is added to the resin suspension along with stirring of
the suspension for about 10 to 15 minutes. The suspension is kept
on standing for 15-20 minutes, to allow settling down of the
particles, followed by decantation of the supernatant. This washing
process may be repeated 3-4 times. The resulting resin particles
may be then washed multiple times with hot water (about
80-90.degree. C.) by following a similar process, until the pH of
water wash reach below 7.5.
[0087] In one aspect, the step of wet milling (step ii) may be
carried out by use of a wet milling equipment, such as NETZSCH
mill, DeltaVita 600 or similar wet milling machines or grinding
mills. The beads used for milling, i.e. the milling medium beads
may be made up of zirconium oxide or glass or similar material. In
this step, the washed resin obtained as per step (i) is subjected
to wet milling for a period of time sufficient to achieve the
target particle size of D.sub.90 between 200 nms to 900 nms and
D.sub.10 of less than 50 nms. The milling is carried out for a
period of time varying from about 2 hours to about 48 hours,
preferably from about 4 hours to 24 hours, such as 5, 5.5, 6, 6.5,
7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14,
14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 20.5,
21, 21.5, 22, 22.5, 23 or 23.5 hours, more preferably from about 5
hours to 20 hours. To carry out wet milling, a slurry of the resin
particles (about 10%) in an aqueous medium such as water for
injection is taken in milling chamber of the wet milling machine
(such as NETZSCH, DeltaVita 600 mill) along with grinding media
beads (such as Zirconium oxide beads of suitable sizes) followed by
wet milling of the resin particles.
[0088] In a preferred embodiment, the step of wet milling is
carried out in two-steps, first using grinding medium having beads
of a higher size, followed by using grinding medium having beads of
size smaller than that used in first step.
[0089] In one embodiment, the step of wet milling is performed in
two steps comprising: (a) milling the resin of step (i) using
grinding medium having bead size that range from 0.5 mm to 1.25 mm,
and (b) milling the resin of sub-step (a) using grinding medium
having bead size that range from 0.1 mm to 0.4 mm.
[0090] In some embodiments, in step (a), the wet milling is carried
out using a grinding medium having bead of size in the range of 0.5
mm to 1.25 mm, for a period of time varying from 1 hour to 10
hours, such as 2, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0,
7.5, 8.0, 8.5, 9.0 or 9.5 hours and in step (b), the wet milling is
carried out using grinding medium having bead of size in the range
of 0.1 mm to 0.4 mm, for a period of time varying from about 2 hour
to 15 hours, such as 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5,
7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5,
13.0, 13.5, 14.0 or 14.5 hours. The period of milling may vary
depending upon certain factors like the weight of resin to be
milled, the type of machine etc.
[0091] In one particular embodiment, having batch size of 2 kg
resin particles, the particle size reduction can be carried out
using a grinding medium having bead of size 0.5 mm for a period of
time of about 5.5 hours, followed by milling by using grinding
medium of size 0.3 mm for a period of time of about 7.0 hours.
[0092] This forms nano-resin particles having desired particle size
such that D.sub.90 value is between 200 nms to 900 nms and D.sub.10
value is less than 50 nms. The process preferably involves use of
two different size grinding media, which advantageously leads to
reduction in particle size to nano range in a shorter period of
time and the particles size achieved is smaller as compared when
single size grinding media is used. In some embodiments, the method
of preparing nano-resin particles of the present invention do not
include techniques like emulsion polymerization, suspension
polymerization or precipitation polymerization techniques.
[0093] Post milling, the milled resin suspension is subjected to a
step of purification by techniques like diafiltration,
ultrafiltration and the like. Due to milling, the level of water
extractable impurities and organic impurities in the nano-resin
suspension rise to levels higher than the desired limits. The step
of purification by diafiltration results in nano-resins particles
that are pure and have impurities within desired limits.
[0094] In one preferred embodiment, the wet milled suspension is
subjected to diafiltration, wherein the milled resin suspension
obtained in step (ii) is subjected to ultrafiltration and
concentration using a ultrafiltration membrane having a molecular
weight in the range of 200 kD to 750 kD. This leads to removal of
water extractable and organic impurities, thus resulting in the
formation of purified nano-resin particles. The ultrafiltration
membranes suitable for this purpose include membrane fibre
cartridges having a molecular weight in the range of 200 kD to 750
kD, preferably in the range of 300 to 500 kD
[0095] Post purification step, the purified nano-resin suspension
is dried. The step of drying the suspension may be carried out by
suitable techniques such as freeze drying, lyophilization etc. In
one preferred embodiment, the purified suspension of nano-resins is
dried by lyophilization to form a dried powder comprising
nano-resin particles. The water content of the dried powder is not
more than 15%, preferably not more than 10%, more preferably not
more than 5% by weight, for example 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%,
9% or 10% by weight of the resin.
[0096] In the context of this specification "comprising" is to be
interpreted as "including".
[0097] Aspects of the invention comprising certain elements are
also intended to extend to alternative embodiments "consisting" or
"consisting essentially" of the relevant elements.
[0098] Where technically appropriate, embodiments of the invention
may be combined.
[0099] Embodiments are described herein as comprising certain
features/elements. The disclosure also extends to separate
embodiments consisting or consisting essentially of said
features/elements.
[0100] Any embodiments specifically and explicitly recited herein
may form the basis of a disclaimer either alone or in combination
with one or more further embodiments.
[0101] While the present invention is disclosed generally above,
additional aspects are further discussed and illustrated with
reference to the examples below. However, the examples are
presented merely to illustrate the invention and should not be
considered as limitations thereto.
Example 1
[0102] Preparation of nanoresin: The method of preparation of the
nano-resin according to the present invention comprises the steps
of washing the ion exchange resin, wet milling the washed resin,
preferably using two different size grinding media's, followed by
diafiltration. According to one embodiment of the present
invention, the nano-resin was prepared by method given below.
[0103] Step (i): Washing: The marketed micron size resin Amberlite
IRP 69 resin (obtained from Rohm and Haas, France) was washed with
methanol to ensure removal of extraneous organic material. The
resin was taken in a SS vessel and methanol was added. The resin
suspension was stirred for about 10 to 15 minutes. The particles
were then allowed to settle down for 15-20 minutes and the
supernatant was decanted. The washing process was repeated 3-4
times. The above material was then washed multiple times with hot
water for injection (80-90.degree. C.) by following similar process
till the pH of water wash reached below 7.5.
[0104] Step (ii): Wet milling--The wet milling was carried out
using NETZSCH, DeltaVita 600 wet milling machine. A 10% slurry of
the resin particles in an aqueous medium such as water for
injection was passed though the milling chamber containing
Zirconium oxide beads of suitable size as grinding media. Wet
milling was then carried out in two stages. Particularly, in step
1, the particle size reduction was carried out using grinding media
of size 0.5 mm for about 5.5 hours. In sub-step 2, the particle
size reduction was carried out by using grinding media of size 0.3
mm for about 7 hours. This results in formation of nano-resin
particles having desired particle size i.e. D.sub.90 value is
between 200 nanometers to 900 nanometers and D.sub.10 value is not
less than 50 nanometers.
[0105] Step (iii): Polishing--In this step, the milled resin
suspension obtained in step (ii) was filtered from 10.mu.
polypropylene capsule filter, (HDC II, KAJ1100P1) under stirring to
make suspension with uniform particle size and to remove any
agglomerates and residual larger particles. The particle size
remains same after and before filtration.
[0106] Step (iv): Purification by diafiltration--The milled resin
suspension obtained in step iii above was found to be pale yellow,
likely due to the water extractable impurities or organic
impurities generated during the process, and this may render it
un-suitable for pharmaceutical use in this form. The water
extractable impurities were measured in unmilled resin and in the
permeate after milling. It was found that during the milling
process the water extractable impurity was increased (Table 1).
Similarly the content of organic impurities also increased (Table
3).
[0107] The milled nano-suspension obtained in step (ii) as a result
of wet milling was subjected to diafiltration wherein
ultrafiltration and concentration of the milled resin suspension
was carried out using an Ultrafiltration membrane system consisting
of 300 kD to 500 kD hollow fiber cartridge/membrane. The milled
resin suspension was diafiltered and washed with water for
injection until the permeate was almost clear and absorbance
(measured using a UV spectrophotometer at 650 nm) was reduced below
0.02 AU. The processing step leads to purification of nano-resin
suspension, wherein the content of water extractable and organic
impurities is reduced and complies with the set specification, the
absorbance of permeate reduces to below 0.02 AU and the permeate
appearance becomes clear. The table 2 gives the results of
absorbance of the permeate, before and after the diafiltration
step. The value of absorbance reduced to 0.003 post diafiltration
step, from 0.04 (before diafiltration).
[0108] The level of water extractable impurity in the milled
suspension was estimated by measuring the weight of the water
soluble impurities extracted in the permeate by diafiltration and
determining the percentage by weight of the weight of total milled
resin taken for diafiltration.
[0109] The level of water extractable impurity was reduced after
washing and complies with the set specification (<1%). The Table
1 represents the level of water extractable impurity before and
after the diafiltration step. The content of water extractable
impurity was reduced to 0.88 post diafiltration step, from 2.96
(before diafiltration). The reduced values post diafiltration
complies with the set specification.
TABLE-US-00001 TABLE 1 Results of water extractable impurity Nano
resin Unmilled suspension Nano resin Resin after suspension after
Specification suspension milling diafiltration Water <1.0% 0.06
2.96 0.88 Extractable Impurity (% w/w)
TABLE-US-00002 TABLE 2 Results of absorbance Sr. No. Sample
Absorbance 1 Extract of Milled resin before diafiltration 0.040 2
Extract of milled resin after diafiltration cycle. 0.003
[0110] The concentrated milled resin suspension was analyzed for
particle size. It was observed that the particle size, was such
that the D.sub.90 value is between 200 nanometers to 900 nanometers
and D.sub.10 value is not less than 50 nanometers. Specifically, in
one batch, the particle size distribution of the nano-resin
particles obtained by following the aforementioned process was such
that D.sub.90 value was 436 nms (0.436.mu.), D.sub.50 value was 153
nms (0.153.mu.), and D.sub.10 value was 74 nms (0.074.mu.). The
histogram of the particle size distribution is presented in FIG. 1.
In another batch, prepared following same process, the nano-resin
particles have particle size distribution characterized in that
D.sub.90 value was 315 nms (0.315.mu.), D.sub.50 value was 147 nms
(0.147.mu.), and D.sub.10 value was 73 nms (0.073.mu.).
[0111] The nano-resins were also analyzed for content of organic
impurities, such as individual unknown and total unknown organic
impurities, by HPLC technique. The HPLC analysis was performed
using dichloromethane as diluent and reference standard solutions
of styrene RS, diethylbenzene RS, naphthalene RS, divinylbenzene RS
and p-xylene RS and DB-624, J & W as chromatographic column.
The results are presented in Table 3. Based on the results,
surprisingly it was found that Individual unknown and total unknown
impurities were increased and not complying the specifications
(<1 ppm and <3 ppm respectively) when the resin was milled to
nano-size of D.sub.90 between 200 nanometers to 900 nanometers and
D.sub.10 of not less than 50 nanometers. When milled resin
suspension was subjected to Diafiltration using water and
ultrafiltration membrane system, the Individual unknown and total
unknown impurities were reduced and complied with specification.
The content of organic impurities in milled resin before and after
diafiltration are presented below in Table 3:
TABLE-US-00003 TABLE 3 Results of Organic impurities in milled
resin powder Milled resin Milled obtained after step Organic
impurities Unmilled resin resin of purification Individual unknown
Below Qualification 6 ppm Not detected, impurity limit, <0.03
ppm 0 ppm Total unknown Below Qualification 13 ppm Not detected,
impurity limit, <0.03 ppm 0 ppm
[0112] The milled nano-resin suspension was subsequently
lyophilized. It was analyzed for water content. The water content
was found to be 4.06% by weight. The milled resin was stored in
bulk for further use in formulating pharmaceutical dosage form.
Example 2
[0113] Biological Reactivity Test: The nanoresin prepared according
to Example 1 was subjected to in-vivo and in-vitro biological
reactivity tests to determine the biological reactivity. The tests
are given below:
1. In-Vivo Biological Reactivity: The in-vivo biological reactivity
of milled resin extract was assessed by Intracutaneous test in New
Zealand White Rabbits. Extraction of Amberlite IRP 69 was done in 1
in 20 solution of alcohol in 0.9% sodium chloride solution as per
procedure mentioned in USP <88> Biological reactivity,
in-vivo. It was observed that the milled nano-resin extract
complied with USP "Intracutaneous test" by biological reactivity
study. 2. In vitro Biological Reactivity: The in-vitro biological
reactivity of milled resin extract was assessed by Agarose
diffusion Assay in NCTC clone 929 (L cell; L-929) ATCC. No
biological reactivity of mammalian cell cultures following milled
resin extract was observed.
Example 3
[0114] The present example provides a particular embodiment of the
present invention wherein the nano-resin particles were loaded with
an anti-glaucoma drug brimonidine and the drug-loaded nanoresin
particles were formulated into an aqueous suspension dosage form
suitable for ophthalmic use:
TABLE-US-00004 TABLE 4 Aqueous suspension of Brimonidine Tartrate
Ingredients Ingredients Function % w/v Brimonidine Tartrate Active
ingredient 0.35 Amberlite IRP 69 Resin 0.35 Hydroxy propyl methyl
cellulose Polymeric vehicle 0.3 Polyvinylpyrrolidone 1.2 Carbopol
974P (carbomer) 0.1 Benzalkonium Chloride Preservative 0.02 Edetate
Disodium Chelating agent 0.1 N-Lauroylsarcosine sodium Preservative
0.06 Mannitol Osmotic agent 4.5 Tromethamine q.s to adjust pH to
7.4 pH adjusting agent 0.32 Water for Injection Vehicle q.s.
[0115] Process: Hydroxy propyl methyl cellulose was dispersed with
high speed in warm water for injection along with stirring to
obtain uniform dispersion. In another container,
polyvinylpyrrolidone K-90 was added and dispersed in water for
injection with stirring to obtain uniform dispersion. Further, a
dispersion of carbopol 974P in water for injection was prepared and
neutralized with tromethamine (pH 7.4). The hydroxy propyl methyl
cellulose and povidone polymeric dispersions obtained above were
added sequentially to the carbopol 974P phase. The polymer mixture
was autoclaved at 121.degree. C. for 20 minutes. N-lauryl sarcosine
sodium was mixed in a portion of water for injection and added to
the polymer phase after filtration through 0.2 micron nylon filter.
Mannitol was dissolved in a portion of water for injection at
50-60.degree. C. and to this, benzalkonium chloride and edetate
disodium were added to form a clear solution. This solution was
added to the above polymer phase.
[0116] The nano-sized resin particles (of Amberlite IRP 69) were
prepared as per Example 1. The particles has a particle size
distribution such that D.sub.90 value is 606 nms (0.606.mu.),
D.sub.50 value is 240 nms (0.240.mu.), and D.sub.10 value of 148
nms (0.148.mu.), were dispersed in water for injection and
sterilized by autoclaving at 121.degree. C. for 20 minutes. To this
sterilized resin dispersion, a solution of brimonidine tartrate in
water for injection, which was filtered through 0.2 micron and 0.45
micron nylon filter, was added and stirred. This drug loaded
nano-resin particles aqueous dispersion was added to the polymer
mixture along with stirring and homogenization. The pH was adjusted
with tromethamine solution to about 7.4.
Example 4
[0117] The drug loaded nano-resin particles in suspension dosage
form as described in Example 3, forms reversible clusters. The
instant example demonstrates the effect of shear on these
reversible clusters of drug loaded nano-resin particles suspended
in Example 3, which decluster into individual drug-loaded
nano-resin particles when subjected to shear, such as a shear
resulting from blinking in the eye. This effect was measured in
terms of particle size distribution, initially and upon application
of shear.
[0118] Procedure: The test samples were subjected to shear by
placing the vials containing the suspension on bath sonicator
(Model type: MC-109 and SI no--1909; Mfg. by Oscar Ultrasonic Pvt.
Ltd.) and shear was applied in the form of sonication frequency of
33.+-.3 kHz for 5 seconds and the sample was withdrawn to measure
the particle size distribution. Following intervals of 1 minute
each the process is repeated 5 times and each time the particle
size was measured.
[0119] The particle size measurement was done using Malvern
Mastersizer 2000, Ver. 5.60, Malvern Instruments Ltd., Malvern, UK
but the analyser's sonication means were not used. The sample was
only subjected to mild stirring by a mechanical stirrer. The
observations are summarized below in Table 5.
TABLE-US-00005 TABLE 5 Effect of shear on the particle size
distribution of the resin particles: Volume mean diameter in
microns recorded by Malvern lazer diffraction method PSD* Initial 1
min 2 min 3 min 4 min 5 min Example 3 D.sub.10 0.852 0.475 0.338
0.151 0.145 0.140 D.sub.50 19.549 13.882 0.996 0.254 0.229 0.213
D.sub.90 58.970 49.111 30.405 1.398 0.512 0.449 PSD* - Particle
Size Distribution in Volume mean diameter in microns
[0120] Observations: It was found that clusters of drug loaded
nano-resin particles of Example 3, disintegrated completely as
shear was applied to the suspension. This was evident by the
decrease in the particle size observed upon application of
shear/sonication as shown in Table 5. The D.sub.50 of drug-resin
nanoparticles was initially about 19.5 microns, which upon
application of shear at regular interval for 5 minutes
disintegrated and converted into individual drug-resin
nanoparticles having D.sub.50 of 0.213 micron (213 nm). The
histograms of the particle size distribution of the drug-loaded
nano-resin particles after application of shear at 5 minute is
represented by FIG. 2. It corresponds to particle size distribution
upon application of shear at 5 minutes and represents largely
individual nano-resin particles and particle size distribution of
the individual drug loaded nano-resin particles.
Example 5
[0121] The present example provides safety test of aqueous
suspension dosage form prepared according to one embodiment of the
present invention. The aqueous suspension dosage form (of Example
3) was subjected to safety studies by daily ocular administration
of the suspension formulation for consecutive 14 days. The
following protocol was followed:
[0122] Twenty New-Zealand White rabbits; (10 males and 10 females)
were randomized, based on body weights, into following five study
groups. Each group comprised of two animals of both gender. The
desired dose was administered by ocular instillation.
G1 (saline {control}, 360 .mu.L/animal/day), 30 .mu.L per
eye/time.times.6 times a day G2 (Placebo, 360 .mu.L/animal/day), 30
.mu.L per eye/time.times.6 times a day G3 (Low dose {test}, 60
.mu.L/animal/day), 30 .mu.L per eye/time.times.1 times a day G4
(Mid dose {test}, 180 .mu.L/animal/day); 30 .mu.L per
eye/time.times.3 times a day G5 (High dose {test}, 360
.mu.L/animal/day) 30 .mu.L per eye/time.times.6 times a day G3, G4
& G5 test=0.35% w/v Brimonidine Tartrate Aqueous Suspension of
the present invention (Example 3)
[0123] The test parameters which were evaluated included--Daily
Clinical Signs and Mortality; Detailed Clinical Sign Observation;
Body Weights; Ophthalmoscopy and Necroscopy. The details of these
test parameters along with the results are described below. Besides
this, other parameters which were also evaluated include: clinical
pathology, histology, biochemistry, prothrombin time and urine
analysis.
[0124] Daily Clinical Signs and Mortality--Cage side observations
were done, twice daily, for all animals to note clinical signs,
adverse effects; including those for eyes, morbidity and mortality
during the dosing period. These observations were performed once
before dosing and post last dosing between 2-4 hours. Animal check
to observe mortality was performed twice daily throughout study
period and findings were recorded. No mortality was observed in
control, placebo as well as in test item dosed groups. During
dosing period of 14 days, yellowish exudates (probably clearing of
excess test item) staining the areas around both eyes was observed
in G4 and G5. No other adverse clinical signs were observed.
[0125] Detailed Clinical Sign Observation--Detailed observations
were performed before initiation of dosing and on Days 1, 7 and 14
post dosing. The animals were examined closely for clinical signs,
general behavior or any other signs. Eyes were examined with
hand-held slit lamp ophthalmoscope and findings were recorded
according to Draize scoring system described in table 6 below:
TABLE-US-00006 TABLE 6 Clinical Sign Observation- Corneal Opacity:
degree of density (the area of corneal opacity noted) (maximum
possible 4) No ulceration or opacity 0 Scattered or diffuse areas
of opacity, details of iris clearly visible 1 Easily discernible
translucent area, details of iris slightly obscured 2 Nacrous area,
no details of iris visible, size of pupil barely discernible 3
Opaque area, iris not discernible through the opcity 4 Iris
(maximum possible 2) Normal 0 Markedly deepened rague, congestion,
swelling, moderate 1 circumcorneal hyperaemia, or injection, any of
these or combination of any thereof it is still reacting to light
(sluggish reaction possible) No reaction to light, hemorrhage,
gross destruction (any or all of 2 these) Conjuctivae (maximum
possible 3) Redness (refers to palpebral and bulbar conjuctivae,
excluding corneas and iris) Normal 0 Some blood vessels definitely
hyperae ic (injected) 1 Diffuse, crimson colour, individual vessels
not easily discernible 2 Diffuse beefy red 3 Chemosis: Swelling
(refers to lids and/or to nictitating membranes) (Maximum possible
4) Normal 0 Some swelling above normal 1 Obvious swelling with
partial eversion of lids 2 Swelling with lids about half closed 3
Swelling with lids more than half closed 4
[0126] During detailed clinical sign observation, no test item
related adverse clinical signs were observed in any group
throughout the study period. Detailed examination of eyes
(including Draize scoring) did not show any adverse finding/sign.
The scoring for all the animals in all groups was zero.
[0127] Ophthalmoscopy: Ophthalmoscopy was performed in all animals
at initiation of dosing; thereafter it was performed on Days 7 and
14. At each observation, both eyes of animal were examined with
hand held ophthalmoscope (Ophthalmoscope Heine). Observations for
following were noted: Eye ball, Lacrimation, Conjunctivae, Eyelids,
Sclera, Pupil reaction to light, Cornea, Iris, Anterior chamber,
Lens, Vitreous body and Fundus with use of mydriatic agent. The
Fluorescein-staining of cornea was done at the end of dosing on Day
14. Examination of cornea was performed with the help of
ophthalmoscope.
[0128] During ophthalmoscopy, no abnormality was detected in the
eye of any animal during pre-dose and on Day 7 and 14 at
post-dosing. No signs of corneal damage or any other abnormality
was noticed for cornea with fluorescein strip staining.
[0129] Necroscopy--On completion of dosing, all animals from G1 to
G5 were necropsied on day 15. Gross pathology was noted. The
cranial, thoracic and visceral cavities were opened and examined
macroscopically. Eye balls, optic nerve and adnexal tissues
(eyelids, accessory glands, nictitating membrane, conjunctivae and
orbital muscles) were examined grossly for any macroscopic change.
Microscopic evaluation of tissues were performed in G1, G2 and G5
and it was not extended to any lower group since no test item
related histopathological adverse effect was noted in G5. Brain,
liver, lung with main stem bronchi were peer reviewed in all
animals from G1, G2 and G5.
[0130] At terminal necropsy, statistically significant increase in
absolute heart weights of G2 males, relative spleen weight in G4
males and relative adrenal weight in G4 females was noted; however,
these changes were not dose depended, hence not considered as test
item related adverse effect. Microscopic evaluation of
organs/tissues in G2 or G5 male and female animals did not show any
finding that could be related to dosing of placebo or test item.
The microscopic findings observed in G2 and G5 were those of
incidental/spontaneous nature and comparable to that in G1.
Microscopic examination of eye and its adnexal tissues/organs did
not show any test item or placebo related findings.
[0131] In summary--No mortality was observed for males and females
of any dose group. During dosing period, yellowish exudates
staining around the eyes was observed both in G4 and G5 which
probably was due to clearing out of excess test item. No test item
related clinical signs were observed during daily or detailed
clinical sign observations. No test item related adverse changes
noticed in body weights, percent body weight changes,
ophthalmoscopy, hematology, biochemistry, urine, absolute organ
weights and relative organ weights of males and females. In males
and females, no test item related macroscopic or microscopic
lesions were observed in any organ including eyes in any dose
group.
[0132] The drug loaded nano-resin particles according to the
present invention not only provides an improved efficacy in terms
of reduction of intraocular pressure but is also found to be safe
without any adverse effects when administered for prolonged period
of time, such as 14 days or more.
Example 6
[0133] Long term safety profile of suspension of Example 3, after
multiple daily instillation for 30 consecutive days in New Zealand
white rabbits, was evaluated. Particularly, the hemodynamic
parameters were assessed. For this, the study design was as
follows: Group 1 received 30 .mu.L per eye 6 times a day (n=6) and
group 2 received the suspension of Example 3 as 30 .mu.L per
eye/time.times.6 times a day (n=6).
[0134] Hemodynamic parameters were recorded for all animals at
pre-dose, Day 15 and at the end of dosing period at Day 30. These
parameters included Electrocardiogram (ECG); BP, Pulse rate,
SpO.sub.2, Respiratory rate and Temperature.
[0135] Summary of observations: No test item related changes were
noticed for hemodynamic parameters in any animal during the study
period. No mortality was observed in any dose group. During dosing
period, in G2 group, a slight yellowish exudate staining around
both eyes was observed (which was probably due to flowing-out of
excessive test item). No test item related changes were noticed in
detailed clinical sign observations, body weights, percent body
weight changes, ophthalmoscopy, hematology and biochemistry of
animals. Therefore, based on these observations, the ocular NOAEL
(no observed adverse effect levels) of 0.35% w/v Brimonidine
tartrate ophthalmic suspension, according to one embodiment of the
present invention, is established to be about 0.33 mg/kg/day in New
Zealand White Rabbits. The NOAEL for systemic effects is also
established to be 0.33 mg/kg/day. This is about 30 times more than
the human maximum dose in mg/m.sup.2 basis.
[0136] It is concluded that ocular delivery of test item at 30
.mu.L/eye in both eyes, up to maximum 6 times per day for 30 days
consecutive daily administration did not produce any adverse
effects in the eye, with no local toxicity at the site of
application as well as no systemic toxicity.
[0137] Thus, the ophthalmic dosage form comprising the drug loaded
nano-resin particles according to the present invention not only
provides an improved efficacy in terms of reduction of intraocular
pressure but is also found to be safe without any adverse effects
when administered for prolonged period of time, such as 30 days or
more.
Example 7
[0138] The example provides a suspension formulation of
Doxycycline, according to one embodiment of the present
invention.
TABLE-US-00007 TABLE 7 Aqueous suspension dosage form of
doxycycline Hydrochloride Ingredients Ingredients function Quantity
% Doxycycline Hyclate (eq to Active ingredient 0.057 Doxyclycline
0.05%) Sodium polystyrene sulphonate Resin 0.019 (Amberlite IRP 69)
Hydroxy propyl methyl cellulose Polymeric vehicle 0.3
Polyvinylpyrrolidone 1.2 Carbopol 974P (carbomer) 0.1 Benzalkonium
Chloride Preservative 0.02 Edetate Disodium Chelating agent 0.1
N-Lauroylsarcosine sodium Preservative 0.06 Mannitol Mannitol 4.5
Tromethamine q.s to adjust pH to 5.0 pH adjusting agent 0.0248
Water for Injection Vehicle q.s. to 100
[0139] Process: Hydroxy propyl methyl cellulose was dispersed with
high speed in a warm water for injection stirring to obtain uniform
dispersion. To it polyvinylpyrrolidone (povidone K-90) was
dispersed in water for injection with stirring to obtain uniform
dispersion. Further, carbopol 974P dispersion in water for
injection, neutralized with tromethamine (pH7.4), was prepared. The
hydroxy propyl methyl cellulose and povidone polymeric dispersions
obtained above were added sequentially to the carbopol 974P phase.
The polymer mixture was autoclaved at 121.degree. C. for 20
minutes. Further, other excipients like mannitol, benzalkonium
chloride, n-lauryl sarcosine and edetate disodium were added
sequentially to above polymer phase and stirred until dissolved and
form a clear solution.
[0140] The nano-sized resin particles (of Amberlite IRP 69)
prepared as per Example 1, having D.sub.90 value of 436 nms
(0.436.mu.), D.sub.50 value of 153 nms (0.153.mu.), and D.sub.10
value of 74 nms (0.074.mu.), were dispersed in water for injection
and sterilized by autoclaving at 121.degree. C. for 20 minutes. To
this sterilized resin dispersion, a solution of doxyclycline
hyclate in water for injection, which was filtered through 0.2
micron and 0.45 micron nylon filter, was added and stirred. This
drug loaded nano-resin particles aqueous dispersion was added to
the polymer mixture along with stirring and homogenization. The pH
was adjusted with tromethamine solution to about 7.4. The aqueous
suspension formulation of Doxycycline is suitable for delivery of
drug via dermal or oral or sublingual or ophthalmic route of
administration.
Example 8
[0141] The example provides a suspension formulation of Asenapine
maleate, according to one embodiment of the present invention.
TABLE-US-00008 TABLE 8 Asenapine maleate suspension Ingredients
Quantity (% w/v) Asenapine Maleate 1.5 Sodium polystyrene
sulphonate 1.5 (Amberlite IRP 69) Water for Injection q.s. to
100
[0142] Asenapine maleate was dissolved under stirring in warm
water. Ion exchange resin of Example 1, having D.sub.90 value of
436 nms (0.436.mu.), D.sub.50 value of 153 nms (0.153.mu.), and
D.sub.10 value of 74 nms (0.074.mu.), was dispersed in a portion of
water for injection heated at 60.degree. C. with stirring. The
asenapine maleate solution was added to the resin dispersion and
allowed to cool it at room temperature under stirring. The so
formed suspension was dried under pressure, to obtain a free
flowing powder. This drug loaded nano sized ion exchange resin
particles were lubricated with a lubricant and were filled into a
hard gelatin capsule, suitable for per-oral ingestion and delivery
of drug in the GIT.
Example 9
[0143] The example provides aqueous suspension formulation of
Bromfenac sodium, according to one embodiment of the present
invention.
TABLE-US-00009 TABLE 9 Bromfenac sodium suspension 0.07% w/v
Example 9 (A) Example 9 (B) Ingredient Function Ingredients % w/v %
w/v Bromfenac sodium (equivalent Active Ingredient 0.0805 to
bromfenac free acid 0.07%) Indion .TM.860 Anion exchange resin 0.07
Carbopol 974 P (Carbomer) Polymeric vehicle -- 0.1 Hydroxy propyl
methyl cellulose 0.3 polyvinylpyrrolidone 1.2 Benzalkonium Chloride
Preservative 0.02 Edetate Disodium Chelating agent 0.1
N-Lauroylsarcosine sodium Preservative 0.06 Mannitol Osmotic agent
4.5 Tromethamine pH adjusting agent qs to adjust pH to 7.8 Water
for Injection Vehicle q.s. to 100 q.s. to 100
[0144] Process: In a stainless steel (SS 316) beaker, about 15%
water for injection of total batch size was taken and heated to
85.degree. C. The specified polymeric vehicle, such as hydroxy
propyl methyl cellulose (hypromellose 2910) was dispersed with high
speed stirring to obtain uniform dispersion. The stirring was
continued till temperature reached 25.degree. C. In another
stainless steel (SS 316) beaker, about 12% water for injection of
total batch size was taken at 25.degree. C. Polyvinylpyrrolidone
(povidone K-90) was dispersed in water for injection with stirring
to obtain uniform dispersion. In case of Example 9 (B) a portion of
water for injection was taken and heated at about 65.degree. C.
Carbopol 974P was dispersed in water for injection with stirring.
The stirring was continued till the temperature reached 25.degree.
C. The Carbopol 974P slurry was neutralized (pH7.4) with
tromethamine. The hypromellose and povidone polymer dispersions
obtained above were added sequentially to the carbopol 974P phase.
The polymer mixture was autoclaved at 121.degree. C. for 20
minutes. N-lauryl sarcosine sodium was mixed in a portion of water
for injection and added to the polymer phase after filtration
through 0.2 micron nylon filter. Mannitol was dissolved in a
portion of water for injection at 50-60.degree. C. and benzalkonium
chloride, and edetate disodium were added to form a clear solution.
This solution was added to the above polymer phase. A portion of
water for injection of total batch size was taken in a vessel and
Indion.TM.860 obtained following a process similar to Example 1,
was dispersed with stirring. This dispersion was autoclaved at
121.degree. C. for 20 minutes. In another vessel, a portion of
water for injection was taken and bromfenac sodium was added with
stirring to dissolve. This solution was filtered through 0.2 micron
and 0.45 micron nylon filter. Filtered bromfenac sodium solution
was added to above autoclaved Indion.TM.860 dispersion and stirred
for 30 minutes.
[0145] The Indion.TM.860 & bromfenac sodium dispersion was
added to the polymer mixture obtained above with stirring and
stirring was continued for about 30 minutes to 1 hour. The volume
of suspension was finally made up to 100% batch size. The
suspension was stirred for about 60 minutes, followed by
homogenization at 15000 rpm for 10 mins. The pH was adjusted with
tromethamine solution to about 7.8. The aqueous suspension
formulation of bromfenac is suitable for ophthalmic use. The
aqueous suspension formulation may also be used for delivery of
drug via dermal or oral or sublingual route of administration.
Example 10
[0146] According to one embodiment of the present invention, this
example provides a suspension formulation of Asenapine maleate
having asenapine nano-resin complex, which is subsequently
formulated into a Tablet dosage form for per oral delivery.
TABLE-US-00010 TABLE 10 Asenapine maleate nanoresin suspension 1.0%
w/v Ingredients Ingredient Function Quantity % Asenapine (eq. to
Asenapine Active 1.0 (eq. to 1.41) maleate) Sodium polystyrene
Cation exchange 1.0 sulphonate (Amberlite IRP 69) Resin Water for
Injection Vehicle q.s. to 100
[0147] Process: The resin sodium polystyrene sulfonate (Amberlite
IRP 69) was processed and obtained as per Example 1. The particle
size distribution of the milled resin was such that D.sub.10=0.134
microns, D.sub.50=0.198 microns and D.sub.90=0.351 microns. The
nanoresin (Amberlite IRP 69) so obtained was dispersed in a portion
of water for injection and heated at 60.degree. C. to 70.degree. C.
with stirring. Asenapine (in the form of a salt Asenapine maleate)
was dissolved in water for injection under stirring at 60.degree.
C. to 70.degree. C. This Asenapine maleate solution was added to
the resin dispersion at heated condition with stirring and then
allowed to cool at room temperature under stirring. The volume of
suspension was finally made up to 100% batch size. Asenapine-resin
complex Suspension was washed with water by centrifugation at 2000
rpm for 50-60 min and then lyophilized to obtain dried powder.
TABLE-US-00011 TABLE 11 Tablet dosage form comprising asenapine
nano-resin complex: Ingredient Ingredient Function Quantity
(mg/tablet) Asenapine-Amberlite Drug with carrier 10 (Both drug and
resin in IRP69 complex equivalent quantity) Mannitol Diluent 47.3
Crosspovidone ultra Disintigrant 10.5 Aerosil-Colloidal Glidant 3.5
Silica Magnesium stearate Lubricant 0.7 Sucralose Sweetener 0.5
[0148] Dried powder of Asenapine-nano resin complex prepared as
above was mixed with mannitol, crosspovidone ultra, aerosil
(colloidal silica) and sucralose and blended manually. Magnesium
stearate was then mixed with the blend and final powder was
homogenously mixed. The blend was compressed to yield white to off
white round biconvex uncoated tablet plain on both sides by direct
compression method. The solid tablet dosage form is suitable for
per-oral administration.
Example 11
[0149] This example provides a suspension formulation comprising
Amitriptyline nano-resin complex, which is subsequently formulated
into a topical dosage form i.e. gel.
TABLE-US-00012 TABLE 12 Amitriptyline nano-resin suspension 1.0%
w/v Ingredients Function Quantity % Amitriptyline (eq. to
Amitriptyline Active 1.0 (eq. to 1.21) hydrochloride) Sodium
polystyrene sulphonate Cation exchange 1.0 (Amberlite IRP 69) Resin
Water Vehicle q.s. to 100
[0150] Process: Sodium polystyrene sulfonate (Amberlite IRP 69) was
processed and obtained as per Example 1. The particle size
distribution of the milled resin was such that D.sub.10=0.134
microns, D.sub.50=0.198 microns and D.sub.90=0.351 microns. The
Amberlite IRP 69 nanoresin so obtained was dispersed in a portion
of water for injection at room temperature with stirring. In a
stainless steel (SS 316) beaker, water for injection was taken at
room temperature. Amitriptyline used in the form of a salt.
Amitriptyline hydrochloride was dissolved under stirring. The
Amitriptyline hydrochloride solution was added to the resin
dispersion at room temperature under stirring. The volume of
suspension was finally made up to 100% batch size.
Amitriptyline-resin complex suspension was washed with water by
centrifugation at 2000 rpm for 5-10 min and then lyophilized to
obtain dried powder.
TABLE-US-00013 TABLE 13 Topical gel composition comprising
Amitriptyline nano-resin complex: Ingredients Function Quantity (%
w/w) Amitriptyline-Amberlite Active with carrier 4.0 (Both drug and
resin IRP69 complex in equivalent quantity) Carbomer homopolymer
Formulation base 1.0 Type B (Carbopol 974P) Sodium hydroxide pH
adjusting agent 0.012 Water Vehicle q.s.
[0151] Process: In a stainless steel (SS 316) beaker, water for
injection was taken and heated to 65.degree. C. The specified
polymeric vehicle, Carbopol 974P was dispersed in heated water for
injection with stirring. The stirring was continued till the
temperature reached 25.degree. C. The Carbopol 974P slurry was
neutralized with sodium hydroxide. Separately dried powder of
amitriptyline-nanoresin complex prepared as above was suspended in
a portion of water. This suspension was mixed with neutralized
Carbopol 974P gel with stirring by glass rod. pH of the resulting
topical gel formulation was adjusted to 5.0 to 5.5. The gel
formulation is suitable for dermal application.
Example 12
TABLE-US-00014 [0152] TABLE 14 Topical gel formulation of
Methotrexate. Ingredients Ingredient Function Quantity % w/w
Methotrexate sodium Active Ingredient 1-10 Indion 860 Resin 1-10
Hydroxy propyl cellulose Thickening agent 5 Edetate Disodium
Chelating agent 0.1 Polyethylene glycol 400 Emollient 10 Butylated
hydroxyl toluene Stabilizer 0.05 Oleic acid Penetration enhancer
2.5 Triethanolamine pH adjusting agent qs Water for Injection
Vehicle q.s. to 100
[0153] Process:
[0154] Hydroxy propyl cellulose was dispersed in heated water for
injection with stirring. Edetate disodium, polyethylene glycol 400,
butylated hydroxyl toluene, oleic acid, triethanolamine were
dissolved in water for injection sequentially and stirred until
dissolved and form a clear solution. This solution was added to the
above polymer phase.
[0155] The Indion 806 nano-resin prepared by step similar to
Example 1, was dispersed in a portion of water for injection with
stirring. In another vessel, methotrexate sodium was dissolved in
water with stirring and filtered. The filtered methotrexate sodium
solution was added to above dispersion of Indion 806 nano-resin
particles and stirred for 30 minutes. The dispersion was subjected
to diafiltration and washing with water for injection. This slurry
was lyophilized to get the dry powder which was then added to the
polymer mixture obtained above with stirring which results in
formation of gel. The gel was stirred for 60 minutes. The gel
formulation is suitable for topical application, such as dermal
application to the skin.
Example 13-14
[0156] Examples 13-14 provides topical ointment formulation of
Methotrexate and Minocycline.
TABLE-US-00015 TABLE 15 Quantity % w/w Ingredients Function Example
13 Example 14 Minocycline Hydrochloride Active 1-5 -- Methotrexate
Sodium Ingredient -- 1-10 Sodium polystyrene sulphonate Resin 1-5
(Amberlite IRP 69) Indion 860 -- 1-10 Mineral oil Emollient 10 10
Glyceryl mono oleate Stabilizer 1 1 White petrolatum Ointment Qs to
100 Qs to 100 base
[0157] Process: The Amberlite IRP 69 nano resin/Indion 860
nano-resin was obtained by a process similar to Example 1. The
resin was dispersed in a portion of water for injection with
stirring. In another vessel, drug (minocycline
hydrochloride/methotrexate sodium) was dissolved in water for
injection with stirring and filtered. The filtered drug solution
was added to above resin dispersion and stirred for 30 minutes. The
dispersion was subjected to diafiltration and washing with water
for injection and the resulting slurry was lyophilized to get the
dry powder. White petrolatum was taken in a beaker and heated it at
70-80.degree. C. In another beaker, the drug-resin complex was
taken along with mineral oil and glyceryl mono oleate and properly
mixed at temperature 50-70.degree. C. This phase was added to the
white petrolatum phase and stir continuously for 1 hour, which
results in formation of ointment, suitable for topical drug
delivery. The gel formulation is particularly suitable for dermal
application to the skin, or drug delivery to the otic or nasal
cavity.
* * * * *