U.S. patent application number 13/695930 was filed with the patent office on 2013-02-28 for ophthalmic composition.
The applicant listed for this patent is Jun Inoue, Tapan Shah. Invention is credited to Jun Inoue, Tapan Shah.
Application Number | 20130053374 13/695930 |
Document ID | / |
Family ID | 44902332 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130053374 |
Kind Code |
A1 |
Inoue; Jun ; et al. |
February 28, 2013 |
OPHTHALMIC COMPOSITION
Abstract
The present invention provides an ophthalmic composition
comprising a hyperbranched polyester. The ophthalmic compositions
may also comprise carbonic anhydrase inhibitors, wherein the
hyperbranched polyester increases the aqueous solubility of the
carbonic anhydrase inhibitor, and increases corneal permeation of
the active agent. The ophthalmic compositions may also comprise
non-ionic surfactants, such as PEG, Polysorbate, HPMC or HEC, and
beta-blockers, such as Carteolol, Levobunolol, Betaxolol,
Metipranolol, Timolol or Propranolol. The concentration of the
hyperbranched polyester in the ophthalmic formulation should be
less than or equal to 4% (w/v) in order to avoid any cytotoxic
effects on human corneal cells and thus the eye irritation.
Inventors: |
Inoue; Jun; (Woodland Hills,
CA) ; Shah; Tapan; (Woodland Hills, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Inoue; Jun
Shah; Tapan |
Woodland Hills
Woodland Hills |
CA
CA |
US
US |
|
|
Family ID: |
44902332 |
Appl. No.: |
13/695930 |
Filed: |
May 4, 2011 |
PCT Filed: |
May 4, 2011 |
PCT NO: |
PCT/US11/35147 |
371 Date: |
November 5, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12774419 |
May 5, 2010 |
8211450 |
|
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13695930 |
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Current U.S.
Class: |
514/226.5 ;
514/236.2; 514/432; 514/781; 514/785; 514/788; 564/512 |
Current CPC
Class: |
A61K 31/138 20130101;
A61K 31/382 20130101; A61K 31/4704 20130101; A61K 31/542 20130101;
A61P 27/06 20180101; A61K 2300/00 20130101; A61P 43/00 20180101;
A61K 9/0048 20130101; A61P 27/02 20180101; A61K 31/5377 20130101;
A61K 47/34 20130101; A61K 31/5377 20130101; A61K 31/138 20130101;
A61K 2300/00 20130101; A61K 2300/00 20130101; A61K 31/4704
20130101; A61K 31/433 20130101 |
Class at
Publication: |
514/226.5 ;
564/512; 514/788; 514/432; 514/781; 514/785; 514/236.2 |
International
Class: |
A61K 47/34 20060101
A61K047/34; A61K 31/382 20060101 A61K031/382; A61P 27/02 20060101
A61P027/02; A61K 47/38 20060101 A61K047/38; A61K 47/22 20060101
A61K047/22; A61K 31/5377 20060101 A61K031/5377; C07C 211/02
20060101 C07C211/02; A61K 31/542 20060101 A61K031/542 |
Claims
1. An ophthalmic composition comprising a hyperbranched polymer,
wherein the hyperbranched polymer comprises a terminal functional
group selected from the group consisting of an amine group, a
hydroxyl group, a fatty acid group, and PEG.
2. The ophthalmic composition according to claim 1, further
comprising a carbonic anhydrase inhibitor.
3. The ophthalmic composition according to claim 1, further
comprising a non-ionic surfactant.
4. The ophthalmic composition according to claim 2, further
comprising a non-ionic surfactant.
5. The ophthalmic composition according to claim 1, wherein the
average molecular weight of the hyperbranched polymer is in the
range from 1,000 to 750,000 Daltons (M.sub.W).
6. The ophthalmic composition according to claim 1, wherein the
hyperbranched polymer comprises a core selected from the group
consisting of Polyethylenimine, Polypropylenimine, and
polyester.
7. The ophthalmic composition according to claim 1, wherein the pH
is in the range from 3.0 to 8.0.
8. The ophthalmic composition according to claim 1, wherein the
concentration of the hyperbranched polymer is in the range from
0.01% to 5% (w/v).
9. The ophthalmic composition according to claim 2, further
comprising a beta-blocker.
10. The ophthalmic composition according to claim 2, wherein the
carbonic anhydrase inhibitor is selected from the group consisting
of Dorzolamide, Brinzolamide and Acetazolamide.
11. The ophthalmic composition according to claim 3, wherein the
non-ionic surfactant is selected from the group consisting of PEG,
polysorbate, Hydroxyl Propyl Methyl Cellulose, and Hydroxy Ethyl
Cellulose.
12. The ophthalmic composition according to claim 4, wherein the
non-ionic surfactant is selected from the group consisting of PEG,
Polysorbate, Hydroxyl Propyl Methyl Cellulose, and Hydroxy Ethyl
Cellulose.
13. The ophthalmic composition according to claim 9, wherein the
beta-blocker is selected from the group consisting of Carteolol,
Levobunolol, Betaxolol, Metipranolol, Timolol and Propranolol.
14. The ophthalmic composition according to claim 6, wherein the
hyperbranched polymer core is polyester, and wherein the
hyperbranched polymer comprises a hydroxyl group, a fatty acid
group, and PEG as terminal functional groups.
15. The ophthalmic composition according to the claim 14, wherein
the average molecular weight of the hyperbranched polymer is in the
range from 1,000 to 12,000 Daltons (M.sub.W).
16. The ophthalmic composition according to claim 14, wherein the
concentration of the hyperbranched polymer is in the range from
0.001 to 4% (w/v).
17. An ophthalmic composition comprising a hyperbranched polyester,
Timolol, Dorzolamide, and Polysorbate 80, wherein the hyperbranched
polyester comprises a terminal functional group selected from the
group consisting of a polyester hydroxyl group, a fatty acid group,
and PEG.
18. An ophthalmic composition comprising a hyperbranched polyester,
Timolol, Brinzolamide, and Polysorbate 80, wherein the
hyperbranched polyester comprises a terminal functional group
selected from the group consisting of a polyester hydroxyl group, a
fatty acid group, and PEG.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an ophthalmic composition
comprising a hyperbranched polymer. The hyperbranched polymer of
the present invention may be any hyperbranched polymer which is
pharmaceutically acceptable, e.g., a hyperbranched polymer with a
Polyethyleneimine, Polypropyleneimine or Polyester.
BACKGROUND OF THE INVENTION
[0002] COSOPT.RTM. and TRUSOPT.RTM. are commercially available
topical ophthalmic solutions developed by Merck for treating an eye
disease called glaucoma. In the case of TRUSOPT.RTM., the active
ingredient is Dorzolamide exclusively. In the case of COSOPT.RTM.,
the active ingredients are Dorzolamide and Timolol (beta blocker).
Dorzolamide is a carbonic anhydraze inhibitor with the aqueous
solubility of 40 mg/mL at pH 4.0-5.5. It is a white to off-white,
crystalline powder, which is soluble in water and slightly soluble
in methanol and ethanol.
[0003] However, these formulations contain 2% (w/v) Dorzolamide,
and are prepared at pH 5.65, due to the limited aqueous solubility
of Dorzolamide at physiological pH. Consequently, the COSOPT.RTM.
and TRUSOPT.RTM. formulations can lead to local irritation, due to
the low pH. Dorzolamide has two pKa values of 6.35 and 8.5, which
correspond to the protonated secondary amine group and the
sulfonamide group, respectively. Dorzolamide is mainly in its
hydrophilic cationic form at pH below 6.4, and in its hydrophilic
anionic form above pH 8.5.
[0004] Thus, Dorzolamide has a relatively low aqueous solubility in
solutions with pH between 6.4 and 8.5, mainly because of
Dorzolamide's non-ionic behavior in that physiological pH
range.
[0005] AZOPT.RTM. (Brinzolamide ophthalmic suspension) 1% is a
sterile, aqueous suspension of Brinzolamide, which has been
formulated to be readily suspended and slow settling, following
shaking. AZOPT.RTM. is developed by Alcon and contains Brinzolamide
as active ingredient. The formulation has a pH of approximately 7.5
and an osmolality of 300 mOsm/kg. It is instilled for the reduction
of elevated intraocular pressure in patients with open-angle
glaucoma or ocular hypertension. Brinzolamide's pKa values are 5.9
(amine) and 8.4 (primary sulfonamide), allowing it to act as an
acid or a base (ampholyte) depending upon the pH. It is mainly in
its hydrophilic cationic form at pH below 5.9 and hydrophilic
anionic form above pH 8.4. It is clear that Brinzolamide is
significantly less protonated (<10%) at physiological pH. Thus,
Brinzolamide has relatively low aqueous solubility in solutions
with pH between 5.9 and 8.4, mainly because of Brinzolamide's
nonionic (lipophilic) behavior in that pH range.
[0006] Dendritic polymers are tree-like polymers that can be
classified into two main types based on their branching
architecture as "perfectly branched" (dendrimers) and "imperfectly
branched" (hyperbranched polymers or HP). Hyperbranched polymers
are molecular constructions having a branched structure, generally
around a core. Unlike dendrimers, the structure of hyperbranched
polymers generally lacks symmetry, as the base units or monomers
used to construct the hyperbranched polymer can be of diverse
nature and their distribution is non-uniform. The branches of the
polymer can be of different natures and lengths. The number of base
units, or monomers, may be different depending on the different
branching. While at the same time being asymmetrical, hyperbranched
polymers can have: an extremely branched structure, around a core;
successive generations or layers of branching; a layer of end
chains. Hyperbranched polymers are generally derived from the
polycondensation of one or more monomers AB.sub.x, A and B being
reactive groups capable of reacting together, x being an integer
greater than or equal to 2. However, other preparation processes
are also possible. Hyperbranched polymers are characterized by
their degree of polymerization DP=100-b, b being the percentage of
non-terminal functionalities in B which have not reacted with a
group A. Since the condensation is not systematic, the degree of
polymerization is less than 100%. An end group T can be reacted
with the hyperbranched polymer to obtain a particular functionality
on the ends of chains.
[0007] Hyperbranched polymers are mainly identified by their core
type and their terminal groups. Examples of a core type for a
hyperbranched polymer are polyethylenimine, polypropylenimine,
polyglycol, polyether, polyester, etc. A hyperbranched polymer with
a polyester core may be referred to as a hyperbranched polyester.
Examples of terminal or surface functional groups of hyperbranched
polymers are amine, hydroxyl, carboxylic acid, a fatty acid,
polyethylene glycol (PEG), polyester, etc. See U.S. Pat. No.
6,432,423, U.S. Pat. No. 7,097,856, and U.S. Patent Publication
2006/0204472, the contents of which are incorporated herein by
reference.
##STR00001##
[0008] In contrast to the "structurally perfect" dendrimers
prepared by multi-step synthesis, somewhat less perfect
hyperbranched polymers can be synthesized in one-step reactions.
Thus, unlike dendrimers, hyperbranched polymers are rapidly
prepared with no purification steps needed for their preparation.
Consequently, hyperbranched polymers are significantly less
expensive than dendrimers. Thus it makes hyperbranched polymers
amenable for large-scale in vivo trials and bringing highly
branched polymers as candidates for drug delivery of even common
drugs as ibuprofen (Kannan, R. M. et al., Biomedical Applications
of Nanotechnology, 2007, John Wiley & Sons Inc., p. 105).
OBJECT OF THE INVENTION
[0009] An object of the invention is to provide an improved
ophthalmic composition, with improved aqueous solubility and
corneal permeation of the active agent.
SUMMARY OF THE INVENTION
[0010] The present inventors have studied ophthalmic compositions
comprising hyperbranched polymers. The present inventors have
discovered that hyperbranched polymers are muco-adhesive polymers
with a high force of bioadhesion, which provide strong
electrostatic interactions between the negatively charged cornea
mucin membrane and the cationic hyperbranched polymers.
[0011] The present inventors have discovered that hyperbranched
polymers increase the aqueous solubility of carbonic anhydrase
inhibitors such as Dorzolamide or Brinzolamide for glaucoma
therapy. Additionally, the present inventors have discovered that
the aqueous solubility of Dorzolamide or Brinzolamide increases
linearly with an increase in the concentration of the hyperbranched
polymer. Furthermore, the present inventors have discovered that
hyperbranched polymers, such as Bis-MPA hyperbranched polyester
with hydroxyl functional groups (2.sup.nd generation), can be
safely employed up to 4% (w/v) with no cytotoxic or eye irritation,
based on in vitro human corneal epithelial cell culture studies.
Additionally, the present inventors have discovered that
hyperbranched polymers increase the corneal permeation and
partitioning of Dorzolamide and Timolol into intact cornea, and
increase the partitioning of Dorzolamide and Timolol into the
lipophilic cornea membrane.
[0012] Accordingly, the present invention provides: [0013] (1) An
ophthalmic composition comprising a hyperbranched polymer, wherein
the hyperbranched polymer comprises a terminal functional group
selected from the group consisting of an amine group, a hydroxyl
group, a fatty acid group, and Polyethylene Glycol (PEG). [0014]
(2) The ophthalmic composition according the above (1), further
comprising a carbonic anhydrase inhibitor. [0015] (3) The
ophthalmic composition according to the above (1) or (2), further
comprising a non-ionic surfactant. [0016] (4) The ophthalmic
composition according to the above (1), wherein the average
molecular weight of the hyperbranched polymer is in the range from
1,000 to 750,000 Daltons (M.sub.w). [0017] (5) The ophthalmic
composition according to the above (1) or (2), wherein the
hyperbranched polymer comprises a core selected from the group
consisting of Polyethylenimine, Polypropylenimine, and polyester.
[0018] (6) The ophthalmic composition according to the above (1),
wherein the pH is in the range from 3.0 to 8.0. [0019] (7) The
ophthalmic composition according to the above (1), wherein the
concentration of the hyperbranched polyester is in the range from
0.01% to 5% (w/v). [0020] (8) The ophthalmic composition according
to the above (2), further comprising a beta-blocker. [0021] (9) The
ophthalmic composition according to the above (2), wherein the
carbonic anhydrase inhibitor is selected from the group consisting
of Dorzolamide, Brinzolamide and Acetazolamide. [0022] (10) The
ophthalmic composition according to the above (3), wherein the
non-ionic surfactant is selected from the group consisting of PEG,
Polysorbate, Hydroxyl Propyl Methyl Cellulose (HPMC), and Hydroxy
Ethyl Cellulose (HEC). [0023] (11) The ophthalmic composition
according to the above (8), wherein the beta-blocker is selected
from the group consisting of Carteolol, Levobunolol, Betaxolol,
Metipranolol, Timolol and Propranolol. [0024] (12) The ophthalmic
composition according to the above (5), wherein the hyperbranched
polymer core is polyester, and wherein the hyperbranched polymer
comprises a hydroxyl group, a fatty acid group, and PEG as terminal
functional groups. [0025] (13) The ophthalmic composition according
to the above (12), wherein the average molecular weight of the
hyperbranched polymer is in the range from 1,000 to 12,000 Daltons
(M.sub.w). [0026] (14) The ophthalmic composition according to the
above (12), wherein the concentration of the hyperbranched polymer
is in the range from 0.001% to 4% (w/v). [0027] (15) An ophthalmic
composition comprising a hyperbranched polyester, Timolol,
Dorzolamide, and Polysorbate 80, wherein the hyperbranched
polyester comprises a terminal functional group selected from the
group consisting of polyester hydroxyl group, a fatty acid group,
and PEG. [0028] (16) An ophthalmic composition comprising a
hyperbranched polyester, Timolol, Brinzolamide, and Polysorbate 80,
wherein the hyperbranched polyester comprises a terminal functional
group selected from the group consisting of polyester hydroxyl
group, a fatty acid group, and PEG.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 shows the pH-solubility profile of Dorzolamide in
0.1% (w/v) phosphate buffer.
[0030] FIG. 2 shows the dependence of hyperbranched polymer
concentration on the aqueous solubility of Dorzolamide in 0.1%
(w/v) phosphate buffer at pH 5.65.
[0031] FIG. 3 shows the dependence of hyperbranched polymer
concentration on the aqueous solubility of Dorzolamide in 0.1%
(w/v) phosphate buffer at pH 7.
[0032] FIG. 4 shows the effect of a combination of PEG 8000 and
hyperbranched polymer (Lupasol.RTM. PS) with various concentrations
on the aqueous solubility of Dorzolamide at pH 7.
[0033] FIG. 5 shows the viscosity as a function of shear rate at
20.degree. C. of different solutions in 0.1% (w/v) phosphate
buffer.
[0034] FIG. 6 shows the force of bioadhesion at pH 7 and shear rate
of 80
[0035] FIG. 7 shows the maximum aqueous solubility of Dorzolamide
at pH 5.65 and pH 7 with addition of additives in the presence of
0.5% Timolol in the aqueous solution in all cases.
[0036] FIG. 8 shows the maximum Dorzolamide solubility at pH 7 with
different combinations of additives in the presence of 0.5%
Timolol.
[0037] FIG. 9 shows the schematic of a standard side by side
diffusion cell.
[0038] FIG. 10 shows the mean permeation profiles (n=2) of
Dorzolamide through intact rabbit corneas for a formulation
containing Lupasol.RTM. PS hyperbranched polymer.
[0039] FIG. 11 shows the mean permeation profiles (n=2) of Timolol
through intact rabbit corneas for a formulation containing
Lupasol.RTM. PS hyperbranched polymer.
[0040] FIG. 12 shows the mean percentage total corneal permeation
of Dorzolamide and Timolol after 3 hours for a formulation
containing Lupasol.RTM. PS hyperbranched polymer.
[0041] FIG. 13 shows the mean corneal permeability coefficients of
Dorzolamide and Timolol for a formulation containing Lupasol.RTM.
PS hyperbranched polymer.
[0042] FIG. 14 shows the mean diffusion coefficients of Dorzolamide
and Timolol for permeation through intact rabbit corneas for a
formulation containing Lupasol.RTM. PS hyperbranched polymer.
[0043] FIG. 15 shows the mean partition coefficients of Dorzolamide
and Timolol for permeation through intact rabbit corneas for a
formulation containing Lupasol.RTM. PS hyperbranched polymer.
[0044] FIG. 16 shows the aqueous solubility of Brinzolamide in 10
mM phosphate buffer at different pH values.
[0045] FIG. 17 shows the maximum aqueous solubility of Brinzolamide
at pH 7 with addition of additives in the absence and presence of
0.5% Timolol in the aqueous solution.
[0046] FIG. 18 shows the mean permeation profiles of Dorzolamide
(n=2) through rabbit corneas for a formulation containing
Boltorn.RTM. H20 hyperbranched polymer.
[0047] FIG. 19 shows the mean permeation profiles of Timolol (n=2)
through rabbit corneas for a formulation containing Boltorn.RTM.
H20 hyperbranched polymer.
[0048] FIG. 20 shows the mean percentage total corneal permeation
of Dorzolamide and Timolol after 2 hours for a formulation
containing Boltorn.RTM. H20 hyperbranched polymer.
[0049] FIG. 21 shows the mean corneal permeability coefficients of
Dorzolamide and Timolol for a formulation containing Boltorn.RTM.
H20 hyperbranched polymer.
[0050] FIG. 22 shows the mean diffusion coefficients of Dorzolamide
and Timolol for permeation through intact rabbit corneas for a
formulation containing Boltorn.RTM. H20 hyperbranched polymer.
[0051] FIG. 23 shows the mean partition coefficients of Dorzolamide
and Timolol for permeation through intact rabbit corneas for a
formulation containing Boltorn.RTM. H20 hyperbranched polymer.
[0052] FIG. 24 shows the maximum aqueous solubility of Brinzolamide
at pH 7.4 with addition of Boltorn.RTM. W3000 (amphiphilic HP) in
the presence of 0.5% (w/v) Timolol in the emulsion solution.
[0053] FIG. 25 shows the mean permeation profiles of Dorzolamide
(n=2) through intact rabbit corneas for a formulation containing
Boltorn.RTM. W3000 hyperbranched polymer.
[0054] FIG. 26 shows the mean permeation profiles (n=2) of Timolol
through intact rabbit corneas for a formulation containing
Boltorn.RTM. W3000 hyperbranched polymer.
[0055] FIG. 27 shows the mean percentage total corneal permeation
of Dorzolamide and Timolol after 3 hours for a formulation
containing Boltorn.RTM. W3000 hyperbranched polymer.
[0056] FIG. 28 shows the mean corneal permeability coefficients of
Dorzolamide and Timolol for a formulation containing Boltorn.RTM.
W3000 hyperbranched polymer.
[0057] FIG. 29 shows the mean diffusion coefficients of Dorzolamide
and Timolol for permeation through intact rabbit cornea for a
formulation containing Boltorn.RTM. W3000 hyperbranched
polymer.
[0058] FIG. 30 shows the mean partition coefficients of Dorzolamide
and Timolol for permeation through intact rabbit cornea for a
formulation containing Boltorn.RTM. W3000 hyperbranched
polymer.
[0059] FIG. 31 shows the maximum aqueous solubility of Brinzolamide
at pH 7.4 with addition of 2.sup.nd Bis-MPA hyperbranched polyester
or 3.sup.rd Bis-MPA hyperbranched polyester in the presence of 0.5%
(w/v) Timolol.
[0060] FIG. 32 shows the in vitro human corneal epithelium cell
viability of different concentrations of hyperbranched polyesters
(hydroxyl groups generation 2 and 3), and AZOPT.RTM..
[0061] FIG. 33 shows the cytotoxicity of Bis-MPA hyperbranched
polyester for different concentrations.
[0062] FIG. 34 shows the solubility and stability of Dorzolamide at
pH 7.4 with addition of Bis-MPA hyperbranched polyester and
non-ionic surfactants in the presence of 0.5% (w/v) Timolol.
[0063] FIG. 35 shows the maximum aqueous solubility of Dorzolamide
at pH 7.4 with addition of different additives in the presence of
0.5% (w/v) Timolol.
[0064] FIG. 36 shows intact cornea permeation profile of
Dorzolamide for formulation containing Bis MPA hyperbranched
polyester (2.sup.nd generation).
[0065] FIG. 37 shows intact cornea permeation profile of Timolol
for formulation containing Bis MPA hyperbranched polyester
(2.sup.nd generation).
[0066] FIG. 38 shows the mean percentage total corneal permeation
of Dorzolamide and Timolol after 3 hours for formulation containing
Bis MPA hyperbranched polyester (2.sup.nd generation).
[0067] FIG. 39 shows the permeability coefficients of Dorzolamide
and Timolol for formulation containing Bis MPA hyperbranched
polyester (2.sup.nd generation).
[0068] FIG. 40 shows the partition coefficients of Dorzolamide and
Timolol for formulation containing Bis MPA hyperbranched polyester
(2.sup.nd generation).
DETAILED DESCRIPTION OF THE INVENTION
[0069] The compositions of the present invention are topically
administratable therapeutic compositions for treatment of
conditions of the eye. Such conditions of the eye include glaucoma,
and ocular diseases such as cataract, conjunctivitis, infection,
inflammation or retinopathy.
[0070] A detailed description of the invention is provided
below.
[0071] The present invention includes an ophthalmic composition
comprising a hyperbranched polymer.
[0072] The hyperbranched polymer according to the present invention
may be any hyperbranched polymer which is pharmaceutically
acceptable, e.g., a hyperbranched polymer with a Polyethyleneimine,
Polypropylenimine or a polyester core. The molecular weight of the
hyperbranched polymer in the ophthalmic compositions of the present
invention is in the range of from 1,000 to 750,000 Daltons,
preferably in the range of 1,000 to 12,000 Daltons. The molecular
weight is weight average molecular weight measured by dynamic light
scattering. The concentration of the hyperbranched polymer in the
ophthalmic compositions of the present invention is in the range
from 0.001% to 10% (w/v), preferably in the range from 0.001% to 5%
(w/v), more preferably in the range from 0.001% to 4% (w/v), more
preferably in the range from 0.01% to 4% (w/v), more preferably in
the range of 0.01% to 3% (w/v).
[0073] The ophthalmic composition discussed above may also comprise
a carbonic anhydrase inhibitor. Carbonic anhydrase inhibitors are a
class of pharmaceuticals that suppress the activity of carbonic
anhydrase, and are known to be useful as anti-glaucoma agents.
Examples of carbonic anhydrase inhibitors which may be present in
the ophthalmic compositions of the present invention are
Dorzolamide, Brinzolamide or Acetazolamide.
[0074] The ophthalmic composition discussed above may also comprise
a non-ionic surfactant. The non-ionic surfactant may be any
non-ionic surfactant which is known as a pharmaceutically
acceptable additive, for example, Polysorbate 80, PEG 8000, HPMC or
HEC.
[0075] The ophthalmic compositions of the present invention are
advantageously used after being adjusted to a pH range which is
conventionally adopted for topical application to the eye, and is
normally employed after being adjusted to a pH of 3 to 8,
preferably a pH of 5 to 8. For the pH adjustment, hydrochloric
acid, acetic acid, sodium hydroxide, etc. can be used.
[0076] The ophthalmic compositions of the present invention may
also comprise a beta-blocker. Beta-blockers are known to reduce the
pressure within the eye (the intraocular pressure), and thus, are
used to lessen the risk of damage to the optic nerve and loss of
vision in patients with glaucoma. The beta-blocker in the
ophthalmic compositions of the present invention may be any
beta-blocker which is known as acceptable in ophthalmic
compositions, such as Carteolol, Levobunolol, Betaxolol,
Metipranolol, Timolol and Propranolol.
[0077] A first specific embodiment of the present invention is an
ophthalmic composition comprising a hyperbranched polymer, Timolol,
Dorzolamide, PEG 8000 and Polysorbate 80.
[0078] Such compositions preferably comprise about 0.001% to 10%
(w/v) of the hyperbranched polymer, most preferably about 1 to 5%
(w/v), and 0.05 to 1% (w/v) of Timolol, most preferably about 0.5%
(w/v), and about 0.05 to 5% (w/v) of Dorzolamide, most preferably
about 0.5 to 2% (w/v), and about 0.05 to 5% (w/v) of PEG 8000, most
preferably about 0.5 to 4% (w/v), and about 0.05 to 5% (w/v) of
Polysorbate 80, most preferably about 0.5 to 4% (w/v), and are to
be administered once or twice a day to each affected eye.
[0079] A second specific embodiment of the present invention is an
ophthalmic composition comprising a hyperbranched polymer, Timolol,
Brinzolamide, PEG 8000 and Polysorbate 80.
[0080] Such compositions preferably comprise about 0.001% to 10%
(w/v) of the hyperbranched polymer, most preferably about 1 to 5%
(w/v), and 0.05 to 1% (w/v) of Timolol, most preferably about 0.5%
(w/v), and about 0.05 to 5% (w/v) of Brinzolamide, most preferably
about 0.5 to 2% (w/v), and about 0.05 to 5% (w/v) of PEG 8000, most
preferably about 0.5 to 4% (w/v), and about 0.05 to 5% (w/v) of
Polysorbate 80, most preferably about 0.5 to 4% (w/v), and are to
be administered once or twice a day to each affected eye.
[0081] A third specific embodiment of the present invention is an
ophthalmic composition comprising a hyperbranched polyester,
Timolol, Dorzolamide, PEG 8000 and Polysorbate 80.
[0082] Such compositions preferably comprise about 0.1% to 10%
(w/v) of the hyperbranched polyester, most preferably about 1 to 5%
(w/v), and 0.05 to 1% (w/v) of Timolol, most preferably about 0.5%
(w/v), and about 0.05 to 5% (w/v) of Dorzolamide, most preferably
about 0.5 to 2% (w/v), and about 0.05 to 5% (w/v) of PEG 8000, most
preferably about 0.5 to 4% (w/v), and about 0.05 to 5% (w/v) of
Polysorbate 80, most preferably about 0.5 to 4% (w/v), and are to
be administered once or twice a day to each affected eye.
[0083] A fourth specific embodiment of the present invention is an
ophthalmic composition comprising a hyperbranched polyester,
Timolol, Brinzolamide, PEG 8000 and PEG 8000.
[0084] Such compositions preferably comprise about 0.1% to 10%
(w/v) of the hyperbranched polyester, most preferably about 1 to 5%
(w/v), and 0.05 to 1% (w/v) of Timolol, most preferably about 0.5%
(w/v), and about 0.05 to 5% (w/v) of Brinzolamide, most preferably
about 0.5 to 2% (w/v), and about 0.05 to 5% (w/v) of PEG 8000, most
preferably about 0.5 to 4% (w/v), and about 0.05 to 5% (w/v) of
Polysorbate 80, most preferably about 0.5 to 4% (w/v), and are to
be administered once or twice a day to each affected eye.
[0085] The ophthalmic compositions according to the present
invention may comprise a pharmacologically acceptable carrier,
excipient or diluent which is known per se and may be formulated by
a method known per se for preparing ophthalmic compositions. The
ophthalmic compositions of the present invention may be provided in
any pharmaceutical dosage form that is conventionally used as an
ophthalmic preparation, e.g., eye drops, emulsions, and eye
ointments.
[0086] The eye drop formulation may, for example, be an aqueous
formulation, such as ophthalmic solution which is clear solution,
ophthalmic suspension, ophthalmic emulsion, as well as non-aqueous
formulations, such as non-aqueous ophthalmic solution and
non-aqueous ophthalmic suspension.
[0087] The ophthalmic solution formulation may contain various
additives incorporated ordinarily, such as buffering agents (e.g.,
phosphate buffers, borate buffers, citrate buffers, tartarate
buffers, acetate buffers, amino acids, Sodium acetate, Sodium
citrate and the like), isotonicities (e.g., saccharides such as
sorbitol, glucose and mannitol, polyhydric alcohols such as
Glycerin, concentrated Glycerin, PEG and Propylene glycol, salts
such as Sodium chloride), preservatives or antiseptics (e.g.,
Benzalkonium chloride, Benzethonium chloride, P-oxybenzoates such
as Methyl p-oxybenzoate or Ethyl p-oxybenzoate, Benzyl alcohol,
Phenethyl alcohol, Sorbic acid or its salt, Thimerosal,
Chlorobutanol and the like), solubilizing aids or stabilizing
agents (e.g., cyclodextrins and their derivative, water-soluble
polymers such as polyvinyl pyrrolidone, surfactants such as
tyloxapol, pH modifiers (e.g., Hydrochloric acid, Acetic acid,
Phosphoric acid, Sodium hydroxide, Potassium hydroxide, Ammonium
hydroxide and the like), thickening agents (e.g., HEC,
Hydroxypropyl cellulose, Methyl cellulose, HPMC, Carboxymethyl
cellulose and their salts), chelating agents (e.g., Sodium edetate,
Sodium citrate, condensed Sodium phosphate) and the like.
[0088] The eye drop formulation in the form of an aqueous
suspension may also contain suspending agents (e.g., Polyvinyl
pyrrolidone, Glycerin monostearate) and dispersing agents (e.g.,
surfactants such as Tyloxapol, ionic polymers such as Sodium
alginate) in addition to the additives listed above, whereby
ensuring that the eye drop formulation is a further uniform
microparticulate and satisfactorily dispersed aqueous
suspension.
[0089] The eye drop formulation in the form of an aqueous
suspension preferably contains Sodium citrate or Sodium acetate as
a buffering agent, concentrated Glycerin and/or Propylene glycol as
an isotonicity and Polyvinyl pyrrolidone as a suspending agent. A
preferred dispersing agent is a surfactant and/or Sodium alginate.
Such surfactant is preferably Tyloxapol.
[0090] The ophthalmic composition of the present invention may be
administered to a mammal which is or may be suffering from an
ophthalmic disease, such as glaucoma (e.g., a human, rabbit, dog,
cat, cattle, horse, monkey).
[0091] While the administration route and the dose may vary
depending on a symptom, age and body weight of a subject, the
concentration of the active agent in the ophthalmic composition of
the present invention is about 0.001 to 5 (w/v) %, preferably about
0.01 to 3 (w/v) % contained in an aqueous eye drop formulation when
given to an adult, and is given preferably 1 to 8 times a day with
a single dose being one to several drops.
[0092] Unless the intended purpose of use is affected adversely,
the ophthalmic compositions of the present invention may contain or
may be used together with other appropriate pharmacologically
effective substances, for example, steroidal anti-inflammatory
agents (Dexamethasone, Prednisolone, Loteprednolm Fluorometholone,
Fluocinolone and the like), non-steroidal anti-inflammatory agents
(Diclofenac sodium, Pranoprofen, Bromfenac, Ketorolac tromethamine,
Napafenac, Flurbiprofen Sodium and the like), antiallergic agents
(Tranilast, Ketotifen fumarate, Olopatadine hydrochloride, Sodium
Cromoglicate, Potassium Pemirolast, Sodium Nedocromil and the
like), antihistamic agents (Epinastine hydrochloride, Azelastine
hydrochloride, Azalastine hydrochrilidem, Diphenhydramine
hydrochloride and the like), glaucoma-treating agents (Pilocarpine
hydrochloride, Physostigmine salicylate, Timolol,
Isopropylunoprostone, Latanoprost, Betaxolol hydrochloride,
Apraclonidine, Brimonidine Tartrate, Carbacol, Dipivefrin,
Bimatoprost, Travoprost, Brimonidine tartrate and the like),
antibiotics (Azithromycin, Gentamycin sulfate, Fradiomycin sulfate,
Tobramycin, Sulbenicillin, Cefinenoxime, Erythromycin, Colistin,
Oxytetracycline, Polymyxin B, Chloramphenicol, Micronomicin,
Dibekacin, Sisomicin and the like), antibacterial agents
(Sulfamethizole, Sulfamethoxazole, Ofloxacin, Norfloxacin,
Lomefloxacin hydrochloride, Moxifloxacin hydrochloride, Enoxacin,
Ciprofloxacin hydrochloride, Cinoxacin, Sparfloxacin, Tosufloxacin
tosylate, Nalidixic acid, Pipemidic acid Trihydrate, Pipemidic
acid, Fleroxacin, Levofloxacin, Gatifloxacin and the like), and
antiviral agents (Idoxuridine, Acyclovir and the like), and
antimycotic agents (Pimaricin, Fluconazole, Miconazole,
Amphotericin B, Flucytosine, Itraconazole and the like), anti VEGF
antibody (Pegaptanib and the like).
[0093] The ophthalmic compositions of the present invention may be
produced by dissolving or dispersing the active agent(s),
hyperbranched polymer and optionally the non-ionic surfactant in a
solution appropriately containing pharmaceutically acceptable
additives, such as isotonicity agents, buffers, preservatives,
suspending agents, thickeners, stabilizers, pH adjusting agents,
and the like.
[0094] The present inventors hereby incorporate by reference prior
filed U.S. application Ser. No. 12/774,419, in its entirety. The
present invention is further illustrated in detail by the following
Experimental Examples. These Experimental Examples are merely
illustrative, and are not intended to limit the scope of the
present invention.
Experimental Example 1
[0095] pH-solubility profile of Dorzolamide in aqueous solution
containing different concentrations of Hyperbranched Polymer (HP)
(Lupasol.RTM. G20, Lupasol.RTM. G 35, Lupasol.RTM. PS) and PEG.
Methods
[0096] Suspensions of Dorzolamide hydrochloride in 0.1% (w/v)
phosphate buffer solution at pH 5.5, pH 6, pH 6.5, pH 7, pH 7, pH 8
and pH 8.5 were prepared. Similar suspensions were also prepared in
aqueous solution containing different concentrations of different
HP and PEG with a molecular weight of 8000. A combination of
Polysorbate 80 and PEG 8000 was also attempted. The pH was measured
accurately with micro-pH electrode (Thermo Scientific). The desired
pH was adjusted using either 1 M NaOH or 1 M HCl. The suspension
solutions were first stirred for 10 min at room temperature (with
heating up to 60.degree. C. for 5 minutes). After allowing the
suspensions to equilibrate at room temperature for an additional 30
minutes, the suspension solutions were then sonicated for 10
minutes and finally filtered through 0.45 .mu.m syringe filters.
The filtrates were analyzed for Dorzolamide concentration using
UPLC. Dorzolamide detection was performed using: a gradient 1%
(v/v) Triethylamine (TEA) in water:acetonitrile method, performed
at room temperature, with the flow rate of 0.7 mL/min, at 254 nm
wavelength and 10 .mu.L injection volume, on BEH C18 1.7 .mu.m,
2.1.times.50 mm column. A calibration curve was prepared to find
Dorzolamide concentration. The properties of polymers used are
listed in Table 1.
TABLE-US-00001 TABLE 1 Properties of HPs in EXPERIMENTAL EXAMPLE 1.
Molecular Solid content Polymer name Viscosity (cP) weight pKa (%
w/v) Lupasol .RTM. G 20 200-500 1300 7-10 >98% Lupasol .RTM. G
35 250-650 2000 7-10 48-52% Lupasol .RTM. PS 1000-2500 750,000 7-10
33%
Results and Discussion.
[0097] FIG. 1 demonstrates that the aqueous solubility of
Dorzolamide decreases as the pH increases from 5.65, and reaches a
bottom at pH 7. Since COSOPT.RTM. is formulated at pH 5.65,
Dorzolamide solubility in 0.1% (w/v) phosphate buffer was
quantified in the presence of different HP of different
concentrations at pH 5.65. The result is presented in FIG. 2. The
solubility of Dorzolamide increased at pH 5.65 with the increase in
concentrations of HP from 0.1% to 1% (w/v). Similarly at pH 7, as
shown in the bar graph of FIG. 3, Dorzolamide solubility increased
linearly with the increase in concentration of HP from 0.1% (w/v)
to 4% (w/v).
[0098] As shown in FIG. 4, combinations of various concentrations
of PEG 8000 and 0.5% and 1% (w/v) of HP (Lupasol.RTM. PS) were
applied at pH 7. It is clear from FIG. 4 that 2% (w/v) solubility
of Dorzolamide (similar to COSOPT.RTM.) in phosphate buffer at pH 7
can be achieved by using about 20% PEG 8000 and 0.5% of
Lupasol.RTM. PS, or 17% of PEG 8000 and 1% Lupasol.RTM. PS.
Conclusion
[0099] The present inventors discovered that the aqueous solubility
of Dorzolamide increased with an increase in the concentration of
HP and PEG. In the case of PEG, the solubility also increased
linearly with an increase in the molecular weight of the PEG.
Further, the Polysorbate 80 assists in dispersing the Dorzolamide
molecules and inhibits the precipitation in water in presence of
PEG.
[0100] From these results, it is concluded that HP significantly
enhances the solubility of Dorzolamide. Additionally, hydrophilic
polyethylene glycol was discovered to be a Dorzolamide solubility
enhancer. The results demonstrate the advantages of using
hyperbranched polymers and PEG as Dorzolamide solubility enhancing
additives at pH values closer to physiological pH.
Experimental Example 2
[0101] A simple rheological method for the in vitro assessment of
mucin-hyperbranched polymer bioadhesive bond strength.
[0102] A simple viscometric method was adopted to quantify the
mucin-polymer bioadhesive bond strength. In order to determine the
muco-adhesive properties of commercially available HP called
Lupasol.RTM. PS, the force of bioadhesion was calculated for
different concentrations of HP with porcine gastric mucin at pH 7
in comparison with the market product COSOPT.RTM.. Porcine gastric
mucin was used as a model mucin. However, since all mucins appear
to share general physical, structural, and rheological properties,
it is believed that porcine gastric mucin is a satisfactory model
for primary evaluation of bioadhesive materials.
Methods
[0103] Brookfield Rotational L VDVE viscometer was employed for all
measurements. Spindle with code number 18 was used for all
viscosity measurements. A factor of 1.32 was used to convert rpm to
shear rate (s.sup.-1) as per the manual. A solution of 15% (w/v) of
gastric mucin was prepared in 0.1% (w/v) phosphate buffer at pH 7.
The individual viscosities 0.5% (w/v) and 1% (w/v) of Lupasol.RTM.
PS in phosphate buffer solution were measured. The viscosities of
15% mucin in phosphate buffer were also measured. The viscosity was
measured at 20.degree. C. at different shear rates D from 2.6 to 80
s.sup.-1 (Hassan, E. et al., Pharm Res. 5 (1990) 491) Five samples
of 10 mL each were prepared with different concentrations of
Lupasol.RTM. PS, PEG and with and without 15% (w/v) gastric mucin
in 0.1% (w/v) phosphate buffer at pH 7.
TABLE-US-00002 TABLE 2 Contents (% w/v) of Test Samples. Content (%
w/v) #1 #2 #3 #4 #5 #6 Lupasol .RTM. PS -- 0.5 0.5 1 1 1 Gastric
mucin 15 -- 15 -- 15 15 PEG 8000 -- -- -- -- -- 2 1M NaOH Adjust pH
Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH to 7.0 to 7.0 to
7.0 to 7.0 to 7.0 to 7.0
[0104] Sample #7 is the original COSOPT.RTM. market product. The
viscosity at 20.degree. C. was measured at different shear rates.
The force of bioadhesion was calculated using equations (1) and
(2), discussed above.
The force of bioadhesion (F) was calculated as per the following
equation (1):
F=.eta..sub.b.tau. (1),
where .tau. is the rate of shear per second, and .eta..sub.b is
based on experimental measured values as per the following equation
(2):
.eta..sub.b=.eta..sub.t-.eta..sub.m-.eta..sub.p (2)
where .eta..sub.t is the viscosity coefficient of the system, and
.eta..sub.m and .eta..sub.p are the individual viscosity
coefficients of mucin and the bioadhesive polymer (e.g., HP and PEG
8000), respectively.
[0105] For equations (1) and (2) to be valid, .eta..sub.t,
.eta..sub.m, and .eta..sub.p should be measured at the same
concentration, temperature, time, and rate of shear. The
bioadhesive phenomenon plays a dominant role in the contact time of
aqueous tear that substitute in the precorneal area.
Results & Discussion
[0106] As shown in FIG. 5, the low concentrations of HP in
phosphate buffer have relatively less viscosity compared to
COSOPT.RTM. (Sample #7) and mucin (Sample #1). The viscosities of
HP (0.5%, Sample #2 and 1%, Sample #4) are relatively close to
water at high shear rates. In addition, at high shear rates the
difference between the viscosities of 0.5% (w/v) HP and 1% (w/v)
are negligible. The result clearly suggests the advantage of using
HP as an additive with rheological properties that may be very
compatible for topical ophthalmic solutions since the addition of
HP to a formulation may not change the rheological properties of
final formulation.
[0107] The force of bioadhesion was quantified based on the data
available from FIG. 5 at shear rate of 80 s.sup.-1. High shear rate
was chosen since the polymers typically exhibit bioadhesive
properties at high shear rates (close to 100 s.sup.-1).
[0108] As shown in FIG. 6, the bioadhesive bond strength of low
concentrations (0.5% (w/v) and 1% (w/v)) of HP-mucin system is
almost more than two times to that of COSOPT.RTM.-mucin system. The
addition of 2% (w/v) PEG did not change the force of bioadhesion of
1% (w/v) HP-mucin system, suggesting that 2% PEG may not have
influence on force of bioadhesion caused by the HP at pH 7.
Overall, the results shown in FIG. 6 indicate that the bioadhesive
strengths of low concentrations of HPs are relatively significant
compared to the polymers present in COSOPT.RTM. formulation. The
bioadhesive phenomenon may be very conducive for increasing the
ocular bioavailability of the drug.
Conclusion
[0109] In conclusion, data generated by the viscometric assessment
method of bioadhesion suggests that the hyperbranched polymers are
bio-adhesive additive materials that could strongly interact with
ocular mucin. These bioadhesive forces between mucin and HP could
eventually lead to enhancement of the ocular bioavailability of the
drug.
Experimental Example 3
[0110] Aqueous solubility of Dorzolamide in the presence of Timolol
for a novel formulation containing HP (Lupasol.RTM. PS) and
Polysorbate 80 or a combination of PEG and Polysorbate 80 at pH
5.65 and pH 7.
Methods
[0111] A suspension of Dorzolamide hydrochloride and 0.5% (w/v)
Timolol in citrate buffer solution at pH 5.65 was prepared (Control
sample). A similar suspension was also prepared in aqueous solution
containing 2% (w/v) of HP in citrate buffer of pH 3. The final pH
was adjusted to 5.65 with 1 M NaOH after addition of HP (sample 1).
The combination of different molecular weight PEG and Polysorbate
80 at pH 5.65 as per Table 3 were also attempted. Table 3 shows all
the different test samples suspensions to be prepared in 10 mM
citrate buffer.
TABLE-US-00003 TABLE 3 Different Test formulations prepared at pH
5.65 in citrate buffer, and at pH 7 in phosphate buffer. Content
Control (% v/w) Sample S #1 S #2 S #3 S #4 S #5 S #6 S #7 S #8
Dorzolamide >2.22 >2.22 >2.22 >2.22 >2.22 >2.22
>2.22 >2.22 >2.22 HCl Timolol 0.683 0.683 0.683 0.683
0.683 0.683 0.683 0.683 0.683 Maleate Lupasol .RTM. PS -- 2 -- --
-- -- -- -- -- (MW = 750k) PEG 200 -- -- 2 -- -- -- -- -- -- PEG
400 -- -- -- 2 -- -- -- -- -- PEG 2000 -- -- -- -- 2 -- -- -- --
PEG 3350 -- -- -- -- -- 2 -- -- -- PEG 4000 -- -- -- -- -- -- 2 --
-- PEG 8000 -- -- -- -- -- -- -- 2 -- PEG 20000 -- -- -- -- -- --
-- -- 2 Polysorbate -- -- 1 1 1 1 1 1 1 80 In 10 mM Adjust pH
Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust
pH Adjust pH citrate or to 5.65/7 to 5.65/7 to 5.65/7 to 5.65/7 to
5.65/7 to 5.65/7 to 5.65/7 to 5.65/7 to 5.65/7 phosphate buffer
[0112] Similarly, the formulations were again prepared in 10 mM
phosphate buffer (Table 3) for the formulations to be tested for
Dorzolamide solubility at pH 7 in phosphate buffer rather than
citrate buffer. The suspension solutions were first stirred for 10
min at room temperature (with heating up to 60.degree. C. for 5
minutes). After allowing the suspensions to equilibrate at room
temperature for an additional 30 minutes, the suspension solutions
were then sonicated for 10 minutes and finally filtered through
0.45 .mu.m syringe filters. The filtrates were analyzed for
Dorzolamide and Timolol concentration using UPLC with the same
condition as EXPERIMENTAL EXAMPLE 1.
Results and Discussion
[0113] In this experiment, the present inventors used HP, PEG, and
Polysorbate 80 as solubility enhancer additives. Different
combinations were attempted at pH 5.65 and pH 7. As shown in FIG.
7, the solubility of Dorzolamide was shown to increase with the
addition of additives, compared to the control sample without
additives, at pH 5.65 and pH 7 in the presence of Timolol. At pH
5.65, in all cases the solubility of Dorzolamide was above 2%, and
therefore the addition of HP or PEG and Polysorbate 80 combination
increased solubility of Dorzolamide in the presence of Timolol.
[0114] While the market COSOPT.RTM. product has 2% (w/v)
Dorzolamide at pH 5.65, the enhancement of solubility at pH 5.65
with more than 2% (w/v) Dorzolamide solubility by addition of HP or
PEG will not have useful contribution to efficacy enhancement of
drug by increasing the dosage. Thus, the solubility data at pH 7 is
more vital, where Dorzolamide has poor solubility (less than 0.5%
w/v solubility) in 10 mM phosphate buffer. It was also noted that
the solubility of Timolol in the formulation samples (each
containing exactly 0.5% w/v Timolol) did not change at pH 5.65 and
pH 7 with the addition of additives. Since COSOPT.RTM. is
formulated at pH 5.65, the Dorzolamide solubility in the presence
of Timolol was quantified by the addition of different HP of
different concentrations at pH 5.65 to the formulation sample. The
result is presented in FIG. 7. As shown in the bar graph,
Dorzolamide solubility increases linearly with the increases in
concentration of HP from 0.5% to 2% (w/v) at pH 5.65 and pH 7.
However, the impact of HP to solubility enhancement of Dorzolamide
is more pronounced at pH 5.65 than pH 7. As shown in FIG. 8, the
addition of Polysorbate 80 to HP increases Dorzolamide
solubility.
[0115] The improvement in aqueous solubility of Dorzolamide in the
presence of Timolol was significant with the additions of a HP or a
combination of PEG and Polysorbate 80 at pH 5.65. In this case, the
Polysorbate 80 helped in dispersing Dorzolamide molecules and
inhibited the precipitation in water in the presence of PEG. A
combination of HP and Polysorbate 80 was the best combination for
enhancement of Dorzolamide solubility in presence of Timolol at pH
7. From the results, it can be concluded that HP and Polysorbate 80
significantly enhance the solubility of Dorzolamide in the presence
of Timolol at pH 7. Hydrophilic PEG also turned out to be
Dorzolamide solubility enhancer. Furthermore, a combination of low
concentrations of Polysorbate 80 and PEG 8000 also proved to be a
very useful additive for enhancement of solubility of Dorzolamide.
Overall, a formulation at pH 7 with optimized concentration of HP
and Polysorbate could be very useful for increasing the ocular
bioavailability.
Conclusion
[0116] The results clearly indicate the advantages of using HP and
Polysorbate 80 as Dorzolamide solubility enhancing additives at pH
values closer to physiological pH that are more conducive for
penetration of close to 1% (w/v) Dorzolamide through cornea
membrane. Polysorbate 80 also proved to be an effective emulsifier,
suppressing the precipitation of poorly soluble Dorzolamide at pH 7
in the presence of a HP.
Experimental Example 4
[0117] In vitro corneal permeation study of Dorzolamide and Timolol
for novel topical formulations containing HP (Lupasol.RTM. PS) and
Polysorbate 80.
[0118] In vitro experiments on the corneal permeation of
Dorzolamide and Timolol (active ingredients of COSOPT.RTM.) were
carried out to investigate the effect of the addition of 0.5% (w/v)
HP, or the addition of 0.5% (w/v) HP and 1% (w/v) Polysorbate 80,
in comparison to the original market topical formulation (only
active ingredients) at pH 5.65.
Materials and Methods
[0119] Experimental Method
[0120] 1. Formulation Preparation: The following three solutions in
10 mM citrate buffer were formulated for examining the in vitro
corneal permeation of Dorzolamide and Timolol, as well as
determining the corneal hydrolysis effect.
TABLE-US-00004 Composition (% w/v) Test sample 1 Test sample 2 Test
sample 3 Content (n = 2) (n = 2) (n = 2) Dorzolamide 2 2 2 Timolol
0.5 0.5 0.5 Lupasol .RTM. PS -- 0.5 0.5 Polysorbate 80 -- -- 1 1M
NaOH Adjust pH to 5.65 Adjust pH to 5.65 Adjust pH to 5.65
[0121] The samples were filtered by 0.45 .mu.m filter syringe. The
initial concentration of both the samples was determined by UPLC
analysis. From the experimental data, the following inferences were
made: [0122] a) HP exclusively (from Test 1 and Test 2 data
comparison). [0123] b) Polysorbate 80 (Test 2 & Test 3
comparison) significance on cornea permeation. [0124] c)
HP+Polysorbate 80 combination significance (from Test 1, Test 2,
Test 3 data comparison).
[0125] 2. In Vitro Rabbit Corneal Permeation Experiment
TABLE-US-00005 TABLE 4 Composition of receptor solution for in
vitro cornea permeation experiment. Composition Chemical Formula
[g/100 mL] Calcium chloride CaCl.sub.2 0.0132 Potassium chloride
KCl 0.04 Magnesium sulfate MgSO.sub.4.cndot.7H.sub.2O 0.02 Sodium
dihydrogen NaH.sub.2PO.sub.4.cndot.2H.sub.2O 0.0187 phosphate
dehydrate Sodium chloride NaCl 0.787 Glucose Glucose 0.1 Sodium
hydroxide NaOH q.s. Water Purified Water q.s pH pH 7.2
[0126] Three male rabbits (New Zealand) weighing 3-4 pounds. The
age of the rabbits was 11-12 weeks. Immediately after sacrifice by
an overdose of carbon dioxide gas, the eyes were enucleated, saline
washed, and the corneas were separated for the use in permeation
experiments. Each cornea was rinsed with freshly prepared receptor
solution (Table 4) to remove excess stain. The six intact and fresh
corneas were fixed between clamped donor and receptor compartments
of an all glass side-by-side diffusion cell in such a way that its
epithelial surface faces the donor compartment. FIG. 9 shows the
schematic of a simple diffusion cell used in this experiment.
[0127] The corneal area available for permeation was 0.211
cm.sup.2. The receptor compartment was filled with freshly prepared
receptor solution at pH 7.2, as per the composition described in
Table 4. An aliquot (5 mL) of sample #1 was placed on the two
intact corneas, and the opening of the donor cells was sealed with
a glass cover slip. After 10 minutes of applying sample #1, an
aliquot (5 mL) of sample #2 was applied on the next two intact
corneas. Again, after 10 minutes, sample #3 aliquot (5 mL) was
applied on the remaining two intact corneas. The receptor fluid (5
mL in each receptor cell) was kept at constant temperature of
34.degree. C. using constant stirring through water jacket in all
the six cases. At predetermined time intervals of 10, 20, 40, 60,
80, 100, 120, 140, 160, and 180 minutes, 200 .mu.L samples were
withdrawn from the receptor solution. Thereafter, the same amount
of the phosphate buffer solution was added to the receptor cell.
The drug concentrations were assayed by UPLC.
[0128] 3. Analysis
[0129] The Dorzolamide and Timolol maleate detection conditions
were a gradient 1% (v/v) Triethylamine (TEA) in water: acetonitrile
method, performed at room temperature, with the flow rate of 0.7
mL/min, at 254 nm and 298 nm wavelength and 1 .mu.L injection
volume, on BEH C 18 1.7 .mu.m, 2.1.times.50 mm column.
[0130] 4. Corneal Permeation Parameters Calculation
[0131] At the end of the experiment, each cornea (free from
adhering sclera) was weighed after soaking in de-ionized water. The
wet cornea was dried overnight in oven, and reweighed. From the
difference of weights, corneal hydration was calculated. The final
results of drug permeation were expressed as cumulative amount
permeated (Q). The parameters that were calculated are as
follows:
Cumulative amount permeated ( Q , ng / cm 2 ) ( t i ) = Conc . ( t
i ) .times. Cell volume ( mL ) + Conc . ( t i - 1 ) .times. 0.2 (
samplingvolume ( mL ) ) Effective area ( cm 2 ) ##EQU00001## i =
sampling number ( 1 - 10 ) , Conc ( t 0 ) = 0 ##EQU00001.2## Q t [
ng / cm 2 / min ] Slope of cumulative amount curve ##EQU00001.3## t
d [ min ] Intercept on the time axis ##EQU00001.4## Diffusion
coefficient ( D ) [ cm 2 / sec ] h 2 6 .times. t d .times. 60
##EQU00001.5## Partition Coefficient ( K ) [ - ] Q t .times. h D .
.times. C d .times. 1 60 ##EQU00001.6## h [ cm ] Thickness of
cornea : 0.04 [ cm ] ##EQU00001.7## C d [ ng / mL ] Initial drug
concentration in donor solution ##EQU00001.8##
Results and Discussion
[0132] The initial concentrations of Dorzolamide and Timolol
determined by UPLC are given in Table 5.
TABLE-US-00006 TABLE 5 Initial concentration of test formulations
Samples Dorzolamide (mg/mL) Timolol (mg/mL) Test 1 23.02 4.70 Test
2 21.48 4.51 Test 3 22.21 4.72
[0133] The corneal hydration was measured based on the net wet
weight and dry weight of cornea. Typically, the % (w/w) hydrations
for cornea in normal mammalian are in the range of 75-80%. Overall,
there was no significant change in the % hydrations for all the
test samples, and they were within the desired range in all the
cases. Thus, the HP or Polysorbate 80 did not have impact on
corneal hydration.
TABLE-US-00007 TABLE 6 Percentage corneal hydration calculation.
Final net wet weight Final net dry weight % (w/w) Sample (g) (g)
corneal hydration Test 1 0.0107 0.0017 84.11 Test 1 0.0112 0.0019
83.06 Test 2 0.0123 0.0023 80.16 Test 2 0.0133 0.0023 82.70 Test 3
0.0150 0.0024 84.00 Test 3 0.0053 0.0012 77.40
[0134] FIGS. 10 and 11 reveal the corneal permeation profiles of
Dorzolamide and Timolol, respectively. The time dependent
permeation of Dorzolamide and Timolol was carefully examined across
the isolated rabbit cornea at 34.degree. C. The Dorzolamide
cumulative total amount permeated through the cornea, and the total
amount permeated after 3 hours was relatively higher for the test
formulation containing 0.5% (w/v) HP compared to the control sample
with no additives. Furthermore, the addition of Polysorbate 80
along with HP enhanced the corneal permeation with more amount of
Dorzolamide permeated than the formulation containing only HP.
Overall, the addition of 0.5% (w/v) HP and 1% (w/v) Polysorbate 80
enhanced the corneal permeation rate of Dorzolamide and Timolol by
about 25-30%. A similar trend was also observed for Timolol (FIG.
11). Thus, the combination of HP and Polysorbate 80 improved the
corneal penetration of active ingredients.
[0135] FIG. 12 shows the percentage total permeation of Dorzolamide
and Timolol. Clearly, the presence of HP and Polysorbate 80
increased the percentage of active ingredients (Dorzolamide and
Timolol) permeated through the cornea. It should be noted that all
test formulations had similar initial concentrations in case of
Dorzolamide and Timolol (less than 10% change). Thus, it was easy
to determine the influence of each additive under similar pH
conditions. In comparing test 2 with test 1, the significance of
using HP as an additive is clearly demonstrated.
[0136] FIG. 13 shows the corneal permeability coefficients of
Dorzolamide and Timolol. The permeability coefficient was inversely
proportional to the initial concentration of the drug in the donor
solution. In the case of Dorzolamide, the permeability coefficients
for test 2 and test 3 were higher, suggesting that Dorzolamide in
the presence of 0.5% HP has enhanced corneal permeability rate
compared to pH 5.65 control formulation (Test 1) containing no HP.
Test 3 had relatively higher corneal permeability than Test 2,
thereby indicating the influence of Polysorbate 80. The Polysorbate
80 may possibly act as a viscosity enhancer, thereby increasing the
bioavailability of Dorzolamide and Timolol for corneal permeation.
Overall, the data from FIG. 13 clearly indicates that the
permeability coefficients of Timolol and Dorzolamide were higher
for formulation tests 2 and 3 containing HP, and HP &
Polysorbate 80, respectively, in comparison to the control test 1
without HP at pH 5.65 (similar to COSOPT.RTM. active ingredient
formulation).
[0137] The diffusion coefficient of Dorzolamide and Timolol, which
is inversely proportional to the lag time, did not change
significantly by the addition of HP and Polysorbate 80 (see FIG.
14). Thus, HP and Polysorbate 80 do not have any impact on the
corneal surface. If the diffusion coefficient would have increased
or decreased significantly, it would indicate the change in corneal
surface properties. Since the diffusion coefficient is the inherent
property of drug compound, it should not change with the addition
of additives.
[0138] HP promotes encapsulation of Timolol and Dorzolamide, and
thus enhances the partitioning of Timolol into corneal epithelium.
This theory is also supported by the data in FIG. 15. The Timolol
and Dorzolamide partition coefficient to the corneal surface for
Test 3 is higher than Test 1, indicating the improvement in
partitioning of Timolol and Dorzolamide into lipophilic corneal
membrane in presence of 0.5% (w/v) highly functional HP. Thus, the
improved permeation in the presence of HP is mainly because of
improved portioning to the epithelium. The partitioning could be
further enhanced by increasing the concentration of HP in the
formulation solution. HP enhances corneal permeation mainly because
a) molecular encapsulation within the branched structures of highly
functional Polyethyleneimine, b) electrostatic interactions between
the drug molecules and ionic functional amine groups of HP, and c)
the muco-adhesive behavior of charged HP.
[0139] The addition of 0.5% (w/v) HP and 1% (w/v) Polysorbate 80
enhanced the corneal permeation rate of Dorzolamide and Timolol by
about 25-30%. The presence of HP increased the partitioning of
Dorzolamide and Timolol at pH 5.65 into the corneal membrane. There
was insignificant change in the corneal diffusion rate and corneal
hydration rate by the addition of HP and Polysorbate 80, suggesting
that these additives did not have a harmful impact on the cornea
surface. The corneal permeability coefficients of Dorzolamide and
Timolol were relatively higher in the presence of HP, suggesting
the significance of HP as an effective drug carrier additive. Thus,
the present inventors discovered a novel formulation with enhanced
corneal permeation compared to the current market product. The
corneal permeation could be further enhanced by increasing the
concentration of HP.
Conclusion
[0140] The cumulative amount permeated of Dorzolamide and Timolol
at pH 5.65 in the presence of additives such as HP was relatively
high, compared to the control formulation with no additives
(COSOPT.RTM. active ingredients formulation). The 0.5% (w/v) HP and
1% (w/v) Polysorbate 80 addition to the formulation enhanced the
corneal permeation rate of Dorzolamide and Timolol by about 25-30%.
The partitioning of active ingredients into the corneal epithelium
increases in presence of HP. Thus, the combination of HP and
Polysorbate 80 could be very effective for increasing the ocular
bioavailability of COSOPT.RTM. active ingredients.
Experimental Example 5
[0141] Solubility enhancement of Brinzolamide in aqueous solution
containing HP (Lupasol.RTM. PS) or a combination of HP and
Polysorbate 80, or PEG and Polysorbate 80 combinations at pH 7 in
phosphate buffer.
[0142] The aqueous solubility of Brinzolamide in the presence of
Timolol at pH 7 in 10 mM phosphate buffer was studied.
Methods
TABLE-US-00008 [0143] TABLE 7 Different Test formulations prepared
in phosphate buffer at pH 7. Content Control (% v/w) Sample S #1 S
#2 S #3 S #4 S #5 S #6 S #7 S #8 Brinzolamide 1 >1 >1 >1
>1 >1 >1 >1 >1 Lupasol .RTM. PS -- 0.5 1 2 0.5 1 2
-- -- (MW = 750k) PEG 400 -- -- -- -- -- -- -- 2 -- PEG 8000 -- --
-- -- -- -- -- -- 2 Polysorbate -- -- -- -- 1 1 1 1 1 80 In 10 mM
Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust pH Adjust
pH Adjust pH Adjust pH citrate or to 7 to 7 to 7 to 7 to 7 to 7 to
7 to 7 to 7 phosphate buffer (add 1M NaOH)
[0144] A suspension of Brinzolamide in phosphate buffer containing
1% (w/v) was prepared for the control sample. Similar suspensions
containing excess of Brinzolamide (>1% (w/v)) were also prepared
in aqueous solution (10 mM phosphate buffer) containing different
combinations of HP, PEG and Polysorbate 80 as per Table 7 above.
The final pH was adjusted to 7 with 1 M NaOH. The suspension
solutions were first stirred for 10 min at room temperature (with
heating up to 60.degree. C. for 5 minutes). After allowing the
suspensions to equilibrate at room temperature for additional 30
minutes, the suspension solutions were then sonicated for 10 min
and finally filtered through 0.45 .mu.m syringe filters. The
filtrates were analyzed for Brinzolamide concentration using UPLC
with the same condition as EXPERIMENTAL EXAMPLE 1.
Results and Discussion
[0145] FIG. 16 shows the Brinzolamide solubility in 10 mM phosphate
buffer at different pH values. It is clear that the aqueous
solubility of Brinzolamide decreases as the pH increases from 4
towards 7. The solubility of Brinzolamide is least at pH 7,
consistent with the complete non-ionic behavior at pH 7. As %
ionization of Brinzolamide increases with the increase in pH from
8.4 towards 10, the solubility increases steeply consistent with
the anionic nature of Brinzolamide in that pH range. The solubility
properties are very similar to Dorzolamide. Therefore, it is
important to develop a lipophilic Brinzolamide drug with enhanced
solubility close to pH 7.4 (pH of tear fluid is 7.44) in order to
enhance ocular bioavailability and to decrease eye irritation
appearance of Brinzolamide.
[0146] In this study, the present inventors used HP, PEG, and
Polysorbate 80 as solubility enhancer additives. Different
combinations were attempted at pH 7. In FIG. 17, the solubility of
Brinzolamide is shown to increase with the addition of
additives.
[0147] As shown in FIG. 17, the solubility of Brinzolamide
increases with the increase in the concentration of HP in both the
cases (with and without Timolol). The solubility of Brinzolamide in
absence of Timolol with 0.5% (w/v) HP and 1% (w/v) Polysorbate 80
is about 11 mg/mL. The addition of PEG 8000 over PEG 400 seems to
enhance the solubility of Brinzolamide. However, the solubility for
control solution as well as all the formulations with additives
containing 0.5% (w/v) Timolol was relatively lower. Thus, Timolol,
which is relatively more soluble in water than Brinzolamide at pH
7, makes an impact on aqueous solubility of Brinzolamide by its
presence in the topical formulation sample. These results are very
similar to the results (EXPERIMENTAL EXAMPLE 1) regarding another
carbonic anhydrase called Dorzolamide. The decrease in solubility
by highly soluble ionic Timolol at pH 7 could be due to change in
ionic strength of the solution by addition of Timolol or salting
out effect. While the market AZARGA.RTM. product has Brinzolamide
10 mg/mL+Timolol 5 mg/mL ophthalmic suspension at pH 7.4, the
enhancement of solubility at pH 7 by addition of HP or PEG will
have useful contribution to efficacy enhancement of drug by
increasing the dosage to greater than 1%.
[0148] The addition of Polysorbate 80 to HP increases the
Brinzolamide solubility by preventing the precipitation.
Polysorbate 80 may act as a surfactant thereby reducing the
aggregation of Brinzolamide after phase separation in presence of
HP. A combination of 0.5% (w/v) HP and 1% (w/v) Polysorbate could
be very effective in the presence of 0.5% (w/v) Timolol formulation
at pH 7.
[0149] The improvement in aqueous solubility of Brinzolamide in
presence of Timolol was significant with the additions of HP or a
combination of PEG and Polysorbate 80 at pH 7. The Polysorbate 80
helps in dispersing the Brinzolamide molecules and inhibits the
precipitation in water in presence of PEG. A combination of HP and
Polysorbate 80 could be good combination for enhancement of
Brinzolamide solubility in presence of Timolol at pH 7. From the
results, it can be concluded that HP and Polysorbate 80
significantly enhance the solubility of hydrophobic Brinzolamide in
presence of Timolol at pH 7. Hydrophilic PEG also turned out to be
a Brinzolamide solubility enhancer. Furthermore, a combination of
low concentrations of Polysorbate 80 and PEG 8000 also proved to be
a very useful additive for enhancement of solubility of hydrophobic
Brinzolamide. Overall, a formulation at pH 7 with optimized
concentration of HP and Polysorbate 80 could be very useful for
increasing the ocular bioavailability.
Conclusion
[0150] The results clearly indicate the advantages of using HP and
Polysorbate 80 as hydrophobic Brinzolamide solubility enhancing
additives at pH values closer to physiological pH. Polysorbate 80
also proved to be an effective emulsifier suppressing the
precipitation of poorly soluble Brinzolamide at pH 7 in presence of
HP. Timolol may have an effect on the solubility of Brinzolamide by
changing the ionic strength of the solution.
Experimental Example 6
[0151] In vitro corneal permeation study of Dorzolamide and Timolol
containing a HP with terminal hydroxyl groups.
[0152] In vitro experiments on corneal permeation of Dorzolamide
and Timolol (active ingredients of COSOPT.RTM.) were carried out to
investigate the effect of the addition of a hyperbranched polyester
with hydroxyl functional groups in comparison to the original
market topical formulation (only active ingredients).
[0153] A novel formulation containing the commercially available HP
called Boltorn.RTM. H20. The generic definition of Boltorn.RTM. H20
is a HP with polyester core and 16 terminal hydroxyl functional
groups. It enhances the solubility of non-ionic (lipophilic)
Dorzolamide that is formulated at pH 7 or pH 7.4.
##STR00002##
[0154] The properties of HP used in this example are listed in
Table 8. It has 16 primary hydroxyl groups per molecule. The solid
content is 100% (w/v).
TABLE-US-00009 TABLE 8 Properties of HP used in this example.
Molecular Polymer Viscosity weight Poly- Partition name (cP)
(Daltons) dispersity pH Coefficient Boltorn .RTM. 7 2100 1.3 2.5-4
-0.2 log POW H20
[0155] The in vitro transcorneal permeation of Dorzolamide and
Timolol was determined from a novel formulation containing up to 2%
(w/v) HP. The effect of the concentration of HP on the active
ingredients was also determined. A standard solution containing
COSOPT.RTM. active ingredients at pH 7.4 was used as a control
sample.
Materials and Methods
[0156] Formulation Preparation
[0157] The following three solutions in 0.1% (w/v) phosphate buffer
(Table 9) were formulated for examining the in vitro corneal
permeation of Dorzolamide and Timolol, as well as for determining
the corneal hydrolysis effect.
TABLE-US-00010 TABLE 9 Composition of Test Formulations. Control
Sample Test Sample Test Sample Content (% w/v) #1 #2 #3 Dorzolamide
HCl 1 1 1 Timolol Maleate 0.683 0.683 0.683 Boltorn .RTM. H20 --
0.5 2 1M NaOH/1M HCl Adjust pH to 7.4 Adjust pH to Adjust pH to 7.4
7.4 Appearance Suspension Suspension Suspension
[0158] First, the 10 mM phosphate buffer was added to the
appropriately weighed mass of solid active ingredients and stirred
thoroughly for 15 minutes. Secondly, the effective volume of 5%
(w/v) HP suspension solution was added to Test Sample 2 and Test
Sample 3 to make up the exact concentrations described in Table
9.
[0159] The three test solutions were then stirred for 10 minutes at
room temperature (with heating up to 60.degree. C. for 5 minutes).
After stirring, the solution was sonicated for 5 minutes. Apart
from the control solution (Control Sample #1), the solutions with
HP were white slurry suspensions before adjusting the pH. After
allowing the complete dilution of all the active and non-active
ingredients, the pH was adjusted to 7.4 by using 1 M NaOH or 1 M
HCl, and additional buffer was added to make up the exact
composition as in Table 8. With the adjustment of pH, suspension
solutions were formed in all cases, which were equilibrated by
stirring for an additional 15 hours or more at room temperature.
The pH of all the sample solutions was measured again to confirm
the final desired pH.
[0160] These suspension solutions were used directly as sample
donor solutions for the cornea permeation study. In order to
determine the solubility, the suspensions were filtered through
0.45 .mu.m syringe filters. The filtrates were analyzed for
Dorzolamide and Timolol concentrations using UPLC, after diluting
each sample with ultrapure water (dilution factor=1000). The in
vitro cornea permeation profile results were also compared to the
data obtained at pH 5.65 for the control sample containing active
ingredients from EXPERIMENTAL EXAMPLE 4.
[0161] Three male rabbits (New Zealand) weighing 2 to 3 kg.
Immediately after sacrifice by an overdose of inhaler isoflurane,
the eyes were enucleated, and the corneas were separated for use in
the permeation experiments. The details of the experimental
procedure are described in previous EXPERIMENTAL EXAMPLE 4.
[0162] The calculated parameters that were calculated are as
described in EXPERIMENTAL EXAMPLE 4, with C.sub.d [ng/mL] being the
initial drug concentration of active pharmaceutical ingredient in
donor solution (Table 10).
Results and Discussion
[0163] The initial concentrations of Dorzolamide and Timolol
determined by UPLC are given in Table 10. The percentage corneal
hydration calculations are given in Table 10.
TABLE-US-00011 TABLE 10 Initial concentration of test formulations.
Samples Dorzolamide (mg/mL) Timolol (mg/mL) Test 1 4.69 4.7 Test 2
6.6 4.5 Test 3 8.9 4.7
TABLE-US-00012 TABLE 11 Percentage corneal hydration calculation.
Final net wet weight Final net dry weight % (w/w) Corneal Sample
(g) (g) hydration Test 1 0.0104 0.0020 80.7 Test 1 0.0124 0.0022
82.2 Test 2 0.0117 0.0025 78.6 Test 2 0.0126 0.0024 80.9 Test 3
0.0146 0.0029 80.1 Test 3 0.0113 0.0026 76.9
[0164] The corneal hydration was measured based on the net wet
weight and dry weight of the cornea. Typically, the % hydrations
for a cornea in a normal mammal are in the range of 75-80%.
Overall, there was no significant change in the % hydrations for
all the test samples, and they were within the desired range in all
the cases. Thus, the HP did not have impact on corneal
hydration.
[0165] FIGS. 18 and 19 reveal the corneal permeation profiles of
Dorzolamide and Timolol, respectively. The control sample
permeation profile at pH 5.65 from EXPERIMENTAL EXAMPLE 4 was also
plotted along with the permeation profiles obtained for Test sample
1, 2 and 3. The time dependent permeation of Dorzolamide and
Timolol was carefully examined across the isolated rabbit cornea at
34.degree. C. The Dorzolamide cumulative total amount permeated
through the cornea, and the total amount permeated after 2 hours
was relatively higher for the test formulation containing 0.5%
(w/v) HP (Test 2) and 2% (w/v) HP (Test 3) compared to the control
sample with no additives. Furthermore, the increased concentration
from 0.5% HP to 2% HP showed an increase in the corneal permeation
of both active ingredients. In the formulation containing 2% (w/v)
HP (Test 3), the corneal permeation of active ingredients is higher
than the market product COSOPT.RTM. (only active ingredients in the
formulation) at pH 5.65 (see FIG. 19 and FIG. 20). In addition, the
formulation containing 2% (w/v) HP provided significant enhancement
in corneal permeation after 2 hours with a higher permeation rate
(change in the slope).
[0166] Overall, the addition of a HP with hydroxyl functional
groups enhances the corneal permeation rate of Dorzolamide and
Timolol significantly, with an increase in the concentration of HP.
Thus, HP improved the corneal penetration of active ingredients,
when compared to the market products known as COSOPT.RTM. or
TRUSOPT.RTM. or AZOPT.RTM., which are used for glaucoma
treatment.
[0167] FIG. 20 shows the percentage total permeation of Dorzolamide
and Timolol after 2 hours. Clearly, the presence of HP increased
the percentage of active ingredients (Dorzolamide and Timolol)
permeated through the cornea. It should be noted that all test
formulations had different initial concentrations in the case of
Dorzolamide, and similar concentrations of Timolol (less than 10%
change). Different initial solubility of Dorzolamide is mainly
because of the increased solubility by HP. In Test 2 and Test 3 in
comparison with Test 1, the significance of using HP as an additive
it is clear from FIG. 20. The slopes from FIGS. 19 and 20 up to 2
hours were used in order to determine the corneal permeability,
partition coefficient and diffusion coefficient.
[0168] FIG. 21 shows the corneal permeability coefficients of
Dorzolamide and Timolol. The permeability coefficient was inversely
proportional to the initial concentration of the drug in the donor
solution. In the case of both active ingredients, the permeability
coefficients for Test 2 and Test 3 are higher, suggesting that
dorozamide in the presence of HP has an enhanced corneal
permeability rate compared to the control formulation (Test 1)
containing no HP. Test 3 had a relatively higher corneal
permeability than Test 2, thereby indicating the influence of
increasing the concentration of HP. Overall, the data from FIG. 21
clearly indicates that the permeability coefficients of Timolol and
Dorzolamide were higher for formulation Tests 2 and 3 containing
HP, in comparison to the Control Test 1 without HP at pH 7.4, and
the COSOPT.RTM. control formulation at pH 5.65 (similar to
COSOPT.RTM. active ingredient formulation).
[0169] The diffusion coefficient of Dorzolamide and Timolol, which
is inversely proportional to the lag time, did not change
significantly by the addition of HP (see FIG. 22). Thus, HP does
not have any impact on the corneal surface. If the diffusion
coefficient would have increased or decreased significantly, it
would indicate the change in corneal surface properties. Since the
diffusion coefficient is an inherent property of the drug compound,
it should not change with the addition of additives.
[0170] HP promotes the encapsulation of Timolol and Dorzolamide,
and thus enhances the partitioning of Timolol and Dorzolamide into
the corneal epithelium. This theory is also supported by the data
suggested in FIG. 23. The Timolol and Dorzolamide partition
coefficient to the corneal surface for Tests 2 and 3 were higher
than Test 1, indicating the improvement in partitioning of Timolol
and Dorzolamide into lipophilic corneal membrane in the presence of
highly functional (hydroxyl group) HP. Thus, the improved
permeation in the presence of HP is mainly because of improved
partitioning to the epithelium. The permeation was further enhanced
by increasing the concentration of HP in the formulation solution
from 0.5% to 2% (w/v). However, the partition coefficient and
permeability coefficient did not change significantly by increasing
the concentration of HP, since these parameters will not be a
function of the concentration of the material.
[0171] The cumulative amount permeated of Dorzolamide and Timolol
at pH 7.4 in the presence of HP additives, such as commercially
available Boltorn.RTM. H20 with hydroxyl functional group, was
relatively high, compared to the control formulation with no
additives. The increase in concentration of such HP in the
formulation enhanced the corneal permeation rate of Dorzolamide and
Timolol significantly. The corneal permeability coefficients of
Dorzolamide and Timolol were relatively higher in the presence of
HP. The partitioning of active ingredients into the corneal
epithelium increased in the presence of HP. Thus, an HP with
hydroxyl functional groups could be very effective for increasing
the ocular bioavailability of COSOPT.RTM. active ingredients.
Experimental Example 7
[0172] The aqueous solubility of carbonic anhydrase inhibitors,
such as Dorzolamide and Brinzolamide, in the presence of HP and
Timolol at pH 7.4 in 10 mM phosphate buffer was studied. A HP
called Boltorn.RTM. W3000 was used. The terminal functional groups
of this HP are PEG (hydrophilic) and unsaturated long chain fatty
acids. The model of the hyperbranched polyester used in this
example is shown below.
##STR00003##
[0173] The properties of HP used in this experiment are described
in Table 12. The HP has 50 primary hydroxyl groups per molecule,
and the solid content is 55% (w/w).
TABLE-US-00013 TABLE 12 Properties of HP used in this study.
Molecular Polymer Viscosity weight Acid number name (mPa-s)
(Daltons) Polydispersity pH (mg KOH/g) Boltorn .RTM. 125 9000 1.3
3-5 10 (max) W3000
[0174] Table 13 shows the different test samples formulations which
were prepared in 10 mM phosphate buffer at pH 7.4.
TABLE-US-00014 TABLE 13 Different Test formulations prepared in
phosphate buffer at pH 7. Content Control (% w/v) Sample S #1 S #2
S #3 S #4 S #5 S #6 CAI >1 >1 >1 >1 >1 >1 >1
Boltorn .RTM. W -- 0.1 0.5 1 2 5 2 3000 Timolol 0.5 0.5 0.5 0.5 0.5
0.5 0.5 maleate HPMC -- -- -- -- -- -- 0.5 In 10 mM Adjust pH pH pH
pH pH pH pH phosphate to 7.4 to 7.4 to 7.4 to 7.4 to 7.4 to 7.4 to
7.4 buffer (add 1M NaOH)
[0175] The emulsion was prepared by slowing dispersing water to the
weighed amount of waxed Boltorn.RTM. W3000 to make 5% (w/v)
emulsion with continuous stirring and heating at 60-70.degree. C.
for at least 30 minutes, followed by continuous vigorous stirring
for an additional 15 hours, to obtain a homogeneous emulsion
mixture in a flask.
[0176] 10 mM phosphate buffer was added to the appropriately
weighed mass of solid active ingredients and stirred thoroughly for
15 minutes. Secondly, the effective volume of 5% (w/v) HP emulsion
solution was diluted appropriately to make up the exact
concentrations described in Table 13. The sample test emulsion
solutions were then stirred for 10 minutes at room temperature
(with heating up to 60.degree. C. for 5 minutes). After stirring,
the emulsion solution was sonicated for 5 minutes. After allowing
the complete emulsion of all the active and non-active ingredients,
the pH was adjusted to 7.4 by using 1 M NaOH, and additional buffer
was added to make up the exact compositions in Table 13. With the
adjustment of the pH, the emulsion solutions were further
equilibrated by stirring for an additional 15 hours or more at room
temperature. The pH of all the sample emulsion solutions was
measured again to confirm the final desired pH of 7.4. The
filtrates were analyzed for CAI concentration using UPLC with the
same condition as EXPERIMENTAL EXAMPLE 1.
Results & Discussion
[0177] In this experiment, an amphiphilic self emulsifying HP was
used as a solubility enhancer additive. Different concentrations of
the HP were attempted at pH 7.4.
[0178] In FIG. 24, the solubility of Brinzolamide and Dorzolamide
is shown to increase with the increase in the concentration of HP.
The solubility of Dorzolamide and Brinzolamide in the presence of
0.5% (w/v) Timolol with 5% (w/v) HP is about 2% (w/v) of CAI. The
addition of HPMC to 2% (w/v) HP did not enhance the solubility.
While the market AZARGA.RTM. suspension product has 1% (w/v)
Brinzolamide at pH 7.4, and COSOPT.RTM. has 2% (w/v) Dorzolamide at
pH 5.65, the enhancement of solubility at pH 7.4 by the addition of
HP will have a useful contribution to the efficacy enhancement of
the drug by increasing the dosage to greater than 1% (w/v).
Therefore, it is important to develop a Brinzolamide or Dorzolamide
with enhanced solubility close to pH 7.4 (pH of tear fluid is 7.4)
in order to enhance ocular bioavailability and to decrease eye
irritation appearance of CAIs.
Experimental Example 8
[0179] In vitro corneal permeation study of Dorzolamide and Timolol
containing HP with amphiphilic functional groups (Boltorn.RTM.
W3000).
[0180] In vitro experiments on corneal permeation of Dorzolamide
and Timolol (active ingredients of COSOPT.RTM.) were carried out to
investigate the effect of the addition of a HP with amphiphilic
functional groups in comparison to the original market topical
formulation (only active ingredients).
[0181] A new topical formulation containing Boltorn.RTM. W3000
(hyperbranched polyester) with non-ionic PEG as hydrophilic
functional groups and unsaturated fatty acid as hydrophobic
functional groups (commercially available), thus making it
amphiphilic. The solubility of Dorzolamide was increased from 4.3
to 15 mg/mL by adding 2% (w/v) of this HP at pH 7.41. In this
experiment, the in vitro transcorneal permeation of Dorzolamide and
Timolol was determined from a novel formulation containing up to 2%
(w/v) HP that was comparable to COSOPT.RTM.. The effect of
concentration of HP on the active ingredients was also determined.
A standard solution containing COSOPT.RTM. active ingredients at pH
7.4 was used as a control sample.
Materials and Methods
[0182] 1. Formulation Preparation
[0183] The following three solutions in 0.1% (w/v) phosphate buffer
(Table 14) were formulated for examining the in vitro corneal
permeation of Dorzolamide and Timolol, as well as determining the
corneal hydrolysis effect.
TABLE-US-00015 TABLE 14 Composition of test formulations Content (%
w/v) Test 1 Test 2 Test 3 Dorzolamide HCI 1.5 1.5 2.22 Timolol
Maleate 0.638 0.683 0.683 Boltorn .RTM. W3000 -- 2 -- 1M NaOH/1M
HCl Adjust pH to Adjust pH to 7.4 Adjust pH to 5.65 7.4 Appearance
Suspension Emulsion Clear Solution
[0184] 10 mM phosphate buffer was added to the appropriately
weighed mass of the solid active ingredients, and stirred
thoroughly for 15 minutes. Secondly, the effective volume of 5%
(w/v) HP suspension solution was added to Test 2 to make up the
exact concentrations as in Table 14. The three test solutions were
then stirred for 10 minutes at room temperature (with heating up to
60.degree. C. for 5 minutes). After stirring, the solution was
sonicated for 5 minutes. After allowing the complete dilution of
all the active and non-active ingredients, the pH was adjusted to
either 7.4 or 5.65 by using 1 M NaOH or 1 M HCl, and additional
buffer was added to make up the exact compositions in the Table 15.
With the adjustment of pH, the appearance was noted as per Table
14, and the formulations were further equilibrated by stirring for
an additional 15 hours or more at room temperature. The pH of the
all sample solutions was measured again to confirm the final
desired pH. These formulations were used directly as sample donor
solutions for the cornea permeation study. In order to determine
the solubility, the suspension/emulsions were filtered through 0.45
.mu.m syringe filters. The filtrates were analyzed for Dorzolamide
and Timolol concentration using UPLC after diluting each sample
with ultrapure water (dilution factor=1000).
[0185] 2. In Vitro Rabbit Corneal Permeation Experiment
[0186] The experimental procedure and analysis to be performed are
described in detail in previous EXPERIMENTAL EXAMPLE 4. The
parameters that were calculated are those described in EXPERIMENTAL
EXAMPLE 4, where C.sub.d [ng/mL] is the initial drug concentration
of active pharmaceutical ingredient in donor solution (from Table
15).
Results and Discussion
[0187] The initial concentrations of Dorzolamide and Timolol
determined by UPLC are given in Table 15. The percentage corneal
hydration calculations are given in Table 16.
TABLE-US-00016 TABLE 15 Solubility of active pharmaceutical
ingredient in test formulations. Samples Dorzolamide (mg/mL)
Timolol (mg/mL) Test 1 4.6 4.7 Test 2 15 4.7 Test 3 20 4.7
TABLE-US-00017 TABLE 16 Percentage corneal hydration calculation.
Final net wet weight Final net dry weight % (w/w) corneal Sample
(g) (g) hydration Test 1 0.0143 0.0028 80.41 Test 1 0.0281 0.0044
84.34 Test 2 0.0201 0.0035 82.59 Test 2 0.151 0.0028 81.46 Test 3
0.0265 0.0042 84.15 Test 3 0.0257 0.0043 83.27
[0188] The corneal hydration was measured based on the net wet
weight and dry weight of the cornea. Typically, the % (w/w)
hydrations for a cornea in a normal mammal are in the range of
75-80%. Tests 1 and 3 are both above 80%. However, there is no
difference in the calculated values of partition and permeability
coefficient, suggesting that there could not be any corneal damage
due to higher hydration %. Overall, there was no significant change
in the % hydrations for all the test samples, which were within the
desired range in all the cases. Thus, the HP did not appear to have
an impact on corneal hydration.
[0189] FIGS. 25 and 26 reveal the corneal permeation profiles of
Dorzolamide and Timolol, respectively. The time dependent
permeation of Dorzolamide and Timolol was examined carefully across
the isolated rabbit cornea at 34.degree. C. The Dorzolamide
cumulative total amount permeated through the cornea, and the total
amount permeated after 2 hours was relatively higher for the test
formulation containing 2% (w/v) HP (Test 2) compared to the control
sample with no additive at pH 7.4 (Test 1). The total permeation of
Dorzolamide of Test 2 (novel formulation) was comparable to the
Test 3 permeation profile for Dorzolamide. However, it should be
noted that Test 1 could be more comfortable for the patient since
it is prepared at pH 7.4, compared to the market product which is
prepared at pH 5.65. The permeation could be further increased by
increasing the concentration of the HP.
[0190] Furthermore, the Timolol permeation significantly increased
in the presence of HP for Test 2 compared to Tests 1 and 3 having
similar aqueous solubility, unlike Dorzolamide (see FIG. 26). In
the formulation containing 2% (w/v) HP (Test 2), the corneal
permeation of Timolol is almost two times higher than the market
product COSOPT.RTM. (only active ingredients in the formulation) at
pH 5.65 (see FIG. 27). This result clearly demonstrates the
importance of using HP as a drug carrier for a topical formulation,
for both Dorzolamide and Timolol.
[0191] Overall, the addition of HP with amphiphilic functional
group enhances the corneal permeation rate of Dorzolamide and
Timolol significantly, with an increase in the concentration of HP.
Thus, a dendritic polyester HP with amphiphilic functional groups
improves the corneal penetration of active ingredients compared to
the market products, known as COSOPT.RTM. or TRUSOPT.RTM. or
AZOPT.RTM., which are used for glaucoma treatment.
[0192] FIG. 27 shows the percentage total permeation of Dorzolamide
and Timolol after 3 hours. Clearly, the presence of HP increases
the percentage of the active ingredients (Dorzolamide and Timolol)
permeated through the cornea (see Test 2). Test 2, prepared at pH
7.4, had a Dorzolamide total % permeation which was slightly
greater than Test 3, which is prepared at pH 5.65. It should be
noted that all test formulations have different initial
concentrations in case of Dorzolamide, and similar concentrations
of Timolol. Different initial solubility of Dorzolamide is mainly
because of the increased solubility by the HP. In Test 2, in
comparison with Test 3 (pH 5.65) and Test 1 (pH 7.4), FIG. 27
demonstrates the significance of using HP as an additive. The
slopes from FIGS. 26 and 27 were used in order to determine the
corneal permeability, partition coefficient and diffusion
coefficient.
[0193] FIG. 28 shows the corneal permeability coefficients of
Dorzolamide and Timolol. The permeability coefficient is inversely
proportional to the initial concentration of the drug in the donor
solution. In the case of both active ingredients, the permeability
coefficients for Test 2 are higher compared to the control samples
at pH 7.4 and pH 5.65, thus suggesting that active pharmaceutical
ingredient in presence of HP has enhanced corneal permeability rate
compared to the control formulations (Tests 1 and 3) containing no
HP. Test 3 had relatively higher corneal permeability than Test 2,
thereby indicating the influence of pH. The active pharmaceutical
ingredient at physiological pH is more conducive for permeation for
similar solubilities. Overall, the data from FIG. 28 clearly
indicates that the permeability, coefficients of Timolol and
Dorzolamide were higher for the formulation of Test 2 containing
HP, in comparison to Test 1 without HP at pH 7.4, and COSOPT.RTM.
control formulation at pH 5.65 (similar to COSOPT.RTM. active
ingredient formulation).
[0194] The diffusion coefficient of Dorzolamide and Timolol, which
is inversely proportional to the lag time did not change
significantly by the addition of HP (see FIG. 29). Thus, HP does
not have any impact on the corneal surface. If the diffusion
coefficient would have increased or decreased significantly, it
would indicate the change in corneal surface properties. Since the
diffusion coefficient is the inherent property of drug compound, it
should not change with the addition of additives.
[0195] The Timolol and Dorzolamide partition coefficients to the
corneal surface for Test 2 were higher than Tests 1 and 3, thus
indicating the improvement in partitioning of Timolol and
Dorzolamide into lipophilic corneal membrane in the presence of a
highly functional (amphiphilic) HP. Thus, the improved permeation
in the presence of HP is mainly because of improved partitioning to
the epithelium. The permeation can be further enhanced by
increasing the concentration of HP in the formulation solution from
2% to 5% (w/v).
[0196] The cumulative amount permeated of Dorzolamide and Timolol
at pH 7.4, in the presence of HP additives, such as commercially
available Boltorn.RTM. W3000 with amphiphilic functional group (2%
w/v), was almost 2 times higher compared to the control formulation
at similar pH values, with no additives. The increase in
concentration greater than 2% (w/v) of such HP in the formulation
could further enhance the corneal permeation rate of Dorzolamide
and Timolol significantly compared to the market product at pH
5.65. The novel topical formulation is prepared at pH 7.4, thus
making it more conducive and comfortable for the patients. The
partitioning of active ingredients into the corneal epithelium
increased in presence of HP. Thus, HP with amphiphilic functional
groups could be very effective for increasing the ocular
bioavailability of COSOPT.RTM. active ingredients.
Experimental Example 9
[0197] Solubility enhancement of carbonic anhydrase inhibitor (CAI)
by Bis-MPA polyester hyperbranched polymer (BMPA-HP) or a
combination of PEG and BMPA-HP.
[0198] The influence of functionalized hyperbranched polymers on
the aqueous solubility of a CAI, such as Dorzolamide and
Brinzolamide, in the presence of Timolol at pH 7.4 in 10 mM
phosphate buffer was studied. The generic definition of BMPA-HP is
a hyperbranched polymer with dimethylolpropionic acid (Bis-MPA)
polyester core and terminal hydroxyl (OH) functional groups. The
number of terminal hydroxyl functional groups depends on the
generation of the hyperbranched polyester. The generation is
defined by the number of branching layers or the extent of
branching from the core to the terminal functional groups. For
example, the 2.sup.rd generation BMPA hyperbranched polyester
contains 16 hydroxyl groups while the 3.sup.rd generation contains
32 hydroxyl groups. The structure of BMPA-HP is shown below.
##STR00004##
[0199] The properties of the polyester HPs of different generations
used in this research study are listed in Table 17.
TABLE-US-00018 TABLE 17 Properties of HP used in this experiment
Molecular Number of OH weight groups per Polymer name Viscosity
(Pa-s) (Daltons) monomer unit pH 2.sup.nd BMPA-HP 0.007-0.25 1750
16 2.5-4 3.sup.rd BMPA-HP 0.007-0.25 3600 32 2.5-4
Materials and Methods
[0200] Table 18 shows the different test sample emulsions, except
the control solution, to be prepared in 10 mM phosphate buffer at
pH 7.4.
TABLE-US-00019 TABLE 18 Different test formulations prepared in
phosphate buffer at pH 7.4 Content Control (% w/v) Sample S #1 S #2
S #3 S #4 S #5 S #6 S #7 CAI >1 >1 >1 >1 >1 >1
>1 >1 2.sup.nd BMPA-HP -- 0.1 0.5 1 2 5 2 2 Timolol 0.5 0.5
0.5 0.5 0.5 0.5 0.5 0.5 maleate PEG 8000 -- -- -- -- -- -- 2 4 In
10 mM Adjust pH pH pH pH pH pH pH pH phosphate to 7.4 to 7.4 to 7.4
to 7.4 to 7.4 to 7.4 to 7.4 to 7.4 buffer (add 1M NaOH) Content (%
w/v) S #8 S #9 S #10 S #11 S #12 S #13 S #14 CAI >1 >1 >1
>1 >1 >1 >1 3rd BMPA-HP 0.1 0.5 1 2 5 2 2 Timolol 0.5
0.5 0.5 0.5 0.5 0.5 0.5 maleate PEG 8000 -- -- -- -- -- 2 4 In 10
mM pH pH pH pH pH pH pH phosphate to 7.4 to 7.4 to 7.4 to 7.4 to
7.4 to 7.4 to 7.4 buffer (add 1M NaOH)
[0201] 10 mM phosphate buffer was added to the appropriately
weighed mass of solid active ingredients and stirred thoroughly for
15 minutes. Secondly, the effective volume of 5% (w/v) BMPA-HP
solution was diluted appropriately to make up the exact
concentrations described in Table 18. The sample test solutions
were then stirred for 10 minutes at room temperature (with heating
up to 60.degree. C. for 5 minutes). After stirring, the solution
was sonicated for 5 minutes. After allowing the complete suspension
of all the active and non-active ingredients, the pH was adjusted
to 7.4 using 1 M NaOH, and additional buffer was added to make up
the exact compositions described in Table 18. With the adjustment
of pH, suspension solutions were further equilibrated by stirring
for an additional 15 hours or more at room temperature. The pH of
the all sample solutions was measured again to confirm the final
desired pH of 7.4. The filtrates were analyzed for CAI using UPLC
with the same condition as EXPERIMENTAL EXAMPLE 1.
Results & Discussion
[0202] In this experiment, 2.sup.nd BMPA-HP or 3.sup.rd BMPA-HP
were employed as solubility enhancer additives, and different
concentrations of each were tested at pH 7.4. It is important to
develop a lipophilic Brinzolamide or Dorzolamide drug with enhanced
solubility close to pH 7.4 (pH of tear fluid is 7.4) in order to
enhance ocular bioavailability and to decrease eye irritation
appearance of CAIs. The solubility of Dorzolamide and Brinzolamide
in the presence of 0.5% Timolol with 5% 3.sup.rd BMPA-HP is
slightly about 1% (w/v) of CAI. With lower generation 2nd BMPA-HP,
the solubility of CAI decreased by less than 10% in comparison to
3.sup.rd BMPA-HP for similar concentration of 2.sup.nd BMPA-HP used
as an additive for all the samples.
[0203] When the combination of 2% (w/v) PEG 8000 and HP is used,
the solubility of CAI increases dramatically (4 times more than the
control). With the addition of 2% (w/v) PEG 8000 to 2% (w/v)
BMPA-HP, the solubility of CAI almost doubled (see FIG. 31).
[0204] While the market Azarga.RTM. suspension product has 1%
Brinzolamide at pH 7.4 and COSOPT.RTM. has 2% (w/v) Dorzolamide at
pH 5.65, the enhancement of solubility at pH 7.4 by the addition of
BMPA-HP will have useful contribution to efficacy enhancement of
the drug, by increasing the dosage to greater than 1% (w/v).
[0205] The results clearly indicate the advantages of using BMPA-HP
as a hydrophobic CAI solubility enhancer at pH values closer to
physiological pH. The addition of PEG to the solution containing
BMPA-HP further improved the solubility of CAI.
Experimental Example 10
[0206] Human Corneal Epithelium (HCE) tissue culture study of
determining the eye irritancy of Bis-MPA hyperbranched polyester
and the optimized sample application time for ophthalmic study
based on the cytotoxicity of the cells.
Method and Materials
[0207] The samples were prepared in accordance with Table 19 below,
in saline phosphate buffer (with the exception of AZOPT.RTM.) and
sterilized using a 0.2 .mu.m Sterile syringe filter. 0.02% BAK was
used as a positive control. The reconstructed human corneal
epithelium was purchased from Skin Ethics laboratory (France).
TABLE-US-00020 TABLE 19 Sample set. Content Blank (% w/v) Sample
+ve Control -ve Control S #1 S #2 S #3 S #4 S #5 Phosphate
Triplicates -- -- -- -- -- -- -- saline (pH 7.4) 0.02% --
Triplicates -- -- -- -- -- -- Benzalkonium Chloride.sup.1 3% Bis
MPA -- -- Triplicates -- -- -- -- -- generation 3 4% Bis MPA -- --
-- Triplicates -- -- -- -- generation 3 2% Bis MPA -- -- -- --
Triplicates -- -- -- generation 2 3% Bis MPA -- -- -- -- --
Triplicates -- -- generation 2 5% Bis MPA -- -- -- -- -- --
Triplicates -- generation 2 Azopt .RTM. -- -- -- -- -- --
Triplicates
[0208] The Cell Culture Method is described below:
[0209] The percentage viability of each of the treated cultures was
calculated from the percentage MTT conversion in the test chemical
treated cultures relative to the corresponding negative controls
(100% viable).
The following equation was used:
Percentage viability=[individual OD.sub.chemical/mean
OD.sub.negative control].times.100.
[0210] HCE viability classification prediction model: NI
(viability.gtoreq.60%), I (viability<60%), i.e., the product is
classified as an irritant (according to in vivo classifications) if
the percentage of viability compared to the negative control
obtained for the test product is <60%.
Results and Discussion
[0211] As shown in FIG. 32, the percentage viability of different
samples (according to Table 19) was calculated using the equation
for percentage viability described above, in the experimental
section. Samples with viability of less than 60% were considered
irritants. The standard deviation of the cell viability based on
triplicates was less than 7% for all the samples. The results from
the cytotoxicity study reveal that ophthalmic samples with up to 4%
(w/v) of 3.sup.rd BMPA-HP will be a non-eye irritants, with greater
than 60% cell viability. (See FIG. 32.) The results from FIG. 32
also reveal that AZOPT.RTM. could be cytotoxic against corneal
epithelim cell with less than 50% cell viability for an application
time of 1 hour. The sample containing 5% (w/v) Bis-MPA generation 2
also caused eye irritation with less than 60% cell viability.
[0212] Combining the results from previous studies, the
cytotoxicity of Bis-MPA commercial hyperbranched polyester for
different concentrations is revealed in FIG. 33. It is evident from
the Figure that the epithelial cell damage, and thus the eye
irritation, caused by the 2.sup.nd BMPA-HP is less than the eye
irritation caused by the 3.sup.rd BMPA-HP, for the same
concentration in the ophthalmic solutions. It is known that the
extent or length of branching and thus the molecular weight and
number of terminal functional groups decrease with the decrease in
the number of HP generations. The result from FIG. 33 indicates
that the decrease in cytotoxicity with the decrease in the number
of generation could be mainly due to decrease in the prolonged
interaction of the terminal functional groups with the epithelial
cells.
Conclusions
[0213] The rate of epithelial cell death increased with the
increase in the concentration dose and the generation (molar mass
and extent of branching). In the case of the AZOPT.RTM. market
product, it causes eye irritation with less than 50% cell
viability, possibly due to 0.01% (w/v) of BAK with exposure time of
one hour.
Experimental Example 11
[0214] Solubility enhancement of CAI containing BMPA-HP or a
combination of non-ionic surfactants and BMPA-HP.
[0215] The aqueous solubility and stability of Dorzolamide was
studied in the presence of Timolol at pH 7.4 in 10 mM phosphate
buffer.
Method and Materials
[0216] First, the 10 mM phosphate buffer was added to the
appropriate weighed mass of solid active ingredients and stirred
thoroughly for 15 minutes. After complete dissolution of active
pharmaceutical ingredient, hyperbranched 2.sup.nd BMPA-HP was added
to the solution. After HP was dissolved, PEG 8000 was added as per
the formulation concentration needed. The sample test solutions
were then stirred for 10 minutes at room temperature (with heating
up to 60.degree. C. for 5 minutes). After stirring, the solution
was sonicated for 20 minutes. After allowing the complete
dissolution of all the active and non active ingredients, the pH
was adjusted to 7.4 by using 1 M NaOH and additional buffer was
added to make up the exact compositions as per Tables 20 and 21.
With the adjustment of pH, the formulations were further
equilibrated by stirring for additional 15 hours or more at room
temperature. The samples were filtered through 0.45 um syringe
filter. Polysorbate 80 was added to the final formulation. In case
of sample number 3, the formulation is equilibrated at 60.degree.
C. (24 hours) after pH adjustment, then Polysorbate 80 was added.
The pH of all the sample solutions was measured again to confirm
the final desired pH of 7.4. All samples were stored for 14 days at
25 and 60.degree. C., and the filtrates were analyzed for
Dorzolamide and Timolol using UPLC after diluting each sample with
ultrapure water (dilution factor=1000).
Results & Discussion
TABLE-US-00021 [0217] TABLE 20 Contents of Dorzolamide and Timolol,
Appearance and pH of Samples at room temperature. Control Sample S
#1 S #2 S #3 S #4 Dorzolamide Initial 4.3 9.6 9.9 9.9 9.5 (mg/mL) 1
W 4.3 8.9 9.5 9.9 8.2 2 W 4.3 8.4 9.3 9.8 6.2 Timolol Initial 4.7
5.3 4.9 5.2 4.8 (mg/mL) 1 W 4.6 5.0 4.7 5.1 4.8 2 W 4.3 4.9 4.7 5.1
4.8 Appearance Initial Clear Clear Clear Clear Clear 1 W Clear
Suspension Suspension Clear Suspension 2 W Clear Suspension
Suspension Clear Suspension pH Initial 7.4 7.4 7.39 7.4 7.4 1 W 7.4
7.4 7.38 7.4 7.39 2 W 7.37 7.38 7.38 7.38 7.36
TABLE-US-00022 TABLE 21 Contents of Dorzolamide and Timolol,
Appearance and pH of Samples at 60.degree. C. Control Sample S #1 S
#2 S #3 S #4 Dorzolamide Initial 4.3 9.6 9.9 9.9 9.5 (mg/mL) 1 W
4.3 8.9 9.5 9.9 8.2 2 W 4.2 9.6 9.8 9.8 9.3 Timolol Initial 4.7 5.3
4.9 5.2 4.8 (mg/mL) 1 W 4.8 5.1 4.8 5.3 4.8 2 W 4.8 5.4 4.8 5.6 4.6
Appearance Initial Clear Clear Clear Clear Clear 1 W Clear Clear
Clear Clear Clear 2 W Clear Clear Clear Clear Clear pH Initial 7.40
7.40 7.39 7.40 7.40 2 W 7.43 7.42 7.37 7.43 7.36
[0218] In this study, 2.sup.nd BMPA-HP was studied as a solubility
enhancer additive. Different combinations with non-ionic
surfactants, such as PEG and Polysorbate 80, were attempted at pH
7.4. All the formulations were clear solutions at room temperature
after sample preparation. In FIG. 34, the solubility of Dorzolamide
is shown to increase with the additions of 4% (w/v) HP and 2% (w/v)
PEG. As shown in FIG. 34, the concentration of Dorzolamide
decreases steadily for the formulation containing 4% (w/v) HP and
2% (w/v) PEG from the 1.sup.st day up to 2 weeks. The formulation
containing 4% (w/v) HP and 2% (w/v) PEG became a suspension after 2
weeks. The present inventors discovered that the rate of decrease
of Dorzolamide concentration decreases with the addition of 1%
(w/v) Polysorbate 80 (sample S#1). The concentration of Dorzolamide
decreased from 9.6 mg/mL to 8.4 mg/mL over a time period of two
weeks.
[0219] Thus, higher concentration of Polysorbate 80 prevents the
precipitation and helps stabilize the new formulation. Negligible
change was observed in the pH of all the formulations over a period
of 2 weeks (See Table 20 and Table 21). The change in Timolol
concentration was insignificant over a period of two weeks. While
the market AZARGA.RTM. suspension product has 1% (w/v) Brinzolamide
at pH 7.4, and COSOPT.RTM. has 2% Dorzolamide at pH 5.65, the
enhancement of solubility at pH 7.4 by addition of HP and non-ionic
surfactants will have useful contribution to efficacy enhancement
of drug by increasing the dosage to greater than equal to 1%
(w/v).
Conclusion
[0220] The results clearly demonstrate the advantages of using
2.sup.nd BMPA-HP in combination with PEG 8000 and Polysorbate 80 as
CAI solubility enhancer at pH values closer to physiological
pH.
Experimental Example 12
[0221] A study to determine the topical formulation at pH 7.4,
based on solubility and stability of carbonic anhydrase inhibitor
(Dorzolamide and Brinzolamide) in the presence of Timolol in an
aqueous solution containing different combinations of Hyperbranched
bis-MPA polyester-16-hydroxyl, generation 2 (2.sup.nd BMPA-HP), PEG
8000 and Polysorbate 80 in phosphate buffer was performed.
Methods and Materials
[0222] Table 22 shows all the different test samples to be prepared
in 10 mM phosphate buffer at pH 7.4.
TABLE-US-00023 TABLE 22 Different Test formulations prepared in
phosphate buffer at pH 7.4. Content Control (% w/v) Sample S #1 S
#2 S #3 S #4 S #5 S #6 CAI 1 1 1 1 1 1 1 Timolol 0.5 0.5 0.5 0.5
0.5 0.5 0.5 2.sup.nd BMPA- -- 4 4 4 -- -- -- HP PEG 8000 -- 2 -- 2
2 2 -- Polysorbate -- 4 4 -- 4 -- 4 80 1M NaOH/ Adjust pH pH pH pH
pH pH pH 1M HCl to 7.4 to 7.4 to 7.4 to 7.4 to 7.4 to 7.4 to
7.4
[0223] First, the 10 mM phosphate buffer was added to the
appropriately weighed mass of solid active ingredients and stirred
thoroughly until the active pharmaceutical agent was dissolved.
Secondly, solid BMPA-HP powder was added to the sample formulations
1, 2 and 3. After dissolution of the HP, the appearance was clear
solution. The appropriate mass of non-ionic surfactants, such as
PEG 8000, was added to the formulations to make up the exact
concentrations as per the formulation content described in the
above Table 22. All test solutions were then stirred for 10 minutes
at room temperature (with heating up to 60.degree. C. for 5
minutes). After stirring, the solution was sonicated for 5 minutes.
After allowing the complete dissolution of all the active and non
active ingredients, the pH was adjusted to 7.4 or 5.65 by using 1 M
NaOH or 1 M HCl, and additional buffer was added to make up the
exact compositions in accordance with the Table 22 sample
compositions. With the adjustment of pH, test solutions were
formed, which were equilibrated by stirring for an additional 24
hours or more at room temperature. For the samples that contain
Polysorbate 80 and hyperbranched polyester (Table 2), Polysorbate
80 was only added after 24 hours of equilibration at 60.degree. C.
of the final formulation. The pH of the all the sample solutions
was adjusted again to confirm the final desired pH.
[0224] The filtrates were analyzed for carbonic anhydrase
inhibitors, Timolol and HP concentration using UPLC after diluting
each sample with ultrapure water (dilution factor=1000). The
optimal conditions obtained from the EXPERIMENTAL EXAMPLE 1 for CAI
and Timolol detection were used. The appearance and pH of each
formulation is recorded over a period of 1 month at room
temperature and 60.degree. C.
Results and Discussion
[0225] This study used a HP with hydroxyl terminal groups, PEG, and
Polysorbate 80 as solubility enhancer additives. Different
combinations were attempted at pH 7.4 in order to determine the
best formulation based on the previous results. FIG. 35
demonstrates that the solubility of Dorzolamide increased
significantly in the presence of 4% (w/v) HP and 2% (w/y) PEG or 4%
(w/v) Polysorbate 80 (Sample 1, 2 and 3). However, the Dorzolamide
solubility did not increase significantly in the presence of PEG
8000 (sample 5) or Polysorbate 80 (sample 6) exclusively, or their
combination (sample 4). Thus, hyperbranched polyester addition to
the formulation clearly indicates its advantage as a solubility
enhancer. However, the formulation containing HP with hydroxyl
group in combination with Polysorbate 80 (sample 2) has similar
solubility in comparison to the formulation containing HP,
Polysorbate 80 and PEG 8000 (sample 1). Thus, the addition of PEG
8000 could be avoided. Overall, it was discovered that sample 2 is
the best formulation, based on the Dorzolamide and Timolol
solubility data. The addition of surfactants such as Polysorbate 80
to HP also increases the Dorzolamide solubility by preventing the
precipitation of Dorzolamide encapsulated within HP.
TABLE-US-00024 TABLE 23 Contents of Dorzolamide and Timolol,
appearance and pH of samples at room temperature. Control S #1 S #2
S #3 S #4 S #5 S #6 Dorzolamide Initial 4.6 10.4 10.1 9.1 5.4 5.2
5.0 (mg/mL) 1 W 4.6 10.1 10.0 8.2 5.2 4.9 4.9 2 W 4.6 10.1 10.1 6.2
5.1 4.8 4.8 4 W 4.5 10.1 10.1 5.9 5.0 4.8 4.6 Timolol Initial 5.2
5.1 5.1 4.9 5.1 5.2 5.0 (mg/mL) 1 W 5.1 5.0 5.1 4.9 5.1 5.1 5.0 2 W
5.0 4.9 5.1 4.9 5.1 5.1 5.0 4 W 5 4.9 5.1 4.8 5.1 5.0 4.9
Appearance Initial suspension clear clear clear suspension
suspension suspension 1 W suspension clear clear suspension
suspension suspension suspension 2 W suspension clear clear
suspension suspension suspension suspension 4 W suspension clear
clear suspension suspension suspension suspension pH Initial 7.40
7.40 7.40 7.39 7.40 7.40 7.39 1 W 7.40 7.40 7.40 7.39 7.40 7.80
7.39 2 W 7.37 7.38 7.38 7.37 7.38 7.37 7.39 4 W 7.35 7.36 7.37 7.37
7.37 7.36 7.38
TABLE-US-00025 TABLE 24 Contents of Dorzolamide and Timolol,
appearance and pH of samples at 60.degree. C. Control Sample S #1 S
#2 S #3 S #4 S #5 S #6 Dorzolamide Initial 4.6 10.4 10.1 9.1 5.4
5.2 5.0 (mg/mL) 1 W 4.6 10.3 10.2 9.0 5.3 5.1 4.9 2 W 4.5 10.3 10.2
8.9 5.3 4.9 4.8 4 W 4.5 10.1 10.2 8.7 5.3 4.9 4.8 Timolol Initial
5.2 5.1 5.0 4.9 5.1 5.2 5.0 (mg/mL) 1 W 5.1 5.1 5.1 4.9 5.1 5.1 5.0
2 W 4.9 4.9 5.0 4.9 5.1 5.1 5.0 4 W 4.9 5.0 5.0 4.8 5.1 5.0 4.9
Appearance Initial suspension clear clear clear suspension
suspension suspension 1 W suspension clear clear clear suspension
suspension suspension 2 W suspension clear clear clear suspension
suspension suspension 4 W clear clear clear clear suspension
suspension suspension pH Initial 7.40 7.39 7.40 7.39 7.40 7.40 7.39
2 W 7.43 7.37 7.43 7.41 7.38 7.38 7.38 4 W 7.40 7.35 7.38 7.40 7.38
7.38 7.38
[0226] Tables 23 and 24 demonstrate the stability test results of
Dorzolamide and Timolol over a period of 4 weeks for all the
formulation samples. It is evident from the Table that sample #1
and sample #2 are relatively stable and clear solutions after 1
month. The presence of PEG in sample #1 could be avoided since
sample #2 without PEG gives similar results.
Conclusion
[0227] The results clearly indicate the advantages of using HP with
hydroxyl terminal functional groups in combination with surfactants
such as Polysorbate 80 and PEG 8000. The surfactant behavior of
Polysorbate 80 is very helpful for increasing the solubility of CAI
by preventing the precipitation. The good formulation based on the
solubility and 1 month stability results is a formulation
containing active ingredients with a combination of 4% (w/v)
2.sup.nd BMPA-HP and 4% Polysorbate 80 only in phosphate buffer at
pH 7.4.
Experimental Example 13
[0228] In vitro corneal permeation study of Dorzolamide and Timolol
for novel topical formulation containing Bis MPA hyperbranched
polyester and Polysorbate 80.
Methods and Materials
[0229] The following three solutions in 0.1% (w/v) phosphate buffer
(Table 27) were formulated for examining the in vitro corneal
permeation of Dorzolamide and Timolol, as well as for determining
the corneal hydrolysis effect.
TABLE-US-00026 TABLE 25 Composition of test formulations. Content
(% w/v) Test 1 Test 2 Test 3 Dorzolamide 2 1 1 Timolol 0.5 0.5 0.5
2.sup.nd BMPA-HP -- 4 4 Polysorbate 80 -- 4 4 1M NaOH/1M HCl Adjust
pH to Adjust pH to 5.65 Adjust pH to 7.4 5.65 Appearance clear
clear clear
[0230] First, the 10 mM phosphate buffer was added to the
appropriately weighed mass of solid active ingredients and stirred
thoroughly for 15 minutes. In case of sample numbers 2 and 3,
2.sup.nd BMPA-HP powder was added to the solution as per the
composition in Table 25. The three test solutions were then stirred
for 10 min at room temperature (with heating up to 60.degree. C.
for 5 minutes). After stirring, the solution was sonicated for 5
minutes. After allowing the complete dissolution of all the active
and non active ingredients, the pH was adjusted to 7.4 or 5.65 by
using 1 M NaOH or 1 M HCl and additional buffer was added to make
up the exact composition as per the Table sample compositions. With
the adjustment of pH, test solutions were formed which were
equilibrated by stirring for additional 24 hours or more at room
temperature for samples 1 and 2. In sample numbers 2 and 3, the
equilibration was conducted for 24 hours at 60.degree. C.
Polysorbate 80 (4% (w/v)) was then added followed by another pH
adjustment. The pH of the all the sample solutions was measured
again to confirm the final desired pH.
[0231] These clear solutions were used directly as sample donor
solutions for the cornea permeation study. In order to determine
the solubility, the test solutions were filtered through 0.45 .mu.m
syringe filters. The filtrates were then analyzed for Dorzolamide
and Timolol concentration using UPLC after diluting each sample
with ultrapure water (dilution factor=1000). The details of the
materials and equipment used, as well as the rabbit cornea study
procedure are given in EXPERIMENTAL EXAMPLE 4.
Results and Discussion
TABLE-US-00027 [0232] TABLE 26 Initial concentration of active
ingredients in test samples. Samples Dorzolamide (mg/mL) Timolol
(mg/mL) Test 1 20.2 5.2 Test 2 10.2 5.1 Test 3 10.0 5.0
[0233] The initial concentrations of Dorzolamide and Timolol
determined by UPLC are given in Table 26.
TABLE-US-00028 TABLE 27 Percentage corneal hydration calculation.
Final net wet weight Final net dry weight % (w/v) corneal Sample
(g) (g) hydration Test 1 0.0534 0.0534 80.42 Test 2 0.0471 0.0471
82.59 Test 3 0.0627 0.0550 84.15 Test 1 0.0684 0.0420 84.34 Test 2
0.0459 0.0365 81.46 Test 3 0.0421 0.0370 83.27
[0234] The corneal hydration was measured based on the net wet
weight and dry weight of the cornea. Typically, the % (w/w)
hydrations for cornea in normal mammalian are in the range of
75-85%. Overall, there was no significant change in the %
hydrations for all the test samples, and all were within the
desired range, as shown in Table 27. Thus, the HP and Polysorbate
80 did not have impact on corneal hydration.
[0235] FIG. 36 and FIG. 37 reveal the corneal permeation profiles
of Dorzolamide and Timolol, respectively. The time dependent
permeation of Dorzolamide and Timolol was examined carefully across
the isolated rabbit cornea at 34.degree. C. From FIG. 36, the
Dorzolamide cumulative total amount permeated through the cornea
and the total amount permeated after 3 hours was relatively higher
for the test formulation containing 4% (w/v) HP and Polysorbate 80
at pH 7.4 (Test 3) compared to the same formulation at pH 5.65
(Test 2). Clearly, Dorzolamide penetration is enhanced at pH 7.4
because of its non-ionic behavior which is very conducive for
cornea epithelial membrane that is lipophilic. Dorzolamide cornea
permeation for Test 3 is comparable to the control solution with no
additives at pH 5.65 (Test 1). Notice that Test 3 contains 1% (w/v)
Dorzolamide while Test 1 contains 2% (w/v) Dorzolamide. While Test
3 contains half the Dorzolamide concentration of Test 1, the cornea
permeation profiles are similar. Test 3 could be more comfortable
for the patient since it is prepared at pH 7.4 compared to the
market product at pH 5.65 that can cause eye irritation. Timolol
permeation profiles from FIG. 37 suggest that Test 3 has
significantly higher cornea permeation compared to Test 1 (control
solution). Clearly, Timolol permeation is enhanced by the presence
of hyperbranched polyester and Polysorbate 80 in Test 3 at pH 7.4
compared to Test 1 having similar aqueous solubility. Overall,
enhanced Timolol permeation and comparable Dorzolamide permeation
to the market product are key advantages of new formulation
containing HP and Polysorbate 80. From FIG. 38, the total
percentage permeation of Dorzolamide and Timolol after 3 hours in
case of Test 3 (novel formulation) was at least 2 times higher than
Test 1 (market product active ingredients). Clearly, the presence
of HP and Polysorbate 80 increase the percentage of active
ingredients (Dorzolamide and Timolol) permeated through the
cornea.
[0236] The slopes from FIGS. 36 and 37 were used in order to
determine the corneal permeability coefficient and partition
coefficient. The permeability coefficient is inversely proportional
to the initial concentration of the drug in the donor solution. The
permeability coefficients (see FIG. 39) and partition coefficients
(see FIG. 40) of Test 2 are relatively higher than Test 1. Notice
that both Test 1 and Test 2 solutions are at pH 5.65. The result
suggests the influence of HP and Polysorbate 80 to enhance the
partitioning and permeations of active ingredients. The
permeability coefficient and partition coefficient of Test 3 is
higher than Test 2 due to the pH effect. Test 3 formulation is
prepared at pH 7.4 which is more conducive for permeation of
non-ionic Dorzolamide and Timolol. Overall, the results clearly
demonstrate the importance of using HP and Polysorbate 80 as drug
carrier for a topical formulation for both Dorzolamide and
Timolol.
[0237] Overall, the data from FIG. 39 clearly indicates that the
permeability coefficients of Timolol and Dorzolamide were higher
for formulation Test 2 containing HP and Polysorbate 80, in
comparison to the Test 1 without HP at pH 7.4 and COSOPT.RTM.
control formulation at pH 5.65 (similar to COSOPT.RTM. active
ingredient formulation).
[0238] HP and Polysorbate 80 promote encapsulation of Timolol and
Dorzolamide, and thus enhance the partitioning of Timolol into
corneal epithelium. This theory is also supported by the data in
FIG. 40. The Timolol and Dorzolamide partition coefficient to the
corneal surface for Test 3 at pH 7.4 was the highest than Test 1
and Test 2 indicating the improvement in partitioning of Timolol
and Dorzolamide into lipophilic corneal membrane in presence of
highly functional HP at pH 7.4 rather than pH 5.65. Thus, the
improved permeation in presence of HP is mainly because of improved
partitioning to the epithelium.
Conclusion
[0239] The cumulative amount permeated of active pharmaceutical
agent at pH 7.4 in the presence of HP additives such as
commercially available dendritic Bis-MPA HP and Polysorbate 80 was
almost comparable to the market product in case of Dorzolamide and
more than 2 times higher for Timolol permeation. This novel topical
formulation is prepared at pH 7.4, thus making it more conducive
for lipophilic epithelial cornea penetration and comfortable for
the patients. Thus, HP with hydroxyl terminal groups and
Polysorbate 80 could be very effective for increasing the ocular
bioavailability of COSOPT.RTM. active ingredients.
INDUSTRIAL APPLICABILITY
[0240] According to the present invention, an ophthalmic
composition comprising a HP, which shows increased aqueous
solubility of carbonic anhydrase inhibitors, such as Dorzolamide or
Brinzolamide, can be provided. The ophthalmic composition may also
comprise a non-ionic surfactant and/or a beta-blocker. The
ophthalmic compositions of the present invention result in
increased permeation of the active agent into the cornea.
Therefore, the overall ocular bioavailability and hence the
therapeutic activity of the topical ophthalmic solution containing
a carbonic anhydrase inhibitor and beta blocker (active
ingredients) can be increased compared to current relevant
ophthalmic market products available. The topical ophthalmic
compositions presented in this invention provide more potent
anti-glaucoma compositions that may increase patient compliance by
increasing ocular bioavailability.
[0241] While some of the embodiments of the present invention have
been described in detail in the above, those of ordinary skill in
the art can enter various modifications and changes to the
particular embodiments shown without substantially departing from
the novel teaching and advantages of the present invention. Such
modifications and changes are encompassed in the spirit and scope
of the present invention as set forth in the appended claims.
* * * * *