This application claims priority to Provisional Indian Patent Application No.
3763/DEL/2013, filed 24th December 2013, the contents of which are incorporated herein in their
entirety.
FIELD OF THE INVENTION
The present invention provides an aqueous ophthalmic composition comprising an alpha-
2 adrenergic receptor agonist and a non-ionic cellulosic polymer, the solution having a pH less
than 6.5. The present invention also provides an aqueous ophthalmic composition comprising an
alpha-2 adrenergic receptor agonist and a benzododecinium halide. Also provided are methods
of manufacture, use and method of reducing intraocular pressure in a patient in need thereof.
BACKGROUND OF THE INVENTION
The present invention provides a topical ophthalmic solution comprising an alpha-2
adrenergic receptor agonist such as brimonidine tartrate and/or pharmaceutically acceptable
excipients wherein the ophthalmic solution is soluble enough to achieve therapeutic efficacy is
soluble at a lower pH range of from about 5.5 to about 6.5.
The ophthalmic solution of the present invention contains from about 0.05% to about
0.2% (w/v) of brimonidine tartrate.
Brimonidine tartrate is an alpha-2-adrenergic agonist that reduces the elevated intraocular
pressure (IOP) of the eye that is associated with glaucoma. The topical use of brimonidine to
lower intraocular pressure in patients with glaucoma or ocular hypertension is known.
The first ophthalmic brimonidine product in the U.S. was approved by the FDA in 1996.
That product, sold under the trade name Alphagan®, contained brimonidine in the form of
brimonidine tartrate at a concentration of 0.2%. According to the product label, Alphagan® is
adjusted (with NaOH or HCl) to a pH between 5.6 and 6.6, and further contains citric acid,
polyvinyl alcohol, sodium chloride, sodium citrate, and purified water. The preservative
contained in Alphagan® is benzalkonium chloride, the most widely used preservative for topical
ophthalmic compositions.
In 2001, a second ophthalmic brimonidine product was approved by the U.S. FDA. This
product, sold under the trade name Alphagan® P , contained brimonidine tartrate at two
brimonidine concentrations, 0.15% and 0.1%, each of which is lower than the 0.2% brimonidine
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concentration in Alphagan®. Alphagan® P has a pH between 7.15 and 7.8, a range that is higher
than that of Alphagan®. According to the product label, the lower concentration Alphagan® P
formulation is sold at a pH of 7.4 to 8.0; the higher concentration is sold at a pH of 6.6 to 7.4.
The preservative contained in Alphagan® P is chlorine dioxide. See U.S. Patent numbers
US5424078 and US6562873. Alphagan® P also contains an anionic solubility enhancing
component (carboxymethylcellulose) to help solubilize the brimonidine that is unionized at the
pH of the compositions. Currently the innovator has discontinued marketing Alphagan®, the
higher concentration, and low pH product.
Brimonidine has a pKa of 7.4. Hence, at pH below 6.6, it will be substantially ionized.
For example, at a pH of 6.4, brimonidine is about 90% ionized. It is well known that ionized
ophthalmic drugs have greatly reduced ocular permeability. It would have been expected that at
a pH below 6.6 or 6.5, brimonidine would not permeate ocular tissue well, thereby reducing its
efficacy compared to a higher pH product. It is believed that this is why the drug concentration
in Alphagan® is substantially higher than in the higher-pH product Alphagan® P.
To overcome this disadvantage, the inventors of the present invention have formulated
the current product with a non-ionic cellulose derivative, preferably hydroxypropyl
methylcellulose (e.g., HPMC E4M grade). Without being bound by theory, it is believed that
such a polymer reduces the surface tension to around 45 dynes/cm from about 72 dynes/cm,
thereby helping to spread the drop more effectively around the ocular surface. Moreover, due to
its viscosity, it is believed to increase retention of the drop in eye. Both of these effects are
believed to help increase penetration of the drug. Surprisingly the efficacy of this invention
appears to be similar to that of Alphagan® P, if not better (statistically significant), in spite of the
present inventive compositions being at lower pH, wherein most of the drug is in ionized state.
The inventors of the present invention have formulated an ophthalmic solution wherein
the pH of the formulation is acidic, preferably having pH from about 5.5 to about 6.5, yet is
surprisingly effective compared to other low-pH products (e.g., Alphagan®). The lower pH also
removes any need to use a solubility enhancing agent(s) because brimonidine is highly soluble at
acidic pH (5.5-6.5) (though a solubility enhancing agent may be used if desired).
Further, the inventors of the present invention have surprisingly improved the stability of
brimonidine significantly over the commercial product (Alphagan® P). The data are shown in
Table 6.
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Brimonidine tartrate has highly pH-dependent solubility. The solubility decreases sharply
as the pH increases as shown in Table 1 (Refer US Patent No. 6627210 B2 page no. 13-14).
Table 1: Solubility of brimonidine tartrate a
solubility enhancing agent over pH range of 5 to 8.
Study 1 Study 2
pH Solubility pH Solubility
5.55 ≥164.4 5.5 ≥200.6
5.92 132.6 5.92 160.8
6.14 30.4 6.06 50.1
6.57 7.55 6.9 3.19
7 2.69 7.4 1.19
7.45 1.17 7.77 0.63
7.83 0.62 7.86 0.58
7.88 0.54
The original Alphagan® included a detergent preservative, benzalkonium chloride, which
was known to be somewhat irritating to the eye.
Gasset and Grant et al. showed that BAC accumulates in ocular tissue and remains there
for long periods, adversely affecting both the corneal surface and the conjunctiva. Therefore,
cessation of the medications may not immediately improve the condition and function of the
ocular surface. These findings also suggest that corneal cell necrosis may occur in some patients
who are taking multiple BAC-preserved ocular medications over long periods of time, even
when the amount of BAC in any one medication is below the threshold concentration at which
necrosis occurs.
It is well known in the reference literature that small organic compounds, such as
benzalkonium chloride (BAC), chlorhexidine, thimerosal have excellent antimicrobial activity;
however, it is now known that these small organic antimicrobials are often toxic to the sensitive
tissues of the eye and can accumulate in cornea, contact lenses, particularly soft, hydrophilic
contact lenses. Medications with BAC may cause disruption of the corneal surface with lower
concentrations of BAC.
The preservative in Alphagan® P is stabilized chlorine dioxide ("SCD"), an oxidative
preservative that was known to be compatible with the eye but Chlorine dioxide is not an ideal
preservative ingredient. It is an oxidative preservative and it would oxidize brimonidine. It is
difficult to stabilize and is light-sensitive as referred in US 7,265,117.
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It has been unexpectedly found that benzododecinium bromide is a quaternary
ammonium compound that does not form a precipitation with brimonidine at pH of around 6.0.
Benzododecinium bromide forms an ion pair with brimonidine, thereby neutralizing the charge
of brimonidine. Thus it was surprising to find that benzododecinium bromide is a quaternary
ammonium compound that does not form precipitation with brimonidine. In the same conditions
brimonidine forms a hazy solution with benzalkonium chloride.
Hence there is an unmet medical need to prepare a topical ophthalmic solution
comprising an alpha-2 adrenergic receptor agonist such as brimonidine tartrate and/or
pharmaceutically acceptable excipients wherein it does not comprises a solubility enhancing
agent and an oxidative preservative. Instead, when the preservative is included in the said
solution, the preservative is preferably benzododecinium bromide. Benzododecinium bromide is
an effective preservative for alpha-2 adrenergic receptor agonists (e.g., brimonidine) in acidic
conditions.
It was surprisingly found by the inventors of the present invention that the formulation of
the present invention has shown statistically significant IOP lowering efficacy when
administered to normotensive and water loaded New Zealand white rabbits by ocular route. The
onset of statistically significant IOP lowering efficacy was 15 minutes earlier in present
invention which is same as compared to Alphagan® P, whereas both the formulations were
found to be comparable at each time point observed, which indicates that the IOP lowering
efficacy of both test formulations (Alphagan® P and the present invention) were statistically
comparable.
OBJECT OF THE INVENTION
The main object of the present invention is to develop an aqueous ophthalmic
composition comprising an alpha-2 adrenergic receptor agonist and a non-ionic cellulosic
polymer and devoid of anionic cellulosic polymer, the solution having a pH less than 6.5.
Another object of the present invention is to develop an aqueous ophthalmic composition
of brimonidine compatible with quaternary ammonium compound used as a preservative other
than oxidative preservatives without forming precipitate.
Yet another object of the present invention is to develop a method to prepare an aqueous
ophthalmic composition comprising an alpha-2 adrenergic receptor agonist and a non-ionic
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cellulosic polymer and devoid of anionic cellulosic polymer, wherein the solution having a pH
less than 6.5.
Yet another object of the present invention provides a method for reducing intraocular
pressure in a patient in need thereof comprising administering an aqueous ophthalmic
composition comprising an alpha-2 adrenergic receptor agonist and a non-ionic cellulosic
polymer, wherein the solution having a pH less than 6.5.
SUMMARY OF THE INVENTION
The present invention provides an aqueous ophthalmic composition comprising an alpha-
2 adrenergic receptor agonist and a non-ionic cellulosic polymer, the solution having a pH less
than 6.5. The present invention also provides an aqueous ophthalmic composition comprising an
alpha-2 adrenergic receptor agonist and a benzododecinium halide. The present invention also
provides a method of reducing intraocular pressure in a patient in need thereof, comprising
administering to the patient the composition of the present invention, the administered
composition comprising an effective amount of the alpha-2 adrenergic receptor agonist.
The alpha-2 adrenergic receptor agonist preferably comprises brimonidine or a
pharmaceutically acceptable salt thereof, preferably brimonidine tartrate. The amount of
brimonidine or pharmaceutically acceptable salt thereof is preferably 0.05-0.2% (w/v)
brimonidine tartrate, based on brimonidine free base. The alpha-2 adrenergic receptor agonist is
dissolved or suspended in the aqueous composition, preferably dissolved.
The non-ionic cellulosic polymer preferably comprises hydroxypropyl methylcellulose,
preferably 0.05-1.5% (w/v) hydroxypropyl methylcellulose.
The pH of the composition is preferably less than or up to 6.6. The pH of the
composition is preferably at least or greater than 5.5.
The composition preferably comprises a preservative, preferably benzododecinium
halide, more preferably benzododecinium bromide. When the preservative is present, the
composition preferably comprises 0.005% to 0.03% (w/v) benzododecinium halide, preferably
benzododecinium bromide.
The composition preferably does not comprise an anionic solubility enhancing
component, and preferably does not comprise carboxymethyl cellulose. The composition
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preferably does not comprise an oxidative preservative, and preferably does not comprise an
oxy-chloro preservative.
Surprisingly the formulation of the present invention is more stable than the commercial
product, Alphagan® P.
The present invention provides a topical ophthalmic solution comprising an alpha-2
adrenergic receptor agonist such as brimonidine tartrate and/or pharmaceutically acceptable
excipients wherein the ophthalmic solution is soluble enough to achieve therapeutic efficacy at
an acidic pH. Preferably, the acidic pH is less than 7, more preferably less than or about 6.7 or
6.5, more preferably less than or about 6.6 or 6.5. Other than physiological considerations (e.g.,
eye irritation), there is no particular lower limit on the pH. Preferably, the pH is greater than or
about 5, more preferably greater than or about 5.25, or 5.5.
More particularly the present invention provides a topical ophthalmic solution comprising
an alpha-2 adrenergic receptor agonist such as brimonidine tartrate and/or pharmaceutically
acceptable excipients which does not comprises a solubility enhancing agent and an oxidative
preservative. When the preservative is included in the said solution, the preservative is
quaternary ammonium compound, preferably benzododecinium bromide.
More preferably, benzododecinium bromide is the only quaternary ammonium compound
which is included in said solution.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
FIG. I shows the intraocular pressure (IOP) lowering effect of Group I (Alphagan® P)
and Group II (present invention) on normotensive New Zealand White Rabbits for treated left
eye. The other (right) eye is left untreated and serves as control.
FIG. II shows the intraocular pressure (IOP) lowering effect of Group I (Alphagan® P)
and Group II (present invention) on New Zealand White Rabbits for treated left eye in water
loaded rabbits. The other (right) eye is left untreated and serves as control.
FIG. III shows the total Impurity levels in various brimonidine formulations i.e.
commercial (Alphagan® P) and present invention formulation (brimonidine tartarate 0.1%) at
40°C/ NMT 25% RH.
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DETAILED DESCRIPTION OF THE INVENTION
As used herein, the term “BAC” wherever appears is an abbreviation for “benzalkonium
chloride”.
As used herein, the “SCD” wherever appears is an abbreviation for “stabilized chlorine
dioxide”.
As used herein, the “NMT” wherever appears is an abbreviation for “not more than”.
As used herein, the “RH” wherever appears is an abbreviation for “relative humidity”.
As used herein, the “HPMC” wherever appears is an abbreviation for “hydroxypropyl
methyl cellulose”.
As used herein, the “IOP” wherever appears is an abbreviation for “intraocular pressure”.
Unless indicated otherwise, all ingredient amounts are presented in units of %
weight/volume (% w/v).
Brimonidine tartrate is a known compound that can be made by known methods and is
commercially available. See, for example, German Patent No. 2,538,620.
In one embodiment of the present invention, an aqueous ophthalmic composition
comprising an alpha-2 adrenergic receptor agonist and a non-ionic cellulosic polymer.
In another embodiment of the present invention, an aqueous ophthalmic composition
comprising an alpha-2 adrenergic receptor agonist, a non-ionic cellulosic polymer and devoid of
anionic cellulosic polymer.
In yet another embodiment of the present invention, an aqueous ophthalmic composition
comprising an alpha-2 adrenergic receptor agonist, a non-ionic cellulosic polymer and devoid of
anionic cellulosic polymer and oxidative preservative.
In yet another embodiment of the present invention, an aqueous ophthalmic composition
comprising an alpha-2 adrenergic receptor agonist, a non-ionic cellulosic polymer and devoid of
anionic cellulosic polymer and oxidative preservative, optionally along with a preservative.
In yet another embodiment of the present invention, an aqueous ophthalmic composition
comprising an alpha-2 adrenergic receptor agonist and a preservative.
In yet another embodiment of the present invention, an aqueous ophthalmic composition
comprising an alpha-2 adrenergic receptor agonist and a preservative and devoid of an anionic
solubility enhancing component.
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In yet another embodiment of the present invention, an aqueous ophthalmic composition
comprising an alpha-2 adrenergic receptor agonist and a preservative and devoid of an anionic
solubility enhancing component and oxidative preservative.
In yet another embodiment of the present invention, an aqueous ophthalmic composition
comprising an alpha-2 adrenergic receptor agonist and a preservative and devoid of an anionic
solubility enhancing component and oxidative preservative, optionally along with a non-ionic
cellulosic polymer.
According to the present invention, an alpha-2 adrenergic receptor is selected from
Brimonidine or a pharmaceutically acceptable salt or solvate or hydrate thereof.
According to the present invention, a non-ionic cellulosic polymer is selected from
hydroxypropyl methylcellulose, hydroxypropyl cellulose, hydroxymethyl cellulose,
hydroxyethyl cellulose or combinations thereof. More preferable is hydroxypropyl
methylcellulose.
According to the present invention, a preservative is selected from benzododecinium
halide, chlorobutanol, sodium perborate, cetrimonium chloride, thiomersal, methyl
parahydroxybenzoate, propyl parahydroxybenzoate, sorbic acid and derivatives thereof,
polyquaternium ammonium chloride, polyaminopropyl biguanide, phenyl mercuric nitrate,
phenyl mercuric acetate, hydrogen peroxide. More preferably is benzododecinium halide. Still
more preferable is benzododecinium bromide.
In yet embodiment of the present invention, an aqueous ophthalmic composition
comprising a brimonidine in the range of 0.01-0.5 % (w/v), more preferable in the range of 0.05-
0.2% (w/v) and a non-ionic cellulosic polymer in the range of 0.05-1.5 % (w/v), more preferable
in the range of 0.1-1.0% (w/v).
In yet embodiment of the present invention, an aqueous ophthalmic composition
comprising a brimonidine in the range of 0.01-0.5 % (w/v), more preferable in the range of 0.05-
0.2% (w/v) and non-ionic cellulosic polymer in the range of 0.05-1.5 % (w/v), more preferable in
the range of 0.1-1.0% (w/v) along with a preservative in the range of 0.001% to 0.1% (w/v) and
more preferable 0.005% to 0.03% (w/v).
The ophthalmic solution of the present invention contains an effective amount of alpha-2
adrenergic agonist, preferably brimonidine. Preferred amounts are at least 0.01%, more
preferably at least about 0.02%, more preferably at least about 0.05%, percentages being w/v.
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Preferred amount are less than about 1.0%, more preferably less than about 0.5%, 0.2%. Some
preferred amounts include 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, and 0.15%. Preferred ranges
include ranges formed from any two of these amounts. Weight of brimonidine is based on the
free base. Salts of brimonidine are included, preferably including brimonidine tartrate..
In an embodiment the present invention provides a topical ophthalmic solution
comprising an alpha-2 adrenergic receptor agonist such as brimonidine tartrate and/or
pharmaceutically acceptable excipients wherein the ophthalmic solution is at an acidic pH.
In another embodiment the present invention provides a topical ophthalmic solution
comprising an alpha-2 adrenergic receptor agonist such as brimonidine tartrate and/or
pharmaceutically acceptable excipients which does not comprises a solubility enhancing agent
and an oxidative preservative. Instead, when the preservative is included in the said solution, the
preservative is a quaternary ammonium compound, preferably benzododecinium halide.
In yet another embodiment benzododecinium halide, preferably benzododecinium
bromide is the only quaternary ammonium compound which is included in said solution.
It has been found that benzododecinium halide is a quaternary ammonium compound that
does not form a precipitation with brimonidine at pH of around 6.0. Benzododecinium halide
(e.g., bromide) forms an ion pair with brimonidine, thereby neutralizing the charge of
brimonidine. It had been believed that quaternary ammonium preservatives other that BAC were
generally not compatible with brimonidine. Thus it was surprising to find that benzododecinium
halide is compatible with brimonidine. In particular, benzododecinium bromide does not form
precipitation with brimonidine. The observation that benzododecinium bromide is compatible
with brimonidine indicates it should be an effective preservative for various dosage forms
comprising brimonidine, including solutions and suspensions.
Multi-use containers preferably comprise a preservative. Single-use containers may
optionally comprise preservative. When used, any safe and effective preservative amount of
benzododecinium halide, preferably bromide, may be used in compositions of the present
invention. Amounts between 0.001% to 0.1% w/v are suitable. An amount of about 0.005% to
0.03% is preferred. A preferred composition comprises about 0.01% (e.g., 0.012%).
As a result of the various studies, it has been found that there is no need to add any
solubility enhancing agent because brimonidine is soluble at acidic pH range between about 5.5
to about 6.5.
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Compositions of the present invention preferably comprise a non-ionic cellulosic
polymer. The non-ionic cellulosic polymer can be any water-soluble polymer that increases the
viscosity of the composition. Non-limiting examples include hydroxypropyl methyl cellulose
(HPMC), hydroxypropyl cellulose (HPC), hydroxyethyl cellulose, hydroxymethyl cellulose and
other modified celluloses. A preferred non-ionic cellulosic polymer is HPMC. Any amount of
non-ionic cellulosic polymer may be used to obtain a suitable viscosity. Preferred amounts
include at least 0.05%, more preferably at least 0.1% or 0.2%, all percentages being w/v.
Preferred amounts include up to 1.5%, more preferably up to 1%. Some preferred amounts
include 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8% and 0.9%. Preferred ranges include ranges formed
from any two of these amounts. For the purposes of the present invention, the non-ionic
cellulosic polymer does not include carboxymethylcellulose.
Surprisingly the formulation of the present invention is more stable than the commercial
product, Alphagan® P. The inventors of the present invention have further studied extensively
and completed the present invention. Namely, the present invention relates to:
1. An aqueous ophthalmic composition comprising an alpha-2 adrenergic receptor
agonist, a non-ionic cellulosic polymer and devoid of anionic cellulosic polymer, optionally
along with a preservative and pharmaceutically acceptable excipients, wherein the pH of said
composition is less than 6.5.
2. The composition according to the above 1 wherein the alpha-2 adrenergic
receptor agonist is brimonidine or a pharmaceutically acceptable salt or solvate or hydrate
thereof.
3. The composition according to the above 1 or 2, wherein the composition
comprises 0.01-0.5 % (w/v) of brimonidine tartrate.
4. The composition according to the above 1 or 2, wherein the composition
comprises 0.05-0.2% % (w/v) of brimonidine tartrate.
5. The composition according to the above 1, wherein the non-ionic cellulosic
polymer is selected from the group consist of hydroxypropyl methylcellulose, hydroxypropyl
cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose or combinations thereof.
6. The composition according to the above 1 or 5, wherein the non-ionic cellulosic
polymer is hydroxypropyl methylcellulose.
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7. The composition according to the above 6, wherein the composition comprises of
0.05-1.5 % (w/v) hydroxypropyl methylcellulose.
8. The composition according to the above 7, wherein the composition comprises of
0.1-1.0% (w/v) hydroxypropyl methylcellulose.
9. The composition according to the above 1 to 8, wherein the pH is less than 6.5.
10. The composition as claimed in claim 1 to 8, wherein the pH of the composition is
in the range of 5.5-6.5.
11. The composition according to the above 1, wherein the preservative is selected
from the group consist of benzododecinium halide, chlorobutanol, sodium perborate,
cetrimonium chloride, thiomersal, methyl parahydroxybenzoate, propyl parahydroxybenzoate,
sorbic acid and derivatives thereof, polyquaternium ammonium chloride, polyaminopropyl
biguanide, phenyl mercuric nitrate, phenyl mercuric acetate, hydrogen peroxide.
12. The composition according to the above 1 or 11, wherein the preservative is
benzododecinium halide.
13. The composition according to the above 1 or 11, wherein the preservative is
benzododecinium bromide.
14. The composition according to the above 1 to 13, wherein the composition is
further devoid of an oxidative preservative.
15. A method of reducing intraocular pressure in a patient in need thereof, comprising
administering to the patient the composition according to the above 1 to 14, the administered
composition comprising an effective amount of the alpha-2 adrenergic receptor agonist.
16. An aqueous ophthalmic composition comprising an alpha-2 adrenergic receptor
agonist and benzododecinium halide.
17. The composition according to the above 16, wherein the composition comprises
0.001% to 0.1% (w/v) of benzododecinium halide.
18. The composition according to the above 17, wherein the composition comprises
0.005% to 0.03% (w/v) of benzododecinium halide.
19. The composition according to the above 16 to 18, wherein the benzododecinium
halide is benzododecinium bromide.
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20. The composition according to the above 16, wherein the alpha-2 adrenergic
receptor agonist is brimonidine or a pharmaceutically acceptable salt or solvate or hydrate
thereof.
21. The composition according to the above 16, wherein the composition further
comprises a non-ionic cellulosic polymer.
22. The composition according to the above 21, wherein the non-ionic cellulosic
polymer is selected from the group consist of hydroxypropyl methylcellulose, hydroxypropyl
cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose and combinations thereof.
23. The composition according to the above 21 or 22, wherein the non-ionic
cellulosic polymer is hydroxypropyl methylcellulose.
24. The composition according to the above 16 to 23, wherein the pH of the
composition is in the range of 5.5-6.5.
25. The composition according to the above 16 to 24, wherein the composition is
devoid of an anionic solubility enhancing component.
26. The composition according to the above 25, wherein the composition is further
devoid of an oxidative preservative.
27. An aqueous ophthalmic composition comprising
a) brimonidine tartrate in an amount of 0.01-0.5 % (w/v);
b) hydroxypropyl methylcellulose in an amount of 0.1-1.0% (w/v)
c) benzododecinium halide in an amount of 0.001% to 0.1% (w/v) which is devoid
of anionic cellulosic polymer, wherein the pH of said composition is less than 6.5.
28. A method of reducing intraocular pressure in a patient in need thereof, comprising
administering to the patient the composition according to the above 16 to 27, the administered
composition comprising an effective amount of the alpha-2 adrenergic receptor agonist.
29. Use of a composition according to the above 1 to 14 and 16 to 27 for reducing
intraocular pressure in a patient in need thereof comprising safe and effective amount of alpha-2
adrenergic receptor agonist.
30. A method for the preparation of an aqueous ophthalmic composition according to the
above 1 to 14 and 16 to 27, wherein the method comprises of:
a) Adding required quantity of non-ionic cellulosic polymer to one part of water for
injection at 60 – 70 OC under stirring to form the solution.
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b) Cooling the solution as obtained in step a) to room temperature under stirring to form
Part-A of the solution.
c) Adding pharmaceutically acceptable excipients as described herein, preservative and
alpha-2 adrenergic receptor agonist under stirring to another part of water for injection which is
cooled to room temperature before such addition to form Part-B of the solution.
d) Adding Part-B solution to Part-A solution under stirring to form a solution.
e) Checking and adjusting the pH of the solution as obtained in step d) with 1N HCl/1N
NaOH and finally making up the volume to 100% with water for injection to obtain an aqueous
ophthalmic composition.
In addition to brimonidine or salt thereof, the solution of the present invention preferably
also contains buffer components to stabilize or maintain the ophthalmic formulation at the
desired pH. Any suitable buffer component can be employed which is compatible with the other
ingredients of the ophthalmic solution, and which does not have deleterious or toxic properties
which could harm the eye. Examples of suitable ophthalmically acceptable buffer components
include acetate buffers, citrate buffers, phosphate buffers, borate buffers and mixtures thereof.
Specific buffer components useful in the present invention include boric acid, sodium borate,
sodium phosphates, including mono, di- and tri-basic phosphates, such as sodium phosphate
monobasic monohydrate and sodium phosphate dibasic heptahydrate, and mixtures thereof.
In an embodiment of the present invention, tonicity adjusting agents may be added and
included without limitation such as glycerin, sorbitol, sodium hydroxide, sodium chloride,
potassium chloride, and mannitol, dextrose, propylene glycol and combinations thereof or any
other suitable ophthalmically acceptable tonicity adjusting agents.
In one embodiment, the tonicity component is selected from inorganic salts and mixtures
thereof.
The amount of ophthalmically acceptable tonicity component utilized can vary widely. In
one embodiment, the tonicity component is preferably present in the ophthalmic formulation in
an amount in the range of about 0.5 to about 0.9 weight/volume percent of the formulation.
Typical of ophthalmically acceptable inorganic salt tonicity components are alkali metal
chlorides and alkaline earth metal chlorides, such as sodium chloride, potassium chloride,
calcium chloride and magnesium chloride.
15
The pH adjusting agents include hydrochloric acid, sodium hydroxide, phosphoric acid,
acetic acid and the like.
In another embodiment one or more additional components can be included in the present
solution based on the particular application for which the formulations are made. The additional
component or components included in the present solution are chosen to impart or provide at
least one beneficial or desired property to the solutions. Examples of such additional components
include cleaning agents, non-ionic polymers, nutrient agents, sequestering agents, viscosity
builders, contact lens conditioning agents, antioxidants, and the like.
These additional components are each included in the present ophthalmic solution in an
amount effective to impart or provide the beneficial or desired property to the compositions.
Exemplary non-ionic polymers include, but are not limited to, Povidone (PVP: polyvinyl
pyrrolidone), polyvinyl alcohol, copolymer of PVP and polyvinyl acetate, gelatin, polyethylene
oxide, acacia, dextrin, starch, polyhydroxyethylmethacrylate (PHEMA), water soluble nonionic
polymethacrylates and their copolymers, modified non-cellulosic polysaccharides, nonionic
gums, nonionic polysaccharides, and/or mixtures thereof, such as referred in US20130287821
and EP2659881.
Examples of useful sequestering agents include disodium ethylene diamine tetraacetate,
alkali metal hexametaphosphate, citric acid, sodium citrate and mixtures thereof.
Examples of useful viscosity builders include hydroxyethyl cellulose, hydroxymethyl
cellulose, HPMC (hydroxypropyl methylcellulose), polyvinyl pyrrolidone, polyvinyl alcohol and
mixtures thereof.
Examples of useful antioxidants include sodium metabisulfite, sodium thiosulfate, Nacetylcysteine,
butylated hydroxyanisole, butylated hydroxytoluene, sodium sulfite, potassium
sulpfite, sodium metabisulfite, sodium thiosulfate and mixtures thereof.
The excipients used in the present invention are preferably selected to be non-toxic and
have no substantial detrimental effect (preferably, in the amount used) on the present ophthalmic
solutions, on the use of the solutions or on the human or animal to which the ophthalmic
compositions are to be administered.
In an embodiment, the present invention provide the ophthalmic compositions in the form
of aqueous liquids, solutions, emulsion, dispersion, suspension, reverse emulsion and
16
microemulsion, nanoemulsion, nano reservoir system, in-situ gel drops, nanoparticulate system,
liposomal drops, bioadhesive gel drops, drops and the like.
In another embodiment, the present invention preferably provides the ophthalmic solution
for topical ophthalmic delivery comprising administering said solution in the eyes, ear, and/or
nose of the humans or animals.
In yet another embodiment, the stable, solution would be an aqueous solution having a
pH value within the range of from about 5.5 to about 6.5 and osmolality in range of at least about
200 mOsmol/kg, preferably in the range of about 200 to about 350 or about 400 mOsmol/kg.
In further embodiment, the present invention provides a process of preparing a stable,
ophthalmic solution comprising brimonidine tartrate and/or pharmaceutically acceptable
excipients, that is more stable than the commercial product, Alphagan® P. stability data is shown
in stability section.
Still further, the present invention may also be presented as a kit comprising a stable,
aqueous solution comprising brimonidine tartrate and/or pharmaceutically acceptable excipients,
the aqueous solution being contained within a container prepared from a pharmaceutically
acceptable packaging material.
Any pharmaceutically acceptable packaging material may be use, preferably packaging
material that is suitable for containing ophthalmic aqueous solution, more preferably brimonidine
tartrate ophthalmic aqueous solution. Pharmaceutically acceptable packaging materials include
but are not limited to low density polyethylene ("LDPE"), high density polyethylene ("HDPE"),
polypropylene, polystyrene, polycarbonate, polyesters (such as polyethylene terephthalate and
polyethylene naphthalate), nylon, polyvinyl chloride), poly(vinylidine chloride),
poly(tetrafluoroethylene) and other materials known to those of ordinary skill in the art. Flexible
bottles prepared from, or comprising, LDPE, HDPE or polypropylene are particularly preferred.
The present invention provides a method to lower intraocular pressure in patients with
glaucoma or ocular hypertension wherein the method comprises a topical application to the eye
of the patient in need of a topical ophthalmic solution comprising an alpha-2 adrenergic receptor
agonist such as brimonidine tartrate and/or pharmaceutically acceptable excipients.
The present invention provides a method of using the inventive ophthalmic solution for
lowering intraocular pressure in patients with glaucoma or ocular hypertension.
17
The present invention provides a process of preparing a topical ophthalmic solution
comprising an alpha-2 adrenergic receptor agonist such as brimonidine tartrate and/or
pharmaceutically acceptable excipients.
The term preservative used in this invention has the meaning commonly understood in
the ophthalmic art. The preservatives comprises one or more of benzalkonium chloride,
benzyldodecinium bromide, chlorobutanol, sodium perborate, cetrimonium chloride, thiomersal,
methyl parahydroxybenzoate, propyl parahydroxybenzoate, sorbic acid and derivatives thereof,
polyquaternium ammonium chloride, polyaminopropyl biguanide, phenyl mercuric nitrate,
phenyl mercuric acetate, hydrogen peroxide and the like.
The amount of preservative to be included in the compositions of the present invention
will generally range from 0.001 to 0.03%, preferably 0.001 to 0.015%.
One particularly suitable preservative for use in the compositions of the present invention
is benzododecinium bromide.
EXAMPLES:
The scope of the present invention is illustrated by the following example which is not
meant to restrict the scope of the invention in any manner whatsoever.
The term 'q.s.' wherever appears in the examples is an abbreviation for 'quantity
sufficient' which is the amount of the excipient in such quantities that is just sufficient for its use
in the composition of the present invention.
Example 1:
Ingredients Present Invention
% w/v
Brimonidine Tartrate 0.1
HPMC (E4M) 0.5
Boric acid 1.1
Sodium borate 0.07
Sodium chloride 0.18
Potassium chloride 0.14
Calcium chloride 0.02
Magnesium chloride 0.006
Benzododecinium bromide 0.012
Hydrochloric acid q. s. to adjust pH (approx. 6)
Sodium hydroxide q. s. to adjust pH (approx. 6)
Milli-Q water q. s. to 1 mL
18
Example 2:
Ingredients Present Invention
% w/v
Brimonidine Tartrate 0.15
HPMC (E4M) 0.5
Boric acid 1.1
Sodium borate 0.07
Sodium chloride 0.18
Potassium chloride 0.14
Calcium chloride 0.02
Magnesium chloride 0.006
Benzododecinium bromide 0.012
Hydrochloric acid q. s. to adjust pH (approx. 6)
Sodium hydroxide q. s. to adjust pH (approx. 6)
Milli-Q water q. s. to 1 mL
Manufacturing process:
I. Part A – (Preparation of hydroxypropyl methylcellulose (HPMC) solution)
1. Add required quantity of HPMC to water for injection (WFI) (40% of batch size)
at 60 – 70ºC under stirring.
2. Cool this solution up to room temperature (up to 25ºC) under stirring.
II. Part B – (Preparation of API solution)
1. Take water for injection (50 % of batch size) in clean container.
2. Cool water for injection up to room temperature (up to 25ºC).
3. Add and dissolve Boric Acid in above water for injection under stirring.
4. Add and dissolve Sodium Borate to step 3 under stirring.
5. Add and dissolve Sodium Chloride to step 4 under stirring.
6. Add and dissolve Potassium Chloride to step 5 under stirring.
7. Add and dissolve Calcium Chloride to step 6 under stirring.
8. Add and dissolve Magnesium Chloride to step 7 under stirring.
9. Add and dissolve Benzododecinium Bromide to step 8 under stirring.
10. Add and dissolve Brimonidine Tartrate to step 9 under stirring.
III. Add Part-B (API solution) to Part-A (HPMC Solution) under stirring.
IV. Check the pH of above solution and adjust the pH of solution with 1N hydrochloric acid/1N
sodium hydroxide solution.
19
V. Make up the volume up to 100% with water for injection (WFI).
Stability Studies:
Stable, topical ophthalmic solutions comprising an alpha-2 adrenergic receptor agonist
such as brimonidine tartrate and/or pharmaceutically acceptable excipients are prepared as
shown in Table 2 and exposed to accelerated conditions at 40±2°C and relative humidity of
NMT 25%RH for 1, 2, 3 and 6 months to determine the stability of the present invention as
shown in Table 4. An initial study of commercially available Alphagan® P is initiated to
demonstrate the physico-chemical parameters as shown in Table 3.
Table 2
Ingredients Present Invention
% w/v
Brimonidine Tartrate 0.1
HPMC (E4M) 0.5
Boric acid 1.1
Sodium borate 0.07
Sodium chloride 0.18
Potassium chloride 0.14
Calcium chloride 0.02
Magnesium chloride 0.006
Benzododecinium bromide 0.012
Hydrochloric acid q. s. to adjust pH (approx. 6)
Sodium hydroxide q. s. to adjust pH (approx. 6)
Milli-Q water q. s. to 1 mL
Results and Observations:
The formulation of Alphagan® P is evaluated to demonstrate the physico-chemical
parameters such as brimonidine tartrate content and related substances for accelerated conditions
at 40±2°C and relative humidity of NMT 25%RH. Results are shown in Table 3.
Initial testing of commercial product:
Table 3
Parameters Commercial product
(Alphagan® P)
Commercial product
(Alphagan® P)
Description Clear, greenish yellow colored
solution
Clear, greenish yellow
colored solution
pH 7.60 7.60
20
Osmolality 265 mOsmol/Kg 266 mOsmol/Kg
Viscosity 3.05 cps 3.13 cps
Assay of Brimonidine Tartrate 96.2 % 96.2 %
Related Substances
a Debromobrimonidine - -
b 6-Amino-quinoxalina ND ND
c 5-Bromoquinoxaline-6-
Amine ND ND
d Highest Unknown
Impurity 1.49 % 1.43 %
e Other Unknown Impurity 1.16 % 1.43 %
f Total Impurities 2.65 % 2.86 %
The ophthalmic solution of present invention is evaluated to demonstrate the physicochemical
parameters such as brimonidine tartrate content and related substances at 1, 2, 3 and 6
months for accelerated conditions at 40±2°C and relative humidity of NMT 25%RH. Results are
shown in Table 4.
Table 4
Stability Data of Brimonidine Tartrate Ophthalmic Solution of the present invention:
Batch No. PR3F044-06
Parameters Initial
40±2°C /NMT 25%RH
1 Month 2 Month 3 Month 6 Month
Description
Clear,
greenish
yellow
colored
solution
Clear,
slightly
greenish
yellow
colored
solution
Clear,
slightly
greenish
yellow
colored
solution
Clear,
slightly
greenish
yellow
colored
solution
Clear,
slightly
greenish
yellow
colored
solution
pH 6.04 5.92 5.99 5.92 5.56
Osmolality 283
mOsmol/Kg
281
mOsmol/Kg
279
mOsmol/Kg
293
mOsmol/Kg
302
mOsmol/Kg
Viscosity 17.5 cps 17.0 cps 16.2 cps 15.7 cps 14.7 cps
Assay of Brimonidine
Tartrate 96.0 % 99.7 % 99.8 % 99.3 % 101.0 %
Content of
Benzododecinium 91.0 % 88.8 % 92.3 % 90.3 % 87.7 %
21
Bromide
Related Substances
a Debromobrimonidine ND 0.01 % 0.01 % 0.01 % 0.29 %
b 6-Amino-quinoxalina ND ND ND ND ND
c 5-Bromoquinoxaline-
6-Amine ND 0.02 % 0.02 % 0.04 % 0.10 %
d Highest Unknown
Impurity 0.03 % 0.03 % 0.05 % 0.09 % 0.014 %
e Other Unknown
Impurity 0.03 % ND 0.04 % 0.11 % 0.12 %
f Total Impurities 0.03 % 0.06 % 0.12 % 0.25 % 0.65 %
The results at accelerated conditions at 40±2°C and relative humidity of NMT 25%RH for
Alphagan® P as a commercial product:
The brimonidine tartrate content is measured and found to be 96.2 % (Limit: 90.0 -
110.0%) which is within the acceptable limit range, the highest unknown impurity is measured
and found to be 1.49 % (Limit: NMT 1.0%) which is above the acceptable limit range and total
impurity is measured and found to be 2.65 % (Limit: NMT 3.0%) which is within the acceptable
limit range.
The results at accelerated conditions at 40±2°C and relative humidity of NMT 25%RH for
6 months for the present invention:
The brimonidine tartrate content is measured and found to be 101% (Limit: 90.0 -
110.0%) which is within the acceptable limit range, the highest unknown impurity is measured
and found to be 0.014 % (Limit: NMT 1.0%) which is within the acceptable limit range and total
impurity is measured and found to be 0.65 % (Limit: NMT 3.0%) which is within the acceptable
limit range.
The above stability study of the present invention indicates that the all the parameters of
the present invention are well within narrow limits and the solution prepared by the present
invention formulation is stable with respect to all physico-chemical parameters which indicate
that at stability testing conditions there appears to be no considerable degradation in the present
solution.
22
Comparison of impurity profile of Commercial product (Alphagan® P) and present
invention formulation (brimonidine tartarate 0.1%):
Further the two (2) lots of Commercial product {Alphagan® P (0.1%)} and four (4) lots
of present invention formulation (brimonidine tartarate 0.1%) are compared at accelerated
stability conditions (40°C/ NMT 25%RH) and then compared the Impurity profiles of the two
and the results are tabulated in Tables 5 and Table 6.
Table 5 (Commercial product {Alphagan® P (0.1%)})
Related
substances/Impurity
Commercial product {Alphagan® P (0.1%)}
Lot No-79087 Lot No-77611
Initial 1M 2M 3M 6 M Initial 1M 2M 3M 6 M
Debromobrimonidine
0.01 0.01 0.02 0.02 0.03 0.01 0.01 0.02 0.02 0.02
6-Amino-quinoxaline
ND ND ND 0.01 ND ND ND ND ND ND
5-Bromoquinoxaline-
6-amine 0.03 0.08 0.11 0.17 0.35 0.03 0.06 0.13 0.24 0.52
Highest Unknown
Impurity 0.30 0.60 0.86 1.18 1.85 0.26 0.58 0.91 1.33 1.12
Unknown Impurity
0.58 0.62 0.63 0.6 1.06 0.49 0.64 0.92 0.96 2.17
Total Impurity
0.92 1.31 1.62 1.98 3.29 0.79 1.29 1.98 2.55 3.83
Table 6 {Present invention formulation (brimonidine tartarate 0.1%)}
Related
substances/Impurity
{Present invention formulation (brimonidine tartarate 0.1%)}
PR3F044-06 PR3F044-22
Initial 1M 2M 3M 6 M Initial 1M 2M 3M 6 M
Debromobrimonidine *ND 0.01 0.01 0.01 0.29 BQL BQL 0.02 0.15 0.04
6-Amino-quinoxaline ND ND ND ND ND ND ND ND BQL 0.01
5-Bromoquinoxaline-
6-amine ND 0.02 0.02 0.04 0.1 ND 0.01 0.02 0.05 ND
Highest Unknown
Impurity 0.03 0.03 0.05 0.09 0.14 BDL BDL 0.09 0.13 0.49
Unknown Impurity 0.03 ND 0.04 0.11 0.12 ND BDL 0.15 0.11 0.66
Total Impurity 0.03 0.06 0.12 0.25 0.65 BDL 0.01 0.28 0.44 1.2
23
Related
substances/Impurity
{Present invention formulation (brimonidine tartarate 0.1%)}
PR3F044-31 PR3F044-32
Initial 1M 2M 3M 6 M Initial 1M 2M 3M 6 M
Debromobrimonidine **BQL 0.02 0.03 0.04
Ongoing
BQL 0.02 0.04 0.05
Ongoing
6-Amino-quinoxaline ND BQL ND BQL ND BQL ND BQL
5-Bromoquinoxaline-6-
amine ND ND 0.01 0.01 ND 0.01 0.01 0.02
Highest Unknown
Impurity
***BD
L 0.06 0.1 0.14 BDL 0.06 0.1 0.14
Unknown Impurity BDL ND BDL BDL BDL ND BDL BDL
Total Impurity BDL 0.08 0.14 0.19 BDL 0.09 0.15 0.21
*ND - Not Detected
**BQL - Below Quantitation Limit
***BDL - Below Disregard Limit.
The total Impurity levels in various brimonidine formulations i.e. Commercial product
(Alphagan® P) and present invention formulation (brimonidine tartarate 0.1%) at 40°C/ NMT
25% RH are tabulated in Table 7 and as plotted in Figure III:
Table 7
Time
(mon
ths)
Total Impurity Level (%)
Commercial product
(Alphagan® P) Present invention formulations
Alphagan®
P 79087
Alphagan®
P 77611
Present
Invention-06
Present
Invention-22
Present
Invention-31
Present
Invention-32
0 0.92 0.79 0.03 BDL BDL BDL
1 1.31 1.29 0.06 0.01 0.08 0.09
2 1.62 1.98 0.12 0.28 0.14 0.15
3 1.98 2.55 0.25 0.44 0.19 0.21
6 3.29 3.83 0.65 1.2
ANIMAL EFFICACY STUDIES: Two studies were conducted to compare the efficacy of the
present invention formulation with the commercial product (Alphagan® P) in two different
models:
1. Normotensive model
2. Water loaded model.
24
1. NORMOTENSIVE MODEL:
Objective
The objective of the study is to test and compare the IOP lowering efficacy of two
formulations (Present Invention and commercial product) on normotensive New Zealand white
rabbits.
Materials and methods
Twelve adult female New Zealand white rabbits are selected for this study. Body weights
of all 12 rabbits are within ± 20% of the mean body weight at the time of randomization. The
selected animals are randomly grouped into two groups having 6 animals per group. Group I is
treated with Alphagan® P and Group II is treated with another formulation (Present Invention),
topically in left eye. The other (right) eye is left untreated and serves as control.
Dose level
50 μL of each formulation was instilled once in left eye.
Test
After randomization and grouping, intra ocular pressure is measured initially for 24 hours
at 2 hours interval to observe the degree of diurnal variations. On day 1 of experiment, baseline
IOP is measured for both eyes of each animal. After baseline estimation, the commercial
formulation (SRC/Aravali/78115) is instilled in left eye of all rabbits in group I and another
present invention formulation (SRC/Aravali/022) in group II. The contra lateral eye serves as
control.
Subsequent to the test item instillation, IOP estimations are repeated at 1 hr intervals until
the baseline IOP is achieved.
OBSERVATIONS:
Cageside observations & physical examinations
All the animals are observed for cageside observations and physical examinations for 2
days for each group.
Mortality
All the animals are observed for mortality for 2 days of experiment.
25
Intra ocular pressure measurement
After randomization and grouping, and before initiating the experiment, intra ocular
pressure is measured initially for 24 hours at 2 hours interval to observe the degree of diurnal
variations. On the testing day before the instillation of test item IOP is measured to determine the
baseline IOP and after every 1 hour interval after dosing till the baseline IOP is achieved.
INTERPRETATION OF RESULTS:
IOP readings of formulations instilled in the left eye of each animal are compared for IOP
lowering efficacy with respect to the extent and duration within its own group. At the same time
IOP lowering ability of both formulations is compared between the groups of animals i.e.
commercial formulation (SRC/Aravali/78115) and present invention formulation
(SRC/Aravali/022). To derive the statistical significance, Student’s t test is used for IOP data.
The statistical significance is disclosed at 95% confidence interval (p < 0.05).
RESULTS AND DISCUSSION:
Cageside observations & physical examinations
All the animals are normal in appearance throughout the observation period. The
cageside observations and physical examinations data are reported in Table 8.
Table 8
Cage side observations & physical examinations
Group No. No. of animals
used Clinical sign
Cage side observations &
physical examination
Day 0 Day 1
I 6F Normal 6 of 6 6 of 6
II 6F Normal 6 of 6 6 of 6
Mortality
There is no mortality observed in both dose groups. The mortality data is reported in
Table 9.
Table 9
Mortality
Group No. No. of animals
used
Mortality
Day 0 Day 1
26
I 6F 0/6 0/6
II 6F 0/6 0/6
Intra ocular pressure measurement
Diurnal intra ocular pressure measured for 24 hr (at 2 hr interval) does not have any
statistically significant (p<0.05) difference among left and right eyes of animals within the group
for both groups. Intraocular pressure for left eye of Groups I and II are also comparable and this
is also true for right eye of both groups.
Before test item instillation baseline IOP is measured and then for the next 5 hrs at 1 hr
intervals. Peak statistically significant (p<0.05) drop of IOP in Groups I & II is observed at 2nd
hour of instillation as compare to control eye. When particular time point is compared with
baseline statistically significant difference is observed at 2nd and 3rd hour in both groups.
At the same time, IOP readings of animals from Group I are compared with animals of
Group II and there are no statistically significant changes observed. The extent and duration of
IOP lowering effect of two formulations {commercial product (Alphagan® P) and present
invention} are comparable.
Based on observations obtained from the present study, it is concluded that two
formulations {commercial product (Alphagan® P) and present invention} have statistically
significant IOP lowering effect.
The intra ocular pressure data for Normotensive Model is reported in Table 10 and
presented in Figure I.
Table 10
Intra ocular pressure (mmHg)
Baseline & after instillation
Group Eye Baseline 1 hr 2 hr 3hr 4hr 5 hr
I
Left
Mean 21.0 20.1 14.5 16.4 19.0 20.3
SEM 0.9 0.7 0.7 0.6 0.7 0.6
P VALUE (BL
Vs. time) - 0.56 0.00 0.00 0.11 0.55
Right
Mean 20.3 19.8 19.8 18.2 20.6 20.9
SEM 0.3 0.7 1.0 0.9 0.5 0.5
P VALUE (BL
Vs. time) - 0.51 0.63 0.05 0.59 0.35
II Left Mean 20.0 19.2 15.7 16.0 19.3 20.9
27
SEM 0.4 0.5 0.6 0.9 0.8 0.5
P VALUE (BL
Vs. time) - 0.21 0.00 0.00 0.37 0.20
Right
Mean 18.9 17.9 19.1 17.4 20.3 19.8
SEM 0.6 0.7 1.0 0.8 0.3 0.4
P VALUE (BL
Vs. time) - 0.27 0.92 0.15 0.06 0.28
N = 6 animals per group; SEM = Standard Error of Mean; BL = Baseline.
CONCLUSION:
Based on the observations obtained from this study, it is concluded that the two
formulations, {commercial product (Alphagan® P) and present invention} show statistically
significant IOP lowering effect when administered to New Zealand white rabbits and the efficacy
of both the formulations is statistically comparable.
2. WATER LOADED MODEL:
Objective
The objective of the study is to test and compare the IOP lowering efficacy of two
different formulations on water loaded New Zealand white rabbits.
Materials and methods
Twelve adult female New Zealand white rabbits those used in normotensive study are
used for this study. The animals are randomly grouped into two different groups containing 6
animals per group at the time of randomization in normotensive study. Group I is treated with
commercial product (Alphagan® P) and Group II is treated with another present invention
formulation, topically in left eye. Same grouping is followed for both the dose groups as
followed in normotensive study.
Dose level
50 μL of each formulation is instilled once in left eye.
Test
After weighing, the baseline IOP is noted and rabbits are first orally administered with
water @ 70 mL/kg through orogastric tube and IOP is measured till the baseline IOP achieved
(for 2.5 hrs) at 0.25 hr interval to observe the IOP pattern. The time at which the peak IOP is
achieved is noted.
28
On the next day of experiment, initially baseline IOP is measured for both eyes. After the
baseline estimation, commercial product (Alphagan® P) formulation is instilled in left eye of all
rabbits in Group I and present invention in Group II. The right eye serves as control.
Test item instillation is followed by rapid oral administration of water (70 mL/kg)
through an orogastric tube.
The interval between drug administration and water loading is kept at 1.5 hr based on the
following observations, time to peak intraocular pressure lowering effect of the drug as observed
in normotensive rabbit study numbered 132101 (2 hrs) and the time of peak IOP elevation
observed in water loaded untreated rabbits (15 min to 90 min) in this study numbered 132102.
Afterwards, IOP estimations are carried out for 2.25 hours at 0.25 hr interval till the IOP returns
to original baseline IOP.
OBSERVATIONS
Cageside observations & physical examinations
All the animals are observed for cageside observations & physical examinations for 2
days for each group.
Mortality
All the animals are observed for mortality for 2 days of experiment.
Intra ocular pressure measurement
After weighing of animals, the baseline IOP is measured and then rabbits are orally
administered with water @ 70 mL/kg through orogastric tube and IOP is measured till the
baseline IOP achieved (for 2.5 hrs) at 0.25 hr interval to observe the IOP pattern. The time at
which the peak IOP achieved is noted.
On the day of test item instillation, IOP is measured prior to the test item instillation for
baseline IOP estimation. After baseline IOP measurement, test items are instilled to respective
group, which is followed by rapid oral water loading. IOP estimations are measured at every 0.25
hour interval after water loading till the baseline IOP is achieved.
INTERPRETATION OF RESULTS
IOP readings of the test item instilled in the left eye of each animal are compared for IOP
lowering effect with respect to the extent and duration within its own group. At the same time
IOP lowering ability of both test items is compared in two groups of animal’s i.e. commercial
29
product (Alphagan® P) formulation and present invention groups. To derive the statistical
significance, Student’s t test is used for IOP data. The statistical significance is disclosed at 95%
confidence interval (p < 0.05).
RESULTS AND DISCUSSION
Cageside observations & physical examinations
All the animals are normal in appearance throughout the observation period. The
cageside observations and physical examinations data are reported in Table 11.
Table 11
Cage side observations & physical examinations
Group No. No. of animals
used Clinical sign
Cage side observations &
physical examination
Day of water
leading only
Day of
instillation &
water loading
I 6F Normal 6 of 6 6 of 6
II 6F Normal 6 of 6 6 of 6
Mortality
There is no mortality observed in both dose groups. The mortality data are reported in
Table 12.
Table 12
Mortality
Group No. No. of animals
used
Mortality
Day of water
loading only
Day of instillation
& water loading
I 6F 0/6 0/6
II 6F 0/6 0/6
Intra ocular pressure measurement
On first day, initially baseline IOP is measured and then rabbits are administered with
water @ 70 mL/kg through orogastric tube and IOP is measured till the baseline IOP achieved
(for 2.5 hrs) at 0.25 hr interval to observe the IOP pattern. Statistically significant (p<0.05)
increased intraocular pressure is observed from 15 min to 90 min in both eyes of rabbits from
Group I, from 15 min to 75 min in left eye and 15 min to 90 min in right eye of rabbits from
30
Group II as compared to its baseline reading. At the same time, when within the group left eyes
are compared with right eyes, it shows comparable increase in IOP and no statistically significant
(p<0.05) changes in IOP is observed for both dose groups. Same way, when left and right eyes of
Group I are compared with left and right eyes of Group II, there are no statistically significant
(p<0.05) changes observed in IOP, except significant higher IOP is observed in left eye of Group
I at baseline and 15 minutes as compare to left eye of Group II, which is believed attributable to
biological variation.
On the next day, test items are instilled in left eye of respective groups after baseline IOP
measurement. 1.5 hours after test item instillation, animals are orally dosed rapidly with 70
mL/kg of water. This time gap is derived from time to peak intraocular pressure lowering effect
of the drug observed in normotensive rabbit study numbered 132101 which was 2 hr and the time
of peak IOP elevation observed in water loaded untreated animals (15 min – 90 min) in this
study numbered 132102.
As compare to baseline, there is a statistically significant (p<0.05) increase in IOP at 15
min in left eyes of both dose groups, at 15 to 75 min in right eye of Group I and at 15 to 105 min
in right eye of Group II. In left eyes (treated eyes) of both dose groups, from 30 min onward IOP
is reduced and becomes statistically non-significant (p<0.05) as compared to baseline.
At the same time, when both left and right eyes are compared, there is statistically
significant (p<0.05) lower IOP observed in left eyes as compared to right eyes from 30 min to 75
min in Group I and from 15 min to 105 min in Group II.
Same way, when left and right eyes of Group I are compared with left and right eyes of
Group II, there are no statistically significant (p<0.05) changes observed in IOP, except
significant (p<0.05) slight higher IOP observed at 90 minute in left eyes of Group I as compared
to left eyes of Group II. This difference might be due to difference in baseline of left eyes of both
groups and considered as biological variation.
Lower IOP levels in left eyes of rabbits belonging to both dose groups indicate desired
IOP lowering efficacy of both test items. Also, IOP levels in left eyes of both dose groups are
comparable hence it can be concluded that the effect of both test items are equivalent to each
other. The extent and duration of present invention is longer by 0.5 hour than commercial
product (Alphagan® P) formulation as Group II reveals IOP lowering effect up to 105 min as
compare to Group I, which reveals IOP lowering effect up to 75 min and response to present
31
invention started 15 min earlier as compare to commercial product (Alphagan® P) formulation
when compared to right eyes of respective groups.
Based on observations obtained from present study, it is concluded that two formulations
{commercial product (Alphagan® P) formulation and present invention} have statistically
significant IOP lowering efficacy and are comparable to each other. Present invention reveals
slightly longer duration of action than the commercial product (Alphagan® P) formulation, when
compared to right eyes of respective groups.
The intra ocular pressure data for Water Loaded Model are reported in Table 13 and
presented in Figure II.
Table 13
Intra ocular pressure (mmHg)
Baseline & after instillation
Grou
p
Eye 9:30 12:45 13:00 13:15 13:30 13:45 14:00 14:15 14:30 14:4
5
Baseline 15
min
30
min
45
min
60
min
75 min 90
min
105
min
120
min
135
min
I
Left
Mean 19.8 24.9 21.3 20.7 18.2 18.7 19.8 19.5 19.5 18.9
SEM 0.4 1.3 1.1 0.8 0.8 0.7 0.6 0.6 0.6 0.0
P VALUE (BL
Vs. time) - 0.00 0.21 0.31 0.12 0.19 0.98 0.70 0.70 0.05
Right
Mean 19.2 27.5 27.5 27.8 25.1 23.7 21.2 20.8 20.7 20.4
SEM 0.7 2.2 2.3 2.0 1.8 1.8 1.6 1.2 0.9 0.7
P VALUE (BL
Vs. time) - 0.00 0.01 0.00 0.01 0.04 0.29 0.30 0.22 0.26
II
Left
Mean 18.9 21.6 19.0 19.2 17.4 17.9 17.4 17.9 18.9 19.2
SEM 0.4 0.9 0.9 0.5 0.6 0.7 0.5 0.5 0.4 0.5
P VALUE (BL
Vs. time) - 0.02 0.91 0.68 0.07 0.22 0.05 0.14 1.00 0.68
Right
Mean 19.2 26.1 25.5 25.5 24.9 23.2 22.2 20.9 20.7 20.3
SEM 0.3 1.5 2.1 2.0 1.0 1.0 0.9 0.7 0.8 0.5
P VALUE (BL
Vs. time) 0.00 0.01 0.01 0.00 0.00 0.01 0.04 0.12 0.09
N = 6 animals per group; SEM = Standard Error of Mean; BL = Baseline.
CONCLUSION
Based on the observations obtained from this study, it is concluded that the two
formulations, commercial product (Alphagan® P) formulation and the present invention,
demonstrate statistically significant IOP lowering efficacy when administered to water loaded
32
New Zealand white rabbits by ocular route. The onset of statistically significant IOP lowering
efficacy is 15 minutes earlier in present invention as compared to commercial product
(Alphagan® P) formulation, whereas both the formulations are found to be comparable at each
time point observed, which indicates that the IOP lowering efficacy of both test formulations
(commercial product (Alphagan® P) formulation and present invention) are statistically
comparable.
33
We Claim:
1. An aqueous ophthalmic composition comprising an alpha-2 adrenergic receptor
agonist, a non-ionic cellulosic polymer and devoid of anionic cellulosic polymer, optionally
along with a preservative and pharmaceutically acceptable excipients, wherein the pH of said
composition is less than 6.5.
2. The composition as claimed in claim 1 wherein the alpha-2 adrenergic receptor
agonist is brimonidine or a pharmaceutically acceptable salt or solvate or hydrate thereof.
3. The composition as claimed in claims 1 or 2, wherein the composition comprises
0.01-0.5 % (w/v) of brimonidine tartrate.
4. The composition as claimed in claims 1 or 2, wherein the composition comprises
0.05-0.2% % (w/v) of brimonidine tartrate.
5. The composition as claimed in claim 1, wherein the non-ionic cellulosic polymer
is selected from the group consist of hydroxypropyl methylcellulose, hydroxypropyl cellulose,
hydroxymethyl cellulose, hydroxyethyl cellulose or combinations thereof.
6. The composition as claimed in claims 1 or 5, wherein the non-ionic cellulosic
polymer is hydroxypropyl methylcellulose.
7. The composition as claimed in claim 6, wherein the composition comprises of
0.05-1.5 % (w/v) hydroxypropyl methylcellulose.
8. The composition as claimed in claim 7, wherein the composition comprises of
0.1-1.0% (w/v) hydroxypropyl methylcellulose.
9. The composition of any of claims 1 to 8, wherein the pH is less than 6.5.
10. The composition as claimed in claim 1 to 8, wherein the pH of the composition is
in the range of 5.5-6.5.
11. The composition as claimed in claim 1, wherein the preservative is selected from
the group consist of benzododecinium halide, chlorobutanol, sodium perborate, cetrimonium
chloride, thiomersal, methyl parahydroxybenzoate, propyl parahydroxybenzoate, sorbic acid and
34
derivatives thereof, polyquaternium ammonium chloride, polyaminopropyl biguanide, phenyl
mercuric nitrate, phenyl mercuric acetate, hydrogen peroxide.
12. The composition as claimed in claims 1 or 11, wherein the preservative is
benzododecinium halide.
13. The composition as claimed in claims 1 or 11, wherein the preservative is
benzododecinium bromide.
14. The composition as claimed in any of the claims 1 to 13, wherein the composition
is further devoid of an oxidative preservative.
15. An aqueous ophthalmic composition comprising an alpha-2 adrenergic receptor
agonist and benzododecinium halide.
16. The composition as claimed in claim 15, wherein the composition comprises
0.001% to 0.1% (w/v) of benzododecinium halide.
17. The composition as claimed in claim 16, wherein the composition comprises
0.005% to 0.03% (w/v) of benzododecinium halide.
18. The composition as claimed in claims 15 to 17, wherein the benzododecinium
halide is benzododecinium bromide.
19. The composition as claimed in claim 15, wherein the alpha-2 adrenergic receptor
agonist is brimonidine or a pharmaceutically acceptable salt or solvate or hydrate thereof.
20. The composition as claimed in claim 15, wherein the composition further
comprises a non-ionic cellulosic polymer.
21. The composition as claimed in claim 20, wherein the non-ionic cellulosic polymer
is selected from the group consist of hydroxypropyl methylcellulose, hydroxypropyl cellulose,
hydroxymethyl cellulose, hydroxyethyl cellulose and combinations thereof.
22. The composition as claimed in claims 20 or 21, wherein the non-ionic cellulosic
polymer is hydroxypropyl methylcellulose.
35
23. The composition as claimed in any of the claims 15 to 22, wherein the pH of the
composition is in the range of 5.5-6.5.
24. The composition as claimed in any of the claims 15 to 23, wherein the
composition is devoid of an anionic solubility enhancing component.
25. The composition as claimed in claim 24, wherein the composition is further
devoid of an oxidative preservative.
26. An aqueous ophthalmic composition comprising
a) brimonidine tartrate in an amount of 0.01-0.5 % (w/v);
b) hydroxypropyl methylcellulose in an amount of 0.1-1.0% (w/v)
c) benzododecinium halide in an amount of 0.001% to 0.1% (w/v) which is devoid
of anionic cellulosic polymer, wherein the pH of said composition is less than 6.5.
27. A method for the preparation of an aqueous ophthalmic composition as claimed in
claims 1 to 26, wherein the method comprises of:
a) Adding required quantity of non-ionic cellulosic polymer to one part of water for
injection at 60 – 70 OC under stirring to form the solution.
b) Cooling the solution as obtained in step a) to room temperature under stirring to form
Part-A of the solution.
c) Adding pharmaceutically acceptable excipients as described herein, preservative and
alpha-2 adrenergic receptor agonist under stirring to another part of water for injection which is
cooled to room temperature before such addition to form Part-B of the solution.
d) Adding Part-B solution to Part-A solution under stirring to form a solution.
e) Checking and adjusting the pH of the solution as obtained in step d) with 1N HCl/1N
NaOH and finally making up the volume to 100% with water for injection to obtain an aqueous
ophthalmic composition.