FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(SECTION 10; RULE 13)
"TOPICAL PHARMACEUTICAL COMPOSITIONS CONTAINING ADAPALENE
MICROSPHERES"
Glenmark Pharmaceuticals Limited, an Indian Company,
registered under the Indian company's Act 1957 and
having its registered office at
Glenmark House,
HDO - Corporate Bldg, Wing -A,
B.D. Sawant Marg, Chakala,
Andheri (East), Mumbai - 400 099, INDIA.
The following specification particularly describes the invention and the manner in which it is to be performed.
1

FIELD OF THE INVENTION
The present invention generally relates to topical pharmaceutical compositions comprising adapalene microspheres and a process for making the same. More particularly, the present invention relates to topical adapalene gel and cream microsphere formulations for the treatment of skin conditions such as acne vulgaris.
BACKGROUND OF THE INVENTION
Over the past 40 years, the ability to control the delivery rate of active agents to a predetermined site in the human body has been one of the biggest challenges. Transdermal patches, developed in the 1970s, improved the delivery of drugs such as nitroglycerin and scopolamine, resulting in better control of therapeutic doses, simpler dosage regimens, and fewer side effects than the more traditional oral or parenteral administration of the same drugs. In general, these delivery systems have improved the efficacy and safety of many drugs that now may be better administered through the skin.
Although transdermal delivery systems can be efficient in supplying drugs for systemic effects, they are not practical for controlling the delivery of materials whose final target is the skin itself. Controlled release of drugs onto the skin or epidermis is an area of research that has recently been addressed with success. However, no efficient vehicles have been developed for the controlled and localized delivery of drugs into the stratum corneum and underlying skin layers. However, there are many instances when epidermal localization of a drug is still desirable.
Many of conventional topical vehicles require high concentrations of active agents for effective therapy because of their low efficiency as delivery systems. As a result, irritation or allergic responses can be elicited while treating skin conditions or disorders. Other disadvantages of existing topical drug formulations can be uncontrolled evaporation of the active ingredient, unpleasant odor, and the potential incompatibility of one or more drugs with each other or with the vehicle.
2

From the past, an important area of concern is the topical treatment of skin conditions like acne. Acne is a chronic, inflammatory disorder of the pilosebaceous unit that affects almost everyone at some stage between the ages of 12 and 24 years. It is a multifactorial disease, the main pathophysiological factors that influence the development of acne are excessive sebum secretion, abnormal keratinisation and desquamation of sebaceous-follicle epithelium (comedogenesis), proliferation of Propionibacterium acnes in the pilosebaceous duct and inflammation.
Acne occurs in response to clogged hair follicles. Initially, sebaceous glands associated with a hair follicle fill the follicle with sebum, an oil-like substance. Dead skin cells lining the hair follicle slough off into the follicle. Normally, sebum, dead skin cells, and other substances are routinely eliminated from the follicle. When the sebum and dead skin cells form a plug in the follicle, however, a comedone develops. An open comedone occurs when the opening of the follicular canal dilates and the plug protrudes form the canal, turning a characteristic dark color upon exposure to the air. Open comedones are also referred to as "blackheads" because of this dark color. Closed comedones occur when the follicle is covered, e.g., with a layer of cells, such that the plug does not reach the external environment. Closed comedones are also referred to as "whiteheads," due to their characteristic white color. The production of sebum and dead skin cells lining the follicle increases dramatically during puberty in response to hormonal changes. It is this increased production of these products that causes adolescents to be the most likely individuals to suffer from acne.
In general, topical treatment of acne includes a wide variety of topical dosage forms such as, for example gels, creams, ointments, lotions and solutions. More often, these products use a combination of benzyl peroxide, aliphatic acids, antibiotics, salicylic acid, vitamin A derivatives, tretinoin, isotretinoin and adapalene e.t.c. Treatment with topical anti acne compositions such as gels, creams or lotions is normally the first choice of treatment for mild to moderate acne infections. Serious infections, however, require a longer course of treatment from a few days to several months.
Treatments for acne address the various factors responsible for it and include estrogens and antiandrogens to reduce the impact of androgens, antibacterial agents to reduce P. acnes
3

colonisation of the pilosebaceous unit, and retinoids to reduce hyperproliferation and keratosis of ductal corneocytes. The choice of treatment is dependent on the type and severity of the disorder. If the acne is mainly comedonal, retinoids are the first-line treatment. In the case of inflammatory acne, topical and/ or systemic antimicrobial agents may be used in addition to retinoids.
Adapalene, a retinoid, binds selectively to specific nuclear retinoic acid receptors (RARs), thus activating genes responsible for cellular differentiation. Topical application of adapalene is thought to modulate keratinization, inflammation and differentiation of follicular epithelial cells. This result in a reduction in the formation of microcomedones and of the inflammatory lesions associated with acne vulgaris. By virtue of its low absorption, rapid onset of action, a favourable tolerability profile, adapalene is assured of a role in the first-line treatment of acne vulgaris. However, adverse effects such as erythema, scaling, dryness, pruritus and burning, have been reported in 10-40% of patients treated with 0.1% Adapalene gel.
Microsponge technique is advantageously more beneficial in skin care products by using microscopic reservoirs that entraps drug. The microsponge releases the drug into the skin relatively more gradually for longer duration of time. In this manner, the skin is continuously exposed to the drug, thereby minimizing irritation to the skin. Microsponge polymeric delivery systems consisting of porous microspheres can entrap a wide range of active ingredients. These entrapped active ingredient microspheres can then be further incorporated into the suitable topical dosage forms like gels, creams, ointments and lotions etc. When this composition is applied to the skin, the entrapped active agents are delivered to the skin for longer period of time in a controlled time release pattern or a programmed manner. The active ingredient present in the microspheres is released to the skin site by rubbing or pressing the formulation upon application at the desired skin area. The skin surface temperature may also enhance the release of entrapped active ingredient from microsphere formulations.
US 5,955,109 assigned to Advanced Polymer Systems, Inc. is directed to the topical pharmaceutical compositions comprising retinoic acid which is incorporated into the pores of microspheres or porous solid particles. The pores form a continuous network open to the
4

exterior of the particles, permitting outward diffusion of the retinoic acid impregnant at a controlled rate depending on the pore size.
Conventional topical pharmaceutical dosage forms such as gels, creams, ointments and lotion usually causes adverse skin effects such as irritation to the skin upon application. Accordingly, there remains a need for a less irritating topical pharmaceutical composition comprising an effective amount of active pharmaceutical ingredient (API) such as adapalene for the treatment of acne vulgaris. Surprisingly, inventors of the present invention have found that formulations according to the present invention can fulfill the objectives cited above. Therefore, the present invention describes the topical pharmaceutical compositions comprising an effective amount of adapalene microsphere in a suitable pharmaceutically acceptable carrier. The present invention also describes a process for making microsphere adapalene topical dosage forms. Also provided is a method of treating acne vulgaris by applying the said composition to skin.
The microsphere pharmaceutical compositions of the present invention are advantageously effective in treating or clearing the acne/pimples, whiteheads and black heads by cleaning the pores of the oil blocking skin cells. The compositions of the present invention assist in shedding skin cells norm rather than allowing them to accumulate in the pores. The present invention topical pharmaceutical compositions comprising an effective amount of adapalene microsphere in a suitable pharmaceutically acceptable carrier helps in releasing Adapelene into the pilosebaceous units and prevents any skin surface contact directly with Adapalene. A study was conducted to assess the efficacy, safety and tolerability of microsphere adapalene 0.1% gel versus conventional adapalene 0.1% gel in adult patients with mild to moderate acne vulgaris. Thus adverse effects such as irritation, erythema, scaling, dryness, pruritus and burning which have been reported in 10-40% of patients treated with 0.1% conventional Adapalene gel has been circumvented with the microsphere adapalene gel formulation in the present invention.
5

SUMMARY OF THE INVENTION
One aspect of the present invention provides a topical pharmaceutical composition comprising an effective amount of adapalene microsphere in a suitable pharmaceutically acceptable carrier for the treatment of acne vulgaris.
In another aspect of the present invention provides a topical pharmaceutical composition, wherein the microsphere adapalene is formulated in various dosage forms such as gel, cream, ointment, lotion e.t.c. Preferably microsphere adapalene is formulated as Adapalene gel.
Another aspect of the present invention provides a topical pharmaceutical composition, comprising microsphere adapalene wherein the effective amount of adapalene is present in the concentration range of 0.1 - 0.3% formulated as Adapalene gel. Preferably, the microsphere adapalene is present in the concentration of 0.1 % formulated as Adapalene gel.
Another aspect of the present invention provides a topical pharmaceutical composition, comprising microsphere adapalene gel having less irritation potential which is characterized by burning, erythema and pruritus in comparison to plain Adapalene gel when administered to human or patient's skin.
Another aspect of the present invention provides a process of preparing the adapalene microsphere compositions comprising the steps of: a) impregnation of adapalene into plain microspheres employing a solvent system and b) incorporation of adapalene microspheres into a suitable carrier.
A further aspect of the present invention provides a process for preparation of Adapalene microsphere compositions which are formulated as Adapalene gel, creams, ointments, lotions. Preferably a process of incorporation of adapalene microspheres into a gel is provided.
Another aspect of the present invention provides a topical pharmaceutical composition and a process of preparing the said composition comprising a) microsphere adapalene and b) a
6

pharmaceutically acceptable carrier, where in the said carrier is selected from polymers, buffering agents, surfactants, viscolyting agents/gelling agents, chelating agents, preservatives, and suitable solvents thereof.
Another aspect of the present invention provides a method of treating acne vulgaris in a human subject, wherein said method comprises, topically administering a pharmaceutical composition comprising Adapalene microspheres in a suitable dosage forms such as gel, creams, ointments and lotions. The topical pharmaceutical composition of the present invention has less irritation potential in comparison to plain Adapalene gel.
DETAILED DESCRIPTION OF THE INVENTION
Before describing the present invention in detail, it is to be understood that this invention is not limited to specific pharmacologically active carriers, formulation types, treatments, and so forth, as such may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
DEFINITIONS
The terms "topical" or "topical administration" or "local" are used in its conventional sense to mean delivery of a topical drug or pharmacologically active agent to the skin or mucosa. Topical administration, in contrast to transdermal administration, provides exclusively or predominantly a local rather than a systemic effect. The term "transdermal" is intended to include "transmucosal" drug administration, i.e., administration of a drug to the mucosal (e.g., sublingual, buccal, vaginal, rectal) surface of an individual so that the drug passes through the mucosal tissue and into the individual's blood stream.
The term "topical pharmaceutical composition" refers to a composition that is employed to prevent, reduce in intensity, cure or otherwise treat a target condition or disease.
The terms "active agent" or "active pharmaceutical ingredient" or "drug" are used interchangeably herein to refer to a chemical material or compound that induces a desired
7

pharmacological, physiological effect, and include agents that are therapeutically effective, prophylactically effective, or cosmeceutically effective. The active ingredients, for example, retinoids such as adapalene and the like are used in the present invention.
The term "effective amount" or a "therapeutically effective amount" of a pharmacologically active agent is meant a non-toxic but sufficient amount of the drug or agent to provide the desired effect. The "effective amount" will vary depending on the compound, the disease and its severity and the age, weight, physical condition and responsiveness of the mammal to be treated. Thus, it is not always possible to specify an exact "effective amount." However, an appropriate "effective" amount in any individual case may be determined by one of ordinary skill in the art using routine experimentation. In the present invention, the effective amount of active ingredient such as adapalene is used in the range of 0.1 to 0.3%.
The term "treating" or "treatment" of a state, disorder or condition as used herein means: (1) preventing or delaying the appearance of clinical symptoms of the state, disorder or condition developing in a mammal that may be afflicted with or predisposed to the state, disorder or condition but does not yet experience or display clinical or subclinical symptoms of the state, disorder or condition, (2) inhibiting the state, disorder or condition, i.e., arresting or reducing the development of the disease or at least one clinical or subclinical symptom thereof, or (3) relieving the disease, i.e., causing regression of the state, disorder or condition or at least one of its clinical or subclinical symptoms. The benefit to a subject to be treated is either statistically significant or at least perceptible to the patient or to the physician.
The term "acne" is used herein as a general term to include inflammatory diseases of the pilosebaceous unit. In the medical field, the specific type of acne is usually indicated by a modifying term, although the term acne is frequently used alone to designate common acne or acne vulgaris.
The term "subject" or "a patient" or "a host" as used herein refers to mammalian animals, preferably human.
8

The term "microspheres" shall include any particle capable of containing a bio-active agent that is to be released up on application to the skin.
The term "irritation" or "irritation potential" or "irritate" or "irritating" as used herein means that a portion of skin exhibits signs characterized by burning, erythema and pruritus.
The term "pharmaceutically acceptable" such as in the recitation of a "pharmaceutically acceptable carrier" or a "pharmaceutically acceptable derivative" is meant a compound that is not biologically or otherwise undesirable, i.e., the compound may be incorporated into a topical formulation of the invention and administered to a patient without causing any undesirable biological effects or interacting in a deleterious manner with any of the other components of the formulation in which it is contained.
The term "carriers" or "vehicles" as used herein refer to pharmaceutically acceptable carrier materials suitable for topical drug administration. Carriers and vehicles useful herein include any such materials known in the art that are nontoxic and do not interact with other components of the composition in a deleterious manner.
The term "polymer" is intended to mean an agent who forms a closed chain structures used to delay the drug release. Such compounds include, by way of example and without limitation, those known to one of ordinary skill in the art. Examples include alone or in mixtures gum arabic, sodium based lignosulfonate, methyl methacrylate, ethylene glycol dimethacrylate for plain microsphere formation and the like or mixtures thereof.
The term "buffering agent" is intended to mean a compound used to resist a change in pH upon dilution or addition of acid of alkali. Such compounds include, by way of example and without limitation, sodium hydroxide, potassium hydroxide, ammonium hydroxide and the like
The term "surfactant" is intended to mean an agent that reduces the surface tension between the two different phases to distribute them to form a homogenous phase. Such compounds include, by way of example poloxamer and the like.
9

The term "chelating agent" is intended to mean a compound which complexes with the metal ions in the formulation and avoids the unwanted chemical reactions from occurring and to enhance the preservative or preservative system. Preferred chelating agents are mild agents, such as, for example, ethylenediaminetetraacetic acid (EDTA), disodium edetate and EDTA derivatives, or any combination thereof.
The term "gelling agent" or "viscolyting agent" is intended to mean an agent that increases the viscosity of the formulation by forming a cross linking structure in contact with water. Such compounds include, by way of example and without limitation, carbomers (carbopol), modified cellulose derivatives, naturally-occurring, synthetic or semi-synthetic gums such as xanthan gum, acacia and tragacanth, sodium alginate, gelatine, modified starches, cellulosic polymers such as hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose, hydroxypropyl methylcellulose phthalate, and methyl cellulose; co-polymers such as those formed between maleic anhydride and methyl vinyl ether, colloidal silica and methacrylate derivatives, polyethylene oxides, polyoxyethylene-polyoxypropylene copolymers, polyvinylalcohol and the like.
The term "preservative" is intended to mean an agent that protects the formulation from degradation by avoiding oxidation, hydrolysis, or photolytic chemical reactions. Such compounds include, by way of example and without limitation, phenoxyethanol, parabens such as methylparaben and propylparaben, propylene glycols, sorbates, urea derivatives such as diazolindinyl urea, and the like or any combinations thereof.
The pharmaceutical composition of the present invention further comprises suitable solvents. Examples of such solvents include but not limited are water, tetrahydrofuran, isopropyl alcohol and Propylene glycol, liquid petrolatum, ether, petroleum ether, alcohols including methanol, ethanol and higher alcohols, aromatics including benzene and toluene, alkanes including pentane, hexane and heptane, ketones including acetone and methyl ethyl ketone, chlorinated hydrocarbons including chloroform, carbon tetrachloride, methylene chloride and ethylene dichloride, acetates including ethyl acetate, and oils including isopropyl myristate, diisopropyl adipate and mineral oil.
10

The term "aqueous" refers to a formulation or drug delivery system that contains water or that becomes water-containing following application to the skin or mucosal tissue.
Most of these excipients are described in detail in, e.g., Howard C. Ansel et al., Pharmaceutical Dosage Forms and Drug Delivery Systems, (7th Ed. 1999); Alfonso R. Gennaro et al., Remington: The Science and Practice of Pharmacy, (20th Ed. 2000); and A. Kibbe, Handbook of Pharmaceutical Excipients, (3rd Ed. 2000), the contents of which are incorporated by reference herein.
The present invention provides a topical pharmaceutical composition comprising an effective amount of adapalene microsphere in a suitable pharmaceutically acceptable carrier for the treatment of acne vulgaris. The present invention also provides a process of preparing the adapalene microsphere compositions comprising the steps of impregnation of adapalene into plain microspheres employing a solvent system and incorporation of adapalene microspheres into a suitable carrier. The microsphere adapalene topical pharmaceutical compositions of the present invention are formulated in various dosage forms such as gel, cream, ointment, lotion. The compositions of the present invention have less irritation potential in comparison to plain Adapalene gel.
The topical pharmaceutical compositions of the present invention can further contain pharmaceutically acceptable carriers. The pharmaceutically acceptable excipients include, but are not limited to, polymers, chelating agents, gelling agents, preservatives, surfactants, buffering agents, solvents or vehicles and the like and mixtures thereof that are typically used in the art for locally applied semisolid dosage forms.
The microsphere pharmaceutical compositions of the present invention are particularly useful in delivery of one or more active pharmaceutical ingredients for the treatment acne vulgaris.
In an embodiment of the present invention, microsphere gel dosage forms of the pharmaceutical compositions herein are provided comprising the steps of:
11

i) Preparation of plain microspheres as disclosed in U.S. Patent No. 5,955,109, the content of
which are incorporated by reference herein; ii) incorporation of the drug in the microsphere; and iii) preparation of the gel using the microspheres.
The following examples are provided to enable one skilled in the art to practice the invention and are merely illustrative of the invention. The examples should not be read as limiting the scope of the invention.
EXAMPLE-1
Preparation of topical microsphere adapalene gel
The ingredients for use in this example are set forth below in Table 1. The process of
manufacture of plain microspheres is disclosed in example 3 of U.S. Patent No.5,955,109.
Table 1: Plain microspheres

STEP NAME OF INGREDIENTS Quantities in PARTS GM/BATCH
I AQUEOUS PHASE
Purified Water 600.0 4.8 liter
Gum Arabic 6.0 48.0
Sodium based Lignosulfonate 6.0 48.0
Aqueous phase heated upto 50°C in water bath.
II ORGANIC PHASE
Toluene 108.4 1.0 liter
Benzoyl Peroxide (70%) 2.0 16.0
Methyl Methacrylate 72.0 576.0
Ethylene Glycol Dimethacrylate 78.0 624.0
Organic phase added to aqueous phase at 50°C at approx. 1000 rpm
III REACTION CONDITIONS
Temp, of reaction mixture : 80°C
12

80°C temp, to be maintained for : 12 hours Nitrogen flow : 6 ml / minute
IV COOLING AND FILTRATION
Cool down the temperature below 40°C
V WASHING
A Purified Water 1000 8.0 liter
B Purified Water 1000 8.0 liter
C Purified Water 1000 8.0 liter
A Isopropyl Alcohol 1000 8.0 liter
B Isopropyl Alcohol 1000 8.0 liter
C Isopropyl Alcohol 1000 8.0 liter
VI DRYING
Dryat65°Cfor 12 hours.
Into a 10 liter four-necked reaction flask (which was evacuated and purged with nitrogen) kept in water-bath equipped with motorized stirrer, reflux condenser, thermometer and nitrogen inlet was added 4.8 liter purified water, 48.0 gm gum arabic and 48.0 gm sodium based lignosulfonate. The mixture was heated up to 50°C to form an aqueous phase. Next, into a 3.0 liter container was added 1.0 liter toluene, and dissolved with 16.0 gm Benzoyl peroxide (70%), and further added 576.0 gm methyl methacrylate, and 624.0 gm ethylene glycol dimethacrylate. The mixture was stirred to mix uniformly to form an organic phase. The organic phase was added slowly to the aqueous phase (step 1) at 50°C under stirring at 1000 rpm (To be measured by tocometer). The reaction mixture was heated to 80°C and maintained at that temperature for 12 hours while maintaining a nitrogen flow of 6 ml/minute and stirring speed at approx. 1000 rpm to form porous beads. The reaction mixture was cooled to below 40°Cand the beads were collected by Filtering through a 200# mesh nylon cloth.
The collected beads were washed three times in a 20 liter container with 8.0 liter purified water and stirred each time for 25 minutes, and then three times with 8.0 liter isopropanol (IPA) and stirred each time for 25 minutes, and then dried at 65°C for 12 hours.
13

Table 2: Incorporation of Adapalene in plain microsphere
To prepare Adapalene microspheres with mixture of IPA and MC

STEP NAME OF INGREDIENTS (%) O. A. % OF FORM GM/BATCH
I Isopropyl alcohol - 1.2 liter 1.2 liter
Methylene Chloride - 3.4 liter 3.4 liter
II Adapalene - 10.0 10.0
III Plain microspheres - 90.0 90.0
In 5.0 liter RBF add 1.2 liter Isopropyl Alcohol and 3.4 liter Dichloromethane (Methylene
Chloride), 10.0 gm Adapalene (200#) was dissolved under stirring and 90.0 gm plain
microspheres are added with slow stirring.
Set up the distillation unit (simple distillation)
Temperature set up as follows: RPM
Initial temperature :45°C 30 to 40
After 4 hours, temperature was increased gradually: 55°C, 60°, 70°, 80°C, 90°C, 40 to 50, 60
to 70, and 100 to 120. When about 500 ml to 900 ml is left to distill. Transferred to 1 liter
bucchi flask. Evaporated to dryness in buchhi evaporator initially under low vacuum at 50°C
and then at high vacuum for at least 3 hours. The beads are dried at 60°C under vacuum for 3
hours. The net weight was recorded
Table 3: Adapalene gel microsphere formulation

Ingredients/Components Qty (mg/g) % w/w
PHASE I
Purified Water 808.75 80.875
Disodium edetate 0.500 0.050
Carbopol 940 5.500 0.550
PHASE II
Propylene Glycol 80.000 8.000
Methyl Paraben 1.000 0.100
Poloxamer 407 1.000 0.100
14

Purified Water 30.000 3.000
Phenoxyethanol 2.500 0.250
Adapalene, microspheres 10.000 1.000
Purified Water (rinsing) 50.000 5.000
PHASE III
Purified Water 10.000 1.000
Sodium Hydroxide 0.750 0.075
Phase I:
The ingredients in part I are mixed with low speed homogenization until the Carbomer is
dispersed.
Phase II:
The ingredients in part II are mixed with low speed mechanical stirrer until the active drug is
dispersed uniformly.
Phase III:
Sodium Hydroxide is dissolved in Purified Water.
Mixing: Phase III is added to Phase I to form a viscous gel. Phase II is slowly added under
stirring to form opaque viscous gel.
Validation results show that homogenization, storage and filling of the gel does not have any
adverse impact on the homogeneity of content throughout the tube and on droplet size.
The finished product specification includes appearance, assay, related substances tests, droplet
size, as well as test for consistency and homogeneity of the gel.
EXAMPLE 2
Preparation of topical microsphere adapalene gel
A micropshere pharmaceutical gel was prepared in essentially the same manner as Example 1
except that the solvent used in this example was tetrahydrofuran.
The ingredients for use in this example are set forth below in Table 4.
Table 4: Plain microspheres

STEP NAME OF INGREDIENTS Quantities in GM/BATCH
15

PARTS
I AQUEOUS PHASE
Purified Water 600.0 4.8 liter
Gum Arabic 6.0 48.0
Sodium based Lignosulfonate 6.0 48.0
Aqueous phase heated upto 50°C in water bath.
II ORGANIC PHASE
Toluene 108.4 1.0 liter
Benzoyl Peroxide (70%) 2.0 16.0
Methyl Methacrylate 72.0 576.0
Ethylene Glycol Dimethacrylate 78.0 624.0
Organic phase added to aqueous phase at 50°C at approx . 1000 rpm
III REACTION CONDITIONS
Temp, of reaction mixture : 80°C 80°C temp, to be maintained for : 12 hours Nitrogen flow : 6 ml / minute
IV COOLING AND FILTRATION
Cool down the temperature below 40°C
V WASHING
A Purified Water 1000 8.0 liter
B Purified Water 1000 8.0 liter
C Purified Water 1000 8.0 liter
A Isopropyl Alcohol 1000 8.0 liter
B Isopropyl Alcohol 1000 8.0 liter
C Isopropyl Alcohol 1000 8.0 liter
VI DRYING
Dry at 65°C for 12 hours.
Table 5: Incorporation of Adapalene in plain microsphere
To prepare Adapalene microspheres with tetrahydrofuran

STEP NAME OF INGREDIENTS (%) % OF GM/BATCH
16

O.A. FORM
I Tetrahydro Furan (THF) - 1.4 liter 1.4 liter
II Adapalene - 10.0 10.0
III Plain microspheres - 90.0 90.0
In 2.0 liter RBF add 1.4 liter Tetrahydrofuran (THF) dissolve under stirring 10.0 gm Adapalene
(200#) Add with slow stirring 90.0 gm Plain microspheres. Set up the distillation unit (simple
distillation)
Temperature set up as follows: RPM
Initial temperature: 65°C 80 to 90
After 4 hours, temperature was increased gradually: 70°, 80°, 100 to 120, to 130. When about
500ml to 900ml is left to distill. Transferred to 1 liter bucchi flask. Evaporated to dryness in
buchhi evaporator initially under low vacuum at 50°C and then at high vacuum for at least 3
hours. The beads are dried at 60°C under vacuum for 3 hours. Net weight was recorded.
Table 6: Adapalene gel formulation

Ingredients/Components Qty (mg/g) % w/w
PHASE I
Purified Water 808.75 80.875
Disodium edetate 0.500 0.050
Carbopol 940 5.500 0.550
PHASE II
Propylene Glycol 80.000 8.000
Methyl Paraben 1.000 0.100
Poloxamer 407 1.000 0.100
Purified Water 30.000 3.000
Phenoxyethanol 2.500 0.250
Adapalene, microspheres 10.000 1.000
Purified Water (rinsing) 50.000 5.000
PHASE III
Purified Water 10.000 1.000
17

Sodium Hydroxide 0.750 0.075 1
Phase I:
The ingredients in part I are mixed with low speed homogenization until the Carbomer is
dispersed.
Phase II:
The ingredients in part II are mixed with low speed mechanical stirrer until the active drug is
dispersed uniformly.
Phase III:
Sodium Hydroxide is dissolved in Purified Water.
Mixing: Phase III is added to Phase I to form a viscous gel. Phase II is slowly added under
stirring to form opaque viscous gel.
Validation results show that homogenization, storage and filling of the gel does not have any
adverse impact on the homogeneity of content throughout the tube and on droplet size.
The finished product specification includes appearance, assay, related substances tests, droplet
size, as well as test for consistency and homogeneity of the gel.
Before application of topical microspheres formulation of the present invention on to the skin,
the affected areas should be washed and dried and then the gel applied once daily, e.g., at bed
time, wherein the eyes, lips and nose should be avoided. At first there may be a worsening of
acne during the first few weeks of therapy because adapalene promotes the growth of pimples
that have begun to form but are not yet visible. Therefore, treatment should not be stopped
even if acne appears to be worsing. Beneficial effects should be seen by about 8 to about 12
weeks.
EXAMPLE 3: Assessment of the efficacy, safety and tolerability of microsphere adapalene 0.1% gel versus conventional adapalene 0.1% gel in adult patients with mild to moderate acne vulgaris.
A prospective, randomized assessor blind, multi-centric (four centres) comparative, evaluation study was undertaken in 200 patients with mild to moderate acne. A minimum of 20 inflammatory (mean range at baseline 20-50) and 20 non-inflammatory (mean range at baseline 20-100) lesions are required for inclusion. Adult male and non-pregnant (2
18

pregnancy tests 1 before and 1 after the study, with the exception of those who were menopausal or who had undergone a hysterectomy, bilateral tubal ligation or bilateral ovariectomy) female patients aged between 12-40 years were included in the study if they had mild to moderate facial acne vulgaris. Subjects with no known medical conditions that, in the investigator's opinion, could interfere with study participation and willing to provide written informed consent were included in the study. Patients with any skin phototype were enrolled in the study provided the degree of skin pigmentation did not interfere with the test site evaluation. Patients were excluded from the study if they were pregnant or breast-feeding as were those with an abnormal skin hyper-pigmentation. Subjects who had a history of skin disease that could confound site analysis (such as Atopic dermatitis, Psoriasis), those with a history of known sensitivity to Adapalene, other ingredients of the formulation, other skin care products, topical medications, latex or any other specific kind of tape, or to any metal especially aluminium used in Finn chambers were also not included in the study. Patients with active, flaring dermatitis that covered more than 25% of the body surface area, those with scars, moles, sunburns, or other blemishes on the test area that would interfere with grading were also excluded from the study. Patients receiving concomitant treatment with systemic corticosteroids, immunosuppresants (cyclophosphamide, azathioprine, etc.) and ultraviolet B or PUVA therapy were not included in the study. Patients with any dermatological disorder or personal appearance issue which, in the investigator's opinion, could interfere with the accurate evaluation of the subject were excluded from the study. Also excluded were men with facial hair that would interfere with the assessments, patients with facial nodules or cysts, those with drug -induced or severe acne, such as acne conglobata or fulminans, or those who had taken systemic retinoids within the previous 6-12 months those who have taken systemic antibacterial agents or other anti-acne treatments within 2-6 weeks of commencement of the trial. Subjects who were unwilling or unable to comply with the requirements of the protocol were also not included in the study. Each investigator secured Institutional review board approval of the clinical trial protocol and informed consent document before enrolling patients. The study was conducted in compliance with Good Clinical Practice guidelines and the Declaration of Helsinki and its amendments. All eligible patients were explained about the nature of the study and about the drug. A patient information sheet was given to them in a language understood by them and a written informed consent was obtained from each participant before initiation of any study procedures. A
19

computer generated randomization list was drawn up by the statistician in a 1:1 ratio and given to the sponsors (Medical department of Glenmark Pharmaceuticals Ltd). Patients fulfilling the selection criteria were advised to apply microsphere Adapalene (0.1%) gel once daily in the evening for 12 weeks and conventional Adapalene (0.1%) gel once daily in the evening for 12 weeks as per the randomized list provided by the sponsor. The duration of the study was 13 weeks including a 12-week week active treatment period preceded by a 1-week washout period.
Use of any topical drug on the application area within 1 week before beginning the study, or any systemic drug that could have affected the irritation within 2 weeks before study onset was not permitted during the study period.
Efficacy assessments:
The efficacy variables included success rate (the percentage of patients rated "clear" or "almost clear" on the Investigator's Global Assessment [IGA]) (Table 7) and percent lesion reduction from baseline (total, inflammatory, and non-inflammatory). Lesion counts were assessed on the face only. Efficacy was evaluated by analyzing changes in the number of facial acne lesions that included total lesion count (inflammatory + non-inflammatory lesions), Inflammatory lesion count (papules, pustules, nodules) and Non-inflammatory lesion count (open and closed comedones) Individual counts were maintained for comedones (open and closed), papules, pustules and nodules. The efficacy parameters were assessed at baseline and thereafter at visits 1, 2, 4, 8, and 12 weeks.
Table 7: Investigator's Global Assessment (IGA)

Success 0 Clear Residual hyperpigmentation and erythema may be present
1 Almost clear A few scattered comedones, and a few (<5) small papules
Failure 2 Mild Easily recognizable; less than half the face involved; many comedones and many papules and pustules
3 Moderate More than half of the face is involved; numerous comedones, papules, and pustules
4 Severe Entire face is involved; covered with comedones, numerous papules, and pustules, and few nodulesand cysts
20

5 Very severe High inflammatory acne covering the face with nodules and cysts present
Safety assessments:
Safety and Tolerability was assessed on the basis of physical examination and monitoring of treatment -emergent adverse events.
A total 175 patients (88 in microsphere group and 87 in the conventional adapalene group) with mild to moderate acne vulgaris were enrolled in the study. Of these 9 patients in the microsphere adapalene group and 12 in the conventional adapalene group were lost to follow-up and considered as drop-outs. A total 79 patients in the microsphere group and 75 in the conventional adapalene group completed the study and were included in the efficacy assessment. Table 8 depicts the demographic data of the patients enrolled in the study. Both the groups were comparable with regard to age, sex and physical characteristics (Table 8).
Table 8: Demographic data of the patients enrolled in the study

Parameters microsphere Adapalene 0.1% gel conventional Adapalene 0.1% gel
No. of patients 88 87
@ Age (yrs)Mean + SDRange 20.01 +.4.15 13-34 yrs 17.32+2.74 12-26 yrs
©Weight (kg)Mean + SDRange 60.66 ±_13.78 35-88 kg 55.03 + 13.26 34-88 kg
@ Height (cm) Mean±_SD Range 163.34+10.00 126-185 cm 161.45+.7.93 120-181 cm
# Sex (%)Male : Female 37 (42): 51 (58) 39 (44.8): 48 (55.2)
@ By Student't' Test P > 0.05 Not Significant
# By Chi - Square Test
21

TABLE 9: Comparison of changes in mean scores after the treatment between two groups

Duration in weeks Mean papules(X±SD) Mean pustules(X±SD) Mean nodules(X±SD)
microsphereAdapalene().l%gel conventionalAdapalene 0.1%gel microsphereAdapalene0.1% gel conventionalAdapalene0.1%gel microsphere Adapalene0.1% gel conventionalAdapalene0.1% gel
Baseline 1 2 4 8 12 17.58 ± 7.65*13.49±7.45 *11.77±7.27 *10.51±6.83 *8.15±6.33 *5.73 ±5.13 17.15 ±8.03*13.37±7.95 * 12.16 ±8.06 *10.13±7.00 *8.15±5.29 *6.48±5.51 6.29 ±5.09 *4.40±3.92 *3.70±3.74 *3.01 ±3.35 *2.05 ± 2.44 *1.17 ± 1.86 6.21 ±4.32*4.52±3.87 *3.91 ±3.40 *2.93 ±3.12 *2.10±2.54 *1.64±1.85 0.71 ±1.03*0.43 ± 0.67*0.33±0.80*0.15±0.44*0.07±0.48*0.04±0.21 0.84 ±1.17 *0.71 ± 1.13*0.48±0.81 *0.38 ± 0.47 *0.15±0.45 *0.05 ± 0.59
ByANOVA *P<0.05 Significant within group
Between Group P > 0.05 Not Significant
Mean number of papules were 17.58 among microsphere Adapalene 0.1% gel and 17.15 in conventional Adapalene 0.1% gel at baseline which was same and difference was not significant. After treatment at the end of 1st week mean no. of papules had a significant fall in both the groups i.e. 23.3% among microsphere Adapalene 0.1% gel and 22.0% in conventional Adapalene 0.1% gel which was same and difference was not significant. At the end of 12th week fall were more among microsphere Adapalene 0.1% gel i.e. 67.4% as compared to 62.2% in conventional Adapalene 0.1% gel but difference was not significant. The mean numbers of pustules were 6.29 among microsphere Adapalene 0.1% gel and 6.21 in conventional Adapalene 0.1% gel at baseline which was comparable and not statistically different. After treatment at the end of 1st week mean number of pustules had a significant reduced in both the groups by. 30.0% in the microsphere Adapalene 0.1% gel and 27.2% in
22

conventional Adapalene 0.1% gel. The reduction was similar and difference was not statistically significant. At the end of 12th week fall were greater in the microsphere Adapalene 0.1% gel patients i.e. 81.4% as compared to 13.6% in conventional Adapalene 0.1 % gel although the difference was not statistically significant.
The mean numbers of nodules were 0.71 in the microsphere Adapalene 0.1%> gel group and 0.84 in conventional Adapalene 0.1% gel group at baseline which was comparable and not statistically significant. After treatment at the end of 1st week the mean number of nodules reduced significantly in both the groups by. 39.4% among microsphere Adapalene 0.1%> gel and 15.5%) in conventional Adapalene 0.1 % gel. Moreover the reduction in the microsphere Adapalene group was greater as compared to the conventional formulation and the difference between the two groups was statistically significant. However, at the end of the 12th week the reductions were 94.4%>in the microsphere Adapalene 0.1% gel as compared to 94.0% in conventional Adapalene 0.1% gel. Thus, at the end of the therapy the reductions in the number of nodules were comparable and not statistically significant.
TABLE 10: Comparison of changes in mean total inflammatory lesion count after the treatment between two groups

Duration in Weeks Mean totalinflammatory lesioncount(X + SD) Mean closed comedones(X±SD) Mean open comedones(X±SD)
microsphereAdapalene0.1% gel conventionalAdapalene0.1%gel microsphereAdapalene0.1% gel conventionalAdapalene0.1%gel microsphereAdapalene0.1% gel conventionalAdapalene0.1%gel
Baseline 23.81 ± 10.59 23.49 ± 11.03 16.56 ±13.03 18.54 ± 16.57 10.66 ± 10.02 9.64 ± 10.04
1 *17.76± 10.15 *18.09± 11.15 13.10 ± 10.99 15.60 ±15.75 9.33 ± 9.73 9.44 ± 11.71
2 * 15.51 ± 9.90 ♦16.31 ± 10.75 *11.01 ±10.65 *12.76± 13.43 *7.70±7.66 *6.26± 4.00
4 *13.22± 9.37 *13.15± 9.10 *8.17 + 8.03 *10.96± 13.70 *5.96±6.72 *4.81 ± 3.64
8 *10.02± 8.06 *10.03± 7.09 *7.04±6.95 *8.54± 11.41 *4.47±4.82 *3.71 + 2.95
23

12 *6.76±6.38 ♦7.81 ± 7.15 *4.93 ± 6.04 *5.53± 7.20 *3.09±4.07 *2.84 ± 2.45
ByANOVA *P < 0.05 Significant
Between Group P < 0.05 Significant
In this study group the mean number of total inflammatory lesion count were 23.81 in the microsphere Adapalene 0.1% gel and 23.49 in conventional Adapalene 0.1% gel at baseline which was similar and difference was not significant. After treatment at the end of 1st week the mean number of total inflammatory lesion count reduced significantly in both the groups by 25.4%o in the microsphere Adapalene 0.1%) gel group and 23.0%> in conventional Adapalene 0.1% gel group which was similar and statistically non-significant. At the end of 12th week the reduction was greater in the microsphere Adapalene 0.1%> gel group i.e., 71.6%) as compared to 66.7% in conventional Adapalene 0.1% gel and difference was statistically significant. (Table 10)
At baseline the mean number of open comedones were similar being 10.66 in patients treated with microsphere Adapalene 0.1% gel and 9.64 in patients treated with conventional Adapalene 0.1 % gel and the difference between groups was not statistically significant. After treatment at the end of the 2nd week the mean number of open comedones reduced significantly in both the groups by 27.8% among microsphere Adapalene 0.1%) gel and 35.1%) in conventional Adapalene 0.1% gel. However the difference in reduction between the two groups was not statistically significant. At the end of 12th week the reductions were 71.0% in the microsphere Adapalene 0.1% gel group as compared to 70.5% in conventional Adapalene 0.1%) gel which was also similar and did not attain statistical significance. (Table 10) Mean number of closed comedones were 16.56 among microsphere Adapalene 0.1% gel and 18.54 in conventional Adapalene 0.1% gel at baseline which was comparable and the difference between the two groups was not statistically significant. After treatment at the end of 2nd week mean no. of closed comedones had a fall in both the groups i.e. 33.5% among microsphere Adapalene 0.1% gel and 31.2% in conventional Adapalene 0.1%) gel which was same and difference was not significant. At the end of 12th week fall were more among microsphere Adapalene 0.1 % gel i.e. 50.7% as compared to 40.9% in conventional Adapalene 0.1% gel but difference was not significant. (Table 10)
24

Mean no. of closed comedones were 16.56 among microsphere Adapalene 0.1%) gel and 18.54 in conventional Adapalene 0.1 % gel at baseline which was same and difference was not significant. After treatment at the end of 2nd week mean no. of closed comedones had a fall in both the groups i.e. 33.5% among microsphere Adapalene 0.1% gel and 31.2% in conventional Adapalene 0.1% gel which was same and difference was not significant. At the end of 12th week fall were more among microsphere Adapalene 0.1 % gel i.e. 50.7% as compared to 40.9% in conventional Adapalene 0.1 % gel but difference was not significant. (Table 10)
TABLE 11: Comparison of changes in mean total lesion count after the treatment between two groups:

Duration in Weeks Mean Total Lesion Count (X±SDJ
microsphere Adapalene 0.1% gel conventional Adapalene 0.1% gel
Baseline 49.41 ± 15.97 51.30 ±16.81
1 *38.83± 15.14 *42.30± 16.67
2 *32.61 ± 15.46 *35.40± 17.28
4 *26.60 ± 14.99 *28.52± 19.45
8 *20.90± 13.11 *21.77± 13.76
12 *14.16± 10.99 *15.63± 12.14
By ANOVA *P < 0.05 Significant
Between group P > 0.05 Not significant
In this study group the mean number of total lesion count were 49.41 among microsphere Adapalene 0.1% gel and 51.30 in conventional Adapalene 0.1%) gel at baseline which were comparable and not statistically different. After treatment at the end of 1st week the mean number of total lesion count reduced significantly in both the groups by. 21.4%) among microsphere Adapalene 0.1% gel and 17.5%) in conventional Adapalene 0.1 %> gel. Although the reduction in the conventional group was lower, the difference between the two groups was not statistically significant. At the end of 12th week the reduction was greater in the microsphere Adapalene 0.1% gel i.e. 71.3% as compared to 69.5%) in conventional Adapalene 0.P/o gel, however the difference between the two groups was not statistically significant.
25

TABLE 12: Profile of adverse events:

Events microsphere Adapalene 0.1% gel (N = 88)) conventional Adapalene0.1% gel (N = 87)
Burning 25 28.4 27 31.0
Dryness 07 07.9 28 32.2
Pruritus/Itching 14 15.9 16 18.4
Scaling 23 26.1 32 36.8
Darkening of Face 01 01.1 -
Hyperpigmentation 02 02.3 01 01.1
Erythema 07 07.9 22 25.3
Oiliness - 07 08.0
No. ofPts 44 50.0 62 71.3
By Chi - Square Test P > 0.05 Not Significant
A total 50.0% of the total cases from microsphere Adapalene 0.1% gel reported a side effects which was low as compared to 71.3%> among conventional Adapalene 0.1%> gel. Of these the most common were burning, dryness and scaling followed by pruritus, erythema. The intensity of events were mild to moderate in all the cases in the microsphere adapalene gel treated group and the side effects disappeared with continued treatment. On the other hand side effects with conventional adapalene gel were of a moderate to severe intensity in many of the patients.
One of the centres reported that patients tolerated and accepted cosmetically the microsphere adapalene gel throughout the study period, while side effects like scaling and burning were noticed to a severe degree in four patients treated with conventional adapalene gel and therapy was actually stopped for two weeks in these patients and then restarted afterwards. In another centre there were 2 drop outs in the conventional adapalene gel arm due to severe erythema, burning and dryness.
The present study confirmed the efficacy of the microsphere adapalene in the treatment of mild to moderate acne. The efficacy was comparable to that of the conventional adapalene. Thus both the formulations were provided comparable reductions in the mean scores of papules, pustules, nodules, inflammatory and non-inflammatory lesions, open and closed comedones.
26

The present study showed that while having comparable efficacy, microsphere adapalene gel scores over the conventional adapalene by virtue of its better tolerability. Thus more number of patients in the conventional adapalene gel treated group (71.3%) reported adverse events compared to those treated with the microsphere formulation (50.0%). The irritation potential of adapalene is characterized by burning, erythema and pruritus/itching. In the present study the percentage incidence of burning, erythema and pruritus/itching was greater with conventional adapalene (74.7%) which occurred with greater severity, where as same was lower as observed in microsphere adapalene group (52.3%) and of mild degree not requiring discontinuation of therapy. The reason for the reduction in the incidence and severity of these symptoms of irritation with the microsphere adapalene formulation could be attributed to the fact that microspherization ensures that the absorption of adapalene takes place in a time controlled manner. This in turn reduces the undesirable exposure of the skin to the drug. Furthermore 8% of the patients treated with conventional adapalene group reported oiliness as compared to none in the microsphere group. This could be further attributed to the property of the microsphere formulation to reduce facial shine. This property of microsphere adapalene to reduce facial shine may enhance patient adherence to the treatment regimen. More number of patients in the conventional adapalene group had to discontinue therapy in the middle of the study due to severe irritation while such a thing did not happen in those who were treated with the microsphere adapalene.
Thus, in conclusion, therapy with the microsphere adapalene provides a better tolerability with minimal irritation compared to conventional adapalene, without compromising on the efficacy. It could thus serve as a better therapeutic option in the therapy of acne vulgaris. It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. For example, the functions described above and implemented as the best mode for operating the present invention are for illustration purposes only. Other arrangements and methods may be implemented by those skilled in the art without departing from the scope and spirit of this invention.
27

We claim:
1. A topical pharmaceutical composition comprising an effective amount of adapalene microsphere in a suitable pharmaceutically acceptable carrier for the treatment of acne vulgaris.
2. A topical pharmaceutical composition, according to claim 2, wherein the microsphere adapalene is formulated as Adapalene gel.
3. A topical pharmaceutical composition, according to claim 2, wherein the microsphere adapalene is present in the concentration of 0.1 % formulated as Adapalene gel.
4. A topical pharmaceutical composition comprising microsphere adapalene gel having less irritation potential in comparison to plain Adapalene gel.
5. A topical pharmaceutical composition according to claim 4 wherein microsphere adapalene gel and plain Adapalene gel is in the concentration of 0.1%.
6. A topical pharmaceutical composition according to claim 4 wherein the irritation potential is characterized by burning, erythema and pruritus.
7. A process of preparing the adapalene microsphere compositions comprising the steps of: a) impregnation of adapalene into plain microspheres employing a solvent system and b) incorporation of adapalene microspheres into a suitable carrier.
8. A process of preparing the adapalene microsphere compositions according to claim 7, wherein the microsphere adapalene is present in the concentration of 0.1 % formulated as Adapalene gel.
9. A topical pharmaceutical composition according to claims 1 and 7, where in the pharmaceutically acceptable carrier is selected from polymers, buffering agents, surfactants, viscolyting agents/gelling, chelating agents, preservatives, and suitable solvents thereof.
10. A method of treating acne vulgaris in a human subject, wherein said method comprises, topically administering a pharmaceutical composition comprising Adapalene microspheres gel present in the concentration of 0.1%.
28




29

ABSTRACT
A topical pharmaceutical microsphere composition comprising an active ingredient such as adapalene in a suitable carrier is provided. There is also provided a method of treating acne by administering the said composition to the patient's skin in need of treatment. Topical adapalene microsphere composition of the present invention provides less irritation to the patient's skin as compared to the conventional topical delivery systems.
Dated this twenty third (23rd) day of August, 2007

1