WO1994007478A1

WO1994007478A1 - Topical pharmaceutical compositions

Info

Publication number: WO1994007478A1
Application number: PCT/US1993/009292
Authority: WO
Inventors: Lorraine E. Pena
Original assignee: The Upjohn Company
Priority date: 1992-10-06
Filing date: 1993-10-05
Publication date: 1994-04-14
Also published as: AU5294393A

Abstract

The present invention provides topical, non-aqueous pharmaceutical compositions containing about 10 % to about 80 % W/W of a pharmaceutically acceptable noncomedogenic cosmetic oil and ethanol or isopropanol. The compositions provided for improved stability and delivery of the drug to the site of action (e.g. hair follicle and sebaceous gland) without excessive greasiness and/or untoward drying effects. The compositions are also provided for an anti-inflammatory effect and reduced irritation when clindamycin is used in combination with retinoids. The topical pharmaceutical compositions of the present invention can optionally contain propylene glycol and/or polyethylene glycol and/or a pharmaceutically acceptable organic amine. In addition, the topical pharmaceutical compositions of the present invention can optionally be gelled with suitable gelling agents, including for example hydroxypropylcellulose.

Description

TOPICAL PHARMACEUTICAL COMPOSITIONS INTRODUCTION

The present invention relates to an improved vehicle for administration of topical drugs, susceptible to oxidative and/or hydrolytic degradation, more particularly stable clindamycin and/or retinoid pharmaceutical compositions for topical administration, which contain clindamycin free base, clindamycin hydrochloride, clindamycin phosphate or clindamycin palmitate hydrochloride. Drugs which are not susceptible to oxidative and/or hydrolytic degradation, but which benefit from facilitated delivery to the site of action (e.g. hair follicle and sebaceous gland) can be incorporated in the improved vehicle of the present invention. The invention also relates to compositions of clindamycin and retinoids in which the clindamycin exhibits an anti-inflammatory effect to reduce the irritation associated with retinoids.

BACKGROUND OF THE INVENTION Clindamycin is an antibiotic also known as methyl 7-chloro-6,7,8-trideoxy-6-(l-methyl- trans-4-propyl-L-2-pyrrolidinecarboxamido)- 1 -thio-L-threo-α-D-galacto-octo-pyranoside or methyl 7-chloro-6,7,8-trideoxy-6-[[(l-methyl-4-propyl-2-pyrrolidinyl)carbonyl]amino]-l-thio-L- threo-α-D-galacto-octo-pyranoside.

Clindamycin Hydrochloride (Clindamycin Hydrochloride, U.S.P.) is the hydrated hydrochloride salt of clindamycin. Clindamycin Hydrochloride is also known as methyl 7-chloro-6,7,8-trideoxy-6-(l-memyl-trans* -propyl-L-2-pyrroIidinecarrx)xamido)-l-thio-L-l_hreo- α-D-galacto-octo-pyranoside monohydrochloride.

Clindamycin Phosphate (Clindamycin Phosphate, U.S.P.) is a water soluble ester of clindamycin. Clindamycin Phosphate is also known as methyl 7-chloro-6,7,8-trideoxy-6-(l- methyl-trans* -propyl-L-2-pyrrolidinecarboxamido)-l-thio-L-threo-α-D-galacto-octo-pyranoside 2-(dihydrogen phosphate). Clindamycin palmitate is also known as methyl 7-chloro-6,7,8-trideoxy-6-(l-methyl- trans-4-propyl-L-2-pyrrolidinecart)θxamido)-l-thio-L-threo-α-D-galacto-octo-pyranoside 2-palmitate or methyl 7-chloro-6,7,8-trideoxy-6-[[(l-methyl-4-propyl-2-pyrrolidinyl)carbonyl] amino]- 1 -thio-L-threo-α-D-galacto-octo-pyranoside 2-palmitate.

Clindamycin palmitate hydrochloride (Clindamycin Palmitate Hydrochloride, U.S.P.) is also known as methyl 7-chloro-6,7,8-trideoxy-6-(l-methyl-trans-4-propyl-L-2-pyrrolidine- carboxamido)-l-thio-L-threo-α-D-galacto-octo-pyranoside 2-palmitate monohydrochloride or methyl 7-cWoro-6,7,8-trideoxy-6-[[(l-methyl-4-propyl-2-pyrrolidinyl)carbonyl]amino]-l-thio-L- threo-α-D-galacto-octo-pyranoside 2-palmitate monohydrochloride. ^"

The uses, properties and methods of synthesis, of clindamycin, clindamycin palmitate, clindamycin hydrochloride and clindamycin phosphate are set forth in U.S. Patent 3,969,516, Stoughton, issued July 13, 1976; Magerlein, et al, Antimicro. Ag. Chemother. (1966) 727; U.S. Patent 3,475,407, Bierkenmeyer, issued in 1969; U.S. Patent 3,487,068, issued in 1969; U.S. Patent 3,509,127 and 3,544,551, Kagan and Magerlein, issued in 1970; U.S. Patent 3,513,155. Bierkenmeyer and Kagan, issued in 1970; Morozowich and Sinkula, U.S. Patent 3,508,904 issued in 1971 and 3,655,885 issued in 1972; U.S. Patent 3,714,141, issued in 1973; U.S. Patent 4,568,741 issued in 1986; U.S. Patent 4,710,565, issued in 1984; Birkenmeyer and Kagan, J. Med. Chem., 13, 616 (1970); Oesterling, J. Pharm Sci. 59, 63 (1970); McGehee, et al, Am. J. Med. Sci. 256, 279 (1968); D.A. Leigh, J. Antimicrob. Chemother. 7 (Supplement A), 3 (1981); JE Gray et al. Toxicol. Appl. Pharmacol. 21, 516 (1972) and LW Brown and WF Beyer in Analytical Profiles of Drug Substances, Vol 10, K. Florey, editor (Academic Press, New York, 1981) pages 75-91, (all of the foregoing references being incorporated herein by reference.) CLEOCIN T® brand clindamycin phosphate topical solution, topical gel and topical lotion are commercially available. CLEOCIN T Topical Solution contains clindamycin phosphate (equivalent to 10 mg. clindamycin per milliliter), isopropyl alcohol 50% v/v, propylene glycol, and water. CLEOCIN T Topical Gel contains clindamycin phosphate (equivalent to 10 mg. clindamycin per milliliter), allantoin, carbomer 934P, methylparaben, polyethylene glycol 400, propylene glycol, sodium hydroxide, and purified water. CLEOCIN T Lotion contains clindamycin phosphate (equivalent to 10 mg. clindamycin per milliliter), cetostearyl alcohol (2.5%), glycerin, glyceryl stearate SE (with potassium monostearate), isostearyl alcohol (2.5%), methylparaben (0.3%), sodium lauroyl sarcosinate, stearic acid and purified water.

"Retinoid" includes all natural and/or synthetic analogs of Vitamin A or retinol-like compounds which possess the biological activity of Vitamin A in the skin as well as the geometric isomers and stereoisomers of these compounds, such as all-trans retinoic acid (more preferably, Tretinoin, U.S.P.), all trans-retinoic acetate, retinaldehyde, 13-cis-retinoic acid, retinoic acid ethylamide, retinoic acid 2-hydroxyethyl amide, retinoic acid p-hydroxyphenyl- amide, axerophthene, retinal, retinol, retinyl methylether, β-all trans-retinoic acid, 7,8-dehydro analog of retinoic acid, 5,6-epoxy analog of retinoic acid, retinyl methylthioether, 4-oxo analog of retinoic acid, N-methyl dimethyl doxolan retinamide, retinyl n-butyl ether, N-(0-carboxy- phenyl) retinamide, retinyl tert-butyl ether, retinylacetate, N-(p-carboxyphenyl) retinamide, N-benzoyl retinylamide, retinyl palmitate, retinylidene ethylcyano acetate.

RETIN-A® brand tretinoin gel, cream and liquid are commercially available. RETIN-A Gel contains tretinoin in either of two strengths, 0.025% or 0.01% by weight, in a gel vehicle of butylated hydroxytoluene, hydroxypropyl cellulose and alcohol (denatured with tert-butyl alcohol and brucine sulfate) 90% w/w. RETIN-A Cream contains tretinoin in either of three strengths, 0.1%, 0.05% or 0.025% by weight, in a hydrophilic cream vehicle of stearic acid, isopropyl myristate, polyoxyl 40 stearate, stearyl alcohol, xanthan gum, sorbic acid, butylated hydroxytoluene, and purified water. RETIN-A Liquid contains tretinoin 0.05% by weight, polyethylene glycol 400, butylated hydroxytoluene and alcohol (denatured with tert-butyl alcohol and brucine sulfate) 55%.

Octyl isononanoate (also known as Ethylhexyl Isononanoate, 2-Ethylhexyl Ester Isononanoic Acid) is the ester of 2-ethylhexyl alcohol and a branched chain nonanoic acid and has the structure

Octyl isononanoate (CAS 71566-49-9) is commercially available as Deπnol 89 (Alzo), Isolanoate (Lanaetex), Kessco Octyl Isononanoate (Stepan), Pelemol 89 (Phoenix) and Witconol 2300 (Witco Organics).

Caprylic/capric triglyceride (also known as octanoic/decanoic acid triglyceride) is the mixed triester of glycerin and caprylic and capric acids. Caprylic/capric triglyceride (CAS 65381-09-1) is commercially available as Lexol GT-865 (Inolex), Miglyol 810 Neutral Oil (Hiils America), Miglyol 812 Neutral Oil (Huls America), Myritol 318 (Henkel) and Neobee M-5 (Stepan).

Cyclomethicone (also known as volatile silicone) is a cyclic dimethyl polysiloxane compound that has the structure

where n averages between 3 and 6. Cyclomethicone (CAS 69430-24-6) is available commercially as Dow Coming 244 Fluid (Dow Corning), Dow Corning 245 Fluid (Dow Coming), Dow Corning 344 Fluid (Dow Corning), Dow Corning 345 Fluid (Dow Coming), Volatile Silicone 7158 (Union Carbide), Volatile Silicone 7207 (Union Carbide), and Volatile Silicone 7349 (Union Carbide). Diisopropanolamine is also known as DD?A, lJ '-iminobis-2-propanol or 2-propanol, lJ '-iminobis) and is commercially available by its generic name from Dow Chemical Company or as Unichem DIPA from Universal Preserv-a-chem, Inc..

Triisopropanolamine (also known as TIPA, lJ'J"-Nitrilotris-2-propanol or 2-propanol, lJ'J"-nitrilotris) is commercially available by its generic name from Dow Chemical Company or as Unichem TIPA from Universal Preserv-a-chem, Inc. Tetrahydroxypropyl ethylenediamine is commercially available as Quadrol or Neutral TE from BASF.

US 3,972,914 and US 4,126,702 are cited in the labeling of a commercial product (Lancome, Clarifiance Oil-Free Hydrating Fluide) which contains cyclomethicone and caprylic/capric triglycerides in an O/W emulsion. These patents describe novel derivatives of glycerol and bear no relationship to the present invention.

Canadian Patent 1253807 describes a topical composition for protection, care and treatment of human skin or hair. The composition contains caprylic/capric triglyceride, lanolin alcohol, squalene and die balance at least one cosmetic or pharmaceutical additive or carrier. While the use of drugs, including antibiotics, in the composition is claimed, no claims are made regarding improved stability. Additionally, die composition does not contain either ethanol or isopropanol.

EP 0 164 716 describes stable clear benzoyl peroxide formulations in short chain triglycerides (C₈-C₁₀). The formulations also contain volatile silicone, but do not contain ethanol or isopropyl alcohol and no other drugs are claimed. EP 0 410 099 Al describes stable tetracycline gels which contain volatile silicone and an emollient ester as cosolvents with polyethylene derivatives as the gelling agent. Neither ethanol nor isopropyl alcohol are used in the gels and the list of emollient esters does not include octyl isononanoate. No other drugs are claimed.

US 4,725,429 and WO 85103434 describe topical anti-acne stick formulations containing volatile silicone which demonstrate enhanced delivery. Apart from containing volatile silicone, the formulations bear no resemblance to the present invention.

US 4,720,353, US 4,613,592 and EP 0150 914 describe water/oil emulsions containing volatile silicone while US 4,917,891 describes a non-comedogenic oil/water emulsion with volatile silicone. While the proposed uses of the compositions are for the treatment of acne, the compositions bear no resemblance to the nonaqueous present invention in that each of the cited references contains water.

US 4,515,784 describes a method and composition for reducing sebum spreading and uses a straight chain dimethyl silicone polymer of MW about 50,000 for this purpose. The composition contains 3-15% volatile silicone to solubilize this polymer. A topical anti-acne composition is claimed, but specific drugs are not mentioned. The focus of the cited reference is the silicone polymer. The volatile silicone (including, for example, cyclodimethicone pentamer or cyclodimethicone tetramer or mixtures thereof) acts as the solubilizer/carrier vehicle for the polymer.

US 4,908,355 describes a method for treating skin disorders. An antibacterially effective amount of a silane and a water immiscible liquid are claimed with the silane being an organosilicon quaternary ammonium compound. The cited reference claims a series of organosilicon quaternary ammonium compounds and further claims their use with abrasives, astringents and fragrances and specifies the polysiloxane to be polydimethylcyclosiloxane. Highly volatile low viscosity low molecular weight silicone fluids (such as siloxanes) are disclosed as the driving force for causing anti -microbial agents to penetrate downwardly within the sebaceous gland.

EP 90 10 96 31 describes topical compositions for the treatment of acne which contain LYCD (live yeast cell derivative) and claims the use of erythromycin, lincomycin hydrochloride, clindamycin phosphate, benzoyl peroxide and retinoic acid in the compositions. The formulations of the compositions bear no resemblance to the present invention. US 5,017,366 describes pharmaceutical compositions containing UV blockers in an alcoholic vehicle with erythromycin. The composition is intended for morning use for patients using an evening application of a tretinoin product The composition does not contain tretinoin and claims no other drugs.

US 4,727,088-A describes stick formulations for retinoids which contain volatile silicone. Apart from the presence of volatile silicone, the compositions bear no similarity to the present invention.

WO 90/14833 and EP 0 408 370 A2 describe stable tretinoin aqueous gels and creams, respectively. EP 0 393 904 describes a water based moisturizing vehicle for topical application of tretinoin which is oil, fat and alcohol free. None of the cited references bear any resemblance to the present nonaqueous invention.

DE 3714937 Al describes esters of retinoic acid formed with clindamycin, lincomycin or erythromycin. The present invention cites retinoic acid, clindamycin, lincomycin and erythromycin as individual entities.

International Publication No. WO 88/01502 discloses sebum-dissolving nonaqueous minoxidil formulations comprising minoxidil, a solvent for minoxidil (e.g. ethanol, isopropanol or propylene glycol), a non-polar solvent which renders the formulation approximately the same polarity as human sebum (e.g. volatile silicone oils such as Dow Coming 344 Fluid, Dow Corning 345 Fluid or less volatile silicone oils such as Dow Coming 200 fluids of various viscosities), and a cosolvent having a polarity between that of the solvent capable of dissolving minoxidil and the non-polar solvent such as butanol, hexanol, octanol, decanol, dodecanol and oleyl alcohol; amines, such as isopropyl amine, diisopropyl amine, triethyl amine, triethanol amine and ethylene diamine; carboxylic acids, such as oleic acid, linoleic acid and linolenic acid; esters, such as dibutyl sebacate, dibutyl phthalate, butyl benzoate and ethyl caprate; and others, such as AZONE®, N methyl pyrolidone, bile salts and urea. Oleyl alcohol is the preferred cosolvent. US 4,642,316 discloses the use of amines as complexing agents with phenytoin in injectable solutions which may be freeze dried. The present invention is intended for topical application and is nonaqueous.

US 4,469,684 discloses a zinc erythromycin composition for acne which contains a solvent of a specified dielectric constant (t-butanol) and a nitrogen containing stabilizer such as diisopropanolamine. Apart from the presence of erythromycin and diisopropanolamine in the disclosure, this patent bears no resemblance to the present invention.

Organic amines are commonly used to neutralize polymers as a means of gel formation. US 5,225,189 discloses the use of water and alcohol soluble amines such as diisopropanolamine to neutralize carbomer in a gel containing minoxidil. AU 9056687 discloses the use of diisopropanolamine to adjust the pH of an aqueous retinoic acid gel containing an acrylic acid polymer as the gelling agent and beta-cyclodextrin as a solubilizing/stabilizing agent. The Japanese application J62051619, Derwent No. 87-104735/15, describes an aqueous clindamycin gel using carboxyvinyl polymers, but does not list alkanolamines specifically as neutralizing agents. Neither the Australian nor the Japanese applications demonstrate prior art to the present invention because they are both aqueous systems. The following patents or applications all demonstrate the use of alkanolamines such as diisopropanolamine to neutralize carboxyvinyl or acrylic acid polymers to form topical gels, ointments or creams: Derwent 92-403378/49, Derwent 92-255645/31, Derwent 92-044318/06, Derwent 91-167138/23, US 4983386, US 4670254, J 90026603, Derwent 86-152475/24, JP 92063852, US 4533546, US 4543251, Derwent 84-137161/22, Derwent 84-110773/18, US 4393076, J 89034968, Derwent 80-44041C, Derwent 88-358512/50, JP 82-115959, EP 151953 A2 and JP 86-140896. None of these citations demonstrate prior art to the present nonaqueous invention because they are all aqueous systems.

GB 1042529 describes a dimethyl sulphoxide composition containing carbopol and diisopropanolamine in a nonaqueous system which when in contact with water generates heat. Although the composition is nonaqueous and intended for topical use, the major point being demonstrated is the generation of heat. Thus, this citation bears no resemblance to the present invention.

J90036570 uses diisopropanolamine as a pH adjusting agent in aqueous topical systems and bears no resemblance to the present invention.

J62228027 demonstrates the use of amines as absorption promoters in topical medications which preferably contain an aqueous base. The present invention uses amines to solubilize clindamycin hydrochloride and clindamycin phosphate in nonaqueous systems designed to target drug delivery to the sebaceous gland.

US 5,116,621 use amines as pH adjusters for an acrylic acid polymer in preparation of transdermal patches and bears no resemblance to the present invention.

M.A. El-Nakeeb and R.T. Yousef, Acta Pharm. Suecica 5, 1 (1968), demonstrate that polyethylene glycol 4000 does not interfere with the antimicrobial activity of erythromycin.

SUMMARY OF THE INVENTION It has unexpectedly been discovered that topical, non-aqueous pharmaceutical compositions containing about 5% to about 90% w/w, preferably 10% to about 80% w/w, more preferably 20% to about 50%, most preferably about 40% w/w of a pharmaceutically acceptable noncomedogenic cosmetic oil [including, for example, fatty acid triglycerides (e.g. a caprylic/ capric triglyceride such as Miglyol 812), volatile silicones (e.g. cyclomethicone such as Dow Coming 344 Fluid), fatty acid esters (e.g. octyl isononanoate), fatty alcohols (e.g. isostearyl alcohol) and natural oils (e.g. olive oil)] and ethanol (e.g. Alcohol USP) or isopropanol (e.g. Isopropyl Alcohol USP) provides for dramatically improved stability and delivery of the drug to the site of action (e.g. hair follicle and sebaceous gland) without excessive greasiness and/or untoward drying effects.

It has unexpectedly been discovered that the use of clindamycin (in particular, clindamycin hydrochloride) in combination with retinoic acid exhibits an anti-inflammatory effect and reduces the irritation associated with the use of retinoids.

Optionally, clindamycin HCl/clindamycin phosphate and retinoic acid can be incorporated in the above vehicle devoid of a noncomedogenic oil provided the clindamycin is solubilized with a suitable organic amine, preferably diisopropanolamine. Suitable formulations of this aspect of the invention include compositions containing a) from about 0% to about 15% propylene glycol, preferably about 0% to about 5%, b) a pharmaceutically acceptable organic amine in a molar ratio from about 1 to about 3 to clindamycin hydrochloride or clindamycin phosphate to solubilize these drugs in the vehicle. Suitable pharmaceutically acceptable organic amines include 2-aminobutanol, aminoethyl propanediol, aminomethyl propanediol, aminomethyl propanol, dietiianolamine, ethanolamine, isopropanolamine, methylethanolamine, diisopropylamine, dipropylenetriamine, mixed isopropanolamines, tromethamine, isopropylamine ethylene diamine, triethylamine and morpholine preferably, triisopropanolamine and tetrahydroxypropyl ethylenediamine (e.g. Quadrol or Neutral TE), more preferably diisopropanolamine. Triethanolamine is not a suitable organic amine since in excess of a 4 to 1 molar ratio to clindamycin hydrochloride or clindamycin phosphate fails to solubilize the drug. Optionally, clindamycin palmitate hydrochloride and retinoic acid can be incorporated in the above vehicle (devoid of a noncomedogenic oil) provided the clindamycin palmitate hydrochloride is solubilized with propylene glycol.

The topical pharmaceutical compositions of the present invention can optionally contain propylene glycol, polyethylene glycol and/or a pharmaceutically acceptable organic amine. Propylene glycol is required to solubilize clindamycin palmitate hydrochloride in die topical pharmaceutical compositions of the present invention containing clindamycin palmitate hydrochloride. A pharmaceutically acceptable organic amine [including for example, diisopropanolamine (DIP A), triisopropanolamine (TIPA) and tetrahydroxypropyl ethylenediamine (Quadrol or Neutral TE)] is required to solubilize clindamycin hydrochloride or clindamycin phosphate, if utilized, in the topical pharmaceutical compositions of the present invention. In addition, the topical pharmaceutical compositions of the present invention can optionally be gelled with suitable gelling agents, including for example hydroxypropylcellulose (e.g. Klucel MF NF).

DETAILED DESCRIPTION OF THE INVENTION The topical pharmaceutical compositions of the present invention comprise:

(a) a drug;

(b) from about 5% to about 90% w/w of a pharmaceutically acceptable noncomedogenic, sebum dissolving cosmetic oil;

(c) from about 10% to about 95% w/w an alcohol selected from the group consisting of ethanol or isopropyl alcohol; with the proviso that when the drug is minoxidil, the cosmetic oil is other than a silicone fluid; and

(d) a pharmaceutically acceptable organic amine in a molar ratio from about 1 to about 3 to solubilize clindamycin hydrochloride or clindamycin phosphate, if present, in the vehicle. Suitable pharmaceutically acceptable organic amines include diisopropanolamine, triisopropanolamine and tetrahydroxypropyl ethylenediamine (Quadrol or Neutral TE).

An embodiment of the present invention are topical pharmaceutical compositions comprising:

(a) a drug susceptible to oxidative or hydrolytic degradation;

(b) from about 5% to about 90% w/w of a pharmaceutically acceptable noncomedogenic, sebum dissolving cosmetic oil; and

(c) from about 10% to about 95% w/w an alcohol selected from the group consisting of ethanol or isopropyl alcohol; with the proviso that when the drug is minoxidil, the cosmetic oil is other than a silicone fluid.

A preferred embodiment of the present invention are topical pharmaceutical compositions comprising:

(a) a drug selected from the group consisting of (i) from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA-S, (ii) from about 0.001% to about 2% w/w of a retinoid, or (iii) a combination of from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C_{] 8}H₃₃C1N₂0₅S)] of CLINDA-S and from about 0.001% to about 2% w/w of a retinoid; (b) from about 5% to about 90% w/w of a pharmaceutically acceptable noncomedogenic, sebum dissolving cosmetic oil; and

(c) from about 10% to about 95% w/w an alcohol selected from the group consisting of ethanol or isopropyl alcohol.

(a) a drug selected from the group consisting of (i) from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA-SS, (ii) from about 0.001% to about 2% w/w of a retinoid, or (iii) a combination of from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA- SS and from about 0.001% to about 2% w/w of a retinoid ;

(c) from about 10% to about 95% w/w an alcohol selected from the group consisting of ethanol or isopropyl alcohol and (d) a suitable pharmaceutically acceptable organic amine in a molar ratio of about 1 to about 3 on the basis of CLINDA-SS.

A more preferred embodiment of the present invention are topical pharmaceutical compositions comprising:

(a) a drug selected from the group consisting of (i) from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C_j8H₃₃ClN₂0₅S)] of CLINDA-SS, (ii) from about 0.001% to about 2% w/w of a retinoid, or (iii) a combination of from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA- SS and from about 0.001% to about 2% w/w of a retinoid;

(b) from about 10% to about 80% w/w of a pharmaceutically acceptable noncomedogenic, sebum dissolving cosmetic oil;

(c) from about 10% to about 85% w/w an alcohol selected from the group consisting of ethanol or isopropanol; and

(d) a pharmaceutically acceptable organic amine in a molar^" ratio of about 1 to about 3 on the basis of CLINDA-SS. A further embodiment of the present invention are topical pharmaceutical compositions comprising: (a) a drug selected from the group consisting of (i) from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA-SS, (ii) from about 0.001% to about 2% w/w of a retinoid, or (iii) a combination of from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0 S)] of CLINDA- SS and from about 0.001% to about 2% w/w of a retinoid;

(b) from about 10% to about 95% w/w an alcohol selected from the group consisting of ethanol or isopropanol; and

(c) a suitable pharmaceutically acceptable organic amine in a molar ratio of about 1 to about 3 on the basis of CLINDA-SS. An additional embodiment of die present invention are topical pharmaceutical compositions comprising:

(a) a drug selected from the group consisting of (i) from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA-S, (ii) from about 0.001% to about 2% w/w of a retinoid, or (iii) a combination of from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA-S and from about 0.001% to about 2% w/w of a retinoid; and

(b) from about 10% to about 95% w/w an alcohol selected from the group consisting of ethanol or isopropanol.

Drugs susceptible to oxidative or hydrolytic degradation include, but are not limited to, antibiotics of the lincomycin family (e.g. lincomycin and clindamycin); macrolide antibiotics (e.g erythromycin, carbomycin, oleandomycin, spiramycin); tetracycline antibiotics (e.g. minocycline hydrochloride, oxytetracycline, chlortetracycline, doxycycline, demeclocycline, methacycline); aminocyclitol antibiotics (e.g. spectinomycin, trospectomycin);retinoids (e.g. all trans-retinoic acid); vitamins (e.g. Vitamin A, D, E and oil/alcohol soluble vitamin C derivatives); therapeutic antioxidants for die treatment of psoriasis/inflammation (e.g. tirilazad also known as 16α-methyl-21-[4-[2,6-bis(l-pyrrolidinyl)-4-pyrimidinyl]-l-piperazinyl]pregna- 1,4,9(1 l)-triene-3,20-dione, see Intemational Publication No. WO87/01706, published March 26, 1987 based on Intemational Patent Application No. PCT/US86/01797, EXAMPLE 109; tirilazad mesylate; (-) enantiomer of 2-[[4-(2,6-Bis-(l-pyπOlidinyl)* -pyrimidinyl)-l-piperazinyl]methyl]- 3,4-dihydro-2,5,7,8-tetramethyl-2H-l-benzopyran-6-ol, see Example 21, Intemational Application Serial No PCT/US88/01212, filed 4-20-88, Intemational Publication No WO88/08424, published 11-3-88); 6,7-dimethyl-2,4-di-l-pyrrolidinyl-7H-pyrrolo(2,3-d)pyrimidine, see Example 52, U.S. Patent Application 07/863,646, filed 3 April 1992 and incorporated herein by reference; or 6,7-dimethyl-2,4-di-l-pyrrolidinyl-7H-pyrrolo(2,3-d)pyrimidine mesylate, see Example 53, U.S. Patent Application 07/863646, filed 3 April 1992); local anesthetics (e.g. benzocaine) and antineoplastics (e.g. fluorouracil). Drugs not susceptible to oxidative or hydrolytic degradation but benefit from facilitated delivery by the vehicle include, but are not limited to hair growtii promoters (e.g. minoxidil and its analogs, N-cyano-N'-(lJ-dimethylpropyl)-N"-3-pyridinyl-guanidine (also known as P-1075, see U.S. Patent Re: 31,244), hair growth inhibitors (e.g 6-α-fluoro- 17,21 -dihydroxy-16β- methylpregna-4,9(l l)-diene-3,20-dione; see Intemational Patent Application PCT/US90/00812, Intemational Publication No. WO90/12577), anti-inflammatories (e.g. hydrocortisone, methylprednisolone, flurbiprofen, ibuprofen), keratolytics (e.g. salicylic acid); and antiandrogens (e.g. cioteronel, spironolactone, inocoterone acetate and cyproterone acetate).

In addition, the vehicle of the present invention can be utilized to incorporate other topical agents, including e.g. sunscreens (e.g. PABA derivatives, benzophenone derivatives), antihistamines (e.g. diphenhydramine) and antifungals (e.g. miconazole nitrate, tolnaftate) which would benefit from the non-greasy/non-drying attributes of the improved vehicle of the present invention.

The term "CLINDA-S" as used in d e specification and claims refers to clindamycin and clindamycin analogs and salts thereof (including ti ose disclosed in U.S. Patent Nos. 3,580,904 and 3,655,885) having a solubility in Alcohol USP (ethanol) or Isopropyl Alcohol USP (2-propanol, Isopropanol) of greater than 1.75 mg/ml or 0J5 mg/ml, respectively. CLINDA-S includes clindamycin free base, clindamycin palmitate and clindamycin palmitate hydrochloride (solubilized with about 5.0% to about 15% propylene glycol, preferably about 5% propylene glycol). CLINDA-S does not include clindamycin phosphate or clindamycin hydrochloride since tiiese compounds are relatively insoluble in Alcohol USP and Isopropyl Alcohol USP. CLINDA-S is expressed on a % w/w basis, calculated on the basis of clindamycin equivalents.

The term "CLINDA-SS" as used in the specification and claims refers to clindamycin hydrochloride and clindamycin phosphate when solubilized with a pharmaceutically acceptable organic amine in a molar ratio of about 1 to about 3 to CLINDA-SS. CLINDA-SS is expressed on a % w/w basis, calculated on die basis of clindamycin equivalents.

The teπn "suitable pharmaceutically acceptable organic amines" refers to an organic amine suitable to solubilize relatively insoluble forms of clindamycin, e.g. clindamycin hydrochloride and clindamycin phosphate. The term "suitable pharmaceutically acceptable organic amines" includes diisopropanolamine, triisopropanolamine and tetrahydroxypropyl ethylenediamine (e.g. Quadrol or Neutrol TE).

The term "cosmetic oil" as used in the specification and claims includes those oils which are noncomedogenic, sebum dissolving and either evaporate or readily rub into the skin upon application such tiiat a greasy residue does not remain. The term "cosmetic oil" also includes isostearyl alcohol, C₁₂-C₁₅ alkyl benzoate (e.g. FINSOLV brand) or olive oil.

Comedogenicity of a cosmetic oil can be readily determined by the standard rabbit ear model, A.M. Kligman and A.G. Katz, Arch. Der. 98, 53 (1968). Sebum dissolving ability of a cosmetic oil can be readily determined by Test Procedure A. Sebum dissolving cosmetic oils of the present invention with dissolved sebum have a refractive index difference of greater than 0.0005 (more preferably greater than about 0.001) when compared to the refractive index of the pure oil.

Pharmaceutically acceptable noncomedogenic, sebum dissolving cosmetic oils include, for example, fatty acid triglycerides (e.g. a caprylic/capric triglyceride such as Lexol GT-865, Miglyol 810, Myritol 318 and Neobee M-5, preferably Miglyol 812; and caprylic/capric linoleic triglyceride), volatile silicones (e.g. cyclomethicone such as Dow Corning Fluids 244, 245, 344 or 345; Union Carbide Volatile Silicone 7158, 7207 or 7349, preferably Dow Coming 344 Fluid), fatty acid esters (e.g. octyl isononanoate, isononyl isononanoate, propylene glycol ricinoleate, glyceryl triacetyl hydroxystearate, octyl palmitate, propylene glycol dicaprylate/ dicaprate, propylene glycol dioctanoate or isostearyl neopentanoate), liquid fatty alcohols (e.g. oleyl alcohol) and natural oils. Preferred cosmetic oils include fatty acid triglycerides (more preferably a caprylic/capric triglyceride), fatty acid esters (more preferably octyl isononanoate) and volatile silicones (more preferably cyclomethicone, including for example cyclodimethicone pentamer, cyclodimethicone tetramer and mixtures thereof).

The non-aqueous topical compositions of die present invention contain from about 5% to about 90% w/w, preferably 10% to 80 %, more preferably 20% to about 50%, most preferably about 40%, of a suitable noncomedogenic, sebum dissolving cosmetic oil.

The non-aqueous topical compositions of die present invention optionally contain from about 2 % to about 15% w/w, preferably about 4 % to 15 %, of propylene glycol.

Compositions of the present invention containing clindamycin palmitate hydrochloride can have an amount in excess of the amount required to solubilize d e clindamycin palmitate hydrochloride. Total propylene glycol content not to exceed about 15% w/w.

The non-aqueous topical compositions of the present invention optionally contain from about 1 % to about 10% w/w, preferably from about 5 % to about 10 %, of a liquid polyediylene glycol more preferably polyethylene glycol 400. Liquid polyetiiylene glycols have an average molecular weight of about 200 to about 900. In addition, d e non-aqueous topical compositions of die present invention optionally contain an antioxidant selected from the group consisting of butylated hydroxytoluene, butylated hydroxyanisole, tocopherol and propyl gallate.

The non-aqueous topical clindamycin compositions of the present invention contain from about 0.05 % to about 5 % w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA-S, preferably 0.5 % to 2 % [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)], of clindamycin palmitate monohydrochloride (solubilized widi a sufficient quantity of propylene glycol) or clindamycin free base.

The non-aqueous topical clindamycin compositions of die present invention contain from about 0.05 % to about 5 % w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA-SS, preferably 0.5 % to 2 % [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)], of clindamycin hydrochloride or clindamycin phosphate solubilized widi a pharmaceutically acceptable organic amine present in the molar ratio of about 1 to about 3 on the basis of CLINDA-SS.

The non-aqueous topical retinoid compositions of die present invention contain a safe and effective amount of a retinoid, preferably from about 0.001% to about 2% w/w, more preferably from about 0.01% to about 1%. Non-aqueous topical retinoic acid compositions of d e present invention contain a safe and effective amount of tretinoin (all trans-retinoic acid), preferably from about 0.01% to about 1% w/w, more preferably from about 0.025% to about 0.1%.

The non-aqueous topical compositions of the present invention contain from about 10% to about 85 % w/w of etiianol (preferably anhydrous ethanol) or isopropanol (preferably anhydrous isopropanol, Isopropyl Alcohol, U.S.P.). Although it is preferred that the compositions of d e present invention be free of water, the compositions may contain up to about 5% water without significant adverse effects on the stability of the active ingredient(s).

The vehicles of the non-aqueous topical compositions of the present invention, for facilitated delivery to die hair follicle or sebaceous gland, have a refractive index difference of greater than 0.003 (more preferably greater than about 0.005) when die formulation with and witiiout dissolved sebum are compared.

As used herein, "safe and effective amount" means an amount of compound or composition sufficient to significantly induce a positive modification in the condition to be treated, but low enough to avoid serious side effects (at a reasonable benefit/risk ratio), within the scope of sound medical judgment. The safe and effective amount of the compound or composition will vary with d e particular condition being treated, die age and physical condition of the patient being treated, die severity of die condition, die duration of the treatment, the nature of concurrent therapy, the specific compound or composition employed, die particular pharmaceutically-acceptable carrier utilized, and like factors within the knowledge and expertise of die attending physician.

The topical pharmaceutical compositions of die present invention may be made into a wide variety of product types, including solutions, sprays and^" gels.

The gel compositions of the present invention may be formulated by conventional mixing, however it is preferred ti at the active ingredients), i.e. clindamycin free base, clindamycin palmitate hydrochloride, clindamycin hydrochloride, clindamycin phosphate and/or a retinoid, be dissolved and die remaining ingredients added prior to the addition of die gelling agent (e.g. hydroxypropylcellulose). The non-aqueous topical gel compositions of die present invention contain from about 0.5 % to about 5 % w/w, preferably 2 % to 3 %, of a suitable gelling agent (e.g. hydroxypropylcellulose). If die topical pharmaceutical compositions of the present invention are formulated as an aerosol and applied to die skin as a spray-on, a propellant is added to a solution composition. Examples of propellants useful herein include, but are not limited to, die chlorinated, fluorinated and chloro-fluorinated lower molecular weight hydrocarbons. A more complete disclosure of propellants useful herein can be found in Sagarin, Cosmetics Science and Technology. 2nd Edition, Vol. 2, pp. 443-465 (1972).

As used herein, all percentages are by weight unless otherwise specified. All percentages of clindamycin hydrochloride, clindamycin phosphate or clindamycin palmitate hydrochloride are based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S) unless otherwise specified. The topical anti-acne pharmaceutical compositions of die present invention are particularly suited for die treatment of acne. The composition is generally applied about 1-4 times daily in conventional amounts, that is, amounts sufficient to thinly spread over die affected areas. The treatment is continued until or after all of the manifestations of acne have disappeared. The otiier topical pharmaceutical compositions of die present invention are particularly suited for conditions susceptible to treatment with die particular active ingredient. The composition is generally applied about 1-4 times daily in conventional amounts, tiiat is, amounts sufficient to tiiinly spread over die affected areas.

The following non-limiting examples illustrate the topical pharmaceutical compositions of the present invention.

The solutions of Examples 1-13, 16-27, 29 , 31-52 and 66-92 (TABLE I) are prepared by weighing and blending die liquid ingredients, tiien adding die drag(s) and mixing at room temperature until dissolved.

The gel compositions of Examples 14, 15, 28, 30 and 53 are prepared by weighing the alcohol and adding die all trans-retinoic acid (if present) and die composition mixed until clear. The Butylated Hydroxytoluene (BHT) is added (if present) and the composition mixed until clear. The remaining solvents are added and the composition mixed until uniform. Clindamycin Palmitate Hydrochloride is added and die composition ^"mixed until clear. The hydroxypropylcellulose is added to a vortex created by high speed mixing to disperse die gelling agent. The speed is reduced and mixing continued until die composition is uniform and clear. Example 93

The following solution is prepared:

Clindamycin Hydrochloride 1.0 all trans-retinoic acid 0.025 Propylene Glycol 5.0

Caprylic/Capric Triglyceride (Miglyol 812) 40.0

Tetrahydroxypropyl ediylenediamine (Quadrol) 0.873

Isopropyl Alcohol USP qs ad 100 by adding and blending the liquid ingredients and adding die dmg. Mix until dissolved. Example 94

The following solution is prepared:

Clindamycin Hydrochloride 1.0 all trans-retinoic acid 0J

Propylene Glycol 5.0 Caprylic/Capric Triglyceride (Miglyol 812) 40.0

Tetrahydroxypropyl ethylenediamine (Quadrol) 0.873

Isopropyl Alcohol USP qs ad 100 by adding and blending the liquid ingredients and adding the dmg. Mix until dissolved. Example 95 The following solution is prepared:

Ingredient %(w/w)

Clindamycin Hydrochloride 1.0 all trans-retinoic acid 0.025

Propylene Glycol 5.0 Caprylic/Capric Triglyceride (Miglyol 812) 40.0

Diisopropanolamine 0.333

Isopropyl Alcohol USP qs ad 100 by adding and blending d e liquid ingredients and adding d e dmg. Mix until dissolved. Example 96

The following solution is prepared:

Ingredient %(w/w)

Clindamycin Hydrochloride 1.0 all trans-retinoic acid 0J

Propylene Glycol 5.0

Caprylic/Capric Triglyceride (Miglyol 812) 40.0

Diisopropanolamine 0.333

Isopropyl Alcohol USP qs ad 100 by adding and blending die liquid ingredients and adding die dmg. Mix until dissolved. Active Ingredients other than CLINDA-S, CLINDA-SS and/or a retinoid can be incorporated into die vehicle of the subject invention and are another aspect tiiereof. Examples

54-65 (Table II) are specific examples which illustrate other drugs which can be incorporated into the vehicle of the present invention. Examples 54, 55 and 57-65 are prepared following die same general procedure for preparing the solutions of Examples 1-13.

The gelled composition of Example 56 is prepared by dissolving die erythromycin in the alcohol, adding die hydroxypropylcellulose to a vortex created by high speed stirring and mixing until dispersed. The remaining liquid ingredients are added and die composition mixed until a uniform gel develops. Tables III- VIII summarize the results of stability studies conducted on Examples of die subject invention and illustrate the surprising stability of the formulations.

TEST PROCEDURE A

by combining all of the ingredients in an Erlenmeyer flask, shaking and heating die mixture to about 57-60°C with stirring until all ingredients are in solution. Upon cooling, die solution turns to a waxy semi-solid which is utilized in Part B.

Part B: Test Procedure 1. Weigh 1 g of test sebum (Part A) into a 1 dram vial with stopper.

2. Add 1 ml of formulation vehicle or cosmetic oil to be tested.

3. Mix briefly on a vortex mixer.

4. Place samples in a shaker water bath at 37°C for 15 minutes.

5. Place in a centrifuge at 4000 rpm for 15 minutes. 6. Note any visual physical change.

7. Take a 30°C refractive index measurement of die clear portion of the centrifuged sample. Also, measure die refractive index of die formulation, vehicle or cosmetic oil witiiout sebum.

8. Calculate the difference in refractive index values between die centrifuged sample and the formulation, vehicle or cosmetic oil witiiout sebum.

Table IX summarizes the results of sebum dissolution tests conducted on various formulations, including Examples 5, 16-20, 22, 23 and 25 of the subject invention.

TEST PROCEDURE B Part A: Animals:

Female Harlan Sprague Dawley Fuzzy rats (HSD:FZ), 10-29 weeks old were used for all evaluations. The Fuzzy rat is a genetically hair deficient animal tiiat has been used in previous skin irritation studies. The animals were housed singly in suspended wire bottom stainless steel cages in a room witii a 12 hour light:dark cycle with Purina Certified Rodent Chow and water available ad libitum.

Part B: TEWL Measurement:

Transepidermal water loss (TEWL) was recorded using die ServoMed EP 1C Evaporimeter. Since movement may influence TEWL measurements, the rats were lightly anesdietized via an IM injection of a mixture of Ketamine, Xylazine, and Acepromazine in sterile water. After an appropriate level of anesthesia was reached, a 4X4 cm area was defined on the dorsal skin of each rat. The evaporimeter probe was then placed on the animal's back (inside die defined area), making sure the probe and skin surface made a tight seal. After a 30 second equilibration period, a 10 second filter (which averages measurements over 10 seconds) was turned on. After 10 seconds, d e TEWL value displayed by d e instrument was recorded. The instrument measures water loss in g/m²/hr, however, this was converted to mg/cm²/h for reporting purposes.

Part C: Treatment:

Supplied solutions were applied to a 4X4 cm site on die dorsal skin of the animal twice daily for 4 consecutive days. There was approximately 8 hours between doses. The solutions were in small opaque plastic bottles containing an applicator pad in die top. Each bottle was gently squeezed until approximately 4 drops fell on die animal's back, tiien die applicator was gently rubbed across die back spreading die solution evenly over the 4X4 cm area. The containers were weighed botii prior to and after treatment for an approximation of dose given. TEWL was recorded just prior to die first treatment and again on day 5 (approximately

18 hours after the last dose on day 4). Depending on die level of skin changes observed, a 6 mm biopsy was taken from at least two animals/treatment, fixed in 10% formalin, and processed for routine light microscopy evaluation.

Clinical signs of irritation were recorded once daily starting on day 2, just prior to the afternoon dose.

Table X summarizes the results of the Fuzzy rat skin irritation studies performed using the formulations from Examples 71, 79, 80 and 84-91 and illustrates the surprising anti- inflammatory effect of the clindamycin hydrochloride.

Claims

1. A topical pharmaceutical composition comprising:

(a) a dmg;

(c) from about 10% to about 95% w/w an alcohol selected from the group consisting of ethanol or isopropyl alcohol;

(d) a pharmaceutically acceptable organic amine in a molar ration from about 1 to about 3 to solubilize clindamycin hydrochloride or clindamycin phosphate, if present; and with the overall proviso that when the dmg is minoxidil, the cosmetic oil is other than a silicone fluid.

2. A composition according to claim 1, wherein component

(b) comprises from about 10% to about 40% w/w of a pharmaceutically acceptable noncomedogenic, sebum dissolving cosmetic oil; and (c) comprises from about 30% to about 85% w/w an alcohol selected from the group consisting of ethanol or isopropyl alcohol.

3. A composition according to claim 1, wherein component (a) comprises a drug susceptible to oxidative or hydrolytic degradation.

4. A composition according to claim 3 wherein component (a) comprises a dmg selected from the group consisting of (i) from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA-S, (ii) from about 0.001% to about 2% w/w of a retinoid, or (iii) a combination of from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C_{] 8}H₃₃C1N₂0₅S)] of CLINDA-S and from about 0.001% to about 2% w/w of a retinoid.

5. A composition according to claim 1 wherein component

(a) comprises a dmg selected from the group consisting of (i) from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA- SS, (ii) from about 0.001% to about 2% w/w of a retinoid, or (iii) a combination of from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C_]8H₃₃C1N₂0₅S)] of CLINDA-SS and from about 0.001% to about 2% w/w of a retinoid;^"

(b) comprises from about 10% to about 80% w/w of a pharmaceutically acceptable noncomedogenic, sebum dissolving cosmetic oil;

(c) comprises from about 10% to about 85% w/w an alcohol selected from the group consisting of ethanol or isopropanol; and

(d) comprises a pharmaceutically acceptable organic amine in a molar ratio of about 1 to about 3 on the basis of CLINDA-SS.

6. A composition according to claim 5, wherein the pharmaceutically acceptable organic amine is selected from the group consisting of diisopropanolamine, triisopropanolamine and tetrahydroxypropyl ethylenediamine.

7. A composition according to claim 4 wherein component (a) comprises from about 0.5% to about 2% w/w of clindamycin palmitate hydrochloride, solubilized with propylene glycol.

8. A composition according to claim 4 wherein component (a) comprises from about 0.5% to about 2% w/w of clindamycin palmitate hydrochloride, solubilized with propylene glycol, and from about 0.01% to about 1% w/w of all trans-retinoic acid.

9. A composition according to claim 4 wherein the cosmetic oil is selected from the group consisting of a caprylic/capric triglyceride, octyl isononanoate or cyclomethicone.

10. A composition according to claim 4 wherein the cosmetic oil is a caprylic/capric triglyceride.

11. A composition according to claim 5 wherein the cosmetic oil is a caprylic/capric triglyceride.

12. A composition according to claim 4 additionally containing from about 5% to about 10% w/w a liquid polyethylene glycol and from about 4% to about 15% w/w of propylene glycol.

13. A composition according to claim 4 wherein component (a) comprises from about 0.5% to about 2% w/w of clindamycin palmitate hydrochloride and from about 4% to about 15% of propylene glycol, and from about 0.01% to about 1% w/w of all trans-retinoic acid; the cosmetic oil is octyl isononanoate; the alcohol is isopropyl alcohol; and the composition optionally contains from about 5% to about 10% polyethylene glycol 400.

14. A composition according to claim 4 wherein component (a) comprises from about 0.5% to about 2% w/w of clindamycin palmitate hydrochloride and from about 4% to about 15% of propylene glycol, and from about 0.01% to about 1% w/w of all trans-retinoic acid; the cosmetic oil is octyl isononanoate; the alcohol is ethanol; and the composition optionally contains from about 5% to about 10% polyethylene glycol 400.

15. A composition according to claim 4 wherein component (a) comprises from about 0.5% to about 2% w/w of clindamycin palmitate hydrochloride and from about 4% to about 15% of propylene glycol, and/or from about 0.01% to about 1% w/w of all trans-retinoic acid; the cosmetic oil is a caprylic/capric triglyceride; and the composition optionally contains from about 5% to about 10% polyethylene glycol 400.

16. A composition according to claim 4 wherein the retinoid is selected from the group consisting of all-trans retinoic acid, all trans-retinoic acetate, retinaldehyde, 13-cis-retinoic acid, retinoic acid ethylamide, retinoic acid 2-hydroxyethyl amide, retinoic acid p-hydroxyphenyl- amide, axerophthene, retinal, retinol, retinyl methylether, β-all trans-retinoic acid, 7,8-dehydro analog of retinoic acid, 5,6-epoxy analog of retinoic acid, retinyl methylthioether, 4-oxo analog of retinoic acid, N-methyl dimethyl doxolan retinamide, retinyl n-butyl ether, N-(0- carboxyphenyl) retinamide, retinyl tert-butyl ether, retinylacetate, N-(p-carboxyphenyl) retinamide, N-benzoyl retinylamide, retinyl palmitate, retinylidene ethylcyano acetate.

17. A composition according to claim 5 wherein the retinoid is selected from the group consisting of all-trans retinoic acid, all trans-retinoic acetate, retinaldehyde, 13-cis-retinoic acid, retinoic acid ethylamide, retinoic acid 2-hydroxyethyl amide, retinoic acid p-hydroxyphenyl- amide, axerophthene, retinal, retinol, retinyl methylether, β-all trans-retinoic acid, 7,8-dehydro analog of retinoic acid, 5,6-epoxy analog of retinoic acid, retinyl methylthioether, 4-oxo analog of retinoic acid, N-methyl dimethyl doxolan retinamide, retinyl n-butyl ether, N-(0- carboxyphenyl) retinamide, retinyl tert-butyl ether, retinylacetate, N-(p-carboxyphenyl) retinamide, N-benzoyl retinylamide, retinyl palmitate, retinylidene ethylcyano acetate.

18. A composition according to claim 6 wherein component (a) comprises from about 0.5% to about 2% w/w of clindamycin hydrochloride and from about 0.01% to about 0.1% w/w of all trans-retinoic acid;

(b) comprises caprylic/capric triglyceride;

(c) comprises isopropanol; and the composition optionally contains about 4% to 15% propylene glycol.

19. A composition according to claim 6 wherein component (a) comprises from about 0.5% to about 2% w/w of clindamycin phosphate and from about 0.01% to about 0.1% w/w of all trans-retinoic acid;

(b) comprises caprylic/capric triglyceride; and

20. A topical pharmaceutical composition comprising:

(a) a dmg selected from the group consisting of (i) from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C₁₈H₃₃C1N₂0₅S)] of CLINDA-SS, (ii) from about 0.001% to about 2% w/w of a retinoid, or (iii) a combination of from about 0.05% to about 5% w/w [based on a potency equivalent to clindamycin (C_{] 8}H₃₃C1N₂0₅S)] of CLINDA- SS and from about 0.001% to about 2% w/w of a retinoid;

(b) from about 10% to about 95% w/w an alcohol selected from the group consisting of ethanol or isopropanol; and (c) a suitable pharmaceutically acceptable organic amine in a molar ratio of about 1 to about 3 on the basis of CLINDA-SS.