AU2010238566B2 - Polymeric topical compositions - Google Patents

Abstract

The present invention relates to topical antibacterial compositions. The compositions comprise an antibacterial agent such as mupirocin, water, a polymer and a volatile solvent 5 present in an amount of less than about 40%. The invention also relates to methods of treatment by administering the compositions to a patient in need thereof, and to the use of such compositions in the treatment of bacterial conditions.

Description

Australian Patents Act 1990 - Regulation 3.2 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title Polymeric topical compositions The following statement is a full description of this invention, including the best method of performing it known to me/us: P/00/0 11 5102 FIELD OF THE INVENTION 5 The present invention relates to topical antibacterial compositions. BACKGROUND OF THE INVENTION Bactroban@ (2% mupirocin) ointment and Bactroban@ (2% calcium mupirocin) cream and ointment are marketed by GlaxoSmithKline for the treatment of furuncle, impetigo and D wounds that have become infected. US Patent No. 5,082,656 (Hui et al.) describes an antibacterial composition for topical administration comprising: from about 0.5% to about 10% of an antibacterial compound, from about 1% to about 30% of a non water soluble polymeric composition, from about 0.5% to about 40% of a plasticizer, and from about 50% to about 95% of a solvent (such as ethanol or isopropanol). Upon topical application of the antibacterial composition, the solvent will evaporate and leave a thin protective film of polymeric composition which retains the antibacterial compound against the skin. US Patent No. 6,211,250 (Tomlinson et al.) describes topical compositions comprising at least one rate modulating polymer, a volatile solvent and at least one physiologically active agent. Tomlinson discloses compositions comprising a hydrophilic polymer and a hydrophobic polymer selected to modulate the rate of release of the active agent. The compositions comprise greater than 50% volatile solvent. A high level of volatile solvent is desirable in as much as it will solubilize the hydrophobic polymer and evaporate to leave a polymeric film on the surface of the skin. However, a high level of volatile solvent has the potential disadvantage of irritating the skin, particularly on open wounds or lesions. US Patent No. 6,582,683 (Jezior) describes a dermal barrier composition which comprises water, a hydrophilic polymer emulsion and a hydrophobic polymer emulsion. The dermal barrier composition is moisture activated, and remains inert until the hydrophobic and hydrophilic polymer emulsions contact a suitable substrate such as human skin. The dermal 0 barrier composition is itself an emulsion, and may contain a biocidal agent for treatment of a skin disorder or condition. The dermal barrier composition may also contain other active agents such as sunscreens, insect repellents and fungicides. The composition does not contain a volatile solvent. US Published Application No. 2005/0175641 (Deo et al.) describes topical 5 compositions comprising at least one physiologically active agent, a volatile solvent, and ethyl cellulose as a hydrophobic polymer, along with a hydrophilic polymer. The volatile solvent is present in an amount of greater than 50% by weight. la US Patent No. 7,678,366 (Friedman et at.) describes a therapeutic nail varnish comprising a pharmaceutically active agent, a humectant, water, less than about 7.5% by weight of a polymeric film forming agent, at least one additional excipient, and a solvent system including at least one volatile solvent. Friedman et al. discloses pharmaceutically active agents which are antifungal agents, such as naftifine or terbinafine. The nail varnish may further comprise a second active ingredient, such as clobetasol. There remains a need in the art for topical preparations that are able to deliver an active agent, particularly an antibacterial, to the surface of the skin in a controlled manner and without irritation. Furthermore, it is desirable that such a preparation would be cosmetically elegant, and rapidly dry after topical application to leave a film on the surface of the skin. The present invention is believed to address these unmet needs. SUMMARY OF THE INVENTION According to an embodiment, the present invention provides a topical pharmaceutical composition comprising an antibacterial agent, a polymer, water and less than about 40% volatile solvent. According to another embodiment the present invention provides for a method of treating a disease, disorder or condition of the skin, in a mammal in need thereof, the method comprises administering to said mammal, preferably a human subject, a topical pharmaceutical composition comprising an antibacterial agent, a polymer, water and less than about 40% volatile solvent. According to a further embodiment, the invention relates to the use of a topical pharmaceutical composition comprising an antibacterial agent, a polymer, water and less than about 40% volatile solvent, in the preparation of a medicament for the treatment of a disease, disorder or condition of the skin. In another embodiment, the invention relates to the use of a topical pharmaceutical composition comprising an antibacterial agent, a polymer, water and less than about 40% volatile solvent, in the treatment of a disease, disorder or condition of the skin. BRIEF DESRCIPTION OF THE DRAWINGS Figure 1 illustrates modulation of the rate of release of calcium mupirocin where different variants of PVPNA are used, i.e. PVPNA 60:40 (e), PVPNA 70:30 (*) and PVP/VA 30:70 (m). 5 Figure 2 illustrates modulation of the rate of release of calcium mupirocin (first order derivative) where different variants of PVPNA are used, i.e. PVPNA 60:40 (e), PVPNA 70:30 (+) and PVPNA 30:70 (i). 2 Figure 3 illustrates the rate constant (k) and release exponent (n) in connection with release of calcium mupirocin from compositions comprising different variants of PVPNA, i.e. PVPNA 60:40, PVPNA 70:30 and PVPNA 30:70. 5 Figures 4a-4c illustrates the rub and water resistance of the compositions of the invention. DETAILED DESCRIPTION OF THE INVENTION The present invention provides for a topical pharmaceutical composition comprising an 0 antibacterial agent, a polymer, water and less than about 40% volatile solvent, and optionally additional dermatologically acceptable excipients. Exemplary antibacterial agents include, but are not limited to, mupirocin, gentamicin, neomycin, streptomycin, cefpodoxime proxetil, clindamycin, lincomycin, erythromycin, bacitracin, gramicidin(s), vancomycin, doxycycline, minocycline, oxytetracycline, tetracycline, 5 fosfomycin, fusidic acid, sulfacetamide, metronidazole, benzoyl peroxide and dapsone, pharmaceutically acceptable salts thereof, and mixtures thereof. Suitably, the antibacterial agent is present in the composition in a therapeutically effective amount. In an embodiment, the antibacterial agent is present in an amount from about 0.1% to about 10% by weight. > In one embodiment, the antibacterial agent is selected from the group consisting of mupirocin, clindamycin, metronidazole and pharmaceutically acceptable salts thereof. In a particular embodiment, the antibacterial agent is mupirocin or a salt thereof. In an embodiment, the mupirocin or a salt thereof is calcium mupirocin. In one embodiment, the mupirocin or a salt thereof is sodium mupirocin. In one embodiment, the mupirocin or a salt ) thereof is calcium mupirocin. In another embodiment, the calcium mupirocin is present either as an amorphous or crystalline form. In another embodiment, the mupirocin or a salt thereof is mupirocin (the free acid). In yet another embodiment, the mupirocin or a salt thereof is a mixture of calcium mupirocin and mupirocin (the free acid). Suitably, the calcium mupirocin and mupirocin in such an embodiment are present in a ratio of about 1:3 to about 3:1, suitably 0 about 1:1. The benefit of combining calcium mupirocin and mupirocin (the free acid) in a single composition according to the present invention is that the respective forms of mupirocin will be released from the topical composition at different rates, so as to facilitate a combination of rapid release and more sustained release of the active agent. These differing release rates arise 5 from the different hydrophilicity / hydrophobicity of calcium mupirocin and mupirocin (the free acid). The same would be present for sodium mupirocin and mupirocin (free acid), as well potentially as other salt forms of mupirocin with the free acid. 3 In an embodiment, the mupirocin or a salt thereof is present in an amount from about 0.1% to about 10% by weight. Suitably, the mupirocin or a salt thereof is present in an amount from about 1% to about 3% by weight, such as about 1%, 2% or 3% by weight, for example. In a particular embodiment, the mupirocin or a salt thereof is present in an amount of about 2% 5 by weight. In an alternative embodiment, the antibacterial agent is clindamycin or a salt thereof. Suitably, the clindamycin or a salt thereof is clindamycin phosphate or clindamycin hydrochloride. In an embodiment, the clindamycin or a salt thereof is clindamycin phosphate. In a further embodiment, the clindamycin or a salt thereof is present in an amount from about ) 0.5% to about 2% by weight, such as about 1% by weight. In another embodiment, the antibacterial agent is metronidazole. Suitably, the metronidazole is present in an amount from about 0.1% to about 2% by weight. In a particular embodiment, the metronidazole is present in an amount of about 1% by weight. 5 Polymer In an embodiment, the polymer present in the formulation is a copolymer. Suitably, the copolymer is polyvinylpyrrolidone-vinyl acetate copolymer, also known as PVPNA. In one embodiment, the ratio of PVP monomer to VA monomer in the PVPNA copolymer is from about 30:70 to about 70:30. In another embodiment, the ratio of PVP ) monomer to VA monomer is about 30:70. In another embodiment, the ratio of PVP monomer to VA monomer is about 60:40. In yet another embodiment, the ratio of PVP monomer to VA monomer is about 70:30. While there are many suppliers of PVPNA, many ratios are available from 70:30 to 20:80 are available under the tradename Luviskol, produced by BASF. Hydrophobic polymers are either insoluble in low ethanolic formulations (s 20% ethanol) or precipitate out of the formulation due to interactions with the hydrophilic drug. Hydrophilic homopolymers (such as hydroxypropylcellulose (HPC)) form thermodynamically stable formulations, but tend to give rise to a burst release of a hydrophilic drug. A difference in drug release has been observed when the hydrophobicity of the copolymer PVPNA is modified by changing the ratio of PVP (hydrophilic moiety) to VA (hydrophobic moiety) as 0 will be further described herein in the Methods Section. A hydrophilic polymer (e.g. a carbomer and PVPNA (60:40)) has also been shown to reduce the drug release of a lipophilic drug as compared to the hydrophilic drug. In an embodiment, the polymer is present in the composition in an amount from about 5 1% to about 60% by weight. In one embodiment, the polymer is present in an amount from about 5% to about 30% by weight, such as about 10% by weight. In another embodiment, the polymer is present in an amount from about 30% to about 60% by weight, such as from about 45% to about 55% by weight, or about 50% by weight. 4 Water In an embodiment, the composition comprises water in an amount from about 20% to about 85% by weight. In one embodiment, the composition comprises water in an amount 5 from about 40% to about 85% by weight. In another embodiment the composition comprises from about 50% to about 70% by weight. In another embodiment, the composition comprises water in an amount from about 20% to about 40% by weight. Volatile solvent 0 In an embodiment, the volatile solvent is an organic solvent. The organic solvent is suitably selected from ethanol, propanol, iso-propanol, n-butyl alcohol, t-butyl alcohol, butoxy ethanol, acetone, ethyl acetate or butyl acetate, and mixtures thereof. In one embodiment the at least one volatile solvent present in the composition is ethanol. In another embodiment, the volatile solvent is a mixture of at least two volatile 5 solvents. Suitably the combination contains ethanol as the first solvent in combination with a second solvent. Suitably, the second solvent is propanol, iso-propanol, n-butyl alcohol, t-butyl alcohol, butoxy ethanol, acetone, ethyl acetate or butyl acetate. In an embodiment, the volatile solvent is a mixture of ethanol and iso-propanol. In another embodiment, the volatile solvent is a mixture of ethanol and ethyl acetate. D In an embodiment, the volatile solvent is present in an amount of less than about 40% by weight. In one embodiment, the volatile solvent is present in an amount from about 5% to about 30% by weight. In another embodiment, the volatile solvent is present in an amount from about 10% to about 25% by weight. Suitably, the ratio of volatile solvent to water in the topical pharmaceutical composition 5 is from about 1:1 to about 1:10. In one embodiment, the ratio of volatile solvent to water in the topical pharmaceutical composition is from about 1:1 to about 1:3. In an embodiment, the ratio of volatile solvent to water in the topical pharmaceutical composition is from about 1:1.25 to about 1:2. In another embodiment the ratio is about 1:1.65. W0 Second pharmaceutically active agent According to an embodiment, the topical pharmaceutical composition may comprise a second pharmaceutically acceptable active agent. In one embodiment, the second pharmaceutically active agent is selected from the group consisting of a second antibacterial agent, a retinoid, a corticosteroid, an antifungal 35 agent, a skin conditioning agent, a nutritional agent, and an antiseptic agent. Suitably, the second pharmaceutically active agent is present in an amount in the composition from about 0.001% to about 20% by weight, depending on the nature of the second active agent. 5 Exemplary antibacterial agents suitable for use as the second antibacterial agent include, but are not limited to, gentamicin, neomycin, streptomycin, cefpodoxime proxetil, clindamycin, lincomycin, erythromycin, bacitracin, gramicidin(s), vancomycin, doxycycline, minocycline, oxytetracycline, tetracycline, fosfomycin, fusidic acid, sulfacetamide, 5 metronidazole, benzoyl peroxide and dapsone, salts thereof, and mixtures thereof. Suitably, the second antibacterial agent is present in an amount from about 0.1% to about 10% by weight. Exemplary retinoids include, but are not limited to, tazarotene, tretinoin, isotretinoin, acitretin, etretinate, adapalene, bexarotene, alitretinoin, retinol, retinal, retinyl palmitate, retinyl 0 acetate, retinyl propionate, retinyl linoleate, ethyl 5-(2-(4,4-dimethylthiochroman-6 yl)ethynyl)thiophene-2-carboxylate, 6-(2-4,4-dimethylthiochroman-6-yl)-ethynyl)-3 pyridylmethanol, 6

-(

2 -(4,4-dimethylthiochroman-6-yl)-ethynyl)pyridine-3-carbaldehyde, pharmaceutically acceptable salts thereof, and mixtures thereof. Suitably, the retinoid is present in an amount from about 0.01% to about 1% by weight. 5 In an embodiment, the retinoid is selected from the group consisting of tretinoin, tazarotene and adapalene. In one embodiment, the retinoid is tretinoin. In another embodiment, the retinoid is tazarotene. In yet another embodiment, the retinoid is adapalene. Exemplary corticosteroids include, but are not limited to, alclometasone dipropionate, amcinonide, beclomethasone dipropionate, betamethasone benzoate, betamethasone ) dipropionate, betamethasone valerate, budesonide, clobetasol propionate, clobetasone butyrate, cortisone acetate, desonide, desoximetasone, diflorasone diacetate, diflucortolone valerate, fluclorolone acetonide, flumethasone pivalate, fluocinolone acetonide, fluocinonide, fluocortin butyl, fluocortolone, fluprednidene acetate, flurandrenolide, flurandrenolone, fluticasone propionate, halcinonide, halobetasol propionate, hydrocortisone, hydrocortisone acetate, hydrocortisone butyrate, hydrocortisone propionate, hydrocortisone valerate, methylprednisolone acetate, mometasone furoate, pramoxine hydrochloride, prednisone acetate, prednisone valerate, triamcinolone acetonide, prednicarbate, salts thereof, and mixtures thereof. Suitably, the corticosteroid is present in an amount from about 0.01% to about 2% by weight. 0 Exemplary antifungal agents include, but are not limited to, those selected from the group consisting of echinocandins such as anidulafunin, caspofungin and micafungin; polyenes such as amphotericin B, candicidin, filipin, fungichromin, hachimycin, hamycin, lucensomycin, mepartricin, natamycin, nystatin, pecilocin, perimycin; allylamines such as butenafine, naftifine and terbinafine; imidazoles such as bifonazole, butoconazole, 5 chlormidazole, cloconazole, clotrimazole, econazole, enilconazole, fenticonazole, flutrimazole, isoconazole, ketoconazole, lanoconazole, miconazole, neticonazole, omoconazole, oxiconazole nitrate, sertaconazole, sulconazole and tioconazole; thiocarbamates such as liranaftate, tolciclate, tolindate and tolnafate; triazoles such as albaconazole, pramiconazole, fluconazole, 6 itraconazole, posaconazole, ravuconazole, saperconazole, terconazole and voriconazole; and other antifungal agents such as acrisorcin, amorolfine, biphenamine, bromosalicylchloranilide, buclosamide, calcium propionate, chlorphenesin, ciclopirox, cloxyquin, coparaffinate, exalamide, flucytosine, haloprogin, hexetidine, loflucarban, nifuratel, potassium iodide, 5 propionic acid, pyrithione, salicylanilide, sodium propionate, sulbentine, tenonitrozole, triacetin, undecylenic acid, zinc propionate, griseofulvin, oligomycins, pyrrolnitrin, siccanin, viridian, pharmaceutically acceptable salts thereof, and mixtures thereof. Suitably, the antifungal agent is present in an amount from about 0.1% to about 5% by weight. Exemplary skin-conditioning agents include, but are not limited to, hydrocarbon oils j and waxes, silicones, fatty acid derivatives, cholesterol, di- and tri-glycerides, vegetable oils, acetoglyceride esters, alkyl esters, alkenyl esters, lanolin, milk tri-glycerides, wax esters, beeswax, sterols, phospholipids, hyaluronic acid, pharmaceutically acceptable salts thereof, and mixtures thereof. In an embodiment, the skin-conditioning agent is hyaluronic acid or a salt thereof, such as sodium hyaluronate. Suitably, the skin conditioning agent is present in an amount from about 0.1% to about 20% by weight. Exemplary nutritional agents include vitamins such as vitamins A, B, C, D, E and K and prodrugs thereof, essential amino acids, essential fats, antioxidants, pharmaceutically acceptable salts thereof, and mixtures thereof. Suitably, the nutritional agent is present in an amount from about 0.0 1% to about 2% by weight. > Exemplary antiseptics include, but are not limited to, hydrogen peroxide, chlorhexidine, cetrimide, povidone iodine, silver sulfadiazine, triclosan, pharmaceutically acceptable salts thereof, and mixtures thereof. In another embodiment, the first antibacterial agent is mupirocin or a pharmaceutically acceptable salt thereof and the second pharmaceutically active agent is a second antibacterial agent. Suitably, the first antibacterial agent is mupirocin, sodium or calcium mupirocin or a mixture thereof. In one embodiment the first antibacterial agent is calcium mupirocin. In one embodiment, the second antibacterial agent is metronidazole. In another embodiment the first antibacterial agent is calcium mupirocin and the second antibacterial agent is metronidazole. In another embodiment, the antibacterial agent is mupirocin or a pharmaceutically 0 acceptable salt thereof and the second pharmaceutically active agent is a retinoid. Suitably, the antibacterial agent is mupirocin, sodium or calcium mupirocin or a mixture thereof. In one embodiment the antibacterial agent is calcium mupirocin. In one embodiment the retinoid is tretinoin. In another embodiment, retinoid is adapalene. In one embodiment the antibacterial agent is calcium mupirocin and the retinoid is tretinoin or adapalene. 5 In another embodiment, the antibacterial agent is mupirocin or a pharmaceutically acceptable salt thereof and the second pharmaceutically active agent is a corticosteroid. Suitably, the antibacterial agent is mupirocin, sodium or calcium mupirocin or a mixture thereof. In one embodiment the antibacterial agent is calcium mupirocin. In one embodiment, 7 corticosteroid is clobetasol propionate. In another embodiment, corticosteroid is hydrocortisone or an ester thereof. In one embodiment the antibacterial agent is calcium mupirocin and the antibacterial agent is clobetasol propionate or hydrocortisone or an ester thereof. 5 In another embodiment, the antibacterial agent is mupirocin or a pharmaceutically acceptable salt thereof and the second pharmaceutically active agent is an antifungal agent. Suitably, the antibacterial agent is mupirocin, sodium or calcium mupirocin or a mixture thereof. In one embodiment the antibacterial agent is calcium mupirocin. In one embodiment, the antibacterial agent is calcium mupirocin and the antifungal agent is clotrimazole. D In another embodiment, the antibacterial agent is mupirocin or a pharmaceutically acceptable salt thereof and the second pharmaceutically active agent is a skin conditioning agent. Suitably, the mupirocin or pharmaceutically acceptable salt thereof is calcium mupirocin. In another embodiment, the antibacterial agent is mupirocin or a pharmaceutically 5 acceptable salt thereof and the second pharmaceutically active agent is an antiseptic agent. Suitably, the mupirocin or pharmaceutically acceptable salt thereof is calcium mupirocin. Dermatologically acceptable excipients In an embodiment, the present topical pharmaceutical compositions further comprise D one or more dermatologically acceptable excipients. Suitably, the excipient is selected from the group consisting of a co-solvent, a pH adjusting agent, a humectant, a film extender, a chelating agent, an antioxidant, a preservative, a gelling agent, a fragrance, a colorant, a penetration enhancer, or a combination or mixture thereof. 5 In one embodiment, the present compositions are formulated as a solution, gel, serum, aerosol spray or aerosol foam. Suitably, the composition is formulated as a solution. In another embodiment, the composition is formulated as a gel. Co-solvent 0 The topical pharmaceutical compositions may further comprise a co-solvent. The function of the co-solvent is to further solubilise (i.e. in conjunction with the volatile solvent) the active agent and/or the polymer in the composition. Exemplary co-solvents include, but are not limited to, alcohols such as amyl alcohol, benzyl alcohol, cyclohexanedimethanol, diacetone alcohol, hexyl alcohol, tetrahydrofurfuryl 5 alcohol; carboxylic acids such as acetic acid or multi carboxylic acid derivatives; diols such as 1,2-hexanediol, butylene glycol, diethylene glycol, dipropylene glycol, ethyl hexanediol, ethylene glycol, hexylene glycol, pentylene glycol, propylene glycol, tetraethylene glycol, 8 triethylene glycol, tripropylene glycol; and polyols such as polyethylene glycol, butanetriol, glycerol and 1,2,6-hexanetriol. In one embodiment, the co-solvent is propylene glycol. In another embodiment, the co solvent is hexylene glycol. In yet another embodiment, the co-solvent is a mixture of at least 5 two co-solvents. In an embodiment, the co-solvent is a mixture of polyethylene glycol and propylene glycol. In one embodiment, the co-solvent is present in the composition in an amount of from about 1% to about 30% by weight. In another embodiment, the co-solvent is present in an amount of from about 1% to about 10% by weight. In yet another embodiment, the co-solvent 0 is present in an amount of from about 15% to about 25% by weight. In an alternative embodiment, the topical pharmaceutical composition is devoid or substantially devoid of co-solvent. In one embodiment, the topical pharmaceutical composition is devoid of co-solvent. In another embodiment, the topical pharmaceutical composition is substantially devoid of co-solvent. 5 In another embodiment, the topical pharmaceutical composition comprises a volatile solvent in an amount from about 10% to about 25% by weight and is substantially devoid of a co-solvent. In yet another embodiment, the topical pharmaceutical composition comprises a volatile solvent in an amount from about 10% to about 25% by weight, and is devoid of co solvent. 0 pH adjusting agent The topical pharmaceutical compositions may further comprise a pH adjusting agent. In one embodiment, the pH adjusting agent is a base. Suitable bases include amines, bicarbonates, carbonates, and hydroxides such as alkali or alkaline earth metal hydroxides, as 5 well as transition metal hydroxides. In an embodiment, the base is sodium hydroxide or potassium hydroxide. In another embodiment, the pH adjusting agent is an acid, an acid salt, or mixtures thereof. Suitably, the acid is selected from the group consisting of lactic acid, acetic acid, maleic acid, succinic acid, citric acid, phosphoric acid, nitric acid, sulphuric acid and 30 hydrochloric acid. In yet another embodiment, the pH adjusting agent is a buffer. Suitably, the buffer is selected from the group consisting of citrate/ citric acid, acetate/ acetic acid, phosphate/ phosphoric acid, propionate/ propionic acid, lactate/ lactic acid, carbonate/ carbonic acid, ammonium/ ammonia and edetate/ edetic acid, or a combination or mixture thereof. In one 35 embodiment, the pH adjusting agent is citrate/ citric acid. In one embodiment, the pH adjusting agent is present in an amount from about 0.01% to about 10% by weight. In another embodiment, the pH adjusting agent is present in an amount sufficient to adjust the pH of the composition to between about 4 to about 9. Suitably, the 9 composition is adjusted to a pH between about 4 to about 6.5, or a pH between about 6.5 to about 9. Humectant 5 The topical pharmaceutical compositions may further comprise a humectant. Exemplary humectants include, but are not limited to, glycerol, sorbitol, maltitol, polydextrose, triacetin, propylene glycol, polyethylene glycol (PEG) esters including PEG-20 stearate, PEG-40 stearate, PEG-150 stearate, PEG-150 distearate and PEG-100 stearate, alkoxylated alcohols including laureth-12, ceteareth-20, laureth-23, glycereth-7, glycereth-12, 3 glycereth-26, PEG-4, PEG-6, PEG-8, PEG-12, PEG-32, PEG-75, PEG-150, or a combination or mixture thereof In an embodiment, the humectant is glycerol. In one embodiment, the present compositions comprise about 0.1% to about 10% by weight of a humectant. In another embodiment, the compositions comprise about 0.5% to about 5% by weight of a humectant. Film extenders The present topical pharmaceutical compositions may further comprise a film extender. Exemplary film extenders include, but are not limited to, calcium carbonate, calcium phosphate, calcium stearate, magnesium stearate, zinc stearate, calcium sulfate, colloidal silicon dioxide, kaolin, magnesium carbonate, magnesium silicate, sodium stearyl fumarate, talc, titanium dioxide, zinc oxide, or a combination or mixture thereof. Suitably, the film extender is present in an amount from about 0.1% to about 2% by weight. Chelating agents The present topical pharmaceutical compositions may further comprise a chelating agent. Exemplary chelating agents include, but are not limited to, citric acid, isopropyl (mono) citrate, stearyl citrate, lecithin citrate, gluconic acid, tartaric acid, oxalic acid, phosphoric acid, sodium tetrapyrophosphate, potassium monophosphate, sodium hexametaphosphate, calcium 0 hexametaphosphate, sorbitol, glycine (aminoacetic acid), methyl glucamine, triethanolamine (trolamine), ethylene diamine tetraacetic acid (EDTA), dihydroxyethylglycine (DEG), diethylene triamine pentaacetic acid (DPTA), nitrilotriacetic acid (NTA), N-(hydroxyethyl) ethylenetriaminetriacetic acid (HEDTA), aminocarboxylates, dimercaperol (BAL), larixinic acid (maltol), unidentate ligands (fluoride and cyanide ions), diphenylthiocarbazone, o 5 phenanthroline, barium diphenylamine sulfonate, sodium glucoheptonate, 8-hydroxyquinoline, olefin complexes (such as dicyclopentadienyl iron), porphyrins, phosponates, or a combination or mixture thereof. In one embodiment, the chelating agent is EDTA. 10 Suitably, the chelating agent is present in an amount from about 0.1% to about 1% by weight. Antioxidants 5 The present topical pharmaceutical compositions may further comprise an antioxidant. Exemplary antioxidants include, but are not limited to, butylated hydroxytoluene (BHT), butylated hydroxyanisole, tocopherol, propyl gallate, vitamin E TPGS, or a combination or mixture thereof. Suitably, the present compositions comprise an antioxidant in an amount from about D 0.00 1% to about 1% by weight. Preservatives The present topical pharmaceutical compositions may further comprise a preservative. Exemplary preservatives include, but are not limited to, benzyl alcohol, diazolidinyl urea, 5 methyl paraben, ethyl paraben, propyl paraben, butyl paraben, phenoxyethanol, sorbic acid, benzoic acid, salts thereof, or a combination or mixture thereof. In one embodiment, the preservative is benzyl alcohol. In another embodiment, the preservative is phenoxyethanol. Suitably, the present compositions comprise a preservative in an amount from about 0.01% to about 2% by weight. Gelling agent The present topical pharmaceutical compositions may further comprise a gelling agent. Exemplary gelling agents include, but are not limited to, agar, alginate, arabinoxylan, carrageenan, carboxymethylcellulose, hydroxypropyl methylcellulose, cellulose, curdlan, gelatin, gellan, p-glucan, tragacanth gum, guar gum, gum arabic, locust bean gum, pectin, starch, a carbomer, acrylate copolymers, silica, xanthan gum, salts thereof, or a combination or mixture thereof. In one embodiment, the gelling agent is xanthan gum. In another embodiment, the gelling agent is a carbomer. In another embodiment, the gelling agent is a mixture of at least 0 two gelling agents. Suitably, the gelling agent is present in the composition in an amount from about 0.1% to about 2% by weight. In one embodiment, the invention provides a topical pharmaceutical composition 5 comprising: (a) calcium mupirocin, (b) a polymer in an amount from about 30% to about 60% by weight, (c) water in an amount from about 20% to about 40% by weight, and 11 (d) a volatile solvent in an amount from about 10% to about 25% by weight. In another embodiment, the invention provides a topical pharmaceutical composition comprising: 5 (a) calcium mupirocin, (b) a polymer in an amount from about 30% to about 60% by weight, (c) water in an amount from about 20% to about 40% by weight, (d) a volatile solvent in an amount from about 10% to about 25% by weight, and (e) a gelling agent. 0 In yet another embodiment, the invention provides a topical pharmaceutical composition comprising: (a) calcium mupirocin, (b) a polymer in an amount from about 30% to about 60% by weight, 5 (c) water in an amount from about 20% to about 40% by weight, and (d) a volatile solvent in an amount from about 10% to about 25% by weight, and wherein the composition is devoid or substantially devoid of co-solvent. In another embodiment, the invention provides a topical pharmaceutical composition O comprising: (a) calcium mupirocin, (b) a polymer in an amount from about 30% to about 60% by weight, (c) water in an amount from about 20% to about 40% by weight, (d) a volatile solvent in an amount from about 10% to about 25% by weight, and 5 (e) a gelling agent, and wherein the composition is devoid or substantially devoid of co-solvent. Suitably, the polymer in any of the above 4 formulations is PVP/VA. In one embodiment, the ratio of PVP monomer to VA monomer in the PVP/VA is from about 30:70 o to about 70:30. In a particular embodiment, the ratio of PVP monomer to VA monomer is about 30:70. In another embodiment, the ratio of PVP monomer to VA monomer is about 60:40. In yet another embodiment, the ratio of PVP monomer to VA monomer is about 70:30. Suitably, the calcium mupirocin is present in an amount from about 1% to about 3% by weight. In one embodiment, the calcium mupirocin is present in an amount from about 2% by 5 weight. In another embodiment, the topical pharmaceutical composition is devoid or substantially devoid of a lipid. In one embodiment, the pharmaceutical composition is devoid 12 of a lipid. In a further embodiment, the pharmaceutical composition is substantially devoid of a lipid. Methods of Treatment According to an embodiment, the invention provides a method of treating a disease, disorder or condition of the skin, the method comprising administering to a subject in need thereof, a topical pharmaceutical composition comprising an antibacterial agent, a polymer, water and less than about 40% volatile solvent. In a particular embodiment, the disease, disorder or condition of the skin is caused by a > bacterial infection. Exemplary bacterial infections include, but are not limited to, infections caused by Gram-positive and Gram-negative bacteria and mycoplasmas, including for example, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus sapropphyticus, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae, Sireptococcus mutans, Streptococcus sanguis, Streptococcus faecium, Streptococcus faecalis, Corynebacterium hofmannii, Bacillus subtilis, Aeisseria meningitides, Neisseria gonorrhoeae, Haemophilus influenzae, Pasteurella multocida, Branhamella catarrhalis, Proteus vulgaris, Propionibacterium acnes, Enterobacter cloacae, Peptostreptococcus anaerobius, Clostridium sporogenes, Clostridium difficile, Moraxella catarrhalis, Mycoplasma pneumoniae and Mycoplasma gallisepticum. Suitably, the bacterial infection is an infection caused by Staphylococcus aureus. In an embodiment, the disease, disorder or condition of the skin caused by a bacterial infection is acne, impetigo, superficially infected dermatoses, wounds which have become infected, rosacea or folliculitis. In one embodiment, the disease, disorder or condition of the skin is acne. In another embodiment, the disease, disorder or condition of the skin is impetigo. In a further embodiment, the present compositions may be used as part of a regimen for the treatment or prevention of a disease, disorder or condition of the skin. In particular, the present compositions may be used in combination with a separate pharmaceutical dosage form. 0 According to an embodiment, the separate pharmaceutical dosage form is an oral preparation. In one embodiment, the oral preparation is a capsule or tablet comprising an antibacterial agent. Definitions 5 The phrases an "effective amount", "an amount effective to" or a "therapeutically effective amount" are used herein to refer to an amount of the composition sufficient to have a therapeutic effect upon administration. Effective amounts will vary with the particular 13 condition or conditions being treated, the severity of the condition, the duration of the treatment, and the specific components of the composition. The terms "administering" and "administration" are used herein to mean any method which in sound medical practice delivers the composition to a subject in such a manner as to 5 provide the desired therapeutic effect. The terms "treatment" or "treating" of a skin disease, disorder or condition encompasses alleviation of at least one symptom thereof, a reduction in the severity thereof, or the delay, prevention or inhibition of the progression thereof. Treatment need not mean that the disorder is totally cured. A useful composition herein need only to reduce the severity of the disorder, 0 reduce the severity of symptoms associated therewith, provide improvement to a patient's quality of life, or delay, prevent or inhibit the onset of the disorder. The term "lipid" is a generic term to describe fats and oils, such as fatty acids, esters of fatty acids, esters of glycerin, fatty alcohols, waxes, unsaponifiables, sterols, siloxanes, silanes, lanolin, hydrocarbons, glyceryl esters, essential oils, vegetable oils, mineral oils, 5 animal oils and edible oils. The term "salt thereof' refers to salts that are pharmaceutically acceptable. Such salts include: (1) acid addition salts, formed with acids such as, for example, acetic acid, benzoic acid, citric acid, gluconic acid, glutamic acid, glutaric acid, glycolic acid, hydrochloric acid, lactic acid, maleic acid, malic acid, malonic acid, mandelic acid, phosphoric acid, propionic j acid, sorbic acid, succinic acid, sulfuric acid, tartaric acid, naturally and synthetically derived amino acids, and mixtures thereof; or (2) salts formed when an acidic proton present in the parent compound is either (i) replaced by a metal ion e.g. an alkali metal ion, an alkaline earth metal ion or an aluminium ion; or (ii) protonates an organic base such as, for example, ethanolamine, diethanolamine, triethanolamine, tromethamine and N-methylglucamine. Any concentration range, percentage range or ratio range recited herein is to be understood to include concentrations, percentages or ratios of any integer within that range and fractions thereof, such as one tenth and one hundredth of an integer, unless otherwise indicated. It should be understood that the terms "a" and "an" as used herein refer to "one or more" of the enumerated components. It will be clear to one of ordinary skill in the art that the use of 0 the singular includes the plural unless specifically stated otherwise. Therefore, the terms "a," "an" and "at least one" are used interchangeably in this application. Throughout the application, descriptions of various embodiments use "comprising" language, however in some specific instances, an embodiment can alternatively be described using the language "consisting essentially of' or "consisting of'. 5 All numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term "about." "Substantially devoid" of a specified component refers to a composition with less than 14 about 1% by weight of the specified component. "Devoid" of a specified component refers to a composition where the specified component is absent. Other terms used herein are intended to be defined by their well known meanings in the art. 5 Examples The invention will now be described by reference to the following examples which are merely illustrative and are not to be construed as a limitation of the scope of the present invention. D The following compositions of Examples 1 and 2 may be prepared by the methods of preparation as set forth below in Example 4. Example 1 - Calcium mupirocin polymeric composition Item Ingredient % by weight I PVP/VA 30:70 10 2 Ethanol 10 3 Water 59.5 4 Hexylene glycol 20 5 Calcium mupirocin 0.5 Total 100 Example 2 - Mupirocin polymeric composition Item Ingredient % by weight I PVP / VA 30:70 10 2 Ethanol 10 3 Water 55.7 4 Hexylene glycol 23.8 5 Mupirocin 0.5 Total 100 0 15 Example 3 - Additional polymeric compositions The following placebo compositions were also prepared. Each composition was a clear solution. The mupirocin calcium or mupirocin may be added to the placebo composition to 5 form the final composition. A number of the compositions prepared were devoid of co-solvent (i.e. devoid of hexylene glycol), but yet were still a clear solution. Item Ingredient % % % % % % % % % % I PVPNA 11.9 12 4 10.2 10.3 3.2 10.7 20.9 49.1 49.8 30:70 2 Ethanol 23.4 24.5 23 21 20.7 23.8 4.7 5.5 17.9 18.9 3 Water 64.7 63.5 73 66.2 66.9 73 65.6 56.3 31.1 31.3 4 Hexylene 0 0 0 2.6 2.1 0 19 17.3 1.9 0 glycol Total 100 100 100 100 100 100 100 100 100 100 ) Example 4 - Methods of preparation Preparation of calcium mupirocin and mupirocin compositions using P VP/VA (30:70) PVPNA (30:70) is available as a 50% mixture in ethanol (Luviskol* VA 37E, BASF). PVP/VA (30:70) as an ethanol solution was added to water and a turbid solution formed. 5 Hexylene glycol was subsequently added to form a transparent solution. Calcium mupirocin or mupirocin was added and dissolved by vigorously shaking and rotating the preparation for 60 minutes (in accordance with Examples 1 and 2 respectively). Preparation of a calcium mupirocin composition using P VP/VA (60:40 and 70:30) 0 Calcium mupirocin was dissolved in water followed by addition of an ethanolic solution of PVPNA (70:30) (Luviskol® VA 73E, BASF). A transparent solution resulted. Hexylene glycol was not required. Similarly, calcium mupirocin was dissolved in water, followed by the addition of ethanol, and then PVPNA (60:40) powder (Plasdon S630, ISP Corp.) was added. A 5 transparent solution resulted. Hexylene glycol was not required. Preparation ofplacebos using PVP/VA (30:70) An ethanolic solution of PVPNA (30:70) was applied to a polypropylene sheet and dried in an oven at 800'C until the ethanol had evaporated so as to afford a dried power. The 16 dried PVP/VA powder was dissolved in ethanol to form a transparent solution, followed by addition of water. Addition of water was carefully monitored to observe the transformation from a transparent solution into a turbid mixture. Where a turbid mixture resulted, hexylene glycol was added dropwise until a transparent solution was obtained. The use of PVP/VA 5 (30:70) powder rather than an ethanolic solution of the polymer, afforded a number of compositions where the polymer could be solubilised in low levels of ethanol, yet be devoid of hexylene glycol. 0 Example 5 - polymeric compositions The following compositions (Examples 5a-5f) further exemplify the present invention. Example 5a - Co-solvent free / low ethanol calcium mupirocin polymeric solution Item Ingredient % by weight I PVP / VA 30:70 48 2 Ethanol 19 3 Water 31 4 Calcium mupirocin 2 Total 100 Example 5b - Co-solvent free / low ethanol calcium mupirocin polymeric gel Item Ingredient % by weight I PVP / VA 30:70 47 2 Ethanol 19 3 Water 31 4 Xanthan gum 1 5 Calcium mupirocin 2 Total 100 Example 5c - Co-solvent free / low ethanol clindamycin phosphate polymeric gel Item Ingredient % by weight 1 PVP / VA 30:70 25 2 Ethanol 10 3 Water 62.75 4 Xanthan gum 1 5 Clindamycin phosphate 1.25 17 Total 100 Example 5d - Co-solvent free / low ethanol metronidazole polymeric gel Item Ingredient % by weight I PVP / VA 30:70 25 2 Ethanol 10 3 Water 63 4 Xanthan gum 1 5 Metronidazole I Total 100 Example 5e - Calcium mupirocin in combination with (1) mupirocin, (2) clotrimazole, (3) hyaluronic acid and (4) clobetasol propionate (1) (2) (3) (4) Ingredient % by weight % by weight % by weight % by weight PVP / VA 10 50 50 50 30:70 Ethanol 10 19 19 19 Water 58 28 27 28.95 Hexylene 20 0 0 0 glycol Actives 1% mupirocin Ca 2% mupirocin Ca 2% mupirocin Ca 2% mupirocin Ca 1% mupirocin 1% clotrimazole 2% hyaluronic 0.05% clobetasol acid propionate Total 100 100 100 100 18 Example 5f - Calcium mupirocin in combination with (5) tretinoin, (6) hydrocortisone, (7) adapalene and (8) metronidazole (5) (6) (7) (8) Ingredient % by weight % by weight % by weight % by weight PVP/VA 50 50 50 50 30:70 Ethanol 19 19 19 19 Water 28.975 28 28.9 28.5 Hexylene 0 0 0 0 glycol Actives 2% mupirocin Ca 2% mupirocin Ca 2% mupirocin Ca 2% mupirocin Ca 0.025% tretinoin 1% 0.1% adapalene 0.5% hydrocortisone metronidazole Total 100 100 100 Example 6 - Drug release The following formulations were also prepared and used to assess drug release from the compositions of the present invention. Ingredient % by weight % by weight % by weight PVP/VA (70:30) (60:40) (30:70) 10 10 10 Ethanol 10 10 10 Water 79.5 78 59.5 Hexylene glycol 0 0 20 Calcium mupirocin 0.5 2 0.5 Total 100 100 100 Methodology. Franz cell drug release studies 5 In vitro drug release experiments were carried out using a Franz cell methodology (Fan et al. (2004) J. Contr. Rel. 98, 355-365). A Franz cell apparatus was used (Permegear, USA) with 12 mL 0.01 M PBS solution, pH 7.4 (Aldrich) in the Franz cell receptor compartment and the donor compartment. Two hydrophilic DuraporeTM polyvinylidene fluoride membranes (Millipore) were placed between 19 the receptor and donor compartments (25 mm diameter, 0.1 ptm pore size with 70% porosity, 125 ptm thickness). The temperature of the Franz cells was optimized and maintained at 30*C. About 30-50 mg of each formulation was placed on the membranes from the donor compartment. 200 pL aliquots of the receptor phase were drawn at certain time intervals and 5 subjected to HPLC analysis for drug content. Each aliquot was replaced by an equivalent amount of PBS solution. HPLC analysis Methanol:H 2 0 (50:50) was used as the diluent for the HPLC sample preparations. A D reversed phase HPLC analytical method was used, with an Apollo C 18 column (150 x 4.6 mm, 5pm), Photodiode array detector (210-300 nm range, detection at 223 nm), with isocratic elution at 1.5 mL/min and a mobile phase containing 55% methanol and 45% 0.1 M ammonium acetate buffer (pH 5.7). The retention time of calcium mupirocin was about 6 minutes and the total run time was 10 minutes. The error of analysis in the HPLC analyses i was found to be 2-5%. Standard deviation (SD) and % relative standard deviation (% RSD) were found to be in the range of 1-7% and about 20%, respectively. Results and discussion In an attempt to prepare a homogeneous topical composition comprising calcium mupirocin where the rate of release of the active is modulated, a number of polymers (Eudragit E100, Eudragit S100, Eudragit NE30D and Eudragit RLPO) were explored, but these polymers generally precipitated from the composition. Desirably, PVP/VA was shown to be able to modulate release of the active agent, but remain solubilized in the composition. In particular, PVPNA with varying ratios of PVP:VA monomers were explored, namely 70:30, 60:40 and 30:70. It was observed that PVPNA 60:40 and 70:30 were soluble in compositions comprising 10% ethanol. However PVPNA 30:70 was not soluble and required the addition of 20% hexylene glycol to solubilize the copolymer. It was later demonstrated, however, that a composition comprising PVPNA 30:70 but devoid of hexylene glycol could be prepared by using PVPNA 30:70 polymer powder, rather than as D an ethanolic solution of the polymer. The PVPNA 30:70 as a powder, rather than an ethanolic solution, afforded greater control over the relative concentrations of polymer, ethanol and water present in the composition. Modulation in the rate of release of calcium mupirocin is illustrated in Figure 1. This figure shows that for the composition comprising PVP:VA 30:70, calcium mupirocin release reached equilibrium after 4 hours. This compares to only 2 hours for the PVP:VA formulations having 60:40 and 70:30 ratios. This demonstrates a more gradual release of 20 active agent where the ratio of the hydrophobic monomer (VA) is greater than the ratio of the hydrophilic monomer (PVP), i.e. as is the case for PCPNA 30:70. Figure 2 illustrates the first order derivative of the release data. These data show a clear difference in the release profile of PVPNA 30:70 copolymer (on the one hand) and PVP:VA 5 60:40 and PVP:VA 70:30. Figure 3 illustrates that as the PVPNA ratio changes from 70:30 to 60:40 to 30:70 (increasing hydrophobicity), wherein the release exponent (n) increases from 0.17 for PVP:VA 70:30 to 0.47 for PVP:VA (60:40) and 0.41 for PVP:VA (30:70). Furthermore, the rate constant (k) is reduced from 0.3 min~' (for PVP:VA 70:30) to 0.08 min-' (for both PVP:VA 0 60:40 and PVP:VA 30:70). Thus, the n and k values are affected by changes in the hydrophobicity of the respective PVPNA copolymers. Example 7 - rub resistance and water resistance 5 The following placebo formulations were to assess the water- and rub-resistance of the compositions of the present invention. Ingredient % by weight % by weight % by weight % by weight Polymer (PVP / VA) 10 11.9 12 11 Ethanol 10 23.4 24.5 20 Water 60 64.7 63.5 69 Hexylene glycol 20 0 0 0 Total 100 100 100 100 ) Methodology Rub resistance studies Around 20 mg of each formulation was spread evenly on separate glass slides. The slides were dried at 45*C for 3 hours. Each film was subjected to abrasion with a 100 gm standard weight covered with a lint free tissue (Kimwipes TM, Kimberley-Clark). In particular, 5 the 100 gm standard weight covered with a lint free tissue was slowly oscillated 20 times back and forth over each dried film. The weight of the glass slides with the dried films before and after the abrasion was measured to evaluate the rub-resistance of each film. Water resistance studies 0 Transpore T M medical tape (3M) was affixed to glass slides. Around 200 mg of each formulation was spread evenly on the medical tape. The slides were then dried at 45'C for 3 hours. The weight of each dried plate was noted. The dried plates were subsequently 21 immersed in water at 45*C for 30 minutes. The plates were removed from the water and dried. Again, the weight of each slide was noted. The difference in the weight of each slide (i.e. before and after being immersed in water) was calculated and represented the wash resistance of the polymeric films. 5 Results and discussion Figure 4(a) illustrates that the addition of hexylene glycol does not impact the rub resistance of the compositions. 0 Figure 4(b) illustrates that good wash resistance may be obtained with compositions comprising low amounts of ethanol e.g. about 20%. Figure 4(c) illustrates that the addition of hexylene glycol negatively impacts the wash resistance of the compositions of the invention. 5 These data demonstrate that a composition with about 20% ethanol, and free of hexylene glycol, will have both adequate water and rub resistance. It was also observed that the compositions without hexylene glycol dried down more rapidly, and result in a cosmetically elegant film (i.e. without the stickiness or tackiness associated with hexylene glycol). All publications, including but not limited to patents and patent applications, cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein as though fully set forth. The above description fully discloses the invention including preferred embodiments thereof. Modifications and improvements of the embodiments specifically disclosed herein are within the scope of the following claims. Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest 0 extent. Therefore, the Examples herein are to be construed as merely illustrative and not a limitation of the scope of the present invention in any way. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. 22 The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. 23

Claims (20)

1. A topical pharmaceutical composition comprising a therapeutically effective amount of an antibacterial agent, PVP/VA copolymer, water, from 5% to 30% by weight of at least one volatile solvent, and optionally one or more dermatologically acceptable excipients, and wherein the PVP/VA copolymer is solubilized in the composition.

2. The composition according to claim 1, wherein the antibacterial agent is mupirocin, gentamicin, neomycin, streptomycin, cefpodoxime proxetil, clindamycin, lincomycin, erythromycin, bacitracin, gramicidin(s), vancomycin, doxycycline, minocycline, oxytetracycline, tetracycline, fosfomycin, fusidic acid, sulfacetamide, metronidazole, benzoyl peroxide and dapsone, pharmaceutically acceptable salts thereof, and mixtures thereof.

3. The composition according to claim 2, wherein the antibacterial agent is present in an amount from 0.1% to 10% by weight.

4. The composition according to any one of claims 1 to 3, wherein the at least one volatile solvent is selected from ethanol, propanol, iso-propanol, n-butyl alcohol, t-butyl alcohol, butoxy ethanol, acetone, ethyl acetate or butyl acetate.

5. The composition according to claim 4, wherein the at least one volatile solvent present in the composition is ethanol.

6. The composition according to claim 5, wherein the volatile solvent is a mixture of at least two volatile solvents, and wherein the first volatile solvent is ethanol.

7. The composition according to claim 6, wherein the volatile solvent is a mixture of ethanol and iso-propanol.

8. The composition according to claim 6, wherein the volatile solvent is a mixture of ethanol and ethyl acetate.

9. The composition according to any one of claims 1 to 8, wherein the topical pharmaceutical composition further comprises a second pharmaceutically acceptable active agent. 23

10. The composition according to claim 9, wherein the second pharmaceutically acceptable active agent is selected from the group consisting of a second antibacterial agent, a retinoid, a corticosteroid, an antifungal agent, a skin conditioning agent, a nutritional agent, or an antiseptic agent.

11. The composition according to any one of claims 1 to 10, wherein the one or more dermatologically acceptable excipients are selected from the group consisting of at least one co-solvent, a pH adjusting agent, a humectant, a film extender, a chelating agent, an antioxidant, a preservative, a gelling agent, a fragrance, a colorant, a penetration enhancer, and a combination or mixture thereof.

12. The composition according to claim 11, wherein the at least one co-solvent is selected from an alcohol, a carboxylic acid, a diol, a polyol or a combination or mixture thereof, present in an amount from 1% to 30% by weight.

13. The composition according to claim 12, wherein the alcohol is selected from amyl alcohol, benzyl alcohol, cyclohexanedimethanol, diacetone alcohol, hexyl alcohol, or tetrahydrofurfuryl alcohol; and the diol is selected from 1,2-hexanediol, butylene glycol, diethylene glycol, dipropylene glycol, ethyl hexanediol, ethylene glycol, hexylene glycol, pentylene glycol, propylene glycol, tetraethylene glycol, triethylene glycol, or tripropylene glycol; and the polyol is selected from polyethylene glycol, butanetriol, glycerol and 1,2,6-hexanetriol.

14. The composition according to claim 11, wherein the at least one co-solvent is propylene glycol.

15. The composition according to any one of claims 1 to 14 which comprises a volatile solvent present in an amount from 10% to 25% by weight and is substantially devoid or devoid of a co-solvent.

16. A topical pharmaceutical composition comprising: (a) calcium mupirocin, (b) a PVP/VA co-polymer in an amount from 30% to 60% by weight, (c) water in an amount from 20% to 40% by weight, and (d) a volatile solvent in an amount from 10% to 25% by weight; and optionally a gelling agent, and other dermatologically acceptable excipients thereof. 24

17. The composition according to claim 16, wherein the ratio of PVP monomer to VA monomer in the PVP/VA is from 30:70 to 70:30.

18. The composition according to claim 16 or 17, wherein the PVP/VA is present in a ratio of about 30:70 and wherein the composition is free of hexylene glycol.

19. A method of treating a bacterial infection of the skin in a mammal in need thereof, comprising administering to said mammal, a topical pharmaceutical composition according to any one of claims 1 to 18.

20. The method according to claim 19, wherein the bacterial infection of the skin is acne, impetigo, superficially infected dermatoses, wounds which have become infected, rosacea or folliculitis. 25