CROSS-REFERENCE TO RELATED APPLICATIONS [0001] None

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0002] This invention generally relates to a substantially anhydrous composition for topical delivery of a lipid soluble pharmaceutical agent. The invention also generally relates to a method of delivering the pharmaceutical agent to a substrate.

2. Description of the Related Art

[0003] Compositions for the topical delivery of lipid soluble pharmaceutical agents are known in the art. For example, compositions containing lipophilic drugs in petrolatum base ointments are known. These petrolatum-based compositions often contain a surfactant or propylene glycol to solubilize the drug and modulate drug release and/or skin permeation.

Petrolatum-based vehicles provide simple vehicles and provide chemical drug stability.

However, petrolatum-based formulations are greasy and, hence, patient compliance is an issue. Additionally, propylene glycol is a well known irritant at higher concentration levels.

[0004] Compositions containing water for the topical delivery of lipid soluble pharmaceutical agents are also known in the art. For example, oil in water emulsions containing lipophilic drugs are known.

[0005] Volatile silicones thickened with silicone elastomers to form gels are also known in the art.

SUMMARY OF THE INVENTION AND ADVANTAGES

[0006] The compositions of this invention comprise a substantially anhydrous mixture containing a silicone elastomer, a solvent for the silicone elastomer, a surfactant and a lipid soluble pharmaceutical agent.

[0007] The method of the invention comprises mixing the solvent, the silicone elastomer, the surfactant and the lipid soluble pharmaceutical agent and applying the mixture to the substrate to which the pharmaceutical agent is to be released.

DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention includes a composition comprising a substantially anhydrous mixture of a silicone elastomer, a solvent for the silicone elastomer, a surfactant and a lipid soluble pharmaceutical agent. The present invention also includes a method of delivering the lipid soluble pharmaceutical agent to a substrate for a variety of applications including transdermal, pharmaceutical, veterinary, and oral health care uses.

[0009] The term "substantially anhydrous" denotes that water is not added to the composition as a component of the invention, but some residual water may be present in minor amounts in one of the other components added to the composition. [0010] Silicone elastomers are known in the art. These are described, for example, in United States Patent No. 4,882,377 (issued November 21, 1989), United States Patent No. 5,654,362 (issued August 5, 1997), United States Patent No. 5,994,459 (issued November 30, 1999), United States Patent No. 6,015,858 (issued January 18, 2004), Unite States Patent No. 6,351,540, United States Patent No. 6,538,061, United States Patent No. 6,444,745, United States Patent No. 6,346,583, United States Patent No. 6,207,717, United States Patent No. 5,811,487, United States Patent 5,880,210, United States patent No. 5,889,108, United States Patent No. 5,929,164, United States Patent No. 5,948, 855, United States Patent No. 5,969,035, United States Patent No. 5,977,280, United States Patent No. 6, 080,394, United States Patent No. 6,168,782, United States Patent No. 6,177,071, United States Patent No. 6,200,581, United States Patent No. 6,207,717, United States Patent No. 6,221,927, United States Patent No. 6,221,979, United States Patent No. 6,238,657, United States Patent No. 4,987,169 and United States Patent Publication No. 2004/0228821, the disclosures of which are hereby incorporated by reference in their entirety.

[0011] These silicone elastomers are also commercially available from a variety of sources such as Dow Corning Corporation. These include Dow Corning® Elastomer 10 and 9041. [0012] The silicone elastomers are present in the composition of the invention in an amount of 0.1 to 75 wt. %, alternatively about 1 to 40 wt. %. Mixtures of silicone elastomers can also be used.

[0013] In one embodiment of the invention, the silicone elastomers are prepared by a crosslinking reaction between (A) ≡Si-H containing polysiloxanes and (B) an alpha, omega- diene in the presence of a platinum catalyst and (C) a low molecular weight linear or cyclic polysiloxane as described in US Patent No. 5,654,362. The elastomers can be swollen with a low molecular weight polysiloxane under a shear force.

[0014] The ≡Si-H containing polysiloxane (A) is represented by compounds of the formula R ₃ Si0(R' ₂ Si0) _a (R"HSi0) _b SiR ₃ designated herein as type A ¹ and compounds of the formula HR ₂ Si0(R' ₂ Si0) _c SiR ₂ H or formula HR ₂ Si0(R ₂ Si0) _a (R"HSi0) _b SiR ₂ H designated herein as type A ² . In these formulas, R, R ¹ , and R", are alkyl groups with 1-6 carbon atoms; a is 0-250; b is 1-250; and c is 0-250. The molar ratio of compounds A ² :A ^! is generally 0-20, alternatively 0-5.

[0015] The alpha, omega-diene (B) is a compound of the formula CH ₂ =CH(CH ₂ ) _X CH=CH ₂ where x is 1-20. Some representative examples of suitable alpha, omega-dienes for use herein are 1,4-pentadiene; 1,5-hexadiene; 1,6-heptadiene; 1,7-octadiene; 1,8-nonadiene; 1,9- decadiene; 1,11-dodecadiene; 1,13-tetradecadiene; and 1,19-eicosadiene.

[0016] The addition and crosslinking reaction requires a catalyst to effect the reaction between the ≡SiH containing polysiloxane and the alpha, omega-diene. Suitable catalysts are Group VIII transition metals, i.e., the noble metals. Such noble metal catalysts are described in US Patent 3,923,705, incorporated herein by reference to show platinum catalysts. One preferred platinum catalyst is Karstedt's catalyst, which is described in Karstedt's US Patents 3,715,334 and 3,814,730, incorporated herein by reference. Karstedt's catalyst is a platinum divinyl tetramethyl disiloxane complex typically containing about one weight percent of platinum in a solvent such as toluene. Another preferred platinum catalyst is a reaction product of chloroplatinic acid and an organosilicon compound containing terminal aliphatic unsaturation. It is described in US Patent 3,419,593, incorporated herein by reference. The noble metal catalysts are used in amounts from 0.00001-0.5 parts per 100 weight parts of the

≡SiH containing polysiloxane, preferably 0.00001-0.02 parts, most preferably 0.00001-0.002 parts.

[0017] The solvent used herein may comprise a solvent for the silicone elastomer described above. The solvent, when combined with the elastomer, serves to suspend and swell the elastomer to provide an elastic, three- dimensional gel network or matrix. The solvent for the polymer is liquid under ambient conditions and preferably has a low viscosity to provide for improved spreading on the skin.

[0018] In one embodiment, the solvent is a low molecular weight silicone oil. The phrase low molecular weight silicone oil is intended to include (i) low molecular weight linear and cyclic volatile methyl siloxanes, (ii) low molecular weight linear and cyclic volatile and non- volatile alkyl and aryl siloxanes, and (iii) low molecular weight linear and cyclic functional siloxanes. In one embodiment, are low molecular weight linear and/or cyclic volatile methyl siloxanes (VMS) are used. The term "volatile" as used herein refers to materials which exhibit a vapor pressure of more than about 0.2 mm Hg at 25° C. at one atmosphere and/or to materials that have a boiling point at one atmosphere of less than about 300° C.

[0019] VMS compounds correspond to the average unit formula (CH ₃ ) _a Si0( _4-a ) _/2 in which a has an average value of two to three. The compounds contain siloxane units joined by ≡Si-O- Si≡ bonds. Representative units are monofunctional "M" units (CHs) ₃ SiO _1Z2 and difunctional "D" units (CH ₃ ) ₂ Si0 _2/2 . [0020] The presence of trifunctional "T" units CH ₃ SiO ₃₇₂ results in the formation of branched linear or cyclic volatile methyl siloxanes. The presence of tetrafunctional "Q" units SiO _4/2 results in the formation of branched linear or cyclic volatile methyl siloxanes.

[0021] Linear VMS have the formula (CH ₃ ) ₃ SiO{(CH ₃ ) ₂ SiO} _y Si(CH ₃ ) ₃ . The value of y is 0-

5. Cyclic VMS have the formula {(CH ₃ ) ₂ Si0} _z . The value of z is 3-6. These volatile methyl siloxane often have boiling points less than about 250 ⁰ C and viscosities of about 0.65-5.0 centistokes (mm^/s).

[0022] Representative linear volatile methyl siloxanes (I) are hexamethyldisiloxane (MM) with a boiling point of 100 ⁰ C, viscosity of 0.65 mm^/s, and formula Me3SiOSiMe3; octamethyltrisiloxane (MDM) with a boiling point of 152 °C, viscosity of 1.04 mm^/s, and formula Me3SiOMe2SiOSiMe3; decamethyltetrasiloxane (MD2M) with a boiling point of

194 °C, viscosity of 1.53 mm ² /s, and formula Me3SiO(Me2SiO)2SiMe3;

dodecamethylpentasiloxane (MD3M) with a boiling point of 229 °C, viscosity of 2.06 mm ² /s, and formula Me3SiO(Me2SiO)3SiMe3; tetradecamethylhexasiloxane (MD4M) with a boiling point of 245 °C, viscosity of 2.63 mm2/s, and formula Me3SiO(Me2SiO)4SiMe3; and hexadecamethylheptasiloxane (MD5M) with a boiling point of 270 °C, viscosity of 3.24 mrn^/s, and formula Me3 SiO(Me2SiO)5SiMe3.

[0023] Representative cyclic volatile methyl siloxanes (II) are hexamethylcyclotrisiloxane (D3) a solid with a boiling point of 134 °C and formula {(Mβ2)SiO}3; octamethylcyclotetrasiloxane (D4) with a boiling point of 176 °C, viscosity of 2.3 mm^/s, and formula {(Me2)SiO}4; decamethylcyclopentasiloxane (D5) with a boiling point of 210 °C, viscosity of 3.87 mnvVs, and formula {(Me2)SiO}5; and dodecamethylcyclohexasiloxane

(Dβ) with a boiling point of 245 ⁰ C ₅ viscosity of 6.62 mm^/s, and formula {(Me2)SiO}6.

[0024] Representative branched volatile methyl siloxanes (III) and (IV) are heptamethyl-3- {(trimethylsilyl)oxy}trisiloxane (M3T) with a boiling point of 192 °C, viscosity of 1.57 mm^/s, and formula ^9!"!3003Si ₄ ; hexamethyl-3,3,bis {(trimethylsilyl)oxy} trisiloxane (M4Q) with a boiling point of 222 °C, viscosity of 2.86 mm^/s, and formula Ci2H36θ ₄ Si5; and pentamethyl {(trimethylsilyl)oxy} cyclotrisiloxane (MD3) with the formula C ₈ H ₂₄ O ₄ Si ₄ .

[0025] As previously noted, the invention also includes using low molecular weight linear and cyclic volatile and non-volatile alkyl and aryl siloxanes. Representative linear polysiloxanes are compounds of the formula R ₃ Si0(R ₂ Si0) _y SiR ₃ , and representative cyclic polysiloxanes are compounds of the formula (R ₂ SiO) ₂ . R is an alkyl group of 1-6 carbon atoms, or an aryl group such as phenyl. The value of y is 0-80, preferably 0-20. The value of z is 0-9, preferably 4-6. These polysiloxanes have viscosities generally in the range of about

1-100 centistokes (mrn^/s). [0026] Other types of solvents can swell the silicone elastomer. Thus, a single solvent or a mixture of solvents may be used. By solvent we mean (i) organic compounds, (ii) compounds containing a silicon atom, (iii) mixtures of organic compounds, (iv) mixtures of compounds containing a silicon atom, or (v) mixtures of organic compounds and compounds containing a silicon atom.

[0027] In general, the organic compounds are aromatic hydrocarbons, aliphatic hydrocarbons, alcohols, aldehydes, ketones, amines, esters, ethers, glycols, glycol ethers, alkyl halides, or aromatic halides. Representative of some common organic solvents are alcohols such as methanol, ethanol, 1-propanol, cyclohexanol, benzyl alcohol, 2-octanol, ethylene glycol, propylene glycol, and glycerol; aliphatic hydrocarbons such as pentane, cyclohexane, heptane, VM &P solvent, and mineral spirits; alkyl halides such as chloroform, carbon tetrachloride, perchloroethylene, ethyl chloride, and chlorobenzene; amines such as isopropylamine, cyclohexylamine, ethanolamine, and diethanolamine; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene; esters such as ethyl acetate, isopropyl acetate, ethyl acetoacetate, amyl acetate, isobutyl isobutyrate, and benzyl acetate; ethers such as ethyl ether, n-butyl ether, tetrahydrofuran, and 1,4- dioxane; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether, and propylene glycol monophenyl ether; ketones such as acetone, methyl ethyl ketone, cyclohexanone, diacetone alcohol, methyl amyl ketone, and diisobutyl ketone; petroleum hydrocarbons such as mineral oil, gasoline, naphtha, kerosene, gas oil, heavy oil, and crude oil; lubricating oils such as spindle oil and turbine oil; and fatty oils such as corn oil, soybean oil, olive oil, rape seed oil, cotton seed oil, sardine oil, herring oil, and whale oil. [0028] Other miscellaneous organic solvents can also be used, such as acetonitrile, nitromethane, dimethylformamide, propylene oxide, trioctyl phosphate, butyrolactone, furfural, pine oil, turpentine, and m-creosol. Still other solvents include volatile flavoring agents such as oil of wintergreen; peppermint oil; spearmint oil; menthol; vanilla; cinnamon oil; clove oil; bay oil; anise oil; eucalyptus oil; thyme oil; cedar leaf oil; oil of nutmeg; oil of sage; cassia oil; cocoa; licorice; high fructose corn syrup; citrus oils such as lemon, range, lime, and grapefruit; fruit essences such as apple, pear, peach, grape, strawberry, raspberry, cherry, plum, pineapple, and apricot; and other useful flavoring agents including aldehydes and esters such as cinnamyl acetate, cinnamaldehyde, eugenyl formate, p- methylanisole, acetaldehyde, benzaldehyde, anisic aldehyde, citral, neral, decanal, vanillin, tolyl aldehyde, 2,6-dimethyloctanal, and 2- ethyl butyraldehyde. [0029] In addition, the term solvent can also include volatile fragrances such as natural products and perfume oils. Some representative natural products and perfume oils are ambergris, benzoin, civet, clove, leaf oil, jasmine, mate, mimosa, musk, myrrh, orris,

sandalwood oil, and vetivert oil; aroma chemicals such as amyl salicylate, amyl cinnamic aldehyde, benzyl acetate, citronellol, coumarin, geraniol, isobornyl acetate, ambrette, and terpinyl acetate; and the various classic family perfume oils such as the floral bouquet family, the oriental family, the chypre family, the woody family, the citrus family, the canoe family, the leather family, the spice family, and the herbal family.

[0030] The solvent is generally used in the invention in an amount of about 1 to 99 wt. %, alternatively 5 to 70 wt. %. Mixtures of solvents can also be used.

[0031] The composition of the present invention also includes a surfactant. The surfactant helps disperse, suspend and/or solubilize the lipid soluble pharmaceutical agent and other ingredients in the form of micelles, vesicles, liquid crystals, lamellar phases, and other thermodynamically stable associative phases or structures. Further, the surfactant provides the ability to coat the substrate and provides additional sensory benefits. Known or conventional surfactants can be used in the composition, provided that the selected surfactant is chemically and physically compatible with essential components of the composition and provides the desired dispersion characteristics.

[0032] Examples of surfactants include those selected from the group consisting of anionic surfactants, nonionic surfactants, amphoteric surfactants, non- lathering surfactants, emulsifiers and mixtures thereof. Non-limiting examples of surfactants useful in the compositions of the present invention are disclosed in U.S. Pat. No. 6,280,757, to McAtee et al., issued Aug. 28, 2001 which is included by reference herein.

[0033] Examples of anionic surfactants useful in the compositions of the present invention are disclosed in McCutcheon's, Detergents and Emulsifiers, North American edition (1986), published by allured Publishing Corporation; McCutcheon's, Functional Materials, North American Edition (1992); and U.S. Pat. No. 3,929,678, to Laughlin et al., issued Dec. 30, 1975, which is incorporated by reference herein. These include those selected from the group consisting of sarcosinates, sulfates, isethionates, taurates, phosphates, lactylates, glutamates, and mixtures thereof. Other anionic materials useful herein are fatty acid soaps (i.e., alkali metal salts, e.g., sodium or potassium salts) typically having from a fatty acid having about 8 to about 24 carbon atoms, preferably from about 10 to about 20 carbon atoms. These fatty acids used in making the soaps can be obtained from natural sources such as, for instance, plant or animal-derived glycerides (e.g., palm oil, coconut oil, soybean oil, castor oil, tallow, lard, etc.) The fatty acids can also be synthetically prepared. Soaps and their preparation are

described in detail in U.S. Pat. No. 4,557,853. Other anionic materials include phosphates such as monoalkyl, dialkyl, and trialkylphosphate salts. Non-limiting examples of anionic lathering surfactants useful herein include those selected from the group consisting of sodium lauryl sulfate, ammonium lauryl sulfate, ammonium laureth sulfate, sodium laureth sulfate, sodium trideceth sulfate, ammonium cetyl sulfate, sodium cetyl sulfate, ammonium cocoyl isethionate, sodium lauroyl isethionate, sodium lauroyl lactylate, triethanolamine lauroyl lactylate, sodium caproyl lactylate, sodium lauroyl sarcosinate, sodium myristoyl sarcosinate, sodium cocoyl sarcosinate, sodium lauroyl methyl taurate, sodium cocoyl methyl taurate, sodium lauroyl glutamate, sodium myristoyl glutamate, and sodium cocoyl glutamate and mixtures thereof.

[0034] Non-limiting examples of nonionic surfactants for use in the compositions of the present invention are disclosed in McCutcheon's, Detergents and Emulsifiers, North American edition (1986), published by allured Publishing Corporation; and McCutcheon's, Functional Materials, North American Edition (1992). These include those selected from the group consisting of alkyl glucosides, alkyl polyglucosides, polyhydroxy fatty acid amides, alkoxylated fatty acid esters, sucrose esters, amine oxides, and mixtures thereof. Specific examples include those selected form the group consisting of C ₈ -C ₁₄ glucose amides, C ₈ -C ₁₄ alkyl polyglucosides, sucrose cocoate, sucrose laurate, lauramine oxide, cocoamine oxide and mixtures thereof. [0035] A wide variety of amphoteric lathering surfactants can be used in the compositions of the present invention. Particularly useful are those which are broadly described as derivatives of aliphatic secondary and tertiary amines, preferably wherein the nitrogen is in a cationic state, in which the aliphatic radicals can be straight or branched chain and wherein one of the radicals contains an ionizable water solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. Non-limiting examples of amphoteric surfactants useful in the compositions of the present invention are disclosed in McCutcheon's, Detergents and Emulsifiers, North American edition (1986), published by allured Publishing Corporation; and McCutcheon's, Functional Materials, North American Edition (1992). [0036] Non-limiting examples zwitterionic surfactants are those selected from the group consisting of betaines, sultaines, hydroxysultaines, alkyliminoacetates, iminodialkanoates, aminoalkanoates, and mixtures thereof.

[0037] A wide variety of non-lathering surfactants are useful herein. Nonlimiting examples of these non-lathering compositions are: polyethylene glycol 20 sorbitan monolaurate (Polysorbate 20), polyethylene glycol 5 soya sterol, Steareth-20, Ceteareth-20, PPG-2 methyl glucose ether distearate, Ceteth-10, Polysorbate 80, cetyl phosphate, potassium cetyl phosphate, diethanolamine cetyl phosphate, Polysorbate 60, glyceryl stearate, PEG-100 stearate, polyoxyethylene 20 sorbitan trioleate (Polysorbate 85), sorbitan monolaurate, polyoxyethylene 4 lauryl ether sodium stearate, polyglyceryW isostearate, hexyl laurate, steareth-20, ceteareth-20, PPG-2 methyl glucose ether distearate, ceteth-10, diethanolamine cetyl phosphate, glyceryl stearate, PEG-100 stearate, and mixtures thereof. [0038] Suitable surfactants also include silicone surfactants. Suitable silicone surfactants include dimethicone based surfactants, surfactant silicone elastomers, and combinations thereof. In one embodiment, surfactant silicone elastomers or other silicone surfactants are uses herein. [0039] In one embodiment, the surfactant is a silicone copolyol. This material also allows a controlled rate of the delivery of the pharmaceutical agent to the substrate. That is, the dispersing agent functions as a drug release modulator to control the rate at which the pharmaceutical agent is released for delivery to the substrate.

[0040] The silicone copolyol (or dimethicone copolyol) are polydimethyl siloxanes that have been modified to include polyether side or pendant chains such as polyethylene oxide chains, polypropylene oxide chains, mixtures of these chains, and polyether chains containing moieties derived from both ethylene oxide and propylene oxide. Also included are polydimethyl siloxanes that have been modified to include polyglycerine side chains. Other examples include alkyl-modified dimethicone copolyols, (i.e., compounds that contain C2- C30 pendant side chains). Still other useful dimethicone copolyols include materials having various cationic, anionic, amphoteric, and zwitterionic pendant moieties.

[0041] Nonlimiting examples of dimethicone copolyols also include lauryl dimethicone copolyol, dimethicone copolyol acetate, dimethicone copolyol adipate, dimethicone copolyolamine, and dimethicone copolyol behenate. See International Cosmetic Ingredient Dictionary, Fifth Edition, 1993. [0042] Examples of commercially available dimethicone copolyols useful herein sold by Dow Coming Corporation are Dow Corning.RTM. 190, 193, Q2-5220, 2501 Wax, 2-5324 fluid, and 3225C (this later material being sold as a mixture with cyclomethicone). Cetyl

dimethicone copolyol is commercially available as a mixture with polyglyceryl-4 isostearate (and) hexyl laurate and is sold under the tradename ABIL.RTM. WE-09 (available from Goldschmidt). Cetyl dimethicone copolyol is also commercially available as a mixture with hexyl laurate (and) polyglyceryl-3 oleate (and) cetyl dimethicone and is sold under the tradename ABIL.RTM. WS-08 (also available from Goldschmidt). Other nonlimiting examples include the SILWET series and SILSOFT series available from Crompton/OSi. [0043] In one embodiment, the composition contains from about 0.1 to about 25 wt. % surfactant, alternatively from about 0.5% to about 10 wt. %. Mixtures of surfactants can also be used. [0044] The pharmaceutical agent used herein is lipid soluble. Examples of such agents include drugs used in dermatology for the treatment of dermatoses (such as clobetasol, betamethasone dipropionate, hydrocortisone, dexamethasone sodium phosphate, retinal, tretinoin, isotretinoin, dapsone, calipotriene, ketoconazole, clotrimazole, itraconazole and arotinoid), drugs for hormonal replacement therapy (such as estradiol, ethinyl estradiol and norethindrone), drugs that inhibit the synthesis and actions of adrenocortical hormones (such as Cortisol, cortisone and prednisone), drugs such as clonidine, scopolamine, propranolol, estradiol, phenylpropanolamine hydrochloride, ouabain, atropine, haloperidol, isosorbide, nitroglycerin, ibuprofen, ubiquinones, indomethacin, prostaglandins, naproxen, salbutamol, guanabenz, labetalol, pheniramine, metrifonate, steroids, antiacne agents such as benzoyl peroxide, triclosan or tretinoin, antibacterial agents such as chlorohexadiene gluconate, antifungal agents such as miconazole nitrate, anti-inflammatory agents such as salicylic acid, corticosteroidal drugs, non-steroidal anti- inflammatory agents such as diclofenac, antipsoriasis agents such as clobetasol propionate or retinoids, anaesthetic agents such as lidocaine, antipruritic agents, antidermatitis agents, and/or agents generally considered barrier films.

[0045] The compositions of the invention contain from about 0.001 to about 10 wt. % lipid soluble pharmaceutical agent, alternatively from about 0.01% to about 5 wt. %. [0046] In addition to the lipid soluble pharmaceutical agent and the surfactant, various excipients may be incorporated into the composition. As generally understood by those skilled in the art, excipients are additives that are used to convert the pharmaceutical agent into appropriate dosage forms that are suitable for application to the substrate. Excipients may also be added to stabilize the composition and to optimize application characteristics,

such as flowability. Examples of potential excipients include, but are not limited to, those that are found in the CTFA ingredient Database and the handbook of pharmaceutical excipients such as absorbents, anticacking agents, antistatic agents, astringents, binders, buffering agents, bulking agents, chelating agents, colorants, cosmetic astringents, cosmetic biocides, deodorant agents, emollients, external analgesics, film formers, flavoring agents, fragrance ingredients, humectants, lytic agents, moisturizing agents, occlusivity enhancers, opacifying agents, oxidizing agents, reducing agents, penetration enhancers including oleic acid, azone, methyl laurate, lauryl alcohol and ethyl oleate, pesticides, plasticizers, preservatives, skin bleaching agents, skin conditioning agents, skin protectants, slip modifiers, solubilizing agents, solvents, sunscreen agents, surface modifiers, surfactants and emulsifying agents, suspending agents, thickening agents, viscosity controlling agents including increasing or decreasing agents, UV light absorbing agent. Other possible excipients include, but are not limited to, sugars and derivatives, starch derivatives, cellulosic materials, polysaccharides, polyethers, polyvinyl alcohols, acrylic and methacrylic acid polymers, pyrrolidone derivatives, glycuronam polymer and derivatives, solid diluents, solid lubricants, suspending agents, cyclodextrins, and others.

[0047] Also, various cosmetic, personal care, and cosmeceutical components may be included aside from the excipient or excipients. Examples of suitable cosmetic, personal care, and cosmeceutical components include, but are not limited to, sunscreen agents, lipid soluble vitamins, alcohols, fatty alcohols and polyols, aldehydes, alkanolamines, alkoxylated alcohols, alkoxylated amides, alkoxylated amines, alkoxylated carboxylic acids, amides including salts, amines, amino acids including salts and alkyl substituted derivatives, esters, alkyl substituted and acyl derivatives, polyacrylic acids, acrylamide copolymers, adipic acid copolymers, alcohols, aminosilicones, biological polymers and derivatives, butylene copolymers, carbohydrates, carboxylic acids, carbomers, esters, ethers and polymeric ethers, glyceryl esters and derivatives, halogen compounds, heterocyclic compounds including salts, hydrophilic colloids and derivatives including salts and gums, imidazolines, inorganic materials, ketones, isethionates, lanolin and derivatives, organic salts, phenols including salts, phosphorus compounds, polyacrylates and acrylate copolymers, protein and enzymes derivatives, synthetic polymers including salts, siloxanes and silanes, sorbitan derivatives, sterols, sulfonic acids and derivatives and waxes.

[0048] The compositions of the invention can be made by merely mixing all the ingredients and subjecting resultant mixture to shear force to form the desired product. Any type of mixing and shearing equipment may be used to perform these steps such as a batch mixer, planetary mixer, single or multiple screw extruder, dynamic or static mixer, colloid mill, homogenizer, sonolator, or a combination thereof.

[0049] In one embodiment, the pharmaceutical agent is first mixed with the surfactant. The resultant mixture is then added to the swollen silicone elastomer.

[0050] The method of delivering the pharmaceutical agent to the substrate further includes the step of applying the composition of the invention to the substrate to deliver the pharmaceutical agent to the substrate. Upon application, a film is formed on the substrate. The film contains the pharmaceutical agent. Following application, the pharmaceutical agent is delivered through the film to the substrate.

[0051] In embodiments where the substrate is skin, the composition is applied to the skin to deliver the pharmaceutical agent to the skin. The composition may be applied, i.e., rubbed or coated, directly onto the skin. Alternatively, the composition may be deposited on a transdermal patch prior to application to the substrate.

[0052] The following examples are included to demonstrate embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention. All percentages are in wt. %.

Examples 1-5

[0053] The following process was used to make the compositions in the Examples: Clobetasol was dispersed in Dow Corning® Emulsifier 10 (a silicone alkylmethyl glycol). Dow Corning® Elastomer 10 (a silicone elastomer blended in decamethyl cyclopentasiloxane to form a gel) or Dow Corning® 9041 (a silicone elastomer in dodecamethyl pentasiloxane) was added to the clobetasol mixture. Decamethyl cyclopentasiloxane was added to the mixture if necessary to make 100 wt %. For the control, the clobetasol was mixed directly with the Elastomer 10.

Example 1

Clobetasol 0.05 %

Emulsifier 10 20 %

Elastomer 10 79.95 %

Example 2

Clobetasol 0.05%

Emulsifier 10 10%

Elastomer 10 79.95%

Decamethyl Cyclopentasiloxane 10%

Example 3

Clobetasol 0.05%

Emulsifier 10 5%

Elastomer 10 79.95%

Decamethyl Cyclopentasiloxane 15%

Example 4

Clobetasol 0.05%

Emulsifier 10 2.5%

Elastomer 10 79.95%

Decamethyl Cyclopentasiloxane 17.5%

Example 5

Clobetasol 0.05%

Emulsifier 10 10%

9041 62.5%

Decamethyl Cyclopentasiloxane 27.45%

Control

Clobetasol 0.05% Emulsifier 10 00%

Elastomer 10 79.95%

Decamethyl Cyclopentasiloxane 20.0%