Skin treatment composition

Claim 2

A cosmetically acceptable product for topical application to human skin comprising: (i) from 0.001 to 20% by weight of an amphiphilic compound having a log partition coefficient in octanol/water of from 0.5 to 3.5; provided that when the amphiphilic compound is one having an unbranched alkyl chain,.that chain contains no more than 12 carbon atoms; (ii) from 1 to 20% by weight of emulsifier which is normally solid at 20°C, which has an average HLB value of from 5 to 11, and which is capable with water of forming a gel phase having an X-ray reflection of from 0.37 to 0.44 nm and which permits substantially no co-crystallisation therewith of the amphiphilic compound; (iii) from 0.1 to 50% by weight of an activity enhancer which is capable, at a concentration of 5% by weight'of increasing the cloud point temperature of a 0.025M aqueous solution of polyoxyethylene (8) nonylphenyl ether by at least 10°C; and (iv) from 5 to 98.899% by weight of water; the product having an aqueous phase which forms from 5 to 99% by volume and a gel phase which forms from 1 to 95% by volume.

Claim 3

A product according to claim 1, in which the amphiphilic compound has a log partition coefficient in octanol/water of from 0.50 to 1.00.

Claim 4

A product according to claim 2, in which the amphiphilic compound is chosen from: morphine triethyl citrate sulphamonomethoxine adenosine diphosphate ephedrine sulphamethoxazole 5-ethyl-5-i-propyl barbituric acid 5,5-diethyl barbituric acid p-methylbenzene sulphonamide o-methylbenzene sulphonamide m-methylbenzene sulphonamide p-aminobenzoic acid saccharin p-dihydroxybenzene o-dihydroxybenzene p-nitrobenzene sulphonamide m-nitrobenzene sulphonamide 2-ethyl-2-propanol crotonic acid, and mixtures thereof

Claim 5

A product according to claim 1, in which the amphiphilic compound has a log partition coeffecient in octanol/water of from 1.01 to 1.50.

Claim 6

A product according to claim 4, in which the amphiphilic compound is chosen from: erythromycin 4'-hydroxyerythromycin colchicine codeine α-hydroxy benzyl penicillin cyclobarbital 5-ethyl-5-phenyl barbituric acid chloramphenicol nicotine niacinamide 4-methyl-6-(2,4,6-trimethyl-pentyl)-2-(1H) -pyridone . 5,5-dimethyl, 1-methyl barbituric acid acetyl salicylic acid coumarin 2-phenyl ethanol ethyl nicotinate m-hydroxybenzoic benzimidazole phenol, and mixtures thereof.

Claim 7

A product according to claim 1, in which the amphiphilic compound has a log partition coefficient in octanol/water of from 1.51 to 2.00.

Claim 8

A product according to claim 6, in which the amphiphilic compound is chosen from: hydrocortisone strychnine quinine thebaine atropine - benzyl pencillin sulphaphenzole procaine sulphadimethoxine adenosine triphosphate azelaic acid amphetamine N-acetyl 0-aminobenzoic acid O-hydroxybenzaldehyde benzoic acid, and mixtures thereof.

Claim 9

A product according to claim 1, in which .the amphiphilic compound has a log partition coefficient in octanol/water of from 2.01 to 3.50.

Claim 10

A product according to claim 8, in which the amphiphilic compound is chosen from: salicylic acid 2-hydroxyoctanoic acid 2-ketooctanoic acid and mixtures thereof.

Claim 11

A product according to any preceding claim, in which the activity enhancer is capable of increasing the cloud point temperature by at least 15°C.

Claim 12

A product according to any preceding claim, in which the activity enhancer is capable of increasing the cloud point temperature by at least 20°C.

Claim 13

A product according to any preceding claim, which further comprises up to 75% by weight of "oil" having a dielectric constant of not greater than 3.0, the product having an oily phase which forms from 2 to 95% by volume.

Claim 14

A product according to claim 1 or any of claims 8 to 12 which comprises: (i) from 0.001 to 20% by weight of 2-hydroxyoctanoic acid; (ii) from 1 to 20% by weight of a mixture of polyoxyethylene(10)cetyl ether and cetyl alcohol; (iii) from 0.1 to 50% by weight " of butan-l,4-diol; (iv) from 1 to 75% by weight of mineral oil; and (v) from 9 to 95% by weight of water.

Claim 15

A product according to any preceding claim which is a solid or semi-solid cream.

Claim 16

A product according to any of claims 1 to 13, which is a gelled, thickened or free flowing liquid.

Claim 17

A process for the preparation of a product according to any preceding claims, comprising the steps of: (i) preparing an aqueous phase by mixing with water, water-soluble ingredients, other than the amphiphilic compounds, including activity enhancers, preservatives and humectants, and heating the mixture to a temperature of at least 50°C; (ii) adding to the aqueous phase, melted emulsifier which is normally solid at 20°C, which has an average HLB value of from 5 to 11 and which is capable of forming a gel phase, with continued heating at a temperature of at least 50°C, and shear mixing to provide an emulsion; (iii) cooling the emulsion to form a gel phase having an X-ray reflection of from 0.37 to 0.44 nm; (iv) adding with continued stirring the amphiphilic compound; and (v) subsequently packaging the product so formed in a sealed container; the product having an aqueous phase which forms from 5 to 99% by volume, an "oil" phase which forms from 2 to 95% by volume and a gel phase which forms from 1 to 95% by volume, the amphiphilic compound forming from 0.001 to 20% by weight, the emulsifier forming from 1 to 20% by weight, the activity enhancer forming from 0.1 to 50% by weight, the "oil" forming from 1 to 75% by weight and the water forming from 5 to 97.899% by weight.

Claim 18

A process for the preparation of a product according to any of claims 1 to 15, comprising the steps of: (i) forming an emulsion between (a) an aqueous phase containing water soluble ingredients, other than amphiphilic compounds, including activity enhancers, preservatives and humectants; (b) an "oil" having a dielectric constant of not greater than 3.0; and (c) emulsifier normally solid at 20°C, which has an average HLB value of from 5 to 11, and which is capable of forming a gel phase with water; at a temperature of at least 50°C; (ii) cooling the emulsion to produce a gel phase having an X-ray reflection of from 0.37 to 0.44 nm, and to solidify an "oil" with a melting point above 20°C; (iii) adding with stirring the amphiphilic compound; and (iv) subsequently packaging the emulsion so produced in a sealed container the product having an aqueous phase which forms from 5 to 99% by volume, an "oil" phase which forms from 2 to 95% by volume and a gel phase which forms from 1 to 95% by volume, the amphiphilic compound forming from 0.001 to 20% by weight, the emulsifier forming from 1 to 20% by weight, the activity enhancer forming from 0.1 to 50% by weight, the "oil" forming from 1 to 75% by weight and the water forming from 5 to 97.899% by weight.