COSMETIC COMPOSITION

Abstract: A therapeutic composition for alleviating or preventing sun-induced desquamation comprises as active ingredients a C₃ to C₃₀ 2-hydroxyalkanoic acid or an ester thereof together with a sunscreen active ingredient in a therapeutically acceptable vehicle. The active ingredients can also be used in the preparation of the composition for the treatment or prevention of this skin condition which can follow exposure to an excessive amount of sunlight.

Description: FIELD OF INVENTION The invention relates to preparation of a composition and its use, and more particularly to the preparation and use of a composition containing 2-hydroxyalkanoic acid, or an ester thereof, together with a sunscreen active ingredient. The composition is intended for topical application to human skin to treat and/or to inhibit desquamation which can follow excessive exposure of the skin to sunlight. The composition can further more reduce erythema which can also result from excessive exposure of the human skin to sunlight. BACKGROUND AND PRIOR ART When normal human skin is exposed to an excessive amount of sunlight, there is usually an inflammatory response which can result in erythema, often described as sunburn. This can subsequently lead to peeling of the upper layer of the skin which can detract from the appearance of the skin, particularly with loss of tan, and which can lead to dehydration and more serious damage to the skin. Treatment of the skin with a sunscreen prior to exposure to sunlight can prevent, or at least limit, erythema. However, if erythema is not limited, sunscreens have little or no effect on subsequent skin peeling (desquamation). Conventional treatment of skin following over-exposure to sunlight usually involves topical application of a moisturiser such as an oil-in-water cream, but this will generally only provide a cooling effect with some relief of the burning and itching sensation that accompanies erythema. Usually it will not prevent peeling of the skin. It has been proposed in US patent 4 424 234 (Lever Brothers Company) to provide a cosmetically acceptable aqueous composition for topical application to human skin to provide skin benefit, the composition comprising an hydroxylated C₆-C₁₀ carboxylic acid and a cosmetically acceptable vehicle other than water. Among a long list of possible cosmetically acceptable vehicles are sunscreen agents, but there is no suggestion in this reference that the combination of an hydroxylated C₆-C₁₀ carboxylic acid together with any specified sunscreen agent can be used in the prevention or treatment of sun-induced desquamation. Applicants have now discovered, contrary to expectation, that topical application of a composition containing both a 2-hydroxyalkanoic acid, or an ester thereof, and a sunscreen active ingredient can be used in the treatment and/or prevention of sun-induced desquamation, following exposure sufficient to cause erythema. DEFINITION OF THE INVENTION Accordingly, the invention provides for the use of a 2-hydroxyalkanoic acid, or an ester thereof, having the structure: CH₃ (CH₂ ) n CH.OH COOR where R is -H, C₂₋₁₀ alkyl or a monoglyceride, diglyceride or triglyceride residue; and n is 0, or an integer of from 1 to 27 or mixtures thereof, together with a sunscreen active ingredient, or mixtures thereof, in the preparation of a composition for treatment of sun-induced desquamation, or the inhibition thereof, following exposure to sunlight sufficient to cause erythema. The invention also provides a method for alleviating the symptoms of sun-induced desquamation comprising topically applying to involved areas of the body, following exposure to sunlight sufficient to cause erythema, an effective amount of a composition comprising as active ingredients, a 2-hydroxyalkanoic acid or an ester thereof, as hereinbefore defined, or a mixture thereof, together with a sunscreen active ingredient, or a mixture thereof, in a therapeutically acceptable vehicle for topical application. The invention also provides for the use of a composition comprising as active ingredients a 2-hydroxyalkanoic acid or an ester thereof, as hereinbefore defined, or a mixture thereof, in an acceptable vehicle for topical application, in the treatment or prevention of sun-induced desquamation following exposure to sunlight sufficient to cause erythema. DISCLOSURE OF THE INVENTION It is accordingly an object of the invention to provide preparation and use of a composition containing one or more 2-hydroxyalkanoic acids, or esters thereof, and one or more sunscreen agents which when applied topically to the skin of a person suffering from over-exposure to sunlight will arrest or prevent the development of sun-induced desquamation. The 2-hydroxyalkanoic acid and esters thereof The composition of the invention Comprises a 2-hydroxyalkanoic acid or an ester thereof having the structure: CH₃(CH₂) n CH.OH COOR where R is -H, C₂₋₁₀ alkyl or a monoglyceride, diglyceride or triglyceride residue; and n is O, or an integer of from 1 to 27 Examples of 2-hydroxyalkanoic acids include: 2-hydroxypropanoic acid 2-hydroxytetranoic acid 2-hydroxyhexanoic acid 2-hydroxyoctanoic acid 2-hydroxydecanoic acid 2-hydroxydodecanoic acid 2-hydroxytetradecanoic acid 2-hydroxyhexadecanoic acid 2-hydroxyoctadecanoic acid 2-hydroxyoctaeicosanoic acid, and mixtures thereof. Preferred 2-hydroxyalkanoic acids are 2-hydroxypropanoic, 2-hydroxyhexanoic acid and 2-hydroxyoctanoic acid. Examples of esters of 2-hydroxyalkanoic acids include: 2-hydroxypropanoic acid ethyl ester 2-hydroxypropanoic acid propyl ester 2-hydroxytetranoic acid ethyl ester 2-hydroxyhexanoic acid methyl ester 2-hydroxyhexanoic acid ethyl ester 2-hydroxyoctanoic acid hexyl ester 2-hydroxyoctanoic acid methyl ester 2-hydroxyoctanoic acid ethyl ester 2-hydroxyoctanoic acid pentyl ester 2-hydroxyoctanoic acid octyl ester 2-hydroxyoctadecanoic acid ethyl ester 2-hydroxyoctanoic acid monoglyceride 2-hydroxyoctanoic acid diglyceride 2-hydroxyoctanoic acid triglyceride, and mixtures thereof. The amount of 2-hydroxyalkanoic acid or ester thereof to be employed in accordance with the invention, as an effective amount, will normally be from 0.1 to 20%, preferably from 0.5 to 10% and most preferably from 0.5 to 2% by weight of the composition. The sunscreen active ingredient The composition also comprises one or more sunscreen active ingredients. Examples of sunscreen active ingredients include: p-Aminobenzoic acid Ethyl dihydroxypropyl p-aminobenzoic acid (such as Amerscreen P) Glyceryl p-aminobenzoic acid (such as Escalol 106) 2,4-Dihydroxy benzophenone (such as Uvinul 400) 2-Ethoxyethyl-p-methoxycinnamate (such as Giv Tan F) Di-ethanolamine p-methoxycinnamate (such as Parsol Hydro) 2-Ethylhexyl salicylate (such as Sun Arome WMO) Homomenthyl salicylate (such as Filtrosol A) 2-Phenylbenzimidazole-5-sulphonic acid (such as Eusolex 232) Ethylhexyl p-methoxycinnamate (such as Parsol MCX). 3-(4-Methylbenzylidine) camphor (such as Eusolex 6300) 2-Hydroxy-4-methoxy benzophenone (such as Eusolex 4360) Butylmethoxydibenzoylmethane (such as Parsol 1789) 4-isopropyl dibenzoylmethane (such as Eusolex 8020) The amount of the sunscreen active ingredient to be employed in accordance with the invention, as an effective amount, will normally be from 0.01 to 10%, preferably from 0.1 to 5% and most preferably from 1 to 5% by weight of the composition. Therapeutically acceptable vehicle The composition of the invention also comprises a therapeutically acceptable vehicle, usually in the form of a lotion, cream, ointment, gel, powder, solid stick or aerosol concentrate formed from cosmetically acceptable ingredients as conventionally employed in the art. The amount of the therapeutically acceptable vehicle to be employed in accordance with the invention will normally form the balance of the composition after taking account of the 2-hydroxyalkanoic acid and/or ester thereof, the sunscreen active ingredient and optional ingredients. Accordingly, the therapeutically acceptable vehicle will normally form from 50 to 99.89%, preferably from 70 to 99.4% by weight of the composition. OPTIONAL INGREDIENTS The composition can also optionally contain further ingredients in addition to those which are conventionally used for the provision of the therapeutically acceptable vehicle. Accordingly, in additon to ingredients conventionally used in preparing a lotion, cream, ointment, gel, powder, solid stick and aerosol concentrate, the composition can optionally comprise further ingredients such as a perfume, colourant, preservative, antioxidant, emollient or aerosol propellant. PREPARATION OF THE COMPOSITION The composition of the invention can be prepared in the form of a solution, lotion, gel, cream, ointment, solid stick, aerosol or powder, or in any other form suited to administration topically to human skin. When the composition is a liquid, such as a lotion or aerosol, or a semi-liquid such as a gel, cream or ointment, or a solid stick, then it is usually necessary to dissolve an effective quantity of the 2-hydroxyalkanoic acid and/or ester thereof and the sunscreen agent in water or ethanol or other aqueous or non-aqueous therapeutically acceptable vehicle, and then to admix this solution, if desired, in a conventional manner with a suitable cream or ointment base containing, for example an oil or silicone oil and water, or stick base containing a gelling agent such as sodium stearate, or with a normally liquefiable gaseous propellant in order to prepare the composition. When the composition is a powder, then it is usually necessary to admix the 2-hydroxyalkanoic acid and/or ester thereof and sunscreen with a powder diluent, such as talc, starch, kaolin, Fuller's earth or other suitable powder base, in order to provide the composition in powder form. If desired, other therapeuticly acceptable carriers, diluents or emollients can be incorporated in the composition, in order to facilitate even distribution over the affected area of the skin at a concentration or dosage suitable for treatment or prevention of the sun-induced desquamation. It is also possible to incorporate in the composition other therapeutic active substances which may further improve the treatment of skin disorders. Adjustment of pH When the composition contains water, then the aqueous phase should have a pH value of from 2 to 9, preferably 3 to 6 and ideally from 4 to 5. Although compositions having a pH value of less than 2 are likely to be effective in the treatment or prevention of sun-induced desquamation, topical application of such compositions has been found to produce stinging, burning or irritation. Compositions having a pH value of greater than 9 are likely to exhibit reduced effectiveness in the treatment or prevention of sun-induced desquamation. Any suitable therapeutically acceptable pH adjustant can be employed to set the pH of the composition at a desired value. Examples of pH adjustants include alkanolamines, especially triethanolamine and buffers such as lactic acid/triethanolamine lactate. METHOD OF TREATMENT The invention also provides a method for the treament or prevention of sun-induced desquamation in man, which method of treatment comprises applying to involved areas of the skin an effective amount of a composition comprising from 0.1 to 20% by weight of the 2-hydroxyalkanoic acid and/or ester thereof and from 0.01 to 10% by weight of the sunscreen agent, together with a therapeutically acceptable vehicle, following exposure to sunlight sufficient to cause erythema. In general, an effective amount of the composition of the invention which can be applied topically to human skin in order to reduce or prevent the occurence of sun-induced desquamation will be from 0.1g to 1g over an area of skin of 100sq cm. Higher or lower doses can be applied if desired. EXAMPLES OF THE INVENTION The following clinical studies illustrate the treatment of skin disorders with compositions in accordance with the invention. In each of the following examples, human subjects were treated by topical application of a formulation containing both 2-hydroxyoctanoic acid and a sunscreen active ingredient. The amounts expressed as percentages are by weight. Example 1 Three patients who had been subjected to excessive sunlight and had developed erythema on the face were treated in the affected areas by topical application of an oil-in-water cream containing 2-hydroxyoctanoic acid (1%) and a sunscreen (Parsol MCX, 2%). The treatment was repeated night and morning on three consecutive days and the anticipated peeling of the skin to result in desquamation was totally prevented. Example 2 One person suffering from extensive peeling of the skin (desquamation) following exposure to an excessive amount of sunlight, which had previously resulted in erythema, was treated by topical application of a cream containing 2-hydroxyoctanoic acid (1%) together with a sunscreen (Parsol MCX, 1.5% and Parsol 1789, 0.5%). This treatment was repeated night and morning for one week and further peeling of the skin was prevented. The above clinical experiments confirm that a mixture of 2-hydroxyoctanoic acid and a sunscreen when applied topically to skin can prevent sun-induced desquamation if applied soon enough. The compositions prepared according to the method defined by this invention are accordingly useful in the prevention of sun-induced desquamation after exposure to excessive amounts of sunlight and following development of erythema. The following Examples 3 and 4 illustrate compositions according to the invention. In each case the oil-in-water (o/w) base referred to had the following formulation: Example 3 This example illustrates the formulation of a sunburn lotion. Example 4 This example illustrates the formulation of a sunburn cream according to the invention. Example 5 This example illustrates the formulation of a lotion. The water-in-oil (w/o) base employed had the following formulation: Example 6 This example illustrate the formulation of a lotion based on the water-in-oil (w/o) base of Example 5. Example 7 This example illustrates a sunburn cream based on the water-in-oil (w/o) base of Example 5. Example 8 This example illustrates a sunburn cream based on the water-in-oil (w/o) base of Example 5. The topical application of the compositions described in the above examples can be used as post-sunburn treatment for the prevention or alleviation of sun-induced skin peeling and for reducing or eliminating erythema.

Claims: The use of a 2-hydroxyalkanoic acid, or an ester thereof, having the structure: CH₃(CH₂) n CH.OH COOR where R is -H, C₂₋₁₀ alkyl or a monoglyceride, diglyceride or triglyceride residue; and n is 0, or an integer of from 1 to 27, or mixtures thereof, together with a sunscreen active ingredient, or mixtures thereof, in the preparation of a composition for the treatment of sun-induced desquamation, or the inhibition thereof following exposure to sunlight sufficient to cause erythema. The use of the 2-hydroxyalkanoic acid or an ester thereof, or mixtures thereof, together with the sunscreen active ingredient, or mixtures thereof, in the preparation of the composition according to claim 1, in which the 2-hydroxyalkanoic acid is chosen from: 2-hydroxypropanoic acid 2-hydroxytetranoic acid 2-hydroxyhexanoic acid 2-hydroxyoctanoic acid 2-hydroxydecanoic acid 2-hydroxydodecanoic acid 2-hydroxytetradecanoic acid 2-hydroxyhexadecanoic acid 2-hydroxyoctadecanoic acid 2-hydroxyoctaeicosanoic acid, and mixtures thereof. The use of the 2-hydroxyalkanoic acid or an ester thereof, or mixtures thereof, together with the sunscreen active ingredient, or mixtures thereof, in the preparation of the composition according to claim 1 or 2, in which the 2-hydroxyalkanoic acid ester is chosen from: 2-hydroxypropanoic acid ethyl ester 2-hydroxypropanoic acid propyl ester 2-hydroxytetranoic acid ethyl ester 2-hydroxyhexanoic acid methyl ester 2-hydroxyhexanoic acid ethyl ester 2-hydroxyoctanoic acid hexyl ester 2-hydroxyoctanoic acid methyl ester 2-hydroxyoctanoic acid ethyl ester 2-hydroxyoctanoic acid pentyl ester 2-hydroxyoctanoic acid octyl ester 2-hydroxyoctadecanoic acid ethyl ester 2-hydroxyoctanoic acid monoglyceride 2-hydroxyoctanoic acid diglyceride 2-hydroxyoctanoic acid triglyceride, and mixtures thereof The use of the 2-hydroxyalkanoic acid or an ester thereof, or mixtures thereof, together with the sunscreen active ingredient, or mixtures thereof, in the preparation of the composition according to claim 1, 2 or 3, in which the 2-hydroxyalkanoic acid or an ester thereof is present at a concentration of from 0.1 to 20% by weight of the total composition. The use of she 2-hydroxyalkanoic acid or an ester thereof, or mixtures thereof, together with the sunscreen active ingredient, or mixtures thereof, in the preparation of the composition according to any preceding claim, in which the sunscreen active ingredient is chosen from: p-Aminobenzoic acid Ethyl dihydroxypropyl p-aminobenzoic acid Glyceryl p-aminobenzoic acid 2,4-Dihydroxy benzophenone 2-Ethoxyethyl-p-methoxycinnamate Di-ethanolamine p-methoxycinnamate 2-Ethylhexyl salicylate Homomenthyl salicylate 2-Phenylbenzimidazole-5-sulphonic acid Ethylhexyl p-methoxycinnamate 3-(4-Methylbenzylidine) camphor 2-Hydroxy-4-methoxy benzophenone Butylmethoxydibenzoylmethane 4-Isopropyl dibenzoylmethane The use of the 2-hydroxyalkanoic acid or an ester thereof, or mixtures thereof, together with the sunscreen active ingredient, or mixtures thereof, in the preparation of the composition according to any preceding claim in which the sunscreen active ingredient is present at a concentration of from 0.01 to 10% by weight of the composition. A method of alleviating the symptoms of sun-induced desquamation comprising topically applying to involved areas of the body, following exposure to sunlight sufficient to cause erythema an effective amount of composition comprising as active ingredients: (i) an effective amount of a 2-hydroxyalkanoic acid or an ester thereof, having the structure: CH₃ (CH₂) n CH.OH COOR where R is -H, C₂₋₁₀ alkyl or a monoglyceride, diglyceride or triglyceride residue, and n is 0, or an integer of from 1 to 27, or a mixture thereof; and (ii) an effective amount of a sunscreen active ingredient or mixtures thereof, in a therapeutically acceptable vehicle for topical application. The use of composition comprising as active ingredients: (i) an effective amount of a 2-hydroxyalkanoic acid or an ester thereof, having the structure: CH₃ (CH₂) n CH.OH COOR where R is -H, C₂₋₁₀ alkyl or a monoglyceride, diglyceride or triglyceride residue, and n is 0, or an integer of from 1 to 27, or a mixture thereof; and (ii) an effective amount of a sunscreen active ingredient or mixtures thereof, in a therapeutically acceptable vehicle for topical application, in the treatment or prevention of sun-induced desquamation following exposure to sunlight sufficient to cause erythema.

Inventors: BOWSER, PAUL, ANTHONY, STURMEY, INGRID CAROLINE
Applicants: UNILEVER N.V., UNILEVER PLC
Application year: 1987
Main classification: A61K7
IPC codes: A61K31, A61K8, A61Q19, A61Q17