Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Patent
1998-11-25
2000-12-19
Krynski, William
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
510158, 510159, 510505, 424 7019, 514844, 514846, C11D 750, A61K 702, A61K 908
Patent
active
061627747
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to compositions for topical application to the skin surface, in particular to skin wash compositions which are applied to water-wetted skin and subsequently rinsed off with water. Specifically, the present invention relates to skin wash compositions comprising an .alpha.-hydroxy acid and other acids as defined herein as an active ingredient formulated in a mild and non-irritant detergent base.
Compounds generally known in the field of cosmetic and therapeutic skin treatments as .alpha.-hydroxy acids and other acids as defined herein include compounds such as salicylic acid, lactic acid and glycolic acid. These compounds constitute the active ingredients of a number of commercially available products which are applied to the skin in order to confer a beneficial effect with respect to appearance and skin condition, in particular smoothness and suppleness. Salicylic acid for example has been shown to have keratolytic and comedolytic activity as well as anti-bacterial efficacy and has been used in the treatment and prevention of mild to moderate acne for more than 100 years. Lactic acid has a beneficial effect on skin hydration and is a constituent of a number of skin tonic and moisturising products.
.alpha.-Hydroxy acids and other acids as defined herein, whilst conferring a beneficial effect on the skin, may cause local irritation when applied to sensitive areas of the skin, in particular the face. Moreover, local irritation may be exacerbated by the carrier system in which the active ingredient is formulated. For example, skin wash compositions and in particular face wash compositions which are generally formulated with a soap-free detergent base selected for effective cleansing and foaming, may confer an irritant effect due to the use of ionic surfactants commonly employed in such detergent systems.
A further problem associated with formulating compositions containing .alpha.-hydroxy acids and other acids as defined herein arises because of the desirability to formulate the composition at an acid pH at which the most efficacious free-acid form of the acid will predominate. For skin wash compositions, this problem is exacerbated by the difficulty of obtaining a detergent base system at sufficiently low pH. A skin wash composition described as having a gentle yet effective cleanser for acne treatment and containing 2.0% w/w salicylic acid in a detergent base comprising a mixture of anionic and amphoteric surfactants is commercially available. Analysis of this product, shows that it has a pH of 5. It follows, having regard to the pKa of salicylic acid which is attributed the value 2.97, that the free-acid form of the hydroxy acid does not predominate in this product and that its efficacy is accordingly not fully optimised.
It is an object of the present invention to provide a skin wash composition containing an .alpha.-hydroxy acid or other acid as defined herein and a detergent base which has good cleansing and foaming characteristics, is mild and non-irritant and wherein the pH of the composition approaches the pKa of the acid such that the efficacy of the acid is enhanced. This object is achieved according to the present invention which is based on the unexpected finding that a detergent base comprising a mixture of a non-ionic alkylpolyglucoside surfactant and an amphoteric surfactant not only has the desired cleansing and foaming characteristics and is mild and non-irritant when applied to the skin but also enables compositions to be formulated at low pH.
According to the present invention there is provided a skin wash composition comprising from 0.1 to 10% w/w of an .alpha.-hydroxy acid or other acid as defined herein and a detergent base consisting of a mixture of a non-ionic alkylpolyglucoside surfactant and an amphoteric surfactant wherein the pH of the composition is in the range 3.0 to 4.5.
Suitable acids for incorporation into skin wash compositions of the invention include salicylic acid, lactic acid, citric acid, glycolic acid, malic acid, maleic acid, pyruvic acid
REFERENCES:
patent: 5429815 (1995-07-01), Faryniarz et al.
patent: 5607980 (1997-03-01), McAtee et al.
Charlton Lynda Rosemary
McGillycuddy Juliet Teresa
Owen Sharon
Garrett Dawn L.
Krynski William
SmtihKline Beecham p.l.c.
Stein-Fernandez Nora
Venetianer Stephen
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