Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Patent
1998-08-24
1999-11-16
Dodson, Shelley A.
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
424 60, 424400, 424401, A61K 742, A61K 744, A61K 700
Patent
active
059852500
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to the use of 2-ethylhexyl .alpha.-cyano-.beta.,.beta.-diphenylacrylate in, or for the manufacture of, cosmetic compositions containing p-methylbenzylidenecamphor in combination with at least one dibenzoylmethane derivative, for the purpose of improving the stability of p-methylbenzylidenecamphor in such compositions.
It is known that light radiation with wavelengths of between 280 nm and 400 nm allow tanning of the human epidermis and that rays with wavelengths of between 280 nm and 320 nm, which are known as UV-B rays, cause skin burns and erythema which hinder the development of a natural tan; this UV-B radiation should thus be screened out.
It is also known that UV-A rays, with wavelengths of between 320 nm and 400 nm, which cause tanning of the skin, are liable to bring about an adverse change therein, in particular in the case of sensitive skin or skin continually exposed to solar radiation. UV-A rays in particular cause a loss of elasticity of the skin and the appearance of wrinkles, leading to premature ageing. They promote triggering of the erythemal reaction or amplify this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions. It is thus desirable also to screen out UV-A radiation.
In this respect, dibenzoylmethane derivatives, and most particularly 4-tert-butyl-4'-methoxydibenzoylmrethane, sold under the trade name "Parsol 1789" by the company Givaudan, are particularly advantageous UV-A screening agents given their high intrinsic power of absorption. However, these screening agents have the drawback of being photoreactive, i.e. they degrade under the action of light and thus lose their photoprotective properties towards the skin and the hair.
The Applicant has already proposed, in patent application FR-2,607,700, to combine p-methylbenzylidenecamphor with 4-tert-butyl-4'-methoxydibenzoylmethane in order to improve the light-stability of cosmetic compositions containing 4-tert-butyl-4'-methoxydibenzoylmethane.
However, this solution is not entirely satisfactory, given the fact that p-methylbenzylidenecamphor is itself subject to gradual disappearance under the action of light. In cosmetic compositions containing it, the concentration of p-methylbenzylidenecamphor falls under the action of light and they thus lose their photoprotective efficacy.
After considerable research conducted in the field of photoprotection mentioned above, the Applicant has now discovered that the introduction of 2-ethylhexyl .alpha.-cyano-.beta.,.beta.-diphenylacrylate into a composition containing p-methylbenzylidenecamphor in combination with at least one dibenzoylmethane derivative, and in particular with 4-tert-butyl-4'-methoxydibenzoylmethane, makes it possible to significantly improve the stability of the p-methylbenzylidenecamphor in such compositions, and thus the overall efficacy of these compositions.
This discovery forms the basis of the invention.
The subject of the present invention is thus the use of 2-ethylhexyl .alpha.-cyano-.beta.,.beta.-diphenylacrylate in, or for the manufacture of, cosmetic compositions comprising p-methylbenzylidenecamphor and a dibenzoylmethane derivative, in particular 4-tert-butyl-4'-methoxyodibenzoylmethane, in order to improve the stability of p-methylbenzylidenecamphor in the said compositions.
The subject of the invention is also a process for improving the stability, and thus the efficacy, of a cosmetic composition comprising p-methylbenzylidenecamphor and a dibenzoylmethane derivative, in particular 4-tert-butyl-4'-methoxydibenzoylrnethane, the said process consisting in introducing into the said composition an effective amount of 2-ethylhexyl .alpha.-cyano-.beta.,.beta.-diphenylacrylate.
Thus, according to the present invention, cosmetic compositions containing at least one dibenzoylmethane derivative in combination with p-methylbenzylidenecamphor can be prepared, in which the concentration of p-methylbenzylidenecamphor remains relatively constant even if these compositions are subjected to the acti
Hansenne Isabelle
Josso Martin
Dodson Shelley A.
Societe l'Oreal S.A.
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