Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2002-08-27
2003-09-09
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
C424S060000, C424S400000, C424S401000
Reexamination Certificate
active
06616919
ABSTRACT:
CROSS-REFERENCE TO PRIORITY APPLICATION
This application claims priority under 35 U.S.C. §119 of FR-01/11139, filed Aug. 27, 2001, assigned to the assignee hereof and hereby expressly incorporated by reference.
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
This present invention relates to cosmetic or dermatological compositions suited for topical application, in particular for UV-photoprotecting human skin and hair, comprising, formulated into a cosmetically acceptable support (vehicle, diluent or carrier),
(a) at least one UV screening agent of the dibenzoylmethane derivative type, and
(b) a photostabilizing amount therefor of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
This invention also relates to a process for improving the stability of at least one dibenzoylmethane compound with respect to UV radiation, which entails combining said dibenzoylmethane compound with an effective amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
2. Description of the Prior Art
It is known to this art that light radiation having wavelengths of from 280 nm to 400 nm permits tanning of the human epidermis and that light rays having wavelengths more particularly from 280 to 320 nm, known as UV-B radiation, cause skin burns and erythema which can harm the development of a natural tan. For these reasons, as well as for aesthetic reasons, there is a constant demand for means of controlling this natural tanning in order, thus, to control the color of the skin; this UV-B radiation should thus be screened from the skin.
It is also known that UV-A radiation, having wavelengths from 320 to 400 nm, which causes tanning of the skin, is apt to induce adverse changes therein, in particular in the case of sensitive skin or skin which is continually exposed to solar radiation. UV-A rays cause, in particular, a loss of elasticity of the skin and the appearance of wrinkles promoting premature aging of the skin. 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. Thus, for aesthetic and cosmetic reasons such as the conservation of the skin's natural elasticity, for example, an increasingly large number of individuals wish to control the effect of UV-A radiation on their skin. It is thus desirable to also screen out UV-A radiation.
Thus, with the goal of ensuring the most complete and most effective protection possible for the skin and the hair against the entire UV radiation spectrum, combinations of screening agents which are active in the UVA range and of screening agents which are active in the UVB range are generally formulated into sunscreen/antisun compositions.
In this respect, one particularly advantageous family of UV-A screening agents currently in favor includes dibenzoylmethane derivatives, and in particular 4-tert-butyl-4′-methoxydibenzoylmethane, which have high intrinsic absorbing power. These dibenzoylmethane derivatives, which are compounds which are now well known per se as screening agents that are active in the UV-A range, are described, in particular, in FR-A-2,326,405 and FR-A-2,440,933, as well as in EP-A-0,114,607; 4-(tert-butyl)-4′-methoxydibenzoyl-methane is moreover currently marketed under the trademark “Parsol 1789” by Hoffmann la Roche.
Unfortunately, it has been determined that dibenzoylmethane derivatives are compounds that are relatively sensitive to ultraviolet radiation (especially UV-A), i.e., more specifically, they have an annoying tendency to be degraded more or less quickly under the influence of this UV. Thus, this substantial lack of photochemical stability of dibenzoylmethane derivatives towards ultraviolet radiation, to which they are by nature intended to be subjected, does not make it possible to ensure constant protection during prolonged exposure to the sun, and so the user must make repeated applications at regular and close time intervals in order to obtain effective protection of the skin against UV rays.
1,3,5-Triazine derivatives are particularly desired in sunscreen/antisun cosmetics due to the fact that they are highly active in the UV-B range, and even in the UV-A range for certain of these compounds depending on the nature of the substituents involved. They are especially described in U.S. Pat. No. 4,367,390, EP-863,145, EP-517,104, EP-570,838, EP-507,691, EP-796,851, EP-775,698, EP-878,469 and EP-933,376, and the following are recognized, in particular:
2,4,6-tris[p-(2′-ethylhexyl-1′-oxycarbonyl)anilino]-1,3,5-triazine or “Ethylhexyl Triazone” (INCI name), marketed under the trademark “Uvinul T 150” by the company BASF, and
2-[(p-(tert-butylamido)anilino]-4,6-bis[(p-(2′ethylhexyl-1′-oxycarbonyl)anilino]-1,3,5-triazine or “Diethylhexyl Butamido Triazone” (INCI name), marketed under the trademark “Uvasorb HEB” by Sigma 3V.
However, it has been determined that when these 1,3,5-triazine derivatives are in the presence of dibenzoylmethane derivatives, in particular 4-tert-butyl-4′-methoxydibenzoylmethane, and under UV radiation, they present the drawback of undergoing substantial chemical degradation. Under these conditions, the combination of the two screening agents no longer provides a prolonged broad sunscreen/antisun protection to the skin and the hair.
SUMMARY OF THE INVENTION
It has now surprisingly and unexpectedly been determined that by combining with the dibenzoylmethane compounds indicated above an effective amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, a substantial and noteworthy improvement in the photochemical stability (or photostability) of these same dibenzoylmethane derivatives is attained.
Furthermore, it too has been determined that incorporation of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane into a composition containing a combination of a dibenzoylmethane derivative with at least one 1,3,5-triazine derivative markedly enhances the photostability of this 1,3,5-triazine derivative in such compositions, and thus the overall efficacy thereof.
Accordingly, a major object of the present invention is the provision of cosmetic or dermatological compositions for topical application, comprising, formulated into a cosmetically acceptable support:
(a) at least one UV screening agent of the dibenzoylmethane derivative type, and
(b) an effective photostabilizing amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
The present invention also features a process for improving the stability of at least one dibenzoylmethane compound in respect of UV radiation, which comprises combining said dibenzoylmethane derivative with an effective photostabilizing amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
The present invention thus features cosmetic or dermatological compositions for topical application, comprising, formulated into a cosmetically acceptable support:
(a) at least one UV screening agent of the dibenzoylmethane derivative type,
(b) at least one UV screening agent of the 1,3,5-triazine derivative type, and
(c) an effective amount of 1,1,1-tris(2-methyl4-hydroxy-5-tert-butylphenyl)butane.
Too, this invention features a process for improving the stability of at least one 1,3,5-triazine derivative in the presence of at least one dibenzoylmethane derivative vis-à-vis UV radiation, by adding thereto an effective amount of 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.
Thus, the present invention features including 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane in cosmetic and dermatological compositions comprising at least one dibenzoylmethane derivative, for purpose of improving the stability of said dibenzoylmethane derivative versus UV irradiation.
Lastly, the present invention features incorporating 1,1,1-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane into cosmetic or dermatological compositions comprising at least one dibenzoylmethane derivative and at least one 1,3,5-triazine derivative, for improving the stability of said 1,
Aubert Fabien
Candau Didier
Burns Doane Swecker & Mathis L.L.P.
Dodson Shelley A.
Societe l'Oreal S.A.
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