Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2002-12-09
2003-09-30
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
06627179
ABSTRACT:
CROSS-REFERENCE TO PRIORITY APPLICATION
This application claims priority under 35 U.S.C. §119 of FR-01/15857, filed Dec. 7, 2001, hereby expressly incorporated by reference.
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to novel topically applicable cosmetic or dermatological sunscreen compositions well suited for the UV-photoprotection of human skin and/or hair, comprising intimate admixture of (i) at least one UV-screening silicon compound having a benzotriazole functional group substituent, as a first screening agent; (ii) at least one UV-screening dibenzoylmethane compound, as a second screening agent; and (iii) at least one UV-screening specific amino-substituted 2-hydroxybenzophenone compound, as a third screening agent, formulated into (iv) a topically applicable, cosmetically/dermatologically acceptable vehicle, diluent or carrier therefor. The combination of these three UV-screening agents provides synergistic results with regard to the protection factors UV-A
PPD
conferred.
This invention also relates to a regime or regimen for the UV-protection of the skin and/or hair against the damaging effects of ultraviolet radiation.
2. Description of the Prior Art
It is known to this art that light radiation with wavelengths of from 280 nm to 400 nm permits browning of the human epidermis and that radiation with wavelengths of from 280 to 320 nm, known as UV-B radiation, causes erythemas and skin burns which may be harmful to the development of natural tanning; this UV-B radiation must therefore be screened out from the skin.
It is also known that UV-A radiation, with wavelengths of from 320 to 400 nm, which causes browning of the skin, is capable of causing a detrimental change in the skin, in particular in the case of sensitive skin or of skin continually exposed to solar radiation. UV-A irradiation causes in particular, a loss in the elasticity of the skin and the appearance of wrinkles, resulting in premature aging. UV-A radiation promotes the triggering of the erythemal reaction or accentuates this reaction in certain individuals and can even be the cause of phototoxic or photoallergic reactions. It is therefore also desirable to screen out UV-A radiation.
A wide variety of cosmetic compositions for the photoprotection (UV-A and/or UV-B) of the skin are known to this art.
The efficacy of antisun/sunscreen compositions is generally expressed by the sun protection factor (SPF), which is expressed mathematically by the ratio of the dose of UV radiation necessary to reach the erythemogenic threshold with the UV screening agent to the dose of UV radiation necessary to reach the erythemogenic threshold without UV screening agent. This factor thus relates to the effectiveness of the UV-protection with respect to erythema, the spectrum of biological action of which is centered in the UV-B region, and consequently describes the protection with respect to this UV-B radiation.
In view of the effects of UV-A radiation on the skin and of the availability of numerous compositions comprising combinations of screening agents capable of absorbing UV-B and/or UV-A radiation, specific techniques for evaluating protection against UV-A radiation have been developed.
For the characterization of protection with respect to UV-A radiation, the PPD (Persistent Pigment Darkening) method, which measures the color of the skin observed 2 to 4 hours after exposure of the skin to UV-A radiation, is particularly recommended and used. This method was adopted in 1996 by the Japanese Cosmetic Industry Association (JCIA) as an official test procedure for the UV-A labeling of products and is frequently used by test laboratories in Europe and the United States (Japan Cosmetic Industry Association Technical Bulletin. Measurement Standards for UVA protection efficacy. Issued Nov. 21, 1995 and effective of Jan. 1, 1996).
The sun protection factor UV-A
PPD
(UV-A
PPD
PF) is expressed mathematically by the ratio of the dose of UV-A radiation necessary to reach the pigmentation threshold with the UV screening agent (MPPD
p
) to the dose of UV-A radiation necessary to reach the pigmentation threshold without UV screening agent (MPPD
np
).
UV
-
A
PPD
PF
=
MPPD
p
MPPD
np
These antisun/sunscreen compositions are generally in the form of an emulsion of oil-in-water type (namely, a cosmetically acceptable vehicle composed of a continuous aqueous dispersing phase and of a noncontinuous oily dispersed phase) which comprises, at various concentrations, one or more conventional, lipophilic and/or hydrophilic, organic screening agents capable of selectively absorbing harmful UV radiation, these screening agents (and their amounts) being selected according to the sun protection factors desired.
Cosmetic UV-screening agents constituted from lipophilic silicone compounds substituted with a benzotriazole functional group exhibiting good screening properties, both in the region of UV-A radiation and in the region of UV-B radiation, are known to this art. They are described in EP-A-0,392,883, EP-A-0,660,701, EP-A-0,708,108, EP-A-0,711,778 and EP-A-711,779.
EP-A-0,742,003 and EP-A-0,860,165 describe the combination of these silicone screening agents substituted with a benzotriazole functional group, with specific water-soluble screening agents having a sulfonic functional group, namely, benzene-1,4-di(3-methylidene-10-camphorsulfonic acid) or 2-phenylbenzimidazole-5-sulfonic acid and its salts, for the purpose of producing a synergistic activity with regard to the sun protection factors. These synergistic screening systems require at least one aqueous phase, which dissolves the water-soluble screening agent, and a fatty phase, for dissolving the silicone screening agent, which substantially reduces the formulation possibilities.
Antisun/sunscreen compositions based on amino-substituted 2-hydroxybenzophenone compounds which can contain other additional screening agents, such as silicone derivatives with a benzotriazole functional group or dibenzoylmethane derivatives, are described in EP-A-1,046,391 and DE-10 012 408.
SUMMARY OF THE INVENTION
It has now unexpectedly and surprisingly been determined that a combination or intimate admixture of three specific families of UV-screening compounds, which families are already known per se in this art, namely, immixture of (1) a dibenzoylmethane compound, (2) a benzotriazole silicon compound and (3) a specific amino-substituted 2-hydroxybenzophenone compound, provides synergistic results in terms of exhibiting markedly improved sun protection factors UV-A
PPD
. Such a combination makes it possible to obtain antisun/sunscreen compositions having sun protection factors UV-A
PPD
which are markedly improved and in any case much higher than those which can be obtained using any of the screening agents alone.
Furthermore, the specific combination of screening agents in accordance with the invention can be easily and readily incorporated in a very wide range of cosmetic vehicles, diluents and carriers.
Thus, the present invention features novel topically applicable cosmetic/dermatological sunscreen compositions, comprising:
(i) at least one UV-screening silicon compound bearing a benzotriazole functional group substituent, as a first screening agent;
(ii) at least one UV-screening dibenzoylmethane derivative, as a second screening agent; and
(iii) at least one UV-screening amino-substituted 2-hydroxy-benzophenone compound of formula (III) as defined below, as a third screening agent, formulated into (iv) a topically applicable, cosmetically/dermatologically acceptable vehicle, diluent or carrier therefor.
The present invention also features a regime or regimen for the photoprotection of the skin and/or hair against the deleterious effects of ultraviolet radiation, in particular solar radiation.
Generally, the said first, second and third UV-screening agents are present in the compositions of the invention in a proportion producing a synergistic effect with regard to the sun protection factors UV-A
PPD
conferred.
DETAILED DESCRIPTION OF BEST M
Burns Doane Swecker & Mathis L.L.P.
Dodson Shelley A.
Societe L'Oreal S.A.
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