Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2002-12-09
2004-03-02
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
06699461
ABSTRACT:
CROSS-REFERENCE TO PRIORITY APPLICATION
This application claims priority under 35 U.S.C. §119 of FR-01/15858, filed Dec. 7, 2001, hereby expressly incorporated by reference.
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The invention relates to a cosmetic or dermatological composition for topical use, characterized in that it comprises, in a cosmetically acceptable vehicle:
(a) at least one UV screening agent of the dibenzoylmethane derivative type and
(b) at least one specific amino-substituted 2-hydroxybenzophenone derivative; the said composition not comprising p-methylbenzylidenecamphor.
The invention also relates to a process for improving the stability with respect to UV radiation of at least one dibenzoylmethane derivative present in a cosmetic or dermatological composition not comprising p-methylbenzylidenecamphor which consists in combining, with the said dibenzoylmethane derivatives, an effective amount of at least one specific amino-substituted 2-hydroxybenzophenone derivative.
2. Description of the Prior Art
It is known that light radiation with wavelengths of between 280 nm and 400 nm makes possible browning of the human epidermis and that rays with wavelengths more particularly of between 280 and 320 nm, known under the name of UV-B, cause erythemas and skin burns which may be harmful to the development of natural tanning. For these reasons and for aesthetic reasons, there exists a continual demand for means for controlling this natural tanning, for the purpose of thus controlling the color of the skin; it is thus advisable to screen out this UV-B radiation.
It is also known that UV-A rays, with wavelengths of between 320 and 400 nm, which cause browning of the skin, are capable of bringing about a detrimental change in the latter, in particular in the case of sensitive skin or of skin continually exposed to solar radiation. UV-A rays cause in particular a loss in the elasticity of the skin and the appearance of wrinkles, resulting in premature aging of the skin. They promote the triggering of the erythemal reaction or accentuate this reaction in some subjects and can even be the cause of phototoxic or photoallergic reactions. Thus, for aesthetic and cosmetic reason, such preservation of the natural elasticitiy of the skin, for example, more and more people with to control the effect of UV-A radiation on their skin. It is therefore desirable also to screen out UV-radiation.
In this respect, a particular advantageous family of UV-A screening agents is currently composed of dibenzoylmethane derivatives and in particular 4-tert-butyl-4′-methoxydibenzoylmethane; this is because derivatives exhibit a high intrinsic absorbance. These dibenzoylmethane derivatives, which are now products well known per se as screening agents active in the UV-A region, are disclosed in particular in French Patent Applications FR-A-2 326 405 and FR-A-2 440 933 and in European Patent Application EP-A-0 114 607; furthermore, 4-tert-butyl-4′-methoxydibenzoylmethane is currently offered for sale under the trademark of “Parsol 1789” by Hoffmann-LaRoche.
Unfortunately, it is found that dibenzoylmethane derivatives are products which are relatively sensitive to ultraviolet radiation (in particular UV-A radiation), that is to say, more specifically, that they have an unfortunate tendency to decompose more or less rapidly under the effect of the latter. Thus, this substantial lack of photochemical stability of dibenzoylmethane derivatives in the face of ultraviolet radiation, to which they are naturally intended to be subjected, does not make it possible to guarantee constant protection during prolonged exposure to the sun, so that repeated applications at regular and frequent intervals have to be carried out by the user in order to obtain effective protection of the skin against UV radiation.
The photostabilization of dibenzoylmethane derivatives with respect to UV radiation constitutes, to date, a problem which has not yet been solved in a completely satisfactory manner.
Antisun compositions formed from amino-substituted 2-hydroxybenzophenone derivatives which can comprise other additional screening agents, such as dibenzoylmethane derivatives, in the presence of p-methylbenzylidenecamphor, are known in Patent Applications DE 10 012 408 and EP-A-1 046 391.
SUMMARY OF THE INVENTION
In point of fact, the Applicant company has now just discovered, surprisingly, that, by combining the abovementioned dibenzoylmethane derivatives with an amount of at least one specific amino-substituted 2-hydroxybenzophenone derivative, it is possible to improve, substantially and notably, the photochemical stability (or photostability) of these same dibenzoylmethane derivatives.
Thus, in accordance with one of the subject-matters of the present invention, a novel cosmetic or dermatological composition for topical use is now provided, which composition is characterized in that it comprises, in a cosmetically acceptable vehicle:
(a) at least one UV screening agent of the dibenzoylmethane derivative type and
(b) at least one specific amino-substituted 2-hydroxybenzophenone derivative of formula (I) which will be defined later; the said composition not comprising p-methylbenzylidenecamphor.
The invention also relates to a process for improving the stability with respect to UV radiation of at least one dibenzoylmethane derivative in a cosmetic or dermatological composition not comprising p-methylbenzylidenecamphor which consists in combining, with the said dibenzoylmethane derivative, an effective amount of at least one specific amino-substituted 2-hydroxybenzophenone derivative.
The term “effective amount of amino-substituted 2-hydroxybenzophenone derivative” in accordance with the invention is understood to mean an amount sufficient to produce a noteworthy and significant improvement in the photostability of the dibenzoylmethane derivative or derivatives of the photoprotective cosmetic composition. This minimum amount of photostabilizing agent to be employed, which can vary depending on the nature of the cosmetically acceptable vehicle used for the composition, can be determined without any difficulty by means of a conventional test for measuring photostability.
Finally, another subject-matter of the present invention is the use of an amino-substituted 2-hydroxybenzophenone derivative of formula (I) in the preparation of a cosmetic or dermatological composition comprising at least one dibenzoylmethane derivative and not comprising p-methylbenzylidenecamphor for the purposed of improving the stability with respect to UV radiation of the said dibenzoylmethane derivative present.
Other characteristics, aspects and advantages of the present invention will become apparent on reading the detailed description which will follow.
DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OF THE INVENTION
The ratio by weight of the amino-substituted 2-hydroxybenzophenone derivative to the dibenzoylmethane derivative is preferably greater than 1.
The amino-substituted 2-hydroxybenzophenone derivatives in accordance with the invention correspond to the following formula (I):
in which:
R
1
and R
2
, which may be identical or different, denote a hydrogen atom, a C
1
-C
20
alkyl radical, a C
2
-C
10
alkenyl radical, a C
3
-C
10
cycloalkyl radical or a C
3
-C
10
cycloalkenyl radical;
R
1
and R
2
can also form, with the nitrogen atom with which they are bonded, a 5- or 6-membered heterocyclic ring member;
R
3
and R
4
, which may be identical or different, denote a C
1
-C
20
alkyl radical, a C
2
-C
10
alkenyl radical, a C
3
-C
10
cycloalkyl radical, a C
3
-C
10
cycloalkenyl radical, a C
1
-C
12
alkoxy radical, a (C
1
-C
20
)alkoxycarbonyl radical, a C
1
-C
12
alkylamino radical, a di(C
1
,C
12
)alkylamino radical, an aryl radical or a heteroaryl which is optionally substituted, or a water-solubilizing substituent chosen from a carboxylate group, a sulphonate group or an ammonium residue;
X denotes a hydrogen atom or a COOR
5
or CONR
6
R
7
group;
R
5
, R
6
and R
7
, which may be id
Burns Doane Swecker & Mathis L.L.P.
Dodson Shelley A.
Societe L'Oreal S.A.
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