Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
1997-11-20
2001-01-16
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
C424S070100, C424S070900, C424S070190, C424S070210, C424S070240, C424S400000, C424S401000
Reexamination Certificate
active
06174517
ABSTRACT:
BACKGROUND OF THE INVENTION
Technical Field of the Invention
The present invention relates to new cosmetic compositions for topical use which are intended more particularly for the photoprotection of the skin and/or hair against ultraviolet radiation (these compositions will be called below, more simply, antisun compositions) and to their use in the abovementioned cosmetic application. Still more precisely, it relates to antisun compositions which comprise, in a cosmetically acceptable vehicle, an association of a specific screening agent, chosen from dibenzoylmethane derivatives, with at least one inorganic titanium oxide nanopigment treated with silanes and/or silicones.
It is known that luminous radiation with wavelengths of between 280 nm and 400 nm allows the human skin to tan, and that rays with wavelengths of between 280 nm and 320 nm, known by the term UV-B, cause erythemas and skin burns which may damage the development of the natural tan; this UV-B radiation must therefore be screened out.
It is also known that UV-A rays, with wavelengths of between 320 nm and 400 nm, which cause the skin to tan, are capable of harming the latter, especially in the case of sensitive skin or skin which is continually exposed to solar radiation. In particular, UV-A rays cause a loss of skin elasticity and the appearance of wrinkles, leading to premature ageing. They promote the triggering of the erythemal reaction or accentuate this reaction in certain individuals and can even be the cause of phototoxic or photoallergic reactions. It is therefore desirable to screen out the UV-A radiation as well.
Numerous organic sunscreens capable of absorbing, with greater or lesser selectivity, the harmful UV-A rays have been proposed to date in the field of cosmetology.
In this context, a particularly advantageous class of UV-A screening agents currently consists of dibenzoylmethane derivatives, and especially 4-methoxy-4′-tert-butyldibenzoylmethane, which in fact exhibit a high intrinsic adsorption capacity. These dibenzoylmethane derivatives, which are now products which are well known per se as UV-A-active screening agents, are described in particular in the French Patent Applications FR-A-2 326 405 and FR-A-2 440 933 and in the European Patent Application EP-A-0 114 607; 4-methoxy-4′-tert-butyldibenzoylmethane, moreover, is currently offered for sale under the trade name “PARSOL 1789” by the company Givaudan.
In order to obtain total protection over the entire solar spectrum in the UV range, it is possible to combine with these dibenzoylmethane derivatives a UV-B screening agent.
Moreover, it is known that the addition of an inorganic pigment, and especially a titanium oxide (TiO
2
) pigment, makes it possible to increase the photoprotective properties of the sunscreen compositions comprising UV screening agents.
Consequently, the combination of dibenzoylmethane derivatives and TiO
2
(nano)pigments is of great interest in the field of antisun compositions.
However, it is found that the combinations of dibenzoylmethane derivatives with inorganic (nano)pigments, and still more especially the combination 4-methoxy-4′-tert-butyldibenzoylmethane/TiO
2
, have a disadvantage which affects not only the character, and therefore the quality, of the products comprising them, but also their attractiveness to consumers; in effect, for compositions containing this type of combination, a colour change is observed which is manifested in a more or less intense yellowing of the formulas. Apart from the fact that this phenomenon reduces the photoprotective power of the dibenzoylmethane derivatives, and in particular of 4-methoxy-4′-tert-butyldibenzoylmethane, this yellowing is obviously undesirable from a cosmetic viewpoint.
It is observed, moreover, that this phenomenon is particularly marked in the case of TiO
2
nanopigments.
In order to solve this problem, certain solutions have already been proposed in the prior art; thus, in Japanese Patent Application JP 61-215314, the use of sequestrants chosen from edetic, metaphosphoric and polyphosphoric acids and/or their salts was recommended in order to reduce this phenomenon of yellowing. However, this solution does not give complete satisfaction.
Now, following major studies carried out in the field of photoprotection set out above, the Applicant has discovered that the use of titanium oxide (nano)pigments treated with a silicone (siloxane or silane derivative) significantly reduced the yellowing which is commonly observed in the antisun compositions containing conventional combinations of the dibenzoylmethane derivative/TiO
2
pigment type.
It is this discovery which forms the basis of the present invention.
It should be noted here that, from the document WO-A-94 04131, photostable screening compositions are known which comprise, in well-defined proportions, a dibenzoylmethane derivative in combination with a benzylidenecamphor derivative. According to this document the benzylidenecamphor, in the proportions indicated, makes it possible to stabilize the dibenzoylmethane derivative to light, in other words to limit its degradation under the action of UV rays, especially UV-A rays. In the same document, it is indicated that these photostable compositions may additionally contain a UV-blocking inorganic pigment, especially a titanium oxide pigment, which can be coated with a compound, especially a silicone-containing compound. However, this document neither describes nor teaches that, by using a titanium oxide pigment treated with a silicone, it is possible to obtain a reduction in the yellowing effect, as is an object of the present invention.
Thus, in accordance with one of the subjects of the present invention, new cosmetic compositions, especially antisun compositions, are now proposed of the type comprising, in a cosmetically acceptable vehicle, at least one dibenzoylmethane derivative and at least one titanium oxide pigment, which compositions are essentially characterized in that the said titanium oxide pigment is coated and/or treated with a silicone, these compositions being, moreover, devoid of compounds of the benzylidenecamphor type, of the following general formula:
in which D and E are radicals chosen independently from the group consisting of hydrogen, linear or branched C
1
-C
20
alkyl radicals and the radical OR in which R is hydrogen or a linear or branched C
1
-C
20
alkyl radical.
As indicated previously, the compositions according to the invention have the advantage of being subject to only a very small extent to the phenomenon of yellowing which is customarily caused by the combination of a dibenzoylmethane derivative with TiO
2
pigments.
The present invention also relates to the use of such compositions as, or for the preparation of, cosmetic compositions intended for the protection of the skin and/or hair against ultraviolet radiation, especially solar radiation.
Yet another subject of the present invention is a method of cosmetic treatment for the protection of the skin and/or hair against ultraviolet radiation, especially solar radiation, which essentially consists in applying to the skin and/or hair an effective quantity of a composition according to the invention.
A further subject of the present invention is the use of at least one titanium oxide (nano)pigment, coated and/or treated with a silicone, in antisun compositions containing a dibenzoylmethane derivative, with the aim of simultaneously improving the photoprotective power and the yellowing resistance of the said compositions.
Other characteristics, aspects and advantages of the present invention will appear on reading the detailed description which follows.
As indicated above, the dibenzoylmethane derivatives used in the context of the present invention are products which are already well known per se and are described, in particular, in the abovementioned documents FR-A-2 326 405, FR-A-2 440 933 and EP-A-0 114 607, the teaching of which documents, where it touches on the actual definition of these products, is included in its entirety by way of refe
Hansenne Isabelle
van Leeuwen Victoria
Burns Doane Swecker & Mathis L.L.P.
Dodson Shelley A.
Societe L'Oreal S.A.
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