Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2001-03-02
2002-06-25
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
06409999
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to novel cosmetic/dermatological compositions for topical application, for the ultraviolet (UV)-photoprotection of human skin and/or hair, comprising (a) at least one silicon compound containing a benzotriazole substituent as a first UV-screening agent, and (b) as a second UV-screening agent, at least one cinnamic acid derivative.
The present invention more especially relates to the aforesaid UV-photoprotecting compositions wherein said first and said second sunscreens are present in such respective amounts as to provide synergistically enhanced activity with respect to the sun protection factors (SPFs) imparted thereto.
2. Description of the Prior Art
It is known to this art that light radiation with wavelengths of from 280 nm to 400 nm promotes tanning of the human epidermis, and that light rays with wavelengths of from 280 to 320 nm, known as UV-B radiation, cause skin burns and erythema which may be harmful to the development of a natural tan; this UV-B radiation should thus be screened from the skin.
It is also known that UV-A rays, with wavelengths of from 320 to 400 nm, which promote tanning of the skin, are liable to induce an adverse change therein, especially in the case of sensitive skin or of 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, leading to premature skin aging. UV-A radiation promotes triggering of the erythemal reaction or amplifies this reaction in certain individuals and may even be the source of phototoxic or photoallergic reactions. It is thus desirable to also screen out UV-A radiation.
A wide variety of cosmetic compositions for the sunblock protection (UV-A and/or UV-B) of the skin have to date been proposed.
These antisun/sunscreen compositions are quite often in the form of an emulsion of oil-in-water type (namely, a cosmetically acceptable support comprising a continuous aqueous dispersing phase and a discontinuous oily dispersed phase) which contains, in various concentrations, one or more conventional lipophilic and/or hydrophilic organic screening agents which are capable of selectively absorbing harmful UV radiation. These screening agents (and the amounts thereof) are selected as a function of the desired sun protection factor ((SPF) which is expressed mathematically by the ratio of the irradiation time necessary to attain the erythema-forming threshold with the UV screening agent to the time required to attain the erythema-forming threshold without UV screening agent.
Cosmetic UV-screening agents comprising lipophilic silicone compounds substituted by a benzotriazole functional group and which have good screening properties both in the UV-A radiation range and in the UV-B radiation range are also known to the prior 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; EP-A-711,779.
EP-A-0,742,003 and EP-A-0,860,165 describe combining these silicone screening agents bearing benzotriazole functional groups with specific water-soluble screening agents containing a sulfonic function, namely, benzene-1,4-bis(3-methylidene-10-camphorsulfonic acid) or 2-phenylbenzinidazole-5-sulfonic acid and salts thereof, in order to impart a synergistic effect with respect to the sun protection factors thereof. These synergistic screening systems require at least one aqueous phase for dissolving the water-soluble screening agent and a fatty phase for dissolving the silicone screening agent; this substantially reduces the options for the formulation thereof.
EP-A-0,835,094 describes combining these silicone screening agents bearing a benzotriazole functional group with two other lipophilic screening agents, namely, a dibenzoylmethane compound and an alkyl P,p-diphenylacrylate compound. In this instance also, the mandatory presence of these three screening agents complicates their formulation into antisun/sunscreen products.
UV-screening compositions based on silicon derivatives of benzotriazole in dissolved form containing at least one cinnamic derivative in an amount which is sufficient by itself to dissolve said silicone screening agent are described in French patent application No. 98/12042. This '042 application, in particular, describes a formulation example in the form of an oil-in-water emulsion containing 0.5% by weight of stearic acid, 2.5% by weight of stearyl alcohol, 2% by weight of polydimethylsiloxane, 0.22% of acrylic thickening polymer, 0.72% by weight of triethanolamine, 8% by weight of moisturizer, 5% by weight of drometrizole trisiloxane and 10% by weight of 2-ethylhexyl p-methoxycinnamate. It does not describe any synergistic effect on the protection factors with the benzotriazole-substituted silicon compound.
SUMMARY OF THE INVENTION
It has now surprisingly and unexpectedly been determined that immixture, in proportions within well-defined limits, of a UV-screening agent of the benzotriazole/silicon derivative type and of a UV-screening agent of the cinnamic acid derivative type elicits a marked synergistic effect on the sun protection factors provided thereby. Such admixture provides antisun/sunscreen compositions whose sun protection factors are markedly improved, and in all instances considerably superior to those which can be obtained with either one of the screening agents formulated alone.
Too, the specific combinatory admixture of UV-screening agents in accordance with the invention is readily formulated into a very wide range of cosmetic/dermatological supports, i.e., vehicles, diluents or carriers therefor.
Briefly, the present invention features novel cosmetic/dermatological compositions, in particular antisun/sunscreen compositions comprising, formulated into cosmetically/dermatologically acceptable supports therefor:
(i) at least one benzotriazole-substituted silicon compound, as a first UV-screening agent; and
(ii) at least one cinnamic acid derivative, as a second UV-screening agent, with the proviso that said first and second UV-screening agents are present in the subject compositions in proportions which provide synergistically enhanced activity on the sun protection factors imparted. The subject compositions are other than oil-in-water emulsions containing 0.5% by weight of stearic acid, 2.5% by weight of stearyl alcohol, 2% by weight of polydimethylsiloxane, 0.22% of acrylic thickening polymer, 0.72% by weight of triethanolamine, 8% by weight of moisturizer, 5% by weight of drometrizole trisiloxane and 10% by weight of 2-ethylhexyl p-methoxycinnamate.
The present invention also features a regime/regimen for protecting the skin and/or the hair against the deleterious effects of ultraviolet radiation, in particular solar radiation.
This invention also features formulating a cinnamic derivative into cosmetic/dermatological compositions suited for photoprotecting the skin and/or the hair against ultraviolet radiation, in particular solar radiation, and comprising at least one UV-screening agent of the benzotriazole/silicon type, to elicit a synergistic effect on the sun protection factors imparted thereto.
DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OF THE INVENTION
More particularly according to the present invention, the silicon compounds substituted by a benzotriazole functional group are preferably silanes or siloxanes containing a benzotriazole function, comprising at least one structural unit of formula (1) below:
O
(3-a)/2
Si(R
7
)
a
—G (1)
in which R
7
is an optionally halogenated C
1
-C
10
alkyl radical, a phenyl radical, or a trimethylsilyloxy radical; a is an integer ranging from 0 to 3, inclusive; and G is a monovalent radical directly bonded to a silicon atom and having the structural formula (2) below:
in which the radicals Y, which may be identical or different, are each a C
1
-C
8
alkyl radical, a halogen atom, or a C
1
-C
4
alkoxy radical, with the proviso that, in the latter instance, two adjacent radicals Y on the same aromatic r
Agostini Isabelle
Arnaud Pascal
Guillard Sylvie
Burns Doane Swecker & Mathis L.L.P.
Dodson Shelley A.
Societe L'Oreal
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