Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2001-01-30
2002-04-16
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
C424S060000, C424S078020, C424S078080, C424S400000, C424S401000
Reexamination Certificate
active
06372200
ABSTRACT:
CROSS-REFERENCE TO PRIORITY APPLICATION
This application claims priority under 35 U.S.C. § 119 of FR-00/01535, filed Feb. 8, 2000, hereby expressly incorporated by reference.
BACKGROUND OF THE INVENTION
Technical Field of the Invention
The present invention relates to novel cosmetic/dermatological compositions for topical application, for the ultraviolet (UV)-photoprotection of the skin and/or the hair against the damaging effects of UV radiation, in particular solar radiation, comprising, formulated into a cosmetically and/or dermatologically acceptable support therefor (vehicle, diluent or carrier), at least one sunscreen system effective for screening out UV radiation and at least one mixture of polyethylene polymers including at least one polyethylene containing a carboxylic acid end function in free, partially neutralized or totally neutralized form and at least one polyethylene.
The present invention also relates to formulating a mixture of polyethylene polymers including at least one polyethylene containing a carboxylic acid end function in free, partially neutralized or totally neutralized state and at least one polyethylene into cosmetic and/or dermatological compositions suited for protecting human skin and/or hair against the damaging effects of UV radiation, in particular solar radiation, and enhancing the sun protection factors (SPF) thereof.
Description of the Invention
It is known to this art that light radiation of wavelengths of from 280 nm and 400 nm promotes tanning of the human epidermis and that irradiation of wavelengths of from 280 nm and 320 nm, i.e., UV-B irradiation, causes 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 to this art that UV-A radiation, of wavelengths of from 320 nm and 400 nm, which causes tanning of the skin, also adversely affects it, 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 elasticity of the skin and the appearance of wrinkles, promoting premature skin aging. Such irradiation promotes triggering of the erythemal reaction or amplifies this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions. It is thus desirable to also screen out UV-A radiation.
A wide variety of cosmetic compositions intended for the sunscreen (UV-A and/or UV-B) protection of the skin is known to this art.
These antisun/sunscreen compositions are quite often in the form of an emulsion of oil-in-water type (i.e., a cosmetically acceptable support comprising a continuous aqueous dispersing phase and a discontinuous oil dispersed phase) which contains, in varying 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) being selected as a function of the desired sun protection factor (the sun protection factor (SPF) being expressed mathematically as the ratio of the irradiation time required to attain the erythema-forming threshold with the UV-screening agent to the time required to attain the erythema-forming threshold in the absence of UV-screening agent).
SUMMARY OF THE INVENTION
It has now surprisingly and unexpectedly been determined that by formulating into appropriate medium or support, for example an oil-in-water emulsion, a specific intimate immixture of polyethylenes with an effective sunscreen system, antisun/sunscreen compositions are provided that have higher sun protection factors than those comprising the same sunscreen system alone.
Thus, the present invention features novel compositions for effectively photoprotecting the skin and/or the hair against the damaging effects of ultraviolet radiation, comprising, and formulated into a topically applicable, cosmetically/dermatologically acceptable vehicle, diluent or carrier therefor, most advantageously an oil-in-water emulsion:
(a) at least one sunscreen system effective for screening out UV radiation;
(b) at least one mixture of polyethylene polymers which comprises at least one polyethylene containing a carboxylic acid end function and at least one polyethylene.
DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OF THE INVENTION
More particularly according to the present invention, by the expression “sunscreen system effective for screening out UV radiation” is intended any compound or any combination of compounds which, by mechanisms that are known per se of absorption and/or reflection and/or scattering of UV-A and/or UV-B radiation, prevents, or at least limits, the contact between such radiation and a surface (skin, hair) on which this or these compounds have been applied. Stated differently, these compounds may be UV-absorbing organic sunscreen screening agents or inorganic (nano)pigments which scatter and/or reflect UV, as well as mixtures thereof.
The present invention thus also features formulating a mixture of polyethylenes which includes at least one polyethylene containing a carboxylic acid endgroup and at least one polyethylene, into compositions suited for protecting the skin and/or the hair against the damaging effects of ultraviolet radiation, such compositions most preferably comprising oil-in-water emulsions and also including a sunscreen system suited for screening out UV radiation and having enhanced sun protection factors (SPF).
The polyethylene mixtures in accordance with the present invention generally comprise from 60% to 99% by weight and more preferably from 80% to 90% by weight of a polyethylene containing a carboxylic acid endgroup and from 1% to 40% by weight and more preferably from 10% to 20% by weight of a polyethylene, per se, both relative to the total weight of the mixture.
In the polyethylene mixtures of this invention, the carboxylic acid endgroup may optionally be partially neutralized or totally neutralized with a mineral base such as sodium hydroxide, potassium hydroxide or aqueous ammonia or an organic base such as an amine or an alkanolamine such as triethanolamine.
The polyethylene mixtures in accordance with the present invention preferably have a number-average molecular weight ranging from 300 to 800, an acid number ranging from 60 to 120 and a melting point ranging from 80° C. to 120° C.
Among the polyethylene mixtures according to this invention which are more particularly preferred are the products marketed under the trademark “Performacid” by New Phase Technologies, such as, for example:
(1) the mixture of polyethylene containing a carboxylic acid end function/polyethylene of molecular weight 350, of acid number 115 and of melting point 89° C. (INCI name: C
20
-C
40
Acid and Polyethylene) marketed under the trademark “Performacid 350”;
(2) the mixture of polyethylene containing a carboxylic acid end function/polyethylene of molecular weight 460, of acid number 94 and of melting point 94° C., marketed under the trademark “Performacid 425”;
(3) the mixture of polyethylene containing a carboxylic acid end function/polyethylene of molecular weight 550, of acid number 72.5 and of melting point 101° C., marketed under the trademark “Performacid 550”;
(4) the mixture of polyethylene containing a carboxylic acid end function/polyethylene of molecular weight 700, of acid number 63 and of melting point 110° C., marketed under the trademark “Performacid 700”.
The polyethylene mixtures of the invention are advantageously formulated into the subject compositions at concentrations preferably ranging from 0.1% to 10% by weight relative to the total weight of the composition and more preferably from 0.2% to 5% by weight.
The sunscreen system according to the invention is generally present in the subject compositions at a content ranging from 0.1% to 30% by weight and preferably from 0.5% to 15% by weight relative to the total weight of the composition.
According to the invention, the sunscreen system may comprise one or more hydrophilic organic scre
Josso Martin
Meurisse Stéphanie
Burns Doane Swecker & Mathis L.L.P.
Dodson Shelley A.
Societe L'Oreal S.A.
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