Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2000-02-24
2002-04-23
Dees, Jose′ G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
C424S060000, C424S070100, C424S070900, C424S070190, C424S070210, C424S070220, C424S070270, C424S070310, C424S400000, C424S401000, C514S937000
Reexamination Certificate
active
06375936
ABSTRACT:
The present invention relates to a cosmetic composition for topical use which is intended more particularly for photoprotecting the skin and/or the hair against ultraviolet radiation, as well as to its use in the abovementioned cosmetic application. More particularly, the present invention relates to a photo-protective composition in the form of a dispersion comprising two immiscible phases stabilized with at least one anionic surfactant, a compound for screening out UV radiation and a cationic or zwitterionic amphiphilic compound.
It is known that light radiation with wave-lengths of between 280 nm and 400 nm permits tanning of the human epidermis, and that light rays with wave-lengths of between 280 nm and 320 nm, known as UV-B rays, cause skin burns and erythema which may be harmful to the development of a natural tan; this UV-B radiation should thus be screened out.
It is also known that UV-A rays, with wave-lengths of between 320 and 400 nm, which cause tanning of the skin, are liable to induce an adverse change in the latter, especially in the case of sensitive skin or of skin which is continually exposed to solar radiation. UV-A rays in particular cause a loss of elasticity of the skin and the appearance of wrinkles, leading to premature ageing of the skin. They promote triggering of the erythemal reaction or amplify this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions. It is thus desirable also to screen out UV-A radiation.
Many cosmetic compositions intended for the photoprotection (UV-A and/or UV-B) of the skin have been proposed to date.
Compositions based on active compounds comprising a free or at least partially neutralized acid function, which screen out UV rays, are known in the prior art. In particular, certain sulphonic compounds are known for their good properties of screening out light radiation with wavelengths of between 280 and 400 nm and more particularly between 280 and 360 nm, their thermal stability and their photochemical stability.
However, the formulation of products with a very high sun protection factor (SPF) involves the use of large concentrations of UV screening agents, which is not desirable, either from a toxicological point of view in certain cases, or from an economic point of view. The sun protection factor (SPF) is expressed mathematically by the ratio of the irradiation time required to reach the erythema-forming threshold with the UV screening agents to the time required to reach the erythema-forming threshold without UV screening agents.
It is thus important to be able to provide novel formulation systems which improve the protection factor for the same content of screening agents and which, consequently, are able to reduce the contents of UV screening agents in formulations.
After considerable research conducted in this matter, the Applicant has discovered, surprisingly and unexpectedly, that it is possible to solve this problem and to improve the sun protection factor of screening agents by modifying the interfacial behaviour of the anionic surfactant by using a cationic or zwitterionic amphiphilic compound which leads, with the anionic surfactant, to the formation of a compound capable of lowering the water/liquid paraffin interface tension at 40° C. by more than 14 mN.m
−1
for an anionic surfactant concentration of 0.1 mmol/100 g, by more than 26 mN.m
−1
for an anionic surfactant concentration of 0.5 mmol/100 g and by more than 33 mN.m
−1
for an anionic surfactant concentration of 1 mmol/100 g.
This discovery forms the basis of the present invention.
A subject of the present invention is thus a cosmetic composition for topical use, in particular for photoprotecting the skin and/or the hair, in the form of a dispersion comprising two immiscible phases stabilized with at least one anionic surfactant chosen from the salts of fatty acids and of monovalent and polyvalent metals, of ammonium or of organic bases, a compound for screening out ultraviolet radiation, consisting of a hydrophilic screening agent-comprising at least one partially or totally neutralized sulphonic acid function, which can be adsorbed at the interface of the said immiscible phases, having the formula:
in which:
Z denotes a group of formula:
R
2
denoting —H or —SO
3
H; n denotes 0 or an integer greater than or equal to 1 and less than or equal to 4;
R
1
represents one or more identical or different, linear or branched alkyl or alkoxy radicals containing from 1 to 4 carbon atoms,
the two methylidenecamphor radicals on the phenyl ring being in a meta or para position relative to each other,
as well as a metal oxide nanopigment chosen from titanium oxide, zinc oxide, iron oxide, zirconium oxide and cerium oxide, and mixtures thereof, coated with hydrophobic hydrocarbon-based coating agents, with an average primary particle size ranging from 5 to 100 nm, this composition being characterized in that it also contains a cationic or zwitterionic amphiphilic compound which leads, with the anionic surfactant, to the formation of a compound capable of lowering the water/liquid paraffin interface tension at 40° C. by more than 14 mN.m
−1
for an anionic surfactant concentration of 0.1 mmol/100 g, by more than 26 mN.m
−1
for an anionic surfactant concentration of 0.5 mmol/100 g and by more than 33 mN.m
−1
for an anionic surfactant concentration of 1 mmol/100 g.
The interface tension is measured according to Lecomte du Noüy's ring method described, for example, in Galenica, (F. Puisieux, M. Seiller), 5 Les Systèmes Dispersés, I Agents de surface et Emulsions, chapter 2, pp. 86-89.
The cationic or zwitterionic amphiphilic compound can be chosen from the compounds of formula:
in which:
R
1
to R
4
, which may be identical or different, represent a linear or branched C
1
-C
30
alkyl, hydroxy-alkyl, alkylcarboxylate, alkylsulphonate, hydroxyalkyl-sulphonate, cycloalkyl, alkenyl, aryl or arylalkyl radical which can be interrupted with one or more hetero atoms such as oxygen or sulphur or with an —NH—or amide —CONH— group, or R
1
and R
2
and/or R
3
and R
4
form, together with the nitrogen atom to which they are attached, a five-or six-membered saturated or unsaturated heterocycle which is unsubstituted or substituted with C
1
-C
30
alkyl, hydroxyalkyl, alkenyl, aryl or arylalkyl radicals, at least one of the radicals R
1
to R
4
or substituents on the heterocycle, and preferably at least two of these radicals or substituents, comprising at least 6 carbon atoms; X
−
represents an inorganic or organic ion chosen from halide, sulphate, bisulphate, methosulphate, para-toluenesulphonate and saccharinate ions, preferably chloride or bromide; it being understood that when at least one of the radicals R
1
to R
4
represents an alkylcarboxylate, alkylsulphonate or hydroxyalkyl-sulphonate radical, the ion X
−
does not exist.
The cationic or zwitterionic amphiphilic compound can also have the formula (II) below:
in which
R
5
represents a linear or branched C
1
-C
30
alkyl, hydroxyalkyl, alkylcarboxylate, cycloalkyl, alkenyl, aryl or arylalkyl radical which can be interrupted with one or more hetero atoms such as oxygen or sulphur or with an —NH— or amide —CONH—group;
A, B or D represents CH, N, N
+
R
6
, R
6
representing a hydrogen atom, a substituted or unsubstituted, linear or branched, saturated or unsaturated C
1
-C
30
alkyl radical which can be interrupted with one or more hetero atoms, it being understood that only one of the symbols A, B or D represents N or N
+
R
6
; with the proviso that at least one of the radicals R
5
or R
6
comprises at least 6 carbon atoms;
X
−
represents an inorganic or organic ion chosen from halide, sulphate, bisulphate, methosulphate, para-toluenesulphonate and saccharinate ions, preferably chloride or bromide;
m=0, 1 or 2.
The radicals R
1
to R
6
comprising at least 6 carbon atoms are preferably C
8
-C
22
radicals.
The cationic or zwitterionic amphiphilic compound of formula (I) is preferably chosen from
Allard Delphine
Candau Didier
Nicolas-Morgantini Luc
Dees Jose′ G.
L'Oreal
Lamm Marina
Nixon & Vanderhye P.C.
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