Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2000-12-20
2002-04-23
Higel, Floyd D. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C424S070900, C424S070120, C424S059000, C424S040000, C424S450000
Reexamination Certificate
active
06376679
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The invention concerns new silicon-bearing derivatives of benz-x-azole that are liposoluble, photostable, and have an excellent absorption power in the UV radiation spectrum. The invention also pertains to compositions, particularly cosmetic compositions, containing these new derivatives, which can be used for photoprotection of the skin and/or hair against UV radiation, particularly solar radiation.
2. Description of the Prior Art
It is a known fact that light radiation in the wavelength range of between 280 nm and 400 nm can darken the human epidermis and that, more specifically, radiation in the wavelength range of between 280 and 320 nm, referred to as UV-B, causes cutaneous erythema and burns which can be detrimental to the development of natural tanning. For these reasons, as well as for esthetic reasons, there is a growing demand for ways of controlling this natural tanning in order to control the color of one's skin. As a result, this UV-B radiation needs to be filtered out.
It is also a known fact that UV-A radiation, having a wavelength of between 320 and 400 nm, which causes the skin to tan, is likely to induce an alteration of the skin, particularly in the case of sensitive skin or skin that is continually exposed to solar radiation. In particular, UV-A rays cause the skin to lose its elasticity and wrinkles to appear, leading to premature skin aging. They promote the triggering of the erythematic reaction or amplify this reaction in certain subjects, and can even be the cause of phototoxic or photoallergic reactions. Consequently, for esthetic and cosmetic reasons, such as maintaining the natural elasticity of the skin, for example, more and more people wish to control the effect of UV-A radiation on their skin. It is therefore desirable to filter out UV-A radiation as well.
Numerous compounds intended for the photoprotection (UV-A and/or UV-B) of the skin have thus far been offered.
Most of them are aromatic compounds providing absorption of UV rays in the spectrum of between 280 and 315 nm, or in the spectrum of between 315 and 400 nm, or still in the combined spectrum of these two ranges. They are most often formulated in sunscreen compositions in the form of an oil-in-water emulsion (that is, a cosmetically acceptable medium consisting of a continuous aqueous dispersing phase and a discontinuous oily dispersed phase) and which therefore contain in various concentrations one or more conventional organic filters having an aromatic function which are lipophilic and/or hydrophilic and capable of selectively absorbing harmful UV radiation, with these filters (and their quantities) being selected according to the desired solar protection factor (the solar protection factor is expressed mathematically as the ratio of the necessary irradiation time to reach the erythematogenic threshold with the UV filter, to the time necessary to reach the erythematogenic threshold without the UV filter).
In addition to their filtration power, these anti-UV compounds must also have good cosmetic properties in the compositions containing them, good solubility in the usual solvents, especially fatty substances such as oils and greases, as well as good resistance to water and perspiration (persistence).
SUMMARY OF THE INVENTION
Among the aromatic compounds that have been proposed for this purpose we can mention the (hydroxy-2′-phenyl)-2-benz-x-azole compounds of patent application CH 350,763. The solubility of these molecules in various types of formulations used in the field of solar protection is still inadequate.
The Applicant made the surprising discovery of new silicon-bearing derivatives of benz-x-azole having improved properties, particularly with regard to their solubility in fatty substances and their stability with light.
More specifically, according to this invention it was found that by grafting one or more benz-x-azole groups to a silicone chain, it was possible to arrive at new compounds that, in addition to excellent filtering properties in the UV-A and/or UV-B radiation range, provide very good solubility in the commonly-used organic solvents and particularly fatty substances such as oils, as well as excellent cosmetic properties, making them particularly appropriate for use as solar radiation filters in, or for the preparation of, cosmetic compositions intended for the protection of the skin and/or hair against ultraviolet radiation.
DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OF THE INVENTION
Consequently, the first object of this invention is new compounds characterized by the fact that they have at least one unit based on the following formula (1) or (2):
A—SiR′
1
R′
2
R′
3
(2)
in which:
R refers to a hydrocarbonic group saturated or unsaturated at C
1
-C
30
, a hydrocarbonic group halogenated at C
1
-C
8
, or a trimethylsilyloxy group;
a is equal to 1 or 2;
R′
1
, R′
2
, and R′
3
, either identical or different, are chosen from among the linear or branched, saturated or unsaturated alkyl and alkenyl radicals at C
1
-C
8
;
A is a radical having the following formula (I):
in which:
L is a divalent radical allowing radical A to latch on to the silicone chain;
radicals R
1
and R
2
, either identical or different, independently represent an atom of hydrogen, a linear or branched alkyl radical at C
1-C
10
, or a linear or branched alkenyl radical at C
2
-C
8
, with two adjacent R
1
or R
2
components being capable of forming an alkylidene dioxy group in which the alkylidene group contains 1 or 2 atoms of carbon;
Y represents C or N;
X represents O; NR
3
; S when Y designates C or C when Y designates N;
R
3
is a hydrogen atom or an alkyl radical at C
1
-C
8
;
n and m are 1 or 2 independently.
Preferably, L satisfies one of the following formulas (a) or (a′):
in which:
W represents O or NH;
Z is a linear or branched, saturated or unsaturated di-yl alkane radical at C
1
-C
6
, possibly substituted with a linear or branched, saturated or unsaturated hydroxyl or alkyl radical at C
2
-C
8
;
R
4
represents an atom of hydrogen, a hydroxyl radical, or a linear or branched, saturated or unsaturated alkyl radical at C
1
-
8
;
p and q are 0 or 1.
Preferably, the compounds according to the invention satisfy one of the following two formulas (3 or 4):
in which:
R designates a saturated or unsaturated hydrocarbonic group at C
1
-C
30
, a halogenated hydrocarbonic group at C
1
-C
8
, or a trimethylsilyloxy group;
the B components, either identical or different, are chosen from among the R radicals and the A radical;
r is a whole number of between 0 and 50 inclusively;
s is a whole number of between 0 and 20 inclusively and if s is 0, then at least one of the B symbols is A;
u is a whole number between 1 and 6 inclusively;
t is a whole number between 0 and 10 inclusively;
t+u is equal to or greater than 3.
The compounds of the invention display excellent liposolubility and can thus be used in large concentrations, thus providing the final compositions with very high protection indices; furthermore, they spread uniformly throughout conventional cosmetic media containing at least one fatty phase or a cosmetically acceptable organic solvent, and can thus be applied to the skin or the hair in order to act as an effective protective film.
In addition, the compounds of the invention have an excellent intrinsic filtration power with regard to UV-A and/or UV-B ultraviolet radiation.
These new silicon-bearing derivatives of benz-x-azole can therefore be used as sunscreens for human skin and hair. They can also be used as protective agents against light in the plastics industry.
Preferably, the R radicals, either identical or different, are chosen from among the linear or branched, saturated or unsaturated alkyl radicals at C
1
-C
10
, the phenyl radical, and the trifluoro-3,3,3-propyl radical, with at least 80% of the R radicals by number being the methyl radical.
In formulas (1) through (4) above, special preference is given
Lagrange Alain
Leduc Madeleine
Richard Herve
Burns Doane Swecker & Mathis L.L.P.
Higel Floyd D.
Societe L'Oreal S.A.
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