Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2000-11-28
2002-04-30
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
06379655
ABSTRACT:
CROSS-REFERENCE TO PRIORITY APPLICATION
This application claims priority under 35 U.S.C. §119 of FR-99/14999, filed Nov. 29, 1999, hereby expressly incorporated by reference.
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to novel cosmetic/dermatological compositions well suited for the photoprotection of the skin and/or of the hair against ultraviolet (UV) radiation, in particular solar radiation, comprising an effective amount of at least one aminoamidine compound.
This invention also relates to the formulation of photoprotective cosmetic/dermatological compositions comprising characteristic aminoamidine sunscreens which are active in the field of UV radiation.
2. Description of the Prior Art
It is known to this art that light radiation having wavelengths of from 280 nm to 400 nm promotes tanning of the human epidermis, and that irradiation having wavelengths more particularly ranging from 280 to 320 nm, i.e., UV-B radiation, causes erythemas and skin burns which can impede the development of natural tanning; this UV-B radiation must therefore be screened from the skin.
It is also known to this art that UV-A radiation having wavelengths of from 320 to 400 nm, which causes tanning of the skin, can also adversely affect it, in particular in the case of a sensitive skin or a skin continuously exposed to solar radiation. UV-A rays cause, in particular, a loss of elasticity of the skin and the appearance of wrinkles, resulting in premature skin aging. Such irradiation promotes the onset of the erythematous reaction or amplifies this reaction in certain individuals and may even be responsible for phototoxic or photoallergic reactions. Thus, for aesthetic and cosmetic reasons such as the preservation of the natural elasticity of the skin for example, an increasing number of individuals wish to control the effect of UV-A rays on their skin. It is therefore desirable to also screen out UV-A radiation.
Numerous compounds for the photoprotection (UV-A and/or UV-B) of human skin are known to this art.
Most are aromatic compounds which absorb UV rays in the region from 280 to 315 nm, or in the region from 315 to 400 nm or else in the entirety of these two regions. These are most often formulated into anti-sun or sunscreen compositions which are provided in the form of an oil-in-water type emulsion (namely, a cosmetically acceptable carrier, vehicle or diluent comprising a continuous aqueous dispersing phase and a discontinuous oily dispersed phase) and which therefore contain, in various concentrations, one or more conventional organic screening agents having an aromatic function, which are lipophilic and/or hydrophilic and which are capable of selectively absorbing harmful UV radiation, these screening agents (and the amounts thereof) being selected according to the desired sun protection factor (the sun protection factor being mathematically expressed by the ratio of the irradiation time necessary to achieve the erythematogenic threshold with the UV-screening agent to the time necessary to achieve the erythematogenic threshold without UV-screening agent).
In addition to their screening power, these compounds exhibiting anti-UV activity should also have good cosmetic properties in the compositions comprised thereof, a good solubility in the customary solvents and in particular fatty substances such as oils and fats, and good stability to UV radiation (photostability).
SUMMARY OF THE INVENTION
It has now surprisingly and unexpectedly been determined that a family of aminoamidine compounds are notable organic UV-screening agents having, in addition to excellent screening properties in the UV-A and/or UV-B radiation regions, a very good solubility in the customary organic solvents and in particular fatty substances such as oils, an excellent photostability, as well as excellent cosmetic properties, rendering same particularly appropriate sunscreens when formulated into cosmetic compositions suited for protecting the skin and/or the hair against the damaging effects of ultraviolet radiation.
DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OF THE INVENTION
More particularly according to the present invention, cosmetic compositions for topical application are provided for the photoprotection of the skin and/or of the hair, advantageously comprising, formulated into a cosmetically acceptable carrier, vehicle or diluent therefor, at least one aminoamidine compound having the following structural formula (I):
in which Ar
1
is (i) an aromatic radical having the following formula (II):
wherein R
1
, R
2
and R
3
, which may be identical or different, are each a hydrogen atom, a linear or branched C
1
-C
8
alkyl radical, or a C
1
-C
8
alkoxy radical, with the proviso that R
1
, R
2
and R
3
can together form an aromatic or unfused ring, or an aromatic heterocycle having 5 or 6 atoms; or (ii) an aromatic radical having 6 atoms, corresponding to the following formula (III):
wherein each Z is C or N; Ar
2
is an aromatic radical Ar
1
as defined above or an aromatic radical having 5 atoms, corresponding to the following formula (IV):
wherein Y is a sulfur, oxygen, carbon or nitrogen atom, W is a carbon or nitrogen atom, R
4
is (a) a hydrogen atom when W is a nitrogen atom, or (b) a hydrogen atom, a linear or branched C
1
-C
8
alkyl radical, a C
1
-C
8
alkoxy radical, or can form an aromatic or unfused ring member, when W is a carbon atom; U is a carbon or nitrogen atom, when W is a carbon atom; and R
5
is (a) a hydrogen atom when U is nitrogen, or (b) a hydrogen atom, a linear or branched C
1
-C
8
alkyl radical, a C
1
-C
8
alkoxy radical, or can form an aromatic or unfused ring member, when U is a carbon atom; and Ar
3
is an aromatic radical Ar
2
as defined above, or a hydrogen atom.
Various aminoamidine compounds of formula (I) in accordance with the invention are known to this art and a variety thereof are described in the article by BILLINGTON, D. C.; COLEMAN, M. D.; IBIABUO, J.; LAMBERT, P. A.; RATHBONE, D. L.; TIMS, K. J.,
Drug Des. Discovery
15(4), 269-275 (1998).
The aminoamidine compounds of formula (I) according to the invention are conveniently prepared via a three-step synthesis from a nitrile per the following reaction scheme:
The step which makes it possible to proceed from (1) to (2) is the synthesis of the Pinner iminoethers which is described, for example, in PINNER, A.,
Chem. Ber.,
1877, 10, 1889; ROGER, R. AND NEILSON D.,
Chem. Rev.
1961, 61, 179; RAPOPORT, H.,
J. Org. Chem.,
1981, 46, 2465.
Numerous aromatic nitriles are commercially available, such as, for example:
4-nitrobenzonitrile (cas: 619-72-7) from Acros, reference 12848-0250;
3-cyanopyridine (cas: 100-54-9) from Acros, reference 110861000;
4-aminobenzonitrile (cas: 873-74-5) from Acros, reference 164470100;
4-fluorobenzonitrile (cas: 1194-02-1) from Acros, reference 160810250;
4-acetylbenzonitrile (cas: 1443-80-7) from Acros, reference 167580250.
Certain iminoethers are also commercially available, such as, for example:
ethyl 4-hydroxybenzimidate hydrochloride (cas: 54998-28-6) from Aldrich, reference 32,446-9;
etlylbenzimidate hydrochloride (cas: 5333-86-8) from Fluka, reference 12268.
The step which permits proceeding from (2) to (3) is carried out by the action of hydrazine and is described in the literature, in particular by CASE F. H.,
J. Org. Chem.,
1965, 30, 931 and also TAYLOR E. C. and MARTIN S. F.,
J. Org. Chem.,
1972, 37, 3958, or also by REPIC O., MATTNER P. G. AND SHAPIRO M. J.,
J. Heterocyclic Chem.,
1982, 19, 1201.
The step which permits proceeding from (3) to (4) is the condensation of an aromatic aldehyde in alcoholic medium. This reaction is described in the literature, in particular by MAMOLO M. G.; VIO L.; BANFI E.; PREDOMINATO M.; FABRIS C.; ASARO F.,
Farmaco,
1992, 47, 1055 and also by BILLINGTON D. C.; COLEMAN M. D.; IBIABUO J.; LAMBERT P. A.; RATHBONE D. L.; TIMS K.,
J. Drug Des. Dis.,
1998, 15, 269.
Numerous aromatic aldehydes are also commercially available, such as, for example:
pyrrole-2-carbox
Burns Doane Swecker & Mathis L.L.P.
Dodson Shelley A.
Societe l'Oreal S.A.
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