Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2002-12-09
2003-09-30
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
06627180
ABSTRACT:
CROSS-REFERENCE TO PRIORITY APPLICATION
This application claims priority under 35 U.S.C. §119 of FR-01/15860, filed Dec. 7, 2001, hereby expressly incorporated by reference.
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The invention relates to novel cosmetic or dermatological compositions for topical use, in particular for the photoprotection of the skin and/or hair, characterized in that they comprise, in a cosmetically acceptable vehicle, at least:
(a) one insoluble organic UV screening agent with a particle size ranging from 10 nm to 5 &mgr;m, as first screening agent, and
(b) one specific amino-substituted 2-hydroxy-benzophenone derivative, as second screening agent. The combination of these two screening agents results in a synergistic effect being obtained with regard to the sun protection factors UV-APPD conferred.
The invention also relates to their applications in the protection of the skin and hair against the effects of ultraviolet radiation.
2. Description of the Prior Art
It is known that light radiation with wavelengths of between 280 nm and 400 nm makes possible browning of the human epidermis and that rays with wavelengths of between 280 and 320 nm, known under the name of UV-B, cause erythemas and skin burns which may be harmful to the development of natural tanning; this UV-B radiation must therefore be screened out.
It is also known that UV-A rays, with wavelengths of between 320 and 400 nm, which cause browning of the skin, are capable of bringing about a detrimental change in the latter, in particular in the case of sensitive skin or of skin continually exposed to solar radiation. UV-A rays cause in particular a loss in the elasticity of the skin and the appearance of wrinkles, resulting in premature ageing. They promote the triggering of the erythemal reaction or accentuate this reaction in some subjects and can even be the cause of phototoxic or photoallergic reactions. It is therefore desirable also to screen out UV-A radiation.
Numerous cosmetic compositions intended for the photoprotection (UV-A and/or UV-B) of the skin have been provided to date.
The efficacy of antisun compositions is generally expressed by the sun protection factor (SPF), which is expressed mathematically by the ratio of the dose of UV radiation necessary to reach the erythemogenic threshold with the UV screening agent to the dose of UV radiation necessary to reach the erythemogenic threshold without UV screening agent. This factor thus relates to the effectiveness of the protection with respect to erythema, the spectrum of biological action of which is centered in the UV-B region, and consequently describes the protection with respect to this UV-B radiation.
In view of the effects of UV-A radiation on the skin and of the development of numerous compositions comprising combinations of screening agents capable of absorbing UV-B and/or UV-A radiation, specific methods for evaluating protection against UV-A radiation have been developed.
For the characterization of protection with respect to UV-A radiation, the PPD (Persistent Pigment Darkening) method, which measures the color of the skin observed 2 to 4 hours after exposure of the skin to UV-A radiation, is particularly recommended and used. This method was adopted in 1996 by the Japanese Cosmetic Industry Association (JCIA) as official test procedure for the UV-A labeling of products and is frequently used by test laboratories in Europe and the United States (Japan Cosmetic Industry Association Technical Bulletin. Measurement Standards for UVA protection efficacy. Issued Nov. 21, 1995 and effective of Jan. 1, 1996).
The sun protection factor UV-A
PPD
(UV-A
PPD
PF) is expressed mathematically by the ratio of the dose of UV-A radiation necessary to reach the pigmentation threshold with the UV screening agent (MPPD
p
) to the dose of UV-A radiation necessary to reach the pigmentation threshold without UV screening agent (MPPD
np
).
UV
-
A
PPD
PF
=
MPPD
p
MPPD
np
These antisun compositions exist fairly often in the form of an emulsion of oil-in-water type (that is to say, a cosmetically acceptable vehicle composed of a continuous aqueous dispersing phase and of a noncontinuous oily dispersed phase) which comprises, at various concentrations, one or more conventional, lipophilic and/or hydrophilic, organic screening agents capable of selectively absorbing harmful UV radiation, these screening agents (and their amounts) being selected according to the sun protection factors desired.
Antisun compositions based on amino-substituted 2-hydroxybenzophenone derivatives are known from Patent Applications EP-A-1,046,391 and DE 100 12 408.
SUMMARY OF THE INVENTION
In point of fact, following much research carried out in the abovementioned field of photoprotection, the Applicant Company has discovered, unexpectedly and surprisingly, that the combination, in proportions within well-defined limits, of two specific sunscreens already known per se in the state of the art makes it possible, due to a notable synergistic effect, to obtain antisun compositions exhibiting sun protection factors UV-A
PPD
which are markedly improved and in any case much higher than those which can be obtained with either of the screening agents used on its own.
This discovery forms the basis of the present invention.
Thus, in accordance with one of the subject-matters of the present invention, novel cosmetic compositions for topical use, in particular for the photoprotection of the skin and/or hair, are now provided, characterized in that they comprise, in a cosmetically acceptable vehicle:
(a) at least one insoluble organic UV screening agent with a particle size ranging from 10 nm to 5 &mgr;m, as first screening agent, and
(b) at least one amino-substituted 2-hydroxy-benzophenone derivative of formula (I) which will be defined later, as second screening agent.
Another subject-matter of the present invention is the use of such compositions in the manufacture of cosmetic compositions intended for the protection of the skin and/or hair against ultraviolet radiation, in particular solar radiation.
Another subject-matter of the present invention is the use of an amino-substituted 2-hydroxybenzophenone derivative of formula (I) which will be defined later in the manufacture of cosmetic or dermatological compositions intended for the protection of the skin and/or hair against ultraviolet radiation, in particular solar radiation, comprising at least one insoluble organic UV screening agent with a particle size ranging from 10 nm to 5 &mgr;m, for the purpose of producing a synergistic effect with regard to the sun protection factors UV-A
PPD
conferred.
The term “insoluble UV screening agent” within the meaning of the present invention is understood to mean any organic or inorganic UV screening agent having a solubility in water of less than 0.1% by weight and a solubility of less than 1% by weight in the majority of organic solvents, such as liquid paraffin, fatty alcohol benzoates and fatty acid triglycerides, for example Miglyol® 812 sold by Dynamit Nobel. This solubility, defined at 70° C. as the amount of product in solution in the solvent at equilibrium with an excess of solid in suspension, can easily be evaluated in the laboratory.
Other characteristics, aspects and advantages of the present invention will become apparent on reading the detailed description which will follow.
DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OF THE INVENTION
Generally, the insoluble UV screening agent and the amino-substituted 2-hydroxybenzophenone derivative are present in the said compositions in a proportion producing a synergistic activity with regard to the sun protection factors UV-A
PPD
conferred.
The insoluble organic UV screening agents according to the invention have a mean particle size which varies from 10 to 5 &mgr;m and more preferably from 10 nm to 2 &mgr;m and more particularly from 20 nm to 2 &mgr;m.
The insoluble organic screening agents according to the invention can be brought to the desired particulate form by a
Dodson Shelley A.
Societe L'Oreal S.A.
LandOfFree
Synergistically UV-photoprotecting compositions comprising... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Synergistically UV-photoprotecting compositions comprising..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Synergistically UV-photoprotecting compositions comprising... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3104825