Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-07-07
2002-07-02
Jones, Dameron L. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S400000, C424S195110
Reexamination Certificate
active
06413526
ABSTRACT:
The present invention relates to an anti-wrinkle composition containing a polymer system comprising at least one polymer of natural origin, and to the use of this polymer system as a tensioning agent in a cosmetic composition or for the manufacture of a dermatological composition, which are intended in particular for the treatment, reduction, elimination and/or smoothing-out of wrinkles and fine lines on human skin.
In the course of the ageing process, different signs appear on the skin, which are very characteristic of this ageing, reflected in particular by a change in the skin's structure and functions. The main clinical signs of ageing of the skin are, in particular, the appearance of fine lines and deep wrinkles, which increase with age. Disorganization of the skin's “grain” is observed in particular, i.e. the microrelief is less uniform and has an anisotropic nature.
It is known to treat these signs of ageing using cosmetic or dermatological compositions containing active agents that are capable of combating ageing, such as &agr;-hydroxy acids, &bgr;-hydroxy acids and retinoids. These active agents act on wrinkles by removing the dead cells from the skin and by accelerating the process of cell renewal. However, these active agents have the drawback of being effective for the treatment of wrinkles only after they have been applied for a certain period. Now, it is increasingly sought to obtain an immediate effect with the active agents used, leading rapidly to a smoothing out of wrinkles and fine lines and the disappearance of fatigue marks.
The subject of the present invention is, precisely, the use of a specific polymer system which makes it possible to obtain this effect immediately.
The Applicant has discovered that certain polymers of natural origin have defined physical characteristics and constitute particularly effective tensioning agents. The term “tensioning agent” is understood to refer to compounds capable of having a tensioning effect, i.e. capable of stretching the skin and, by means of this tensioning effect, making the skin smooth and immediately reducing the wrinkles and fine lines on it, or even making them disappear altogether.
In order to be effective, the polymers used according to the invention must have well defined characteristics, and in particular must have a molecular weight of greater than 670,000 daltons, which means that at least a fraction of the polymer has a molecular weight of greater than 670,000 daltons. Moreover, the polymer systems used according to the invention must be capable of forming a steam-permeable film, they must have a Young's modulus ranging from 10
8
to 9×10
9
N/m
2
and they must produce, at a concentration of 7% in water, a greater than 1.5% retraction of isolated stratum corneum at 30° C. and at a relative humidity of 40%.
Thus, the subject of the present invention is the use of at least one dispersion of a polymer system containing at least one polymer of natural origin having a molecular weight of greater than 670,000 daltons, the said polymer system being capable of forming a steam-permeable film, having a Young's modulus ranging from 10
8
to 9×10
9
N/m
2
and producing, at a concentration of 7% in water, a greater than 1.5% retraction of isolated stratum corneum at 30° C. and at a relative humidity of 40%, in a cosmetic composition for reducing and/or eliminating wrinkles and/or fine lines on the skin by means of a tensioning effect.
The subject of the present invention is also the use of at least one dispersion of a polymer system containing at least one polymer of natural origin having a molecular weight of greater than 670,000 daltons, the said polymer system being capable of forming a steam-permeable film, having a Young's modulus ranging from 10
8
to 9×10
9
N/m
2
and producing, at a concentration of 7% in water, a greater than 1.5% retraction of isolated stratum corneum at 30° C. and at a relative humidity of 40%, as a tensioning agent in a cosmetic composition in order to reduce and/or eliminate wrinkles and/or fine lines on the skin.
The subject of the present invention is also the use of at least one dispersion of a polymer system containing at least one polymer of natural origin having a molecular weight of greater than 670,000 daltons, the said polymer system being capable of forming a steam-permeable film, having a Young's modulus ranging from 10
8
to 9×10
9
N/m
2
and producing, at a concentration of 7% in water, a greater than 1.5% retraction of isolated stratum corneum at 30° C. and at a relative humidity of 40%, for the manufacture of a dermatological composition intended to eliminate wrinkles and/or fine lines on the skin by means of a tensioning effect.
The invention also relates to a process for the cosmetic treatment of wrinkled skin, which consists in applying to the wrinkles at least one dispersion of a polymer system containing at least one polymer of natural origin having a molecular weight of greater than 670,000 daltons, the said polymer system being capable of forming a steam-permeable film, having a Young's modulus ranging from 10
8
to 9×10
9
N/m
2
and producing, at a concentration of 7% in water, a greater than 1.5% retraction of isolated stratum corneum at 30° C. and at a relative humidity of 40%, in an amount which is effective for eliminating the wrinkles by means of a tensioning effect.
The invention also relates to an anti-wrinkle composition, characterized in that it contains, in a medium which is physiologically acceptable on the skin for several hours, at least one dispersion of a polymer system containing at least one polymer of natural origin having a molecular weight of greater than 670,000 daltons, the said polymer system being capable of forming a steam-permeable film, having a Young's modulus ranging from 10
8
to 9×10
9
N/m
2
and producing, at a concentration of 7% in water, a greater than 1.5% retraction of isolated stratum corneum at 30° C. and at a relative humidity of 40%.
The polymer system used according to the present invention has the property of eliminating, immediately after application, the wrinkles and fine lines on the surface of the skin. The composition of the invention is more especially suited to application to the face and the neck, in particular the neckline.
The term “polymer system” is understood to refer either to a polymer alone or to a polymer combined with at least one other polymer or to a polymer combined with at least one plasticizer so as to obtain the desired mechanical properties.
The expression “capable of forming a film” is understood to refer to a polymer system which allows a film to be formed: when it is spread onto glass, the polymer system must dry without becoming individualized like a film of lacquer.
The term “water-permeable” is understood to refer to a film which is porous to steam. The permeability of the film is demonstrated by measuring the IWL (imperceptible water loss) of defatted stratum corneum treated with the polymer system. When the film is steam-porous, the IWL is not modified by the film. The IWL is conventionally measured using an evaporimeter (Servomed) which quantitatively determines water evaporation, i.e. transportation of water by diffusion, using a sample of stratum corneum which closes off a cylindrical capsule containing water, the assembly being placed in a chamber at controlled temperature and relative humidity. Sensors allow the partial pressure of water vapor to be measured at two points located at different distances from the sample. The water vapor partial pressure gradient between the two points is thus determined, and hence the degree of evaporation in accordance with Fick's law.
As indicated above, the polymer system used according to the invention has a Young's modulus ranging from 10
8
to 9×10
9
N/m
2
, determined by instrumented indentation methods (micro- or nanoindentation; ASTM standard E384-89), which corresponds to a modulus of elasticity at least 10 to 100 times as high as that of the s
Bazin Roland
Bernardet Laurent
Candau Didier
Garson Jean-Claude
Malle Gerard
Jones Dameron L.
L'Oreal
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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