Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2000-05-19
2003-03-18
Dees, Jose′ G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S061000, C424S070100, C424S070600, C424S078030
Reexamination Certificate
active
06534071
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present application relates to a composition in the form of an oil-in-water emulsion preferably free of surfactant, and containing cellulose fibrils, and to the use of the composition, particularly for the care, the treatment and/or the makeup of the body's skin, face, hair, eyelashes and/or lips. The application also relates to the use of cellulose fibrils for stabilizing an oil-in-water emulsion that is free of surfactant.
2. Discussion of the Background
For various reasons particularly associated with greater comfort in use (softness, emollience and the like), current cosmetic compositions are usually in the form of an emulsion of the oil-in-water (O/W) type consisting of an aqueous dispersing continuous phase and an oily dispersed discontinuous phase or of an emulsion of the water-in-oil (W/O) type consisting of an oily dispersing continuous phase and an aqueous dispersed discontinuous phase. O/W emulsions are the most demanded in the cosmetic field because they have, as external phase, an aqueous phase, giving them a cooler, less greasy and lighter feel during application to the skin than W/O emulsions.
Emulsions are generally stabilized by suitable emulsifying surfactants which, because of their amphiphilic structure, lie at the oil/water interface and thus stabilize the dispersed droplets. However, these emulsifiers have the drawback of being penetrants and potentially irritants for the skin, eyes and scalp, especially for users with sensitive skin.
Furthermore, such emulsions may have insufficient cosmetic and physicochemical properties (oily feel, instability over time). Increasing the amount of surfactants does not generally solve the problems mentioned. The required stability is not always achieved and the cosmetic properties are not improved (waxy, heavy feel, lack of coolness at application). Moreover, as indicated above, it is also not recommended to use too high a surfactant content for reasons of innocuousness.
One solution for overcoming instability phenomena (creaming and phase separation) in O/W emulsions consists in adding thickeners to the emulsion, the function of these thickeners being to create, within the aqueous phase, a gelled matrix serving to fix the oily droplets and ensuring mechanical integrity of the entire emulsion. However, this solution has the drawback of not making it possible to obtain all the desired textures, and in particular the light textures, which are easily and quickly applied to the skin without leaving a residual film.
Moreover, it has been envisaged to replace the surfactants with polymers having, in their chain, a hydrophilic part and a hydrophobic part consisting of a fatty chain, such as C
10
-C
30
alkyl acrylate/acrylic or methacrylic acid copolymers, such as the product “PEMULEN TR2” sold by Goodrich. However, these polymers have the drawback of providing a tacky effect on applying them to the skin and of not allowing a composition to be obtained which remains stable over a long period of time when the amount of oil is too great.
OBJECTS OF THE INVENTIONS
One objective of the invention is to be able to produce stable oil-in-water emulsions not containing an emulsifying surfactant conventionally used in O/E emulsions, and having good cosmetic properties without having the drawbacks of the prior art. Another object is stable O/E emulsions in general.
SUMMARY OF THE INVENTION
The inventors have discovered unexpectedly that cellulose fibrils can be used to produce stable oil-in-water emulsions, although free of surfactant.
DETAILED DESCRIPTION OF THE INVENTION
While it is known practice to use cellulose fibrils in cosmetic compositions, it has never been envisaged to use them in O/W emulsions to stabilize these emulsions in the absence of any surfactant.
The present invention relates to a composition in the form of an oil-in-water emulsion comprising, in a physiologically acceptable medium, an oily phase dispersed in an aqueous phase, characterized in that the composition is free of surfactant and in that it contains cellulose fibrils which preferably have a length of greater than 1 micron and a length/diameter ratio of greater than 30.
Another subject of the invention is the use of cellulose fibrils for stabilizing an oil-in-water emulsion free of surfactant, and emulsions so stabilized.
The composition obtained has a homogeneous and pleasant texture at application. Furthermore, although free of surfactant, it remains stable over time at room temperature or at higher temperatures. In addition, because of the absence of surfactant, it has the advantage of not being an irritant for the skin, particularly sensitive skin, and of furthermore allowing the incorporation of heat-sensitive active agents, since it can be manufactured at room temperature.
The expression “physiologically acceptable medium” should be understood to mean here a medium compatible with the skin, lips, scalp, eyelashes, eyes and/or hair.
Moreover, the term “cellulose fibrils” should be understood in the present application to include both nanofibrils and microfibrils. These fibrils have a length of greater than 1 &mgr;m and preferably ranging from 5 to 40 &mgr;m, including 10, 15, 20, 25, 30 and 35 &mgr;m, and a length/diameter ratio equal to or greater than 30, including 35, 40, 45, 50, etc. The diameter of the fibrils used may range, for example, from 2 to 100 nm (0.002 to 0.1 &mgr;m) including 5, 10, 20, 30, 40, 50, 60, 70, 80 and 90 nm.
The cellulose fibrils used according to the invention are preferably amorphous, that is to say they preferably have a degree of crystallinity of less than or equal to 50% and preferably ranging from 15 to 50% including 20, 25, 30, 35, 40 and 45%.
Furthermore, the cellulose fibrils used according to the invention may be obtained in any manner including either by mechanical or chemical extraction from plants or algae, or by bacterial fermentation. Moreover, they may be in the form of dry matter or in a dispersion, especially an aqueous dispersion.
The cellulose fibrils used according to the invention may be as produced or they may be modified. Thus, they may be mixed with an additive, and especially with carboxylated cellulose, as described in the documents WO-A-98/02486 and WO-A-98/02487. They may also be in modified form, for example they may be modified by carboxylic acids as described, for example, in document EP-A-726,356, and/or combined with a polyhydroxylated organic compound, as described for example in document FR-A-2,769,836.
The cellulose fibrils used according to the invention are preferably those obtaining after mixing, in an aqueous medium, of cellulose fibrils and carboxylated cellulose, especially carboxymethylcellulose, and drying of this mixture, such as described in the document FR-A-2,769,836.
In particular, it is possible to use, as cellulose fibrils, those sold under the names “CELLULON” by Kelco, that sold under the name “FIBRILIANCE” by Soliance and those from Rhodia, especially that called hereafter “Compound A”, which comprises 85% of nanofibrils and 15% of carboxymethylcellulose and are obtained according to Example 1 of the document FR-A-2,769,836.
The cellulose fibrils are generally introduced into the aqueous phase of the emulsion.
The composition of the invention may preferably contain an amount of cellulose fibrils ranging from 0.05 to 20% by weight, including 1, 3, 5, 8, 10, 12, 15, 17 and 19% preferably from 0.1 to 10% and even better from 0.5 to 5% by weight, with respect to the total weight of the composition.
The oily phase of the composition according to the invention generally represents from 10 to 40% and preferably from 15 to 30% by weight with respect to the total weight of the composition.
The oily phase may contain any of the fatty substances, and especially oils, conventionally used in the cosmetic or dermatological fields.
Among the oils that can be used in the emulsion of the invention, mention may be made, for example, of plant oils such as jojoba, avocado, soft-almond, apricot and corn oils and the liquid fractio
Lorant Raluca
Tournilhac Florence
Dees Jose′ G.
Haghighatian M.
L'Oreal
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