Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2001-03-21
2003-01-21
Moore, Margaret G. (Department: 1712)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S070120, C424S078020, C424S078350, C516S023000, C516S027000, C514S837000, C514S846000
Reexamination Certificate
active
06509024
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a water-in-oil (W/O) emulsion which contains an oxyalkylenated crosslinked organopolysiloxane elastomer and a specific polymer and to its uses. The present invention is particularly suitable in the cosmetic and/or dermatological fields, in products for caring for, cleansing and/or making up the skin.
2. Discussion of the Background
It is commonplace in the cosmetic or dermatological fields to use compositions which have the appearance of a cream and which are composed of a water-in-oil (W/O) emulsion wherein an aqueous phase is dispersed in an oily phase. In the fields under consideration, a cream is a composition which exhibits a degree of viscosity different from liquid or semi-liquid compositions, such as lotions and milks, or from solid compositions.
W/O emulsions include a continuous oily phase and thus make it possible to form, on the surface of the skin, a lipid film which prevents transepidermal water loss and protects the skin from external attacks. These emulsions are particularly appropriate for protecting and nourishing the skin and in particular for treating dry skin.
Creams in the form of W/O emulsions exhibit the disadvantage of being uncomfortable because of the greasy, heavy and sometimes even sticky feeling contributed by this external fatty phase which remains on the skin. Thus, these creams are generally used for dry skin, being too greasy to be used on greasy skin. Furthermore, they do not contribute freshness and are generally too rich in oil to be used during the summer or in hot countries.
To overcome these disadvantages, W/O emulsions with a high water content have been envisaged. The water content cannot be too high, however, for reasons of stability or because the high water content must be offset by the addition of several surfactants (which can undesirably reduce the comfort feeling of the final composition and can even result in skin irritation problems, in particular in subjects with sensitive skin) and/or by the addition of electrolytes (which have the disadvantage of being incompatible with a large number of ingredients and active principles which are used in cosmetic and dermatological compositions).
The need thus remains for a composition in the form of a water-in-oil emulsion which can be used in the cosmetic and/or dermatological fields and which does not exhibit the above-mentioned disadvantages, in particular which provides freshness without contributing a greasy or sticky effect when applied to the skin, while having good stability. The term “emulsion of good stability” is understood to mean in this instance an emulsion which is homogeneous and even and which does not exhibit phase separation (separation of the aqueous phase and the oily phase) or release of oil, at least for two months at 45° C.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a water-in-oil emulsion which can be used in the cosmetic and/or dermatological fields and which does not exhibit the disadvantages of conventional compositions.
Another object of the present invention is to provide a water-in-oil emulsion which provides freshness without contributing a greasy or sticky effect when applied to the skin.
Another object of the present invention is to provide a water-in-oil emulsion having good stability.
Another object of the present invention is to provide a water-in-oil emulsion which is homogeneous.
Another object of the present invention is to provide a water-in-oil emulsion which does not exhibit phase separation (separation of the aqueous phase and the oily phase) or release of oil, at least for two months at 45° C.
Another object of the present invention is to provide a water-in-oil emulsion which can contain a large amount of water while being very stable.
These objects, and others, may be accomplished with the present invention, the first embodiment of which provides a composition, which includes:
an aqueous phase dispersed in an oily phase;
wherein the oily phase includes at least one particle of a crosslinked solid organopolysiloxane elastomer having at least one oxyalkylene group,
and wherein the aqueous phase includes at least one crosslinked and at least partially neutralized poly(2-acrylamido-2-methylpropanesulphonic acid) polymer.
Another embodiment of the present invention provides a method of using the above-identified composition, which method includes applying the composition to at least one selected from the group including hair, scalp, skin, lips, nails, mucous membranes and combinations thereof.
Another embodiment of the present invention provides a method of treating greasy skin, hair, lips or scalp, which method includes applying the above-identified composition to at least one selected from the group including skin, hair, lips, scalp and combinations thereof.
Another embodiment of the present invention provides a cosmetic or dermatological composition, which includes the above-identified composition and a pharmaceutically acceptable medium.
Another embodiment of the present invention provides a method for stabilizing a water-in-oil emulsion that includes an aqueous phase dispersed in an oily phase, the method includes:
contacting the oily phase with at least one particle of a crosslinked solid organopolysiloxane elastomer having at least one oxyalkylene group; and
contacting the aqueous phase with at least one crosslinked and at least partially neutralized poly(2-acrylamido-2-methylpropanesulphonic acid) polymer,
to stabilize the water-in-oil emulsion.
Another embodiment of the present invention provides a method of preparing a water-in-oil emulsion, which includes:
dispersing an aqueous phase in an oily phase; wherein
the oily phase includes at least one particle of a crosslinked solid organopolysiloxane elastomer having at least one oxyalkylene group; and
the aqueous phase includes at least one crosslinked and at least partially neutralized poly(2-acrylamido-2-methylpropanesulphonic acid) polymer.
The composition according to the invention has the advantage of being very stable, even in the absence of electrolyte and/or even in the presence of a large amount of aqueous phase.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description of the preferred embodiments of the invention.
The present inventors have found that it is possible to obtain a water-in-oil emulsion composition, which can contain a large amount of water but which is very stable, which includes a combination of an oxyalkylenated crosslinked organopolysiloxane elastomer and of a crosslinked and at least partially neutralized poly(2-acrylamido-2-methylpropanesulphonic acid) polymer.
A preferred embodiment of the invention is a composition that includes, in a physiologically acceptable medium, an aqueous phase dispersed in an oily phase, characterized in that the oily phase includes particles of a crosslinked solid organopolysiloxane elastomer having at least one oxyalkylene group and in that the aqueous phase includes at least one crosslinked and neutralized poly(2-acrylamido-2-methylpropanesulphonic acid) polymer.
The term “physiologically acceptable medium” is understood to mean, in the present invention, a nontoxic medium compatible with the skin (including the inside of the eyelids), mucous membranes, hair or lips of human beings.
The composition of the invention has the advantage of being homogeneous and of remaining stable over time, even when it contains a large amount of internal aqueous phase. In addition, it has the advantage of not requiring the addition of electrolytes generally used to stabilize W/O emulsions. It can thus advantageously be devoid of electrolytes. More preferably, it is devoid of electrolytes such as MgSO
4
.
Thus, another preferred embodiment is the use of the combination of particles of a crosslinked solid organopolysiloxane elastomer having at least one oxyalkylene group
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