Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-06-30
2001-12-18
Clardy, S. Mark (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S078030, C424S617000, C514S844000, C514S863000, C514S937000, C514S938000, C514S944000
Reexamination Certificate
active
06331306
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a composition which is in the form of a water-in-oil (W/O) emulsion, which has a viscosity, at a shear rate of 200 s−1 and at 25° C., ranging from 3 Pa.s (30 poises) to 20 Pa.s (200 poises) and which comprises a specific silicone surfactant and has a high water content. The present composition has the appearance of a cream and can be used in particular in the cosmetic and/or dermatological fields.
2. Background of the Invention
In the cosmetic or dermatological fields, it is commonplace to use compositions having the appearance of a cream and which are composed of a water-in-oil (W/O) emulsion comprising an aqueous phase dispersed in an oily phase. These emulsions comprise a continuous oily phase and, therefore, make it possible to form, at the surface of the skin, a lipid film which prevents transepidermal water loss and protects the skin from outside attacks. These emulsions are particularly appropriate for protecting and nourishing the skin and in particular for treating dry skin.
A cream is, in the fields under consideration, a composition exhibiting a degree of viscosity, in contrast to liquid or semi-liquid compositions, such as lotions and milks, or to solid compositions. However, creams in the form of W/O emulsions exhibit the disadvantage of contributing a fairly greasy feel to the skin on application, the oily phase being the external phase. Thus, these creams are generally used for dry skin, since they are too greasy to be used on greasy skin. Furthermore, W/O emulsions do not contribute any freshness and are generally too rich in oils to be used during the summer or in hot countries.
To overcome these disadvantages, the preparation of emulsions with a high water content has been proposed. However, the water content of the compositions cannot be too high for reasons of stability, otherwise a high water content has to be compensated for by the addition of several surfactants or of gelling agents, which can be harmful to the comfort of the final composition and can even lead to problems of cutaneous irritation, in particular, in people with sensitive skin.
A need, therefore, remains for a composition which has the viscosity of a cream and which is provided in the form of a stable water-in-oil emulsion, which comprises a large amount of water and which can be used in the cosmetic and/or dermatological fields, which does not exhibit the disadvantages of the prior art.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a cosmetic or dermatological composition for the protection of the skin which, as an emulsion, does not impart a greasy feeling to the skin.
Briefly, this object and other objects of the present invention as hereinafter will become more readily apparent can be attained by a composition comprises an aqueous phase dispersed in an oily phase containing a silicone emulsifying agent, which composition has a viscosity, measured with a Rheomat 180 viscometer at a shear rate of 200 s
−1
and at 25° C., ranging from 3 Pa.s (30 poises) to 20 Pa.s (200 poises), said composition comprising at least 78% by weight of aqueous phase, with respect to the total weight of the composition, including at least 65% of water with respect to the total weight of the composition, and in that the composition comprises, as sole emulsifying agent, the dimethicone copolyol of formula
in which R
1
represents
(C
3
H
6
O)—(C
2
H
4
O)
18
—(C
3
H
6
O)
18
H
p=394 and n=4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In spite of the presence of a large amount of water in the present composition, the composition of the invention is stable over time. In addition, it has a specific rheological characteristic which renders it useful in the fields under consideration particularly advantageous. This is because, during the application to the skin, the composition “breaks”, that is to say that it suddenly fluidizes under the effect of shearing, which is probably attributable to the phenomenon of rupturing within the emulsion. Thus, the composition of the invention contributes very great freshness to the skin.
The composition of the invention has a viscosity ranging from 3 Pa.s (30 poises) to 20 Pa.s (200 poises). This viscosity is measured with a Rheomat 180, that is to say with the RM 180 Rheomat device manufactured by Mettler.
The composition of the invention comprises at least 78% by weight of aqueous phase with respect to the total weight of the composition and preferably at least 80% of the total weight of the composition. The aqueous phase can constitute up to 92% of the total weight of the composition.
Water constitutes at least 65% and preferably at least 70% of the total weight of the composition.
Furthermore, the aqueous phase of the emulsion can comprise at least one lower molecular weight alcohol such as ethanol, in an amount preferably ranging up to 15%, preferably up to 10% of the total weight of the composition and one or more polyols such as glycerol or propylene glycol in an amount ranging, for example, up to 20%, preferably up to 10% of the total weight of the composition.
Furthermore, the composition of the invention comprises, as sole emulsifying agent, the dimethicone copolyol of formula (I). This dimethicone copolyol can be provided in the form of a mixture with a volatile or non-volatile silicone oil and in particular with cyclomethicones (D4 or D5) and/or polydimethylsiloxanes of different viscosities, in particular 5 cSt and 10 cSt. Suitable such mixtures are commercially available, for instance, those as follows sold by the Dow Corning Company:
(i) a mixture of compound of formula (I), of tetracyclomethicone (D4) and of water (ratio by weight 10/88/2), sold under the name DC 3225C;
(ii) a mixture of compound of formula (I), of pentacyclomethicone (D5) and of water (ratio by weight 10/88/2), sold under the name DC 5225C,
(iii) a mixture of compound of formula (I) and of polydimethylsiloxane 5 cSt (ratio by weight 10/90), sold under the name DC 3225C in 200 Fluid 5 cSt;
(iv) a mixture of compound of formula (I) and of polydimethylsiloxane 10 cSt (ratio by weight 10/90), sold under the name DC 3225C in 200 Fluid 10 cSt;
(v) a mixture of compound of formula (I) and of pentacyclomethicone (D5) (ratio by weight 43/57), sold under the name DC 5185C.
The emulsifying agent of the formula (I) is preferably present in an amount of active material ranging from 0.5-5%, preferably from 0.6-2% by weight with respect to the total weight of the composition.
Although the composition is devoid of any other emulsifying agent, the composition obtained is stable over time.
The ratio by weight of oily phase to emulsifying agent is preferably equal to or greater than 5, preferably equal to or greater than 8.
The oily phase of the composition of the invention can comprise, in addition to the silicone oil, optionally, as a mixture with the emulsifying agent, any kind of oil and fatty substance well-known to one of skill in the art such as oils of vegetable origin, oils of animal origin, synthetic oils and in particular fatty esters, silicone oils, fluorinated oils and/or mineral oils, as well as mixtures of these oils.
The oily phase of the composition of the invention preferably comprises at least one volatile silicone oil generally present in an amount ranging from 6-16% by weight with respect to the total weight of the emulsion, such as, for example, a cyclic silicone, such as pentacyclomethicone, tetracyclomethicone or hexacyclomethicone.
The oily phase can additionally comprise other fatty constituents such as fatty alcohols and fatty acids.
The oily phase is present in the composition of the invention in an amount ranging from 8-22%, preferably from 12-20% by weight with respect to the total weight of the composition.
Another advantage of the composition of the invention arises from the fact that a large amount of electrolyte can be incorporated therein without harming the stability of the composition. Suitable such electrolytes include sal
Afriat Isabelle
Boulier Virginie
Clardy S. Mark
L'Oreal
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Williamson Michael A.
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