Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-03-26
2002-08-27
Jones, Dameron L. (Department: 1619)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C516S023000, C516S053000
Reexamination Certificate
active
06440430
ABSTRACT:
The present invention relates to water-in-oil (W/O) emulsions, to compositions for cosmetic, pharmaceutical, or hygiene or dermatological use, comprising such an emulsion, as well as to their use in the cosmetic, pharmaceutical, dermatological and/or hygiene fields.
These compositions may constitute care products for the skin, including the scalp, and/or make-up products for the skin, mucous membranes (the inside of the eyelids), semi-mucous membranes (lips), keratin fibres (hair, eyelashes, nails) or alternatively make-up products for the body.
Make-up compositions, in particular foundations, are generally in the form of a more or less fluid cream comprising fatty substances such as oils and a particulate phase generally composed of fillers and pigments.
It is generally sought to introduce into the fatty phase compounds such as silicones, which provide softness and fluidity. However, it is known that as the silicone oil content increases, it is more difficult to obtain a stable W/O emulsion, not only over time but also when it is subjected to large variations in temperature. In fact, the fluidity of the formula can be the cause of phenomena of instability over time, such as the release of oil at the surface, sedimentation of the pigments, thickening, etc.
With the aim of reducing these phenomena, it has been proposed in U.S. Pat. No. 4,698,178 to use a new class of silicone surfactants associated with polyols for the low temperatures, and with electrolytes or with metal soaps for the high temperatures.
The improvement in the stability of W/O emulsions has also been studied in patent application EP 331,833, which describes the use of oxyalkylenated silicones combined with water-swellable inorganic clays, and in patent application EP-A-612,517, which recommends the use of a combination of a silicone containing oxyalkylene groups and pendant alkyls with a gelling and/or thickening agent.
Nevertheless, when these compositions are applied to the skin, mucous membranes or semi-mucous membranes, they can have the disadvantage of transferring to another surface. This means that the composition, once applied, is liable to be deposited, at least partly, on certain supports with which it is placed in contact, such as, for example, a glass, an item of clothing or the skin.
Once deposited, the said composition leaves a trace on the said support. This thus results in mediocre staying power of the composition on the skin or the mucous membranes, thus making it necessary to regularly renew its application.
Moreover, the appearance of unacceptable traces of the composition on certain items of clothing, and in particular on shirt collars, can discourage women from using this type of make-up.
Another disadvantage of these compositions lies in the problem of migration. Specifically, it has been found that certain compositions have a tendency to migrate or diffuse inside the fine lines and/or wrinkles on the skin, in the case of foundations; in the fine lines surrounding the lips, in the case of lipsticks; and in the folds of the eyelids, in the case of eyeshadows. The appearance of lines in the make-up, generated by the movements of the eyelids, has also been found, in particular in the case of eyeshadows. All of these phenomena generate a displeasing effect which, needless to say, it is desired to avoid.
The aim of the present invention is to provide a water-in-oil emulsion which has good stability, while at the same time retaining good cosmetic properties. In particular, it is desired to have available a stable water-in-oil emulsion which does not transfer after it has been used, in particular on the skin.
It has now been discovered, surprisingly and unexpectedly, that by using an oxyalkylenated silicone, it is possible to obtain W/O emulsions which have a specific viscosity, and which are not only stable over time, but are also stable with respect to variations in temperature, and which also show excellent cosmetic properties, as well as good resistance to transfer.
A subject of the present invention is thus a water-in-oil emulsion, comprising an aqueous phase and a fatty phase comprising a silicone oil, characterized in that it comprises at least one &agr;,&ohgr;-substituted oxyalkylenated silicone, the composition having a dynamic viscosity ranging from 100 mPa.s to 20 Pa.s (100 cps to 200 poises), this viscosity being measured, at 25° C. and at a shear rate of 200 s
−1
.
Another subject of the invention relates to a composition, in particular for cosmetic, dermatological, pharmaceutical or hygiene use, comprising an emulsion as defined above.
The invention also relates to a non-therapeutic treatment process for the skin and/or keratin fibres, in particular a make-up process, which comprises applying an emulsion and/or a composition as defined above to the skin and/or to the keratin fibres.
The W/O emulsion according to the invention fully satisfies the stability standards, i.e.:
resistance to the centrifugation test at 4000 rpm for 1 hour,
resistance to aging for 2 months at room temperature (25° C.) as well as at 45° C.,
resistance to 8 successive cycles of 8 hours each, where the temperatures of each cycle ranged from −20° C. to +20° C.
The emulsion according to the invention satisfies the following criteria:
it has and retains over the course of these tests a uniform and stable macroscopic and microscopic appearance (finely dispersed globules, absence of release) and
its viscosity is constant over time.
The emulsion according to the invention also has very good resistance to transfer. Furthermore, the emulsion applied to the skin has the advantage of not migrating or diffusing into the folds of the skin, in particular on the eyelids and/or the wrinkles on the face, in particular on the lips and on the eyes, and the contours of these areas (crow's feet).
It has been found that the emulsion used according to the invention applies and spreads easily and homogeneously, without leaving a greasy sensation, and has good cosmetic properties. The film obtained also has a light texture and remains comfortable to wear throughout the day.
Moreover, it is possible to add other adjuvants to the emulsion according to the invention, such as oils and/or powders (pigments and/or fillers), while at the same time retaining a stable emulsion. The emulsion is thus compatible with a large number of cosmetic adjuvants.
The emulsion according to the invention moreover has good sensory qualities, in particular great ease of application, comfort, softness, a good matte effect and good coverage, and uniformity and staying power.
The emulsion according to the invention comprises an &agr;,&ohgr;-substituted oxyalkylenated silicone.
Throughout the text hereinabove and hereinbelow, the term “silicone” is intended to denote, in accordance with general acceptance, any organosilicon polymers or oligomers of linear or cyclic, branched or crosslinked structure, of variable molecular weight, obtained by polymerization and/or polycondensation of suitably functionalized silanes, and comprising a repetition of main units in which the silicon atoms are connected together via oxygen atoms (siloxane bond ≡Si—O—Si≡), optionally substituted hydrocarbon-based radicals being linked directly via a carbon atom onto the said silicon atoms. The hydrocarbon-based radicals which are most common are alkyl radicals, especially C
1
-C
10
alkyl radicals and in particular methyl, fluoroalkyl radicals, aryl radicals and in particular phenyl. They may be substituted, for example, with C
1
-C
40
ester or ether groups or C
7
-C
60
aralkyl groups.
Thus, an &agr;,&ohgr;-substituted oxyalkylene silicone which may be used for the emulsifying system according to the invention is an organosilicon polymer as defined above, of linear structure, substituted at the two ends of the main chain with oxyalkylene groups connected to the Si atoms via a hydrocarbon-based group.
Preferably, the &agr;,&ohgr;-substituted oxyalkylenated silicone corresponds to the general formula (I) below:
in which: R=—(CH
2
)
p
O—(C
2
H
4
Bara Isabelle
Collette Annick
Lemann Patricia
Simon Jean-Christophe
Tournilhac Florence
Finnegan, Henderson Farabow, Garrett and Dunner L.L.P.
Jones Dameron L.
L'Oreal (S.A.)
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