Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2000-10-20
2002-01-01
Dudash, Diana (Department: 1619)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S059000, C424S070210, C424S070120, C424S070130, C424S070190, C424S078030
Reexamination Certificate
active
06335025
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a water-in-oil emulsion containing an alkylpolyglycoside having an HLB of less than 7 and at least one volatile oil, and to its uses, in particular, in cosmetics. The present invention may be used, in particular, for caring for the skin, the lips, the nails and the hair, for removing make-up from and/or for cleansing the skin, and/or for making up the skin and/or the lips. Moreover, the present invention may also be used for treating dry skin and/or dry lips and/or sensitive skin.
2. Description of the Background
It is common practice in cosmetics to use creams consisting of a water-in-oil (W/O) emulsion containing an aqueous phase dispersed in an oily phase. These emulsions contain a continuous oily phase, whereby it is possible to form a lipid film at the surface of the skin which prevents transepidermal water loss and protects the skin against external attack. These emulsions are particularly suitable for caring for and repairing dry and dehydrated skin, to which they provide comfort and protection by means of the lipid barrier which they form on the skin.
However, despite their great efficacy, W/O emulsions only constitute a small proportion of the pharmaceutical forms used in cosmetics, since they pose two major problems. Firstly, these emulsions have the drawback of generally lacking in cosmetic pleasantness, i.e. they are greasy, heavy, sticky and lack a fresh sensation on account of the oily outer phase. They are generally difficult to apply to the skin, penetrate with difficulty and leave a shiny and often sticky remnant film on the skin.
Moreover, W/O emulsions have stability problems and it is often necessary, in order to achieve stabilization, to use a large amount of emulsifiers and/or to introduce a certain amount of consistency factors, such as waxes. However, these ingredients exacerbate the cosmetic defects, i.e. stickiness and greasiness, of the W/O emulsions, the result of which is the production of compositions that are often compact and heavy. Furthermore, if the amount of emulsifier in these emulsions is greatly increased in an attempt to overcome their instability, the emulsions obtained are an irritant to certain types of skin, in particular, sensitive skin.
Although alkylpolyglycosides (APGs) are known as emulsifiers, conventionally APGs so used generally have an HLB (hydrophilic-lipophilic balance) of greater than 8, and are generally used to prepare O/W emulsions. In order to prepare W/O emulsions, it is generally necessary to combine them with another APG or with another surfactant. Thus, for example, U.S. Pat. No. 5,639,797 describes a W/O emulsion containing a hydrophilic APG, such as decylglucoside, i.e. having an HLB of greater than 8, which must be combined with a W/O surfactant in order to obtain the desired emulsion. Moreover, it is often necessary to use a large total amount of surfactants in order to obtain a stable W/O emulsion.
Thus, a need exists for a stable water-in-oil emulsion which avoids the above drawbacks.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a water-in-oil emulsion which has good cosmetic properties, such as a simultaneously light, fresh and rich feel, and good stability by using a certain alkylpolyglycoside as emulsifier, and volatile oils.
It is also an object of the present invention to provide a cosmetic composition based upon the water-in-oil emulsion.
In particular, the present invention provides a water-in-oil emulsion, containing an aqueous phase dispersed in an oily phase, containing (i) an alkylpolyglucoside having an HLB of less than 7, and (ii) at least one volatile oil.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a water-in-oil emulsion (w/o) containing an aqueous phase dispersed in an oily phase, which contains (i) an alkylpolyglycoside having an HLB of less than 7, and (ii) at least one volatile oil.
The emulsions of the present invention spread easily and are absorbed quickly and completely into the skin. Along with a rich and nourishing feel, they provide a surprising sensation of freshness. After the product of the present invention has been applied, the skin remains soft and matt. Moreover, the emulsions of the present invention can have a creamy texture or can be fluid while at the same time having good stability. The fluid emulsions generally have a viscosity ranging from about 0.2 Pa.s to 3 Pa.s (2 to 30 poises) and preferably from about 0.6 Pa.s to 2 Pa.s (6 to 20 poises), this viscosity being measured at about 25° C. using a “Mettler Rhéomat” viscometer equipped with a No. 2 spindle (for viscosities of less than 7 poises) or a No. 3 spindle (for viscosities of greater than 7 poises).
The alkylpolyglycosides used according to the present invention have an HLB of less than 7, and preferably of less than or equal to 5. In contrast, the alkylpolyglycosides conventionally used in cosmetic compositions have generally an HLB of more than 10 and are either detergents (HLB generally more than 13) or emulsifying agents for oil-in-water emulsions (HLB about from 10 to 17). HLB may be calculated particularly by either Davies's Method or Griffin's Method.
The alkylpolyglycosides of the present invention are represented more particularly by the formula (I) below:
R—O—(G)
x
(I)
in which R represents a branched and/or unsaturated alkyl radical containing from about 14 to 24 carbon atoms, G represents a reduced sugar containing about 5 or 6 carbon atoms and x denotes a value ranging from 1 to 10 and preferably from 1 to 4.
G, in particular, denotes glucose, fructose or galactose.
The unsaturated alkyl radical (alkylene radical) can contain one or more ethylenic unsaturations, and in particular one or two ethylenic unsaturations.
The alkylpolyglycosides that are preferred according to the present invention are compounds of formula (I) in which R more particularly represents an oleyl radical (unsaturated C18 radical) or an isostearyl radical (saturated C18 radical), G denotes glucose and x is a value ranging from 1 to 2.
The alkylpolyglycoside used in the emulsion of the present invention is preferably isostearylglucoside or oleylglucoside, or mixtures thereof.
According to one particular embodiment of the present invention, the emulsion can contain, besides the alkylpolyglycoside indicated above, a co-emulsifier. The co-emulsifier can be chosen advantageously from fatty alcohols and, in particular, from those containing the same fatty chain as that of the alkylpolyglycoside, i.e. containing from about 14 to 24 carbon atoms and having a branched and/or unsaturated chain, and, for example, isostearyl alcohol when the alkylpolyglycoside is isostearylglucoside, and oleyl alcohol when the alkylpolyglycoside is oleylglucoside.
According to one preferred embodiment of the invention, the mixture of alkylpolyglycoside as defined above with the corresponding fatty alcohol is used in the emulsion according to the present invention in the form of a self-emulsifying composition, as described, for example, in WO-A-92/06778.
The emulsion according to the present invention can contain an amount of alkylpolyglycoside(s) ranging, for example, from about 0.1% to 10%, and preferably from about 0.2% to 5% by weight of active material relative to the total weight of the composition. When it is mixed with the corresponding fatty alcohol, the latter is present in an amount generally ranging from about 60% to 90% by weight and preferably from about 70% to 87% by weight relative to the weight of the mixture of alkylpolyglycoside and fatty alcohol.
The oily phase of the emulsion according to the present invention contains at least one volatile oil. In the present description, the term “volatile oil” means any oil which can evaporate on contact with the skin and/or which has a low flash point, i.e. a flash point of less than about 100° C., and in particular a flash point of between 30° C. and 85° C., i.e. an oil whose flash point is high enough to allow
Dudash Diana
Haghighatian Mina
L'Oreal
LandOfFree
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