Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-08-27
2002-02-12
Dudash, Diana (Department: 1619)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S070120, C424S070190, C424S070310, C514S844000, C514S846000, C514S847000, C514S938000, C514S944000, C514S945000
Reexamination Certificate
active
06346256
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a stable oil/water/oil triple emulsion and to its use, in particular in the cosmetics and/or dermatological fields, especially for the controlled release of active principles, for the purpose in particular of cleansing, treating, protecting and/or moisturizing the skin and/or mucous membranes and/or keratinous fibers and more particularly for the purpose of treating dry skin.
The use of topical compositions in the form of emulsions is known, in particular in the fields of cosmetics and dermatology. These emulsions are generally oil-in-water (O/W) or water-in-oil (W/O) emulsions, or multiple emulsions of the water/oil/water (W/O/W) or oil/water/oil (O/W/O) type. Preferably, multiple emulsions with an aqueous external phase, namely W/O/W emulsions, are used. These W/O/W emulsions combine the advantages of freshness on application, due to the water present in the aqueous external phase, and of comfort, due to the relatively large amount of oil.
However, O/W/O emulsions are also advantageous because of their oily continuous phase, making it possible to form, at the surface of the skin, a lipid film which prevents transepidermal water loss and protects the skin from external attack. In addition, the greasy effect of such emulsions can be avoided by incorporating therein novel light oils which are non-greasy to the touch, such as, for example, low-viscosity silicone oils or certain esters of fatty acids and of fatty alcohols with a short chain. It is therefore advantageous to have available multiple emulsions of the O/W/O type.
However, multiple emulsions are generally not exploited to any great extent because they frequently exhibit problems with stability over time. The most frequently encountered mechanism for destabilization is the migration of oil from the internal droplets to the oily external phase through the intermediate aqueous layer, either by simple diffusion of oil through the aqueous membrane or by prior rupture of the aqueous film, which causes the coalescence of the internal droplets of oil and results in a release of oil into the oily external phase. Generally, this phenomenon, known as loss of the multiple nature, ends up by bringing about macroscopically visible phase separation and the production of an unstable, simple O/W emulsion in place of a triple emulsion.
Various approaches have consequently been envisaged to mitigate this disadvantage. In particular, one approach consists of introducing, into the oily internal or external phase, one or more gelling polymer(s), the role of which is to limit, on a long-term basis, the movements of oil from the internal phase to the external phase. However, polymers capable of gelling oils are not very common and do not have good cosmetic properties: they intensify the feeling of greasiness and are sticky during and after application to the skin. The multiple emulsions obtained exhibit the drawback of being sticky and of taking a long time to penetrate into the skin.
The need therefore remains for a stable O/W/O multiple emulsion which does not have the disadvantages of those of the prior art and which is, in particular, pleasant to use on the skin.
SUMMARY OF THE INVENTION
The Applicant has now found, unexpectedly, that the use of a partially or completely crosslinked organopolysiloxane elastomer comprising a polyoxyethylenated and/or polyoxypropylenated chain makes it possible to obtain a stable O/W/O multiple emulsion without requiring the addition of other stabilizing agents.
DETAILED DESCRIPTION OF THE INVENTION
The subject-matter of the present invention is an O/W/O triple emulsion comprising at least one oily phase and a water phase, characterized in that the triple emulsion comprises at least one partially or completely crosslinked organopolysiloxane elastomer comprising a polyoxyethylenated and/or polyoxypropylenated chain.
Hereinafter, the triple emulsions of the present invention will be described as comprising an oil-in-water primary emulsion and an oily external phase. However, triple emulsion refers to a unique type of emulsion which is distinct from an O/W or W/O emulsion.
Another subject-matter of the present invention is the use of at least one partially or completely crosslinked organopolysiloxane elastomer comprising a polyoxyethylenated and/or polyoxypropylenated chain for the stabilization of an oil/water/oil triple emulsion.
The triple emulsion according to the invention has the advantage of being stable and of being able to retain the activity of active principles, in particular of lipophilic active principles, present in the oily internal phase, whence they are released during the application of the composition to the skin, mucous membranes and/or hair.
The partially or completely crosslinked organopolysiloxane elastomers which can be used in the emulsion according to the present invention can be introduced into either of the oily phases. They are preferably introduced into the oily external phase of the emulsion. The partially or completely crosslinked organopolysiloxane elastomers are generally emulsifiers. They can be chosen in particular from the crosslinked polymers disclosed in Application EP-A-0,545,002, indicated here by way of reference. These organopolysiloxanes are obtained by addition polymerization (for example, by hydrosilation) of the following compounds (I) and (II):
(I) an organohydropolysiloxane of formula (1):
R
1
a
R
2
b
H
c
SiO
(4−a−b−c)/2
(1)
in which R
1
represents a substituted or unsubstituted alkyl, aryl or aralkyl group comprising from 1 to 18 carbon atoms or a halogenated hydrocarbon-comprising group; R
2
represents a group:
—C
n
H
2n
O(C
2
H
4
O)
d
(C
3
H
6
O)
e
R
3
(3)
in which R
3
is a hydrogen, a saturated aliphatic hydrocarbon-comprising group having from 1 to 10 carbon atoms or a —(CO)—R
5
group where R
5
is a saturated aliphatic hydrocarbon-comprising group having from 1 to 5 carbon atoms; d is an integer from 2 to 200 and e is an integer from 0 to 200, provided that d+e is a number ranging from 3 to 200, and n is a number from 2 to 6, a is a value satisfying the inequality:
1.0≦a≦2.5, b is a value satisfying the inequality: 0.001≦b≦1.0 and c is a value satisfying the inequality: 0.001≦c≦1.0;
or an organohydropolysiloxane represented by the following formula (2):
R
1
f
H
g
SiO
(4−f−g)/2
(2)
in which R
1
has the same meaning as in the formula (1), f is a value satisfying the inequality:
1.0≦f≦3.0 and g is a value satisfying the inequality:
0.001≦g≦1.5;
or a mixture of the organohydropolysiloxanes of formulae (1) and (2), and
(II) a polyoxyalkylene represented by the following formula (A):
C
m
H
2m
O(C
2
H
4
O)
h
(C
3
H
6
O)
i
C
m
H
2m−1
(A)
in which h is an integer ranging from 2 to 200, i is an integer ranging from 0 to 200, provided that h+i is a number ranging from 3 to 200, and m is a number ranging from 2 to 6, or an organopolysiloxane represented by the following formula (B):
R
1
j
R
4
k
SiO
(4−g−k)/2
(B)
in which R
1
has the same meaning as in the formula (1), R
4
is a monovalent hydrocarbon-comprising group having an unsaturated aliphatic bond at the end and comprising 2 to 10 carbon atoms, j is a value satisfying the inequality: 1.0≦j≦3.0 and k is a value satisfying the inequality: 0.001≦k≦1.5,
or a mixture of the polyoxyalkylene of formula (A) and of the organopolysiloxane of formula (B), where at least one organohydropolysiloxane of formula (1) or at least one polyoxyalkylene of formula (A) is present as essential component of the addition polymerization.
The organopolysiloxane is preferably mixed with a silicone oil and/or a polyol and is prepared directly as such a mixture. The silicone oil preferably exhibits a viscosity equal to or less than 100 cSt at 25° C. For example, the silicone oil can have a viscosity at 25° C. of 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10,
Berman Alysia
Dudash Diana
L'Oreal
LandOfFree
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