Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Polymer containing
Reexamination Certificate
2002-01-30
2002-10-15
Travers, Russell (Department: 1617)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Polymer containing
Reexamination Certificate
active
06464966
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stable water/oil/water triple emulsion and to its use, for example, in the cosmetics and/or dermatological fields, especially for the controlled release of active agents. The emulsion may be used, for example, for cleansing and/or treating and/or protecting the skin and/or mucous membranes and/or keratinous fibers.
2. Background of the Invention
The use is known, in particular in the cosmetics and dermatological fields, of topical compositions in the form of emulsions. These emulsions are generally oil-in-water (O/W) or water-in-oil (W/O) emulsions. These compositions may also be multiple emulsions of the water/oil/water (W/O/W) or oil/water/oil (O/W/O) type. Use is preferably made, among multiple emulsions, of emulsions with an aqueous external phase, namely W/O/W emulsions, which combine the advantages of freshness on application, contributed by the water present in the aqueous external phase, and of comfort, contributed by a relatively large amount of oil.
However, multiple emulsions are not exploited to any great extent because they frequently exhibit problems of stability over time. The most frequently encountered mechanism for destabilization is the migration of water from the internal droplets to the aqueous external environment through the intermediate oily layer, either by simple diffusion of water through the oily membrane or by prior rupture of the oily film, bringing about the coalescence of the internal droplets of water and resulting in a release of internal water into the aqueous external environment. Generally, this phenomenon, known as loss of the multiple nature, ends up by bringing about macroscopically visible phase separation and the production of a simple O/W emulsion in place of a triple emulsion.
Various means have consequently been envisaged to mitigate this disadvantage. In particular, one of the solutions is adding, into the aqueous internal phase or into the aqueous external phase, one or more gelling polymer(s), the role of which is to limit, on a long-term basis, the movements of water from the internal phase to the external phase. However, the multiple emulsions obtained exhibit the drawback of being sticky and of taking a long time to penetrate into the skin, because of the presence of large amounts of polymers which, because of their polymeric structure, remain at the surface of the skin.
Another solution is introducing lipophilic structuring agents into the oily phase. Thus, FR-A-2,679,788 describes the use of unsaturated linear C
8
to C
14
fatty alcohols, which give rise to soaps and which confer a gel structure on the emulsion. Unfortunately, the sensorial qualities of the emulsions obtained are not very satisfactory because they have a tendency to become waxy on application to the skin. In addition, the presence of soaps in the emulsion has the consequence of causing soaping, i.e., whitening during application to the skin.
In addition, the use is known, for example as described by WO-A-94/1073, in triple emulsions of silicone polymers comprising a polyoxyethylenated and/or polyoxypropylenated chain, which, although polymers, do not have the abovementioned disadvantages. However, the use of this type of emulsifier requires the presence of a certain amount of silicone oil in the oily phase and therefore limits the pharmaceutical dosage composition of the triple emulsion. In addition, in order to obtain satisfactory stability of the triple emulsion, it is often necessary to add a gelling agent to one of the aqueous phases.
The need therefore remains for a stable W/O/W multiple emulsion which does not have the disadvantages of known emulsions and which is, in particular, pleasant to use on the skin while contributing, for example, the advantages of an emulsion with an aqueous external phase.
SUMMARY OF THE INVENTION
The inventors have now found, unexpectedly, that the introduction of a partially or completely crosslinked organopolysiloxane elastomer comprising a polyoxyethylenated and/or polyoxypropylenated chain into a water/oil/water (W/O/W) triple emulsion makes it possible to stabilize the emulsion without requiring the addition of other stabilizing agents.
Accordingly, the present invention provides a water/oil/water triple emulsion comprising an aqueous external phase and a W/O primary emulsion comprising an oily phase and an aqueous internal phase, characterized in that it comprises at least one partially or completely crosslinked organopolysiloxane elastomer comprising a polyoxyethylenated and/or polyoxypropylenated chain.
Another aspect 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 a water/oil/water triple emulsion.
For topical application, the inventive emulsion may contain a topically acceptable medium, i.e., a medium compatible with the skin, mucous membranes and/or keratinous fibers, such as the hair.
The triple emulsion according to the invention has the advantage of being stable and of being able in particular to retain the activity of active agents present in the aqueous internal phase, whence they are released during the application of the composition to the skin, mucous membranes and/or hair.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description.
DETAILED DESCRIPTION OF THE INVENTION
The partially or completely crosslinked organopolysiloxane elastomers which may be used in the inventive emulsion are preferably introduced into the oily phase of the emulsion. They are generally emulsifiers. They can be chosen in particular from the crosslinked polymers disclosed in EP-A-0,545,002. EP-A-0,545,002 is incorporated herein by reference. These organopolysiloxanes are obtained by addition polymerization 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−j−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 a
Berman Alysia
L'Oreal
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Travers Russell
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