Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-10-27
2004-10-12
Padmanabhan, Sreeni (Department: 1617)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S043000, C424S070100, C424S070110, C424S078030, C514S506000, C514S532000, C514S944000
Reexamination Certificate
active
06803047
ABSTRACT:
The present invention relates to a novel vaporizable topical composition consisting of an aqueous gel comprising a specific hydrophilic gelling material. The invention also relates to a device consisting of a container containing the above cosmetic composition and a means for distributing the said composition, more particularly a pump-dispenser bottle or an aerosol device.
To prepare aerosols which are vaporizable in all positions, expensive specific devices are currently used, involving complex mechanical solutions such as specific valves or systems of pockets which are relatively impractical to implement.
The Applicant has now found that by using a gel which has a specific rheological profile, it is possible to obtain a gelled composition which can be vaporized by standard pump-dispenser bottle and aerosol equipment in all positions.
Common gelling materials, such as guar gums, the Carbopols® sold by the company Goodrich, Sepigel® 305 sold by the company SEPPIC, or thickeners of latex type, such as the Acrysols® sold by the company Rohm & Haas, or Viscoatex® 538 sold by the company Coatex, give gels which do not have the rheological profile of the gels according to the invention and thus cannot be vaporized.
It is also known practice to use alumina to obtain vaporizable, so-called “rheofluidizing” gels (WO 94/16808). However, as with all gels of this type described in the prior art, it is necessary to shake the bottle containing the composition vigorously in order to fluidize it and make its vaporization possible.
The gels which have the specific rheological profile according to the invention are a solution to the problems outlined above.
The present invention thus relates to a composition consisting of an aqueous gel comprising a hydrophilic gelling material, the said gel having the following rheological profile:
an initial viscosity V
0
of between 3000 and 50,000 Pa.s, the said initial viscosity V
0
being stable up to a shear strain C
1
,
a viscosity V
2
after shear at a strain C
2
for which the ratio V
0
/V
2
is greater than or equal to 1000,
the difference C
2
-C
1
being less than or equal to 100 Pa.
The gel has an initial viscosity which is stable, i.e. constant at low shear strains, such that the composition can be handled without resulting in a substantial change in its viscosity. This stability of the initial viscosity is expressed by a value of the viscosity of the gel, V
1
, measured at the shear strain C
1
close to V
0
. It is understood that this proximity should be assessed with regard to the fall in viscosity after shear. Advantageously, the ratio V
0
/V
1
is less than or equal to 2.
The shear strain C
1
is characteristic of the force required to obtain fluidization of the gel, in particular allowing its vaporization. This strain C
1
is preferably greater than or equal to 50 Pa. A person skilled in the art will know how to determine the value which this strain should not exceed, as a function of the use which he or she intends to make of the composition according to the invention.
For use in a device allowing its vaporization, the maximum shear strain values C
1
can be illustrated below as a function of the vaporization device.
When the means for distributing the composition according to the invention is a pump-dispenser bottle, the maximum shear strain value C
1
is preferably less than or equal to 150 Pa.
When the means for distributing the composition according to the invention is an aerosol device, the maximum shear strain value C
1
is preferably less than or equal to 200 Pa.
It is understood according to the text hereinabove and hereinbelow that the various viscosity and strain values are measured once the gel has been formed. Before carrying out the viscosity and rheological profile measurements on the gel, it should be ensured that the gel has formed correctly and is stable. It is thus advisable to wait at least 24 hours after preparation of the gel.
Preferably, the falls in viscosity induced by shear on the gel are not immediately reversible, i.e. the material does not break under high strain and remains homogeneous when it has reached its lowest viscosity.
The hydrophilic gelling material according to the invention consists of any gelling material which can form a gel or a composition having the appearance of a gel and having the rheological profile according to the invention.
According to one preferred embodiment of the invention, the hydrophilic gelling material is a hydrophilic gelling polymer. Hydrophilic gelling polymers which are useful according to the invention are, in particular, sulphone polyesters with a weight-average molecular mass of less than 20,000, preferably less than 15,000.
Such polymers can be, more particularly, water-soluble or water-dispersible terephthalic copolyester oligomers essentially comprising dicarboxylate repeating units of formula (I):
Co—A—Co—O—(CH
2
CH
2
O)
n
(I)
in which
A represents a 1,4-phenylene, sulpho-1,3-phenylene and optionally 1,3-phenylene group,
n ranges from 1 to 4,
at least 35 mol % of the said units of formula (I) being units of formula (I) for which A represents a 1,4-phenylene group and n is equal to 1,
at least 7 mol % of the said units of formula (I) being units of formula (I) for which A represents a sulpho-1,3-phenylene group,
the weight-average molecular mass of the said copolyester oligomers being less than 20,000, preferably less than 15,000.
Preferably, at least 40 mol %, more preferably between 40 and 90 mol %, of the units of formula (I) are units of formula (I) for which A represents a 1,4-phenylene group and n is equal to 1.
Preferably, at least 10 mol %, more preferably between 10 mol % and 25 mol %, of the units of formula (I) are units of formula (I) for which A represents a sulpho-1,3-phenylene group.
The ends of the chains of the said copolyester oligomers can be similar or different and can be represented essentially by the groups of formula (I′):
Co—A—Co—O(CH
2
CH
2
O)
n
—OH (I′)
in which A and n are defined above.
The said oligomers can also have at the chain ends, and in smaller amounts, groups of formulae
—A—CO—OH
—A—CO—OR
in which formulae A is defined above and R represents a C
1
-C
4
alkyl group.
When A represents a sulpho-1,3-phenylene group, it is more particularly an alkali metal sulphonate, in particular sodium or potassium sulphonate, or an ammonium or lower mono-, di-, tri- or tetraalkylammonium sulphonate. According to the invention, the term lower alkylammonium is preferably understood to refer to an ammonium in which the alkyl radical(s) is(are) lower alkyls, preferably C
1
-C
6
alkyls. Preferably, it is a sodium sulphonate.
The copolyester oligomer can optionally comprise up to 20 mol %, preferably up to 5 mol %, of units of formula (I) for which A represents a 1,3-phenylene group.
According to a preferred embodiment of the invention, the above copolyester oligomer has a weight-average molecular mass of between 5000 and 14,000, more preferably of between 8000 and 10,000.
The weight-average molecular masses are measured by gel permeation chromatography in dimethylacetamide containing 10
−2
N of LiBr, at 100° C. The results are expressed in polystyrene equivalents.
The said copolyester oligomers can be obtained by the usual molten-route, solvent-route or interface-route processes for preparing polyesters, these processes involving
esterification reactions of diacids and of diols and polycondensation
transesterification reactions of diesters and of diols and polycondensation
autocondensation reactions of hydroxy acids
Schotten-Baumann reactions using diols and acid chlorides and polycondensation
polymerization reactions of lactones
while controlling the minimum content of units of formula (I) for which A represents a 1,4-phenylene group and n is equal to 1, which are similar on the basis of the initial stoichiometric ratios of the various monomers and on the basis of the control of the side reactions.
A particularly advantageous mode of preparation is that by mol %en-route transesterification/polycondensation an
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
L'Oreal
Padmanabhan Sreeni
Wells Lauren Q.
LandOfFree
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