Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-07-20
2001-05-29
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C510S136000, C510S137000, C514S844000, C514S846000
Reexamination Certificate
active
06238681
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates a single-phase transparent aqueous liquid cosmetic composition comprising at least one metabisulfite and at least one alkyl para-hydroxybenzoate (paraben), and to the use of the composition for gently cleaning and/or removing make-up from the skin and/or eyes. Another subject-matter of the invention is a process for dissolving an alkyl para-hydroxybenzoate in an aqueous cosmetic composition by adding at least one metabisulfite thereto.
2. Discussion of the Background
Single-phase (monophase) transparent aqueous liquid compositions are compositions which do not comprise an oily phase and which constitute cleaning and make-up removal lotions. These lotions are commonly used in the cosmetics field, in particular for completing the removal of make-up from the skin and/or eyes after the use of a milk. They comprise a large amount of water and constitute, for example, toning lotions and make-up removers for the eyes.
These monophase aqueous liquid compositions comprise preservatives, in particular alkyl para-hydroxybenzoates, also known as parabens. These parabens, and in particular methylparaben, which are widely used in cosmetics for their antifungal properties, exhibit the disadvantage of having very little solubility in aqueous medium. In fact, if they are not entirely dissolved the parabens have a tendency to recrystallize, which is reflected by the formation of white particles. Such white particles have an unacceptable affect on the visual appearance and the sensorial quality of a transparent composition. In addition, in order to fully carry out their role of preservatives in the aqueous phase, the site of contamination, the parabens have to be completely dissolved in the aqueous phase.
It is therefore essential for the parabens to be entirely dissolved in the aqueous compositions, and in particular the transparent aqueous compositions, in order to achieve the greatest possible effectiveness and also in order to obtain perfect transparency of the composition.
One solution in promoting the solubilization of the parabens consists in adding a primary alcohol, such as ethanol, a polyol, such as a glycol, or a surfactant to the aqueous composition. However, the addition of primary alcohol is to be avoided, in particular in face lotions, because ethanol can have an irritating effect on skin. Furthermore, the addition of an excessively large amount of glycols confers a sticky and clinging nature on a liquid composition, such as a lotion. Moreover, the aim is to avoid the use of an excessively large amount of surfactants, due to their irritating nature with regard to the skin and eyes, in particular in sensitive subjects. In addition, some anionic and nonionic surfactants are incompatible with the parabens, the activity of which they inhibit.
The need therefore remains to have available a single-phase aqueous liquid cosmetic composition which does not have the disadvantages of known compositions and which is perfectly transparent by virtue of complete solubilization of the parabens.
SUMMARY OF THE INVENTION
The present invention is based on the Inventors' finding that, surprisingly, metabisulfites, and in particular sodium metabisulfite, make it possible to obtain entirely transparent aqueous compositions in which the parabens, and in particular methylparaben, are completely dissolved. The final product has good stability and protection from microbiological growth.
Accordingly, the present invention relates to a single-phase transparent aqueous liquid cosmetic composition, which comprises:
at least one alkyl para-hydroxybenzoate, where the alkyl group has from 1 to 6 carbon atoms,
at least 90% by weight of water with respect to the total weight of the composition, and
at least one metabisulfite, where the amount of metabisulfite is at the most of 0.02% by weight with respect to the total weight of the composition.
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
As used herein, the term “transparent” means that it is possible to distinguish, through the bottle comprising the composition, the characters printed on a newspaper page placed behind this bottle. This term also means that a sample of the composition with a thickness of 10 cm has a maximum light transmission of at least 4% in any wavelength between 200 nm and 800 nm.
The term “liquid composition” as used herein refers to a composition comprising a high proportion of water and having a relative density of approximately 1, that is to say ranging from approximately 0.99 to 1.01. The composition of the invention comprises at least 90% by weight of water and preferably at least 95% by weight of water with respect to the total weight of the composition. The amount of water can range up to 99.9% by weight with respect to the total weight of the composition. These ranges include all specific values and subranges therebetween, such as 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% and 99.5% by weight.
It was unexpected that sodium metabisulfite, known for its antioxidizing properties, was capable of being used with success, even in small amounts, in dissolving parabens, thereby allowing good preservation to be obtained at the same time as perfect transparency, as well as excellent tolerance due to the use of quantities of metabisulfite which are sufficiently small (less than or equal to 0.02% by weight) to be non-irritating, which is particularly important for cosmetic use and especially for eye make-up remover.
Another subject-matter of the invention is consequently a process for dissolving an alkyl para-hydroxybenzoate in an aqueous cosmetic composition which consists in adding at least one metabisulfite.
The metabisulfite is generally a metal metabisulfite, such as an alkali metal metabisulfite, and preferably sodium metabisulfite. It is preferably present in an amount effective in ensuring the expected result and can be present, for example, in the composition according to the invention in an amount ranging from 0.001 to 0.02%, preferably from 0.002 to 0.01%, by weight with respect to the total weight of the composition. These ranges include all specific values and subranges therebetween, such as 0.005, 0.008 and 0.015% by weight with respect to the total weight of the composition.
In the alkyl para-hydroxybenzoate, the alkyl radical has from 1, 2, 3, 4, 5 or 6 carbon atoms and preferably from 1 to 4 carbon atoms. Examples of the alkyl para-hydroxybenzoate, include methyl para-hydroxybenzoate (methylparaben), ethyl para-hydroxybenzoate (ethylparaben), propyl para-hydroxybenzoate (propylparaben), butyl para-hydroxybenzoate (butylparaben) and isobutyl para-hydroxybenzoate (isobutylparaben).
In the composition of the invention, use is preferably made of methyl para-hydroxybenzoate, alone or as a mixture with one or more other parabens and/or with another preservative, such as phenoxyethanol. Use may be made, for example, of the mixture of methyl-paraben, ethylparaben, propylparaben and butylparaben sold under the name Nipastat by the company Nipa or the mixture of phenoxyethanol, methylparaben, ethylparaben, propylparaben and butylparaben sold under the name Phenonip by the company Nipa.
The alkyl para-hydroxybenzoate or the mixture of alkyl para-hydroxybenzoates is used in the composition according to the invention in an amount suited to the desired aim, i.e., good preservation of the composition from microorganisms. This amount can range, for example, from 0.01 to 1% and preferably from 0.05 to 0.5% by weight with respect to the total weight of the composition. These ranges include all specific values and subranges therebetween, such as 0.02, 0.03, 0.6 and 0.075% by weight with respect to the total weight of the composition.
The composition is preferably devoid of monohydric C
1
-C
3
alcohol, and, in particular devoid of ethanol, the avoidance of the use
Bui-Bertrand Lien
Carrel Marie-Laure
Dodson Shelley A.
L'Oreal
Lamm Marina
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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