Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Nonionic surfactant containing
Reexamination Certificate
1999-10-12
2001-10-16
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Nonionic surfactant containing
C424S070100, C424S070190, C424S070210, C424S070220, C424S070240, C424S070900, C424S401000
Reexamination Certificate
active
06303109
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to body washes based on aqueous preparations of water-soluble surfactants in which lipid-soluble cosmetic or pharmaceutical active substances are incorporated in a manner which ensures increased absorption of the active substances into the skin during the washing process.
2. Discussion of Related Art
It is known that cosmetic or dermatological agents can be added to body washes in order to exert a dermatologically favorable or cosmetically desirable influence on the condition of the skin during the washing process.
Hitherto, however, only water-soluble active substances have been suitable for this purpose because it is only water-soluble active substances which come into contact with the skin sufficiently to develop an effect in the relatively short time taken by the washing process. Although attempts have been made to incorporate oil-soluble active substances in water-based body washes by emulsification or solubilization, the resulting effects on the skin were not satisfactory because the active substances were either encapsulated in emulsion droplets or solubilized in surfactant micelles.
Accordingly, attempts have been made to find ways of incorporating lipid-soluble active substances in a homogeneous and stable manner in water-based body washes and, at the same time, to achieve improved penetration of the active substances during the relatively short contact time with the skin. As a result of these various attempts, it was found that improved skin penetration can be achieved if the active substances in question are present as a component in lipid/surfactant mixed micelles, lipid microemulsions or wax nanoparticles with an average particle size below 500 nm.
DESCRIPTION OF THE INVENTION
Accordingly, the present invention relates to body washes in the form of an aqueous preparation containing at least 5% by weight of water-soluble surfactants and at least 0.05% by weight of a lipid-soluble cosmetic or dermatological active substance which is solubilized with a polar lipid in lipid/surfactant mixed micelles or liquid crystals or is microemulsified with a non-polar lipid the emulsion droplets essentially having a diameter of less than 500 nm.
Body washes in the context of the present invention are liquid or paste-form aqueous preparations such as, for example, liquid soaps, wash lotions, shower bath preparations, foam baths or hair shampoos which are applied to clean the skin or the scalp and hair and which are rinsed off with water. Water-soluble surfactants in the context of the invention are ionic or nonionic surfactants of which at least 5% by weight dissolves clearly in water at 20° C. Particularly suitable water-soluble surfactants are, for example, high-foaming anionic sulfate or sulfonate surfactants, ampholytic, zwitterionic, nonionic surfactants or mixtures thereof. Examples of such high-foaming anionic surfactants are C
12-16
alkyl sulfates, for example in the form of their alkanolamine salts, C
12-16
alkyl polyglycol ether sulfates, acyl isethionates, acyl sarcosides, fatty acid monoglyceride sulfates, for example in the form of their alkali metal, ammonium or magnesium salts.
Suitable zwitterionic surfactants are, above all, betaine surfactants, for example C
12-18
alkyl dimethyl acetobetaine, cocoacylamidopropyl dimethylacetobetaine or imidazolinium betaines and sulfobetaines.
Suitable high-foaming surfactants are, above all, mixtures of the above-mentioned anionic sulfate and sulfonate surfactants and zwitterionic betaine surfactants. Mixtures of anionic surfactants and nonionic alkyl glycoside surfactants are also known to foam particularly vigorously.
Suitable nonionic surfactants besides the alkyl glycosides and alkyl (oligo)glucosides mentioned above are methyl glucoside fatty acid esters and ethylene oxide adducts thereof. Other suitable nonionic surfactants are, finally, products of the addition of ethylene oxide onto fatty alcohols, fatty acids, fatty acid monoglycerides, sorbitan fatty acid esters, alkyl glucosides, fatty acid alkanolamides and other fatty compounds containing hydroxyl or carboxyl groups, providing they are sufficiently soluble in water. This is generally the case if the content of lipophilic acyl or alkyl groups in the molecule makes up less than 50% by weight.
The body washes according to the invention contain the water-soluble surfactants in a quantity of preferably 5 to 30% by weight and more preferably 0.1 to 1% by weight of a lipid-soluble vitamin as active substance.
Lipid-soluble cosmetic or pharmaceutical active substances in the context of the invention are, above all, dermatologically active compounds which, for example, have an inflammation-inhibiting, local anaesthetic, skin-softening, antimicrobial, radiation-absorbing, skin-protecting, circulation-promoting or anti-skin-ageing effect and which are barely soluble in water, but soluble in paraffin oil, for example, in a quantity of more than 1% by weight.
Particularly suitable lipid-soluble active substances are, for example, vitamins, such as vitamin A (retinols), vitamin E (tocopherols), vitamin F (polyene fatty acids), &bgr;-carotene (provitamin A), and lipid-soluble derivatives (for example esters) thereof. Lipid-soluble esters of ascorbic acid, for example stearyl ascorbate, are also suitable. However, natural or synthetic tocopherols and lipid-soluble derivatives thereof are preferably used in the body washes according to the invention.
Suitable tocopherols are, for example, natural tocopherols and mixtures thereof and also synthetic tocopherols. Suitable esters are, for example, tocopherol acetate, tocopherol nictinate, tocopherol ascorbate, tocopheryl retinoate, tocopheryl succinate, tocopheryl linoleate and tocopheryl benzoate.
Polar lipids in the context of the invention are fatty compounds containing one or two linear C
12-22
alkyl or acyl groups and a hydrophilic group of which the size is not sufficient to make the molecule soluble in water. Hydrophilic groups such as these are, for example, the hydroxyl group, a dihydroxyethyl group or a polyhydroxyalkoxy group containing 3 to 6 carbon atoms and 2 to 5 hydroxyl groups. Polar lipids of the type in question are often referred to as “lipophilic co-emulsifiers”. Suitable examples of such lipids are, for example, cetyl and stearyl alcohol, 1,2-dodecanediol, glycerol monocetyl ether, glycerol monostearate, stearyl monoglucoside, sorbitan monopalmitate or methyl glucoside dioleate.
Other lipids are the phospholipids (lecithins) and the sterols (for example cholesterol and vegetable sterols).
Lipid/surfactant mixed micelles or lamellar liquid crystals containing lipid-soluble active substances are obtained when mixtures of the active substance, a polar lipid and a water-soluble surfactant as dispersant are heated with water to a temperature above the melting point of the lipid and mixed. The ratio by weight of lipid to dispersant is adjusted so that a lamellar liquid crystal dispersion or—below the melting temperature—a lamellar gel phase, which can form lipid/surfactant mixed micelles on dilution with water, is formed. The viscosity of this gel phase can be reduced to the flowable range by addition of short-chain C
1-4
alcohols or glycols, for example ethanol or propylene glycol. The ratio by weight of lipid to dispersant is preferably 1:2 to 2:1. The ratio by weight of polar lipid to lipid-soluble active substance is preferably 10:0.2 to 10:2.
The body washes according to the invention are preferably produced by preparing a concentrate of the active substance solubilized in lipid/surfactant mixed micelles or liquid crystals with a content of 1 to 10% by weight of the active substance and mixing the resulting concentrate with the aqueous body wash. Depending on the quantity ratio between the lamellar liquid crystal concentrate added and the aqueous surfactant preparation of the body wash, the resulting product may be a transparent, optically isotropic product (mixed micelles) or a cloudy product containing lamellar emulsion droplets whi
Foerster Thomas
Hollenbrock Martina
Pittermann Wolfgang
Schmitt Michael
Scholz Wolfhard
Henkel Kommanditgesellschaft auf Aktien
Hild Kimberly R.
Jaeschke Wayne C.
McQueeney P. E.
Murphy Glenn E. J.
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