WO2000010522A1

WO2000010522A1 - Cosmetic and dermatological skin care agents

Info

Publication number: WO2000010522A1
Application number: PCT/EP1999/005723
Authority: WO
Inventors: Thomas Förster; Martina Hollenbrock; Armin Wadle
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1998-08-17
Filing date: 1999-08-07
Publication date: 2000-03-02
Also published as: DE19837191A1

Abstract

Aqueous preparations for cosmetic and dermatological treatment of the skin, containing lipid-soluble, cosmetic or dermatological active substances which are preferably applied when the skin has been cleaned and which are designed to remain on the skin at least until the next time that it is washed. The inventive preparations have significantly improved skin-penetration properties when the active substances contained therein are fine particled wax constituents with a particle size of less than 500 nanometres. Preferably, said wax particles contain 0.1-30 wt. % of a lipid-soluble active substance and the preparations contain 1-10 wt. % of such wax particles.

Description

"Cosmetic and dermatological skin treatment agents"

The invention relates to aqueous preparations for the cosmetic and dermatological treatment of the skin containing lipid-soluble cosmetic or dermatological active ingredients, which are contained therein as a component of finely dispersed wax particles with a particle size of less than 500 nm and are absorbed particularly well by the skin in this way .

It is known to formulate preparations for the cosmetic and dermatological treatment of the skin as oil-in-water emulsions and to incorporate oil-soluble active ingredients into the inner phase, ie into the oil phase. The German patent application DE 197 10 149.6 relates to surfactant-containing personal cleansing agents which contain at least 0.05% by weight of a lipid-soluble cosmetic or dermatological active ingredient with a polar lipid solubilized in lipid-surfactant mixed micelles or liquid crystals or containing microemulsified in a non-polar lipid. The cleaning agents described there are rinsed off the skin in the usual way immediately after use.

It has now been found that a considerably greater skin penetration of lipid-soluble active ingredients can be achieved in so-called "leave on" skin treatment compositions which remain on the skin after use if the lipid-soluble active ingredients as components of finely dispersed wax particles with a particle size of less than 500 nm therein are included. The invention therefore relates to aqueous preparations for the cosmetic and dermatological treatment of the skin containing lipid-soluble cosmetic or dermatological active ingredients, which are contained as components of finely dispersed wax particles with a particle size of less than 500 nm (nanometers).

The preparations according to the invention are those preparations which, after being applied to the skin, remain on the skin at least until the next washing operation, or preparations which are preferably applied to the skin after cleaning and optionally massaged in. Such preparations are e.g. cosmetic or dermatological skin creams, lotions, emulsions or gels that are suitable for the application of lipid-soluble active ingredients.

Lipid-soluble cosmetic or pharmaceutical active substances in the sense of the invention are to be understood in particular as dermatologically active compounds which e.g. have an anti-inflammatory, local anesthetic, skin-softening, antimicrobial, radiation-absorbing, skin-protecting, circulation-promoting or skin-aging protection and hardly in water, but in e.g. Paraffin oil is soluble in an amount of more than 1 wt .-%.

Preferred suitable lipid-soluble active ingredients are e.g. D-biotin, vitamins such as vitamin A (retinols), vitamin E (tocopherols), vitamin F (polyene fatty acids), ß-carotene (pro vitamin A) and the lipid-soluble derivatives (e.g. esters) of these substances. Also suitable are the lipid-soluble esters of ascorbic acid e.g. Stearyl ascorbate. However, natural or synthetic tocopherols and their lipid-soluble derivatives are preferably used in the personal cleansing agents according to the invention.

Suitable tocopherols are, for example, the natural tocopherols and their mixtures and synthetic tocopherols. Suitable esters are, for example, tocopherol acetate, tocopherol nicotinate, tocopherol ascorbate, tocopheryl retinoate, tocopheryl succinate, tocopheryl linoleate or tocopheryl benzoate. The active substances mentioned are incorporated into the wax particles suitable according to the invention by converting them into a finely divided dispersion using suitable wax components and emulsifiers by known processes. Such a method for producing finely dispersed wax dispersions is known, for example, from DE 43 37 030 AI. The dispersions obtained by the phase inversion process (PIT process) described there have a low viscosity and a very small particle size of less than 500 nm, preferably 100-200 nm, and are particularly suitable as carriers for the lipid-soluble active ingredients in cosmetics and dermatological preparations for the treatment and care of the skin.

Suitable waxes are natural or artificially obtained substances that are solid and kneadable at 20 ° C, coarse to fine crystalline and only change to a flowable, low-viscosity state above about 40 ° C without decomposition.

The type and origin of the waxes (A) are not subject to any restrictions in the context of the present invention. The waxes (A) can accordingly be selected from each of the three groups into which the waxes are usually classified. These three groups are:

1) natural waxes:

(a) vegetable waxes, which are divided into recent

Waxes such as candelilla, carnauba, japan, esparto grass, ouricoury wax and in fossil waxes such as montan wax, etc .:

(b) animal waxes such as bees wax, shellac wax, walrus, lanolin (wool wax), pretzel fat, etc .;

(c) mineral waxes (petroleum waxes) such as ceresin, ozokerite (earth wax), petrolium, paraffin and micro waxes,

2) chemically modified waxes e.g. the oxidized products made from raw montan wax,

3) synthetic waxes, also called synthetic waxes, for example from the paraffins obtained by the Fischer-Tropsch process, which are converted into a series of hard waxes by air oxidation, selective solvent treatment, esterification, saponification, etc. Also polyethylene waxes, some of them High-pressure polymerization of ethylene, some of which are produced by cracking, from the high-molecular low-pressure polyethylene, as well as corresponding oxidized products, are among the synthetic waxes.

Also suitable as waxes are fatty acid esters of monohydric or polyhydric alcohols which, because of their consistency and melting range, exhibit waxy behavior. Such products are, for example, the esters of saturated, linear C ₁₂ -C ₂₂ fatty acids and saturated, linear C ₁₂ -C ₂₂ fatty alcohols, for example cetyl palmitate, stearyl stearate or cetyl behenate, triglycerides of saturated, linear C ₁₂ -C ₂₂ fatty acids and hydrogenated vegetable and animal fats such as hardened palm fat, hardened valley or hardened castor oil.

The preparations according to the invention preferably contain the lipid-soluble active substances in an amount of 0.01-2.0% by weight, based on the entire preparation. Such an active ingredient concentration can e.g. achieve when the active ingredient-containing wax particles are contained in the preparation in an amount of 1-10% by weight.

The preparations according to the invention are preferably prepared in such a way that the active ingredient is mixed into the rest of the preparation in the form of an aqueous dispersion of active ingredient-containing wax particles at a temperature below the melting point of the wax particles.

The wax particles contained according to the invention preferably contain

50 - 80 wt .-% of one or more wax components with a melting point in

Range from 40 - 120 ° C 0.1 - 30 wt .-% of a lipid-soluble, cosmetic or dermatological active ingredient and up to 30 wt .-% of one or more emulsifiers. The type and amount of the emulsifiers required are selected in a manner known per se based on the HLB value of the wax components and the amount of the waxes and active ingredients to be emulsified.

Particularly suitable emulsifiers are e.g. nonionic compounds with a lipophilic alkyl or acyl group and a hydrophilic polyol or polyether group. Examples of suitable emulsifiers are e.g. Ethylene oxide addition products on fatty alcohols with 16-22 C atoms, on fatty acid monoglycerides or on sorbitan monoesters of fatty acids with 16-22 C atoms. Suitable emulsifiers preferably have an HLB value of 8-18. The HLB value is understood to be a quantity that results from the relationship HLB = 0.2 (100 - L). L is the weight fraction of the lipophilic groups, i.e. of the fatty alkyl or fatty acyl groups in percent in the nonionic emulsifiers.

The use of a lipophilic co-emulsifier can be advantageous for producing the wax dispersion containing the active ingredient. These are polar lipids with one or two C ₁₂ - C ₂₂ alkyl or acyl groups and a hydrophilic group, the size of which is not sufficient to make the molecule water-soluble, for example the hydroxyl group, a dihydroxyethyl group or a polyhydroxyalkoxy group with 3 - 6 carbon atoms and 2 - 5 hydroxyl groups. Such polar lipids are often also 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.

The finely divided dispersions of active ingredient particles containing active ingredients, for example produced by the PIT process, can be incorporated into any aqueous preparations. Aqueous preparations are understood to be creams, emulsions and dispersions, gels and lotions, the outer phase of which is aqueous. Liquid oil-in-water emulsions or oil-in-water creams are particularly preferred. Mixed emulsion systems, for example of the water-in-oil-in-water type, are also suitable for introducing the wax dispersions loaded with lipophilic active ingredients. Such aqueous preparations can contain all the usual components of such preparations in the usual amounts. For example, customary cosmetic oil components in emulsified or microemulsified form, emulsifiers, thickeners, water-soluble active ingredients, proteins or protein derivatives, complexing agents, buffer salts, preservatives, pigments, dyes and fragrances can be present in customary amounts.

The following examples are intended to explain the subject of the invention in more detail. In particular, they are intended to show that the penetration of vitamin E acetate (as an example of a lipophilic active ingredient) from a conventional OAV emulsion (composition V) is significantly less than from an analog emulsion which contains an equal amount of the vitamin E contains acetate as a component of finely divided wax particles (composition 3).

Examples

1. Production of wax nanoparticle dispersions containing active ingredient

The following dispersions (Table I) were prepared by the process of German Offenlegungsschrift 43 37 030.

Wax components, emulsifiers, vitamins and water were introduced and heated with stirring until the phase inversion temperature (PIT) was reached at approx. 70 - 85 ° C. After exceeding the PIT, the dispersion was cooled to room temperature (25 ° C.) with stirring. Finely divided dispersions with a bluish shimmer in incident light with a wax particle diameter below 500 nm were obtained.

Table I

2. Production of vitamin formulations

Table II

The vitamin-containing wax dispersions (DI, D3 and D5) were added to the cream (40 ° C) in the cooling phase and homogeneously distributed while stirring.

3. Penetration studies

Penetration studies for the creams according to Example 3 and V (comparison) were carried out on the perfused cattle udder, the so-called BUS model (bovine and skin model). carried out. The method is described in more detail, for example, in ALTEX 12, 4/95, pages 196-200.

15 minutes after the start of perfusion, 4 g of the various vitamin-containing creams were applied topically open to skin areas of 100 cm ² . After 4 hours, cream residues were thoroughly wiped off with the help of a paper towel. Thereafter, Tesa ^® strip film breaks (Tesa type 4204, Beiersdorf) were taken. The tesa strips were stored frozen at - 20 ° C.

The upper stratum corneum layers were removed one after the other during the tesa stripping. In each case 10 film breaks were taken, 10 horn layers with a total thickness of approximately 10 μm being removed. The mass of the detached horn cells was constant over all layers approx. 1.1 mg per tesa strip with a standard deviation of ± 0.36 mg for n = 20.

The vitamin E acetate was determined analytically in the skin samples. For this purpose, the tesa tears were extracted and the vitamin E acetate in the extract was isolated by liquid chromatography and determined on a substance-specific basis. The quantification was achieved by standard calibration and comparison with blank samples (untreated skin areas).

The following penetration results were obtained:

Claims

claims

1. Aqueous preparations for the cosmetic and dermatological treatment of the skin containing lipid-soluble cosmetic or dermatological active ingredients, characterized in that the active ingredients are contained therein as components of fine wax particles with a particle size of less than 500 nm.

2. Preparations according to claim 1, characterized in that the active substances are contained in an amount of 0.01-2% by weight, based on the entire preparation.

3. Preparations according to one of claims 1 or 2, characterized in that the wax particles are contained in an amount of 1 - 10 wt .-% in the preparation.

4. Preparations according to one of claims 1-3, characterized in that the wax particles

50-80% by weight of one or more wax components with a melt in the range of 40-120 ° C

0.1 - 30% by weight of a lipid-soluble cosmetic or dermatological active ingredient and up to 30% by weight of one or more emulsifiers.

5. A process for the preparation of a cosmetic or dermatological preparation according to any one of claims 1-4, characterized in that the active ingredient is mixed into the preparation in the form of an aqueous dispersion of active ingredient-containing wax particles at temperatures below the melting point of the wax particles.

6. Use of wax dispersions with a particle diameter of less than 500 nm, preferably with an average particle diameter of 100-200 nm, as a carrier for lipid-soluble active ingredients in cosmetic and dermatological preparations for the treatment and care of the skin.