DE19952410A1 - Solid lipid nanoparticles containing a UV filter material are useful in aqueous dispersion form as high filter content sunscreen compositions - Google Patents

Abstract

Solid lipid nanoparticles contain a UV filter material. Solid lipid nanoparticles contain a UV filter material. An Independent claim for a light-protecting composition comprising an aqueous dispersion of the UV filter-containing nanoparticles.

Description

The invention relates to sunscreens with a content of solid Lipidnano particles comprising at least one UV filter.

The damaging effect of the ultraviolet part of solar radiation on the skin has been going on long known. To protect the skin against both UVA radiation and UVB Radiation has developed numerous chemical and physical filter substances wor those that weaken the effect of the sun's rays.

Through chemical sunscreen, the impact on the skin UV radiation in Heat energy converted. Chemical sunscreens can be lipophilic as well  also have hydrophilic properties, and according to these properties under one separates between oil-soluble and water-soluble filters. To form a light protection preparation UV filter substances are usually in cosmetic carriers worked and formulated in the form of lotions, creams, ointments and the like. Derarti Most formulations are based on emulsions. Emulsions are in the broader sense disperse, more or less viscous preparations consisting of two or more other non-soluble liquids, one of which is aqueous. Lying with two are immiscible liquids and are simple emulsions systems, you can basically differentiate between two basic types of emulsions: oil-in- Water emulsions (O / W emulsions) and water-in-oil emulsions (W / O Emulsio NEN). Depending on their hydrophilicity, the filter substances in different Fashion incorporated into the cosmetic vehicle. Water-soluble filters are in the water phase of an emulsion system and oily or oil-soluble filters in the lipid phase incorporated an emulsion system. The problem with this training is often poor solubility of the filter substances in the water or oil phase of the emulsifier sion system. This is especially true for the very commonly used solid organic UV filter substances. Because of their poor solubility in the commonly used Deten carrier media, these UV filter substances only in relatively small amounts be used. But now the achievable SPF of a Lichtschutzzube depends on the amount of UV filters it contains, it is desirable to highest possible concentrations of these solid organic sunscreen filters in light to realize protective preparations.

Various efforts have been made to increase solubility increase organic sunscreen. Thus, in PCT application WO 97/25020 described that the solubility of the filter Uvinul T150 (available from BASF Aktiengesellschaft) by adding branched and / or unbranched carboxylic acids having chain lengths of 10 to 24 carbon atoms which are at least 10% protonated Form can be increased.

In WO 95/22959 sunscreen preparations are described, the insoluble light protective filter in solid micronized form. Micronization of the filtersub  punching requires complex grinding processes. Those obtained by these milling methods micronised filters can only be obtained by adding emulsifiers in W / O or O / W Incorporate emulsion.

For some time, new carrier materials for drugs, known as so-called solid lipid nanoparticles (SLN®) based, for example, in German Offenlegungsschrift DE 44 40 337 are described. Solid lipid nanopar Particles are particles with a mean particle size in the nanometer range, d. H. about 80 nm to about 1000 nm. They consist of a solid lipid, which in aqueous dispersion with a surfactant or polymer is stabilized. The preparation of solid lipid nanoparticles occurs either by high-pressure homogenization of lipids in the molten state (Hot homogenization) or in the solid state (cold homogenization). In the Hot homogenization dissolves the active ingredient in the molten lipid, which is melted Lipid drug solution in a hot surfactant solution with a temperature that is about 5 ° C higher is poured as the melting point of the lipid and a crude emulsion with a stirrer produced, which is then high pressure homogenized at about 500 bar. After cooling The obtained nanoemulsion form solid lipid nanoparticles. At the Kalthomogenisa tion, the lipid active ingredient melt is cooled, the solidified lipid ge to microparticles ge grind, which are then suspended in cold surfactant solution. The obtained microparticles suspension is then homogenized in the solid state, with the shear and graviations forces are high enough to fine microparticles in the solid state To break up lipid nanoparticles. The product is directly an aqueous dispersion solid Obtained lipid nanoparticles.

The object of the present invention is to provide novel sunscreen preparations, which have a high SPF with good skin tolerance or a compared to previously known sunscreen preparations increased content of UV Filterubstan zen.

This object is achieved by means of the light protection tube defined in the independent claim solved.  

The dependent claims define advantageous embodiments of the invention.

In the underlying of the present invention studies has been surprisingly found that the already described for the field of drugs carrier substances based on solid lipid nanoparticles also as a carrier for UV filter zen and thus can be used for the production of sunscreen preparations, characterized by a particularly high content of UV filter substances and thus a high sun protection factor.

According to one embodiment of the present invention, at room temperature solid oil-soluble filters according to the per se known technology for the production of solid Lipid nanoparticles dissolved in a molten lipid phase and after introduction of the Melt high pressure homogenized in an aqueous solution of a surfactant. On cooling The lipid phase, which is present in nanodroplets, solidifies, as a result of which the filter is solidified is located.

Alternatively and particularly preferably, however, the filter substance itself may be used as the Production of solid lipid nanoparticles serving lipid phase can be used. According to In this embodiment of the present invention, the UV filter substance is applied melted, dispersed in an aqueous, at least one surfactant comprising phase and high pressure homogenization. After cooling, the solid UV filter is in Nanopar form either crystalline or using suitable crystallization inhibitors, such as As gelatin PVP or other polymers, in an amorphous form.

Those prepared according to these two alternative methods of the present invention Nanoparticles containing UV filter substances can be converted into customary cosmetic carriers systems, such as O / W creams or emulsions, W / O creams or lotions or hydrodispersion gels. The formed nanodispersion can particularly advantageous but also directly as a thin aqueous preparation as a spray on the skin will be applied. The sunscreen preparation prepared according to the invention gene show at the same Konzentra compared to conventional sunscreens tions on UV filter substances increased by at least a factor of 2 to 4 light  protection factor. Further advantages of the sunscreen preparations according to the invention, the ver probably based on the fact that the filter substances are enclosed in a fat matrix, are an increased water resistance, a lower skin penetration, resulting in a verbes Sert compatibility of the preparations according to the invention results, as well as an increased Photostability of UV filter substances.

The preparation of the sunscreen preparations according to the invention is in itself unproblema Table and carried out according to the already known regulations for the production of nano suspensions of solid lipid nanoparticles; Reference is made by way of example to those in DE OS 44 40,337 disclosed methods. The ent for the production of UV filters according to the invention lipid phase used, as stated above, either from consist of the filter substance itself or by conventional lipids, such as Cetyl palmitate, beeswax or tristearin are formed. The formation of the solid Lipid nanoparticles used surfactants are according to the invention preferably substances, which show a good skin compatibility. Particularly preferred is the use of Cholesterol, lecithin or methylglucosides, such as those from the Tego- Care® series. In addition to the UV filters contained in the lipinanoparticles, the preparations according to the invention further UV filter substances, in particular also physical filter substances contained.

The nanoparticle dispersions according to the invention preferably comprise 0.1 to 50% by weight. Nanoparticles. The content of the nanoparticles according to the invention on UV filter substance is between 0.1 and 100% by weight. The content of the nanodispersion in the inventive Sunscreen preparations are between 0.1 and 100 wt .-%.

The following examples illustrate the invention without limiting it.  

example 1

A nanoparticle suspension containing UV filter substance is prepared according to the following composition:

ingredient Content [% by weight] Uvinul T150 30 cholesterol 2 Tego Care® 4 glycerol 3 ethanol 5 water ad. 100

Uvinul T150 UV filter (2,4,6-trianilino-p- (carbo-2'-ethyl-hexyl-1'-oxy) 1,3,5-triazine) was melted and immersed in an aqueous solution of cholesterol and Tego Care® brought about a temperature of about 5 ° C above the melting temperature of the UV-fil ters had. The resulting emulsion is Nanopar in a high pressure homogenizer dispersed particles and the resulting nanoemulsion then cooled. Then glycerol and ethanol added. The nanoparticle dispersion thus obtained can be applied directly as a spray the skin will be applied.

Example 2

Nanoparticle dispersions according to Example 1 were prepared in which instead of the UV filters Uvinul T150 the UV filters UVA Sorb HEB or Eusolex 6300 and / or Parsol 1789 were used.  

Example 3

A nanoparticle dispersion of the following composition is prepared:

ingredient Content [% by weight] Uvinul T150 5 tristearin 30 Tego Care® 5 lecithin 0.5 glycerol 3 water ad. 100

First, a melt of tristearin and Uvinul T150 was formed, which in a Lö Tego Care® and lecithin, which has a temperature of about 5 ° C above the temperature of the melt. As previously described in Example 1 formed by high-pressure homogenization, a nanodispersion. After cooling the Glycerol is added to the resulting dispersion. The dispersion thus obtained can be directly in Form of a spray can be applied to the skin.

Example 4

According to Example 3, nanoparticle dispersions were prepared in which instead of of the Uvinul T150 the UV filters UVA Sorb HEB or Eusolex 6300 or Parsol 1789 were used.  

Example 5

An oil-in-water emulsion of the following composition is prepared:

ingredients Content [% by weight] UV nanoparticle dispersion according to Example 1-4 25 Tego Care® 450 2 Softisan 100 0.5 cetyl alcohol 1.5 Myritol 331 5 α-tocopherol acetate 1 Carbopol 981 0.2 glycerol 3 caustic soda 0.05 ethanol 7 water ad. 100

Example 6

A water-in-oil lotion of the following composition is produced:

ingredients Content [% by weight] UV nanoparticle dispersion according to Example 1-4 25 Dehymuls PGPH 3 Monomuls 90-018 1 Myritol 318 6 isopropyl 10 Vitamin E acetate, liquid 0.5 beeswax 1 magnesium stearate 0.5 Neo Heliopan AV 10 Sodium EDTA disodium 0.1 glycerin 3.0 dexpanthenol 1.0 magnesium sulfate 0.5 ethanol 8th water ad. 100

Example 7

A hydrodispersion gel of the following composition is prepared:

ingredients Content [% by weight] UV nanoparticle dispersion according to Example 1-4 25 Pemulen TR1 0.5 Sodium EDTA disodium 0.1 glycerol 3.0 dexpanthenol 1.0 Neo Heliopan AV 5 Neo Heliopan 1000 5 DL-α-tocopherol 0.5 sodium hydroxide 0.19 alcohol 9 water ad. 100

Claims (8)

1. Solid lipid nanoparticles comprising at least one UV filter substance. 2. Sunscreen preparation comprising an aqueous dispersion of at least one UV filter substance-containing, solid lipid nanoparticles. 3. sunscreen preparation according to claim 2, characterized in that it comprises 0.1 to 50% by weight of solid lipid nanoparticles. 4. sunscreen preparation according to claim 2 or 3, characterized in that the at least one UV filter substance is selected from the Group consisting of Uvinul T150, UVA Sorb HEB, Eusolex 6300 and Parsol 1789. 5. sunscreen preparation according to one of claims 2 to 4, characterized in that, in addition to the at least one, in the solid Lipidnano Particles contained UV filter substance at least one more, not in the solid Lipid nanoparticles containing UV filter substance. 6. sunscreen preparation according to claim 5, characterized in that the UV filters not contained in the lipid nanoparticles substance is a physical sunscreen. 7. sunscreen preparation according to one of claims 2 to 7, preparable by melting a lipid phase, introducing the molten lipid phase in an aqueous solution of at least one surfactant and subsequent high pressure homo genisation. 8. sunscreen preparation according to claim 7, characterized in that the lipid phase exclusively of at least one UV-Fil tersubstanz is formed.