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Granulates of micronized UV Filter actives Disclosure Number: IPCOM000202511D
Publication Date: 2010-Dec-20

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Disclosed is a granulate composition, comprising (a) 40 to 95 % b.w. of a micronized insoluble organic UV Filter; (b) 3 to 20 % b.w. of at least one water-soluble surfactant, dispersant or polymer; (c) 0 to 10 % b.w. of further additives; (d) 0.5 to 10 % b.w. of water; wherein the micronized insoluble organic UV Filter (a) has a particle size from 20 to 200 micro meter. The granulate compositon is used for cosmetic sunscreen applications.

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Granulates of micronized UV Filter actives

The present invention relates to a granulate compositions comprising a UV absorber, method of preparation of these granulate compositions and to their use in sunscreen compositions which, in turn, are useful, in particular, for the protection of human skin.

It has long been known that prolonged exposure to that UV radiation which reaches the surface of the earth can lead to the formation of erythemas or light dermatoses, as well as to an increased incidence of skin cancers or accelerated skin aging.

Various sunscreen formulations have been proposed which include a material which is intended to counteract UV radiation, thereby inhibiting the said undesired effects on the skin.

A great number of compounds has been proposed for use as UV protectants in sunscreen formulations, especially soluble organic UV absorbers and insoluble micronized organic inorganic compounds, in particular Methylene Bis-Benzotriazolyl Tetramethylbutylphenol (Tinosorb® M), zinc oxide and titanium dioxide.

With respect to the use in sunscreen formulations of soluble organic UV absorbers, they have the disadvantages that their effectiveness as UV protectants in terms of SPF (Sun Protection Factor) in a sunscreen formulation is often too low for commercial purposes; as a result of their solubility, they exhibit relatively high allergenic potential; and that as a result of intrinsic photochemical lability, the duration of the protective effect is often too low.

The high specific weight of insoluble inorganic compounds, such as titanium dioxide leads to a reduced stability of formulations containing them. Moreover, such inorganic compounds have been claimed to generate toxic radicals under the influence of light and water ("Redox Mechanisms in Heterogeneous Photocatalysis", Serpone et al, Electrochemistry in Colloids and Dispersions, Editors Mackay and Texter, VCH Publishers Inc., NewYork 1992).

In GB-A-2303549, there is described a method of producing micronised, insoluble organic UV absorbers, as well as a sunscreen composition comprising a micronised formulation of an insoluble organic UV absorber, produced according to the said method.

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When the so obtained UV absorbers are used in sunscreen formulations they provide ex- cellent UV protection and have an SPF rating which is at least as high as corresponding sunscreen formulations containing a known inorganic UV absorber. Unlike the latter UV absorbers micronised insoluble organic UV absorbers show no tendency for generating radicals which could damage or sensitise human skin under the influence of light.

However micronised organic UV absorbers which are usually formulated in an aqueous dis- persion with an active content of UV absorber of 40 to 50 %, are subject to degradation which results in agglomeration / ripening and thus loss in product value.

Surprisingly it was found that granulates obtained out of the water-based dispersion of the...