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The use of UV filters in cosmetic and pharmaceutical sunscreen formulations

IP.com Disclosure Number: IPCOM000007599D
Publication Date: 2002-Apr-09

Publishing Venue

The IP.com Prior Art Database

Abstract

UV-B and UV-A radiations have acute, delayed and long term effects on the skin and hair. The use of UV absorbers can effectively protect skin as well as natural and dyed hair from the damaging rays of the sun. It has been found that certain triazine derivatives provide effective UV protection.

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Page 1 of 35

The use of UV filters in cosmetic and pharmaceutical sunscreen formulations - Page 1 of 35

The use of UV filters in cosmetic and pharmaceutical sunscreen formulations

UV-B and UV-A radiations have acute, delayed and long term effects on the skin and hair. The use of UV absorbers can effectively protect skin as well as natural and dyed hair from the damaging rays of the sun. It has been found that certain triazine derivatives provide effective UV protection (Ciba Specialty Chemicals, WO 9822447). The triazine derivatives correspond to formula 1 in WO 9822447 (page 2). Typical examples are as follows (formulas 1-8):

OH

OH

O
H
(4)

OH

O

O

O

N

N

N N

O

O (5 )

O

O

Page 2 of 35

The use of UV filters in cosmetic and pharmaceutical sunscreen formulations - Page 2 of 35

O

The UV absorbers as described in WO 9822447 can be used either in the dissolved state or in the micronised state.

Any known process suitable for the preparation of microparticles can be used for the preparation of the micronised UV absorbers, for example:

- wet-grinding with a hard grinding medium, for example zirconium silicate and a protective surfactant or a protective polymer in water or in a suitable organic solvent;

- spray-drying from a suitable solvent, for example aqueous suspensions or suspensions containing organic solvents, or true solutions in water, ethanol, dichloroethane, toluene or N-methylpyrrolidone etc..

- by the expansion according to the RESS process (Rapid Expansion of Supercritical Solutions) of supercritical fluids (e.g. CO 2) in which the UV filter or filters is/are dissolved, or the expansion of fluid carbon dioxide together with a solution of one or more UV filters in a suitable organic solvent;

- by reprecipitation from suitable solvents, including supercritical fluids (GASR process = Gas Anti-Solvent Recrystallisation / PCA process = Precipitation with Compressed Anti-solvents).

As grinding apparatus for the preparation of the micronised organic UV absorbers there may be used, for example, a jet mill, ball mill, vibratory mill or hammer mill, preferably a high-speed mixing mill. The grinding is preferably carried out with a grinding aid, for example an alkylated vinylpyrrolidone polymer, a vinylpyrrolidone/vinyl acetate copolymer, an acyl glutamate, an alkyl polyglucoside, ceteareth-25 or a phospholipid.

The micronised UV absorbers so obtained usually have an average particle size that is from 0.02 to 2 [mu] m, preferably from 0.05 to 1.5 [mu] m, and more especially from 0.1 to 1.0 [mu] m.

The UV absorbers can also be used dry in powder form. For that purpose the UV absorbers are subjected to known grinding methods, such as vacuum atomization, countercurrent spray-drying etc.. Such powders have a particle size of from 0.1 [mu] m to 2 [mu] m. To avoid the occurrence of agglomeration, the UV absorbers can be coated with a surface-active compound prior to the pulverisation process, for example with an anionic, non-ionic or amphoteric surfactant,...