Use of benzotriazole derivatives
Publication Date: 2005-Jul-21
The IP.com Prior Art Database
Dislosed is the use of specific hydroxyphenyl benzotriazole derivatives, preferably 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (branched and linear) for enhancing the photostability of cosmetic or dermatologic compositons comprising at least one further organic UV absorber.
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Use of benzotriazole derivatives
The present invention relates to the use of specific benzotriazole derivatives for enhancing the photostability of sunscreen compositions.
There is a growing need for effective topical sun protection preparations in order to prevent the damaging effects of UV light on human skin, for example sunburn, photo-allergic reactions, premature ageing of the skin and skin cancer. Most sun protection preparations now provide good protection against ultraviolet radiation in the wavelength range from 290 to 320 nm (UV-B range).
Numerous studies in recent years have shown that ultraviolet radiation in the wavelength range from 320 to 400 nm (UV-A range) makes a significant contribution to the skin damage caused by sunlight. Therefore an increasing requirement for adequate protection against UVA radiation exists. In addition, the availability of sun protection preparations having a high sun protection factor (hereinafter also referred to as SPF) has led to concerns that users are able to stay in the sun for longer and, as a result, are exposed to an increased amount of UVA radiation.
A UV filter should ideally convert absorbed UV radiation quickly and efficiently into harmless thermal energy without degradation of its protective action and any negative effects in the sunscreen preparations.
Although there is a large choice of suitable UVB filters good UVA absorbers are rare
because they are mostly of low activity or of inadequate photostability. In particular, di-
benzoylmethane derivatives, for example 4-tert-butyl-4'-methoxydibenzoylmethane, the most
common UVA filter, which is availabel under the trade name Parsol 1789 are degraded
relatively quickly under the action of sunlight and, as a result, lose their protective action (R.
M. Sayre et al., Allured's Cosmetics & Toiletries, 114 (5) : 85-91, 1999). In addition, it is known that the photostable UVB filters cinnamic acid esters, such as octyl methoxycinnamate which is available under the tradename Parsol MCX are frequently used in combination with dibenzoylmethane derivatives. They may, however, form cycloaddition products with the dibenzoylmethane derivative in a photoreaction processand consequently become destabilised.
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As a result the photostability of the combination of these UV filters is decreased significantly.
Surprisingly it was found that specific benzotirazole derivatives may enhance the photostability of UV absorber systems comprising further organic UV absorbers like cinnamic acid esters or dibenzolymethan derivatives or combinations thereof.
Therefore, the present invention relates to the use of benzotriazole derivatives of formula
R1 is C1-C30alkyl; C1-C5alkoxy; C1-C5alkoxycarbonyl; C5-C7cycloalkyl; C6-C10aryl;
C6-C10aryl-C1-C5alkyl; -SO3M; or a radical of formula (1a)
R3 is hydrogen; C1-C5alkyl; C1-C5alkoxy; halogen, preferably Cl; or hydroxy;
R4 and R5 are each indepen...