Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations – Aromatic acid or derivative containing
Patent
1999-01-25
2000-06-27
Dodson, Shelley A.
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
Aromatic acid or derivative containing
424 59, 424400, 424401, A61K 744, A61K 742, A61K 700
Patent
active
060803886
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to cosmetic and dermatological light protection formulations, in particular skin care cosmetic and dermatological light protection formulations.
The damaging effect of the ultraviolet part of solar radiation on the skin is generally known. While rays having a wavelength of less than 290 nm (the UVC region) are absorbed by the ozone layer in the Earth's atmosphere, rays in the region between 290 nm and 320 nm, the UVB range, cause erythema, simple sunburn or even burns of varying severity.
The narrower region around 308 nm is stated as the erythema activity maximum of sunlight.
Numerous compounds are known for protecting against UVB radiation; these are usually derivatives of 3-benzylidenecamphor, 4-aminobenzoic acid, cinnamic acid, salicylic acid, benzophenone and also 2-phenylbenzimidazole.
For the region between about 320 nm and about 400 nm, the UVA region, it is also important to have available filter substances, since the rays of that region can also cause damage. Thus, it has been found that UVA radiation leads to damage of the elastic and collagenic fibres of connective tissue, causing premature ageing of the skin, and that it is to be regarded as a cause of numerous phototoxic and photoallergic reactions. The damaging effect of UVB radiation can be intensified by UVA radiation.
However, UV radiation can also lead to photochemical reactions, in which case the photochemical reaction products intervene in the skin's metabolism.
Such photochemical reaction products are predominantly free-radical compounds, for example hydroxyl radicals. Undefined free-radical photo-products which are formed in the skin itself can also display uncontrolled secondary reactions because of their high reactivity. However, singlet oxygen, a non-radical excited state of the oxygen molecule, can also be formed during UV irradiation, as can short-lived epoxides and many others. Singlet oxygen, for example, differs from the normal triplet oxygen (free-radical ground state) by its increased reactivity. However, excited, reactive (free-radical) triplet states of the oxygen molecule also exist.
UV radiation is also a type of ionizing radiation. There is therefore the risk that UV exposure may also produce ionic species, which then, for their part, are capable of oxidative intervention in the bio-chemical processes.
An advantageous UVB filter is tris(2-ethylhexyl) 4,4',4"-(1,3,5-triazine-2,4,6-triyltriimino)trisbenzoate, synonym: 2,4,6-tris[anilino(p-carbo-2'-ethyl-1'-hexyloxy)]-1,3,5-triazine. ##STR1##
This UVB filter substance is marketed by BASF Aktiengesellschaft under the trade name UVINUL.RTM. T 150 and is distinguished by good UV absorption properties.
The main disadvantage of this UVB filter is poor solubility in lipids. Known solvents for this UVB filter can dissolve a maximum of about 15% by weight of this filter, corresponding to about 1-1.5% by weight of dissolved, and thus active, UV filter substance.
It was therefore surprising, and could not have been foreseen by the person skilled in the art, that light protection active ingredient combinations of tris(2-ethylhexyl) 4,4',4"-(1,3,5-triazine-2,4,6-triyltriimino)trisbenzoate and branched and/or unbranched alkanecarboxylic acids having chain lengths of from 10 to 24 carbon atoms, at least 10% of these alkanecarboxylic acids being in protonated form, overcome the disadvantages of the prior art.
The invention also relates in particular to the use of branched and/or unbranched alkanecarboxylic acids having chain lengths of from 10 to 24 carbon atoms, at least 10% of these alkanecarboxylic acids being in protonated form, as solvents, solubility promoters or solubilizers for tris(2-ethylhexyl) 4,4',4"-(1,3,5-triazine-2,4,6-triyltriimino)trisbenzoate, in particular for the use in light protection formulations.
A prerequisite for the suitability of the active ingredient combinations according to the invention for the purposes according to the invention is of course the cosmetic and dermatological acceptability of the base substances.
According to t
Gers-Barlag Heinrich
Kropke Rainer
Beiersdorf AG
Dodson Shelley A.
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