Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Patent
1998-11-27
2000-02-08
Dodson, Shelley A.
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
424 60, 424400, 424401, 574937, 574938, A61K 742, A61K 744, A61K 700
Patent
active
060225300
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to cosmetic and dermatological light protection formulations, in particular skincare 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 region, 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 biochemical 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. ##STR2##
This UVB filter substance is marketed by BASF Aktiengesellschaft under the trade name UVINUL.degree. T 150 and is distinguished by good UV absorption properties.
The main disadvantage of this UVB filter is its 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.
UV absorbers or UV reflectors are most inorganic pigments, which are used in a known manner in cosmetics for protecting the skin against UV rays. Said inorganic pigments are oxides of titanium, zinc, iron, zirconium, silicon, manganese, aluminium and cerium and mixtures thereof, as well as modifications.
Inorganic pigments are notable per se for their good photoprotective effect. They do, however, have the disadvantage that it is difficult to incorporate them satisfactorily into such formulations. Only when the particles in the final formulation are very small are they not observed to produce a disturbing "whitening" (formation of white spots on the skin) following application to the skin. The particle sizes of such pigments are usually in the range below 100 nm. In a conventional emulsion the particles tend, to a greater or lesser extent, to combine to form agglomerates which are visible even under the light microscope. Moreover, such agglomeration does not end with the manufacturing process of a corresponding formulation, but continues during storage. The "whitening" can therefore inc
REFERENCES:
patent: 4454113 (1984-06-01), Hemker
Seifen, Ole, Fette, Wachse, Bd. 115, Nr. 18, pp. 661-662, K. Sperling: "UV filter . . . Formulierungen".
Database WPI, Week 9233, Derwent Publications Ltd., London, G.B., AN 92-272108, "Emulsified cosmetic . . . water", & JP 04 178 316 A (KAO), Jun. 25, 1992.
Dorschner Albrecht
Gers-Barlag Heinrich
Kropke Rainer
Muller Anja
Nissen Bente
Beiersdorf AG
Dodson Shelley A.
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