Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
1999-03-10
2004-11-09
Barts, Samuel (Department: 1623)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C424S059000, C424S060000
Reexamination Certificate
active
06815453
ABSTRACT:
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 so-called UVC range) are absorbed by the ozone layer in the earth's atmosphere, rays in the range between 290 nm and 320 nm, the so-called UVB range, cause erythema, simple sunburn or even burns of greater or lesser severity.
The narrower range around 308 nm is stated as the erythema activity maximum of sunlight.
Numerous compounds are known for protection against UVB radiation, these usually being derivatives of 3-benzylidinecamphor, of 4-aminobenzoic acid, of cinnamic acid, of salicylic acid, benzophenone and also of 2-phenylbenzimidazole.
For the range between about 320 nm and about 400 nm, the so-called UVA range, it is also important to have available filter substances, since the rays thereof can also cause damage. Thus, it has been proved that UVA radiation leads to damage to the elastic and collagenic fibres of connective tissue, which makes the skin age prematurely, 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, the photochemical reaction products then intervening in the skin metabolism.
Such photochemical reaction products are chiefly free-radical compounds, for example hydroxyl radicals. Undefined free-radical photoproducts which are formed in the skin itself can also show uncontrolled secondary reactions because of their high reactivity. However, singlet oxygen, a non-radical excited state of the oxygen molecule, may also occur under UV irradiation, as can short-lived epoxides and many others. Singlet oxygen, for example, is distinguished from the triplet oxygen normally present (free-radical ground state) by an increased reactivity. Nevertheless, excited, reactive (free-radical) triplet states of the oxygen molecule also exist.
UV radiation is furthermore counted among ionizing radiation. There is therefore the risk of ionic species also being formed during UV exposure, which then in turn are capable of intervening oxidatively in biochemical processes.
An advantageous UVB filter is 4,4′,4″-(1,3,5-triazine-2, 4,6-triyltriimino)-trisbenzoic acid tris(2-ethylhexyl ester), synonym: 2,4,6-tris-[anilino-(p-carbo-2′-ethyl-1′-hexyloxy)]-1,3,5-triazine.
This UVB filter substance is marketed by BASF Aktiengesellschaft under the trade name UVINUL® T 150, and is distinguished by good UV absorption properties.
The main disadvantage of this UVB filter is the 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 therefore active, UV filter substance.
It was surprising, however, and unforeseeable to the expert that active compound combinations, which have a light protection action, of 4,4′,4″-(1,3,5-triazine-2,4,6-triyltriimino)-trisbenzoic acid tris(2-ethylhexyl ester) and one or more emulsifiers chosen from the group of substances of the general structural formula
wherein R
1
, R
2
and R
3
independently of one another are chosen from the group which comprises: H and branched and unbranched, saturated and unsaturated fatty acid radicals having 8 to 24 carbon atoms, in which up to three aliphatic hydrogen atoms can be replaced by hydroxyl groups, and n is a number from 2 to 8, remedy the disadvantages of the prior art.
The invention also particularly relates to the use of one or more emulsifiers chosen from the group of substances of the general structural formula
wherein R
1
, R
2
and R
3
independently of one another are chosen from the group which comprises: H and branched and unbranched, saturated and unsaturated fatty acid radicals having 8 to 24 carbon atoms, in which up to three aliphatic hydrogen atoms can be replaced by hydroxyl groups, and n is a number from 2 to 8, as a solvent, solubilizing agent or solubilizer for 4,4′,4″-(1,3,5-triazine-2,4, 6-triyltriimino)-trisbenzoic acid tris(2-ethylhexyl ester), in particular for use in light protection compositions.
A prerequisite for the usability of the active compound combinations according to the invention for the purposes according to the invention is of course cosmetic or dermatological acceptability of the substances on which they are based.
It is possible, according to the invention, to increase the amounts of 4,4′,4″-(1,3,5-triazine-2,4,6-triyltriimino)-trisbenzoic acid tris(2-ethylhexyl ester) employed in cosmetic or dermatological formulations considerably with respect to the prior art.
It was furthermore astonishing that by addition of emulsifiers used according to the invention, chosen from the group of substances of the general structural formula
wherein R
1
, R
2
and R
3
independently of one another are chosen from the group which comprises: H and branched and unbranched, saturated and unsaturated fatty acid radicals having 8 to 24 carbon atoms, in which up to three aliphatic hydrogen atoms can be replaced by hydroxyl groups, and n is a number from 2 to 8, a stabilization of solutions of 4,4′,4″-(1,3,5-triazine-2,4,6-triyltriimino)-trisbenzoic acid tris(2-ethylhexyl ester) is effected, since the latter substance not only has a poor solubility but also readily crystallizes out again from its solution.
The invention therefore also relates to a process for stabilizing solutions of 4,4′,4″-(1,3,5-triazine-2,4,6-triyltriimino)-trisbenzoic acid tris (2-ethylhexyl ester), characterized in that an active content of emulsifiers used according to the invention is added to such solutions.
The emulsifier “polyglyceryl 2-polyhydroxy-stearate”, which is filed under registration numbers 156531-21-4 and 144470-58-6 in “Chemical Abstracts” and which is obtainable, for example, under the trade name DEHYMULS® PGPH from Henkel KGaA has proved to be especially advantageous.
Japanese laid-open specification JP-H i-04/178316 indeed describes cosmetic formulations having a content of emulsifiers which fall under the structural formula given under (b), but no indication of the present invention is given therein.
The total amount of 4,4′,4″-(1,3,5-triazine-2,4,6-triyltriimino)-trisbenzoic acid tris(2-ethylhexyl ester) in the finished cosmetic or dermatological formulations is advantageously chosen from the range of 0.1-10.0% by weight, preferably 0.5-6.0% by weight, based on the total weight of the formulations.
The total amount of one or more emulsifiers used according to the invention, chosen from the group of substances of the general structural formula
wherein R
1
, R
2
and R
3
independently of one another are chosen from the group which comprises: H and branched and unbranched, saturated and unsaturated fatty acid radicals having 8 to 24 carbon atoms, in which up to three aliphatic hydrogen atoms can be replaced by hydroxyl groups, and n is a number from 2 to 8, in the finished cosmetic or dermatological formulations is advantageously chosen from the range of 0.01-250.0% by weight, preferably 0.5-6.0% by weight, based on the total weight of the formulations.
It is advantageous to choose weight ratios of 4,4′,4″-(1,3,5-triazine-2,4,6-triyltriimino)-trisbenzoic acid tris(2-ethylhexyl ester) and one or more emulsifiers used according to the invention, chosen from the group of substances of the general structural formula
wher in R
1
, R
2
and R
3
independently of one another are chosen from the group which comprises: H and branched and unbranched, saturated and unsaturated fatty acid radicals having 8 to 24 carbon atoms, in which up to three aliphatic hydrogen atoms can be replaced by hydroxyl groups, and n is a number from 2 to 8, from the range from 1:10 to 10:1, preferably
Gers-Barlag Heinrich
Kröpke Rainer
Müller Anja
Barts Samuel
Beiersdorf AG
Norris McLaughlin & Marcus PA
Owens Howard V.
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