Sulphonic acids and their use as UV absorbers

Details Sulphonic acids and their use as UV absorbers Sulphonic acids and their use as UV absorbers

1998-04-16

2000-03-28

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, 514213, A61K 744, A61K 742, A61K 700, A61K 3155

Patent

active

060428147

DESCRIPTION:

BRIEF SUMMARY
The invention relates to new sulphonic acids, a process for their preparation and the use as UV absorbers, in particular in sunscreen compositions.
UV rays are designated, according to wavelength, as UV-A rays (320-400 nm, UV-A-I: 340-400 nm, UV-A-II; 320-340 nm) or UV-B rays (280-320 nm). The following applies very generally: the damaging action of the UV rays on the human skin increases with decreasing wavelength and increasing time of exposure.
UV rays can thus cause skin damage, it being possible for UV-B radiation to cause sunburn (erythema) up to very severe skin burns. Very frequent and unprotected irradiation of the skin with sunlight also leads to a loss of the elasticity of the skin and to increased wrinkle formation, and as a whole to premature ageing of the skin. In extreme cases, pathological skin changes as far as skin cancer can occur.
The UV-A radiation causes a rapid, weak direct pigmentation of the skin. UV-A rays penetrate into deeper layers of the skin and there can accelerate the skin-ageing process. The shorter wavelength UV-A-II radiation assists the formation of sunburn. Furthermore, the UV-A radiation can produce phototoxic or photoallergic skin reactions. Confirmed relationships between UV-A exposure and increased risk of skin cancer exist.
According to the position of their absorption maxima, UV absorbers for cosmetic and pharmacological preparations are divided into UV-A and UV-B absorbers.
For toxicological reasons, nowadays UV absorbers which are applied to the human skin should, if possible, not penetrate the skin.
All sorts of compounds, such as, for example, phenylbenzimidazolesulfonic acid (DE-OS [German Published Specification] 42 03 072), 2-hydroxy-4-methoxybenzo-phenone-5-sulphonic acid (EP-A 557 089) and terephthalylidene-dibornane-sulphonic acid (DE-OS [German Published Specification] 33 21 679) have already been proposed as UV absorbers. These compounds either do not absorb the desired wavelength or have only a small absorption or because of the necessary raw materials or the unproductive preparation processes are not as accessible as would be desirable.
The invention is therefore based on the object of making available improved UV absorbers.
The invention relates to compounds of the formula ##STR2## in which R.sup.1 to R.sup.5 (including R.sup.4', R.sup.4", R.sup.5', R.sup.5") independently of one another denote hydrogen, C.sub.1 -C.sub.8 -alkyl or C.sub.5 -C.sub.10 -cycloalkyl, with the proviso that two substituents on adjacent C atoms from the group consisting of .sup.1 C to .sup.4 C together can also together denote an optionally substituted polymethylene group, in particular C.sub.3 -C.sub.4 -alkylene, it being possible for a methylene group to be replaced by --O--, --S-- or --NH--, -cycloalkyl, hydroxyl, C.sub.1 -C.sub.8 -alkoxy, COOR.sup.60, CONR.sup.61 R.sup.62, C.sub.1 -C.sub.6 -alkyl, CONR.sup.10 R.sup.11, COR.sup.10 C.sub.1 -C.sub.8 -alkyl radical, a C.sub.5 -C.sub.10 -aryl radical, in particular phenyl, or a heteroaryl radical having 5 to 6 ring atoms (of these 1 to 2 hetero-atoms from the group consisting of N, O, S), for the completion of a 5 to 7-membered ring which can contain up to 3 heteroatoms, in particular oxygen and/or nitrogen, it being possible for the ring atoms to be substituted (in particular with exocyclically doubly bonded oxygen (keto oxygen) and/or C.sub.1 -C.sub.8 -alkyl and/or C.sub.5 -C.sub.10 -cycloalkyl radicals) and/or to contain C.dbd.C double bonds, sodium potassium, 1/2 equivalents of alkaline earth metal ion, preferably calcium, magnesium or the cation of an organic nitrogen base employed for the neutralization of the free acid group, particular C.sub.1 -C.sub.8 -alkyl or cycloalkyl, in particular having 5 to 10 ring atoms, and
The sulphonic acids according to the invention are particularly highly suitable for use in sunscreen compositions, preferably in cosmetic and pharmacological preparations. They are distinguished by very high absorption, excellent photostability and by a very low tendency for skin penetration.
Preferred

REFERENCES:
patent: 3637745 (1972-01-01), Heller
patent: 4250315 (1981-02-01), Poncioni
patent: 4654434 (1987-03-01), Lang et al.
patent: 4792609 (1988-12-01), Scholl et al.
patent: 5474762 (1995-12-01), Carr et al.
patent: 5595215 (1997-01-01), Wallace et al.

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