Patent ID: 7144570

Claim:
A method of reducing or preventing harmful effects of solar radiation on skin comprising, applying a composition, the composition comprising: one or more agents that provide a UV-B filter; and, an effective amount of a compound of formula I: wherein R 1 and R 2 are, independently, hydrogen, an alkyl group, or, taken together, NR 1 R 2 comprise a heterocyclic ring; R 3 and R 4 are, independently, selected from hydrogen and pi electron donating groups; R b and R c are, independently, hydrogen, hydroxy(lower)alkyl, (lower)alkanoyl(lower)alkyl, (lower)alkyl, (lower)alkoxycarbonyl(lower)alkyl, (lower)alkenyl, carboxy(lower)alkyl, carboxy(lower)alkyloxyimino, alkoxycarbonyl, (C 6 or C 10 ) aryl, (C 5 or C 9 ) heteroaryl, wherein the heteroaryl group contains one oxygen, one sulfur or one nitrogen, or Ar(lower)alkyl; Y is S, O, or N—R′ where R′ is aryl, heteroaryl or lower alkyl; Z is N or C—R b ; and X- is a pharmaceutically acceptable anion; wherein the compound of the formula I is not a 3-[2-(4-diethylaminophenyl)-2-oxoethy]thiazolium salt.