title: Photochemical studies on the anti-inflammatory drug diclofenac.
abstract: Irradiation with UVA light of the anti-inflammatory drug diclofenac [2-(2,6-dichloroanilino)phenylacetic acid] in aqueous buffer or methanol solution leads to sequential loss of both chlorine substituents and ring closure to carbazole-1-acetic acid as the major product. Minor products result from substitution by the solvent. The photosensitizing properties of diclofenac and its major photoproduct were tested with singlet oxygen substrates and in the free radical polymerization of acrylamide. Although the major carbazole product is a weakly phototoxic agent, able to generate singlet oxygen more efficiently than diclofenac, the free radical photodechlorination process is postulated as the probable initiation step of in vivo photosensitivity responses.
authors.affiliation: Department of Pharmacy, University of Sydney, Australia.
authors.forename: D E
authors.initials: DE
authors.lastname: Moore
authors.forename: S
authors.initials: S
authors.lastname: Roberts-Thomson
authors.forename: D
authors.initials: D
authors.lastname: Zhen
authors.forename: C C
authors.initials: CC
authors.lastname: Duke
mesh_terms: D004008:Diclofenac / Q000737:chemistry* / Q000528:radiation effects; D010777:Photochemistry; D014466:Ultraviolet Rays
chemical_list: D004008:Diclofenac