title: Photosensitizing activity of the anti-bacterial drugs sulfamethoxazole and trimethoprim.
abstract: The photochemical reactions in vitro of sulfamethoxazole alone and in combination with trimethoprim were studied to obtain information on the photosensitization mechanism. Sulfamethoxazole in aqueous solution, on exposure to UVB radiation, generates free radicals and singlet oxygen, with the neutral molecule being at least twice as active as the sulfamethoxazole anion. Photoexcited sulfamethoxazole can participate in electron transfer to cytochrome-c and nitro blue tetrazolium, and sensitizes the peroxidation of linoleic acid and the hemolysis of human erythrocytes, predominantly by a free radical mechanism. Trimethoprim is relatively inactive in the same photochemical systems.
authors.affiliation: Department of Pharmacy, University of Sydney, N.S.W., Australia.
authors.forename: W
authors.initials: W
authors.lastname: Zhou
authors.forename: D E
authors.initials: DE
authors.lastname: Moore
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D004579:Electron Transport; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D005609:Free Radicals; D006461:Hemolysis; D006801:Humans; D015227:Lipid Peroxidation; D015394:Molecular Structure; D010100:Oxygen; D017319:Photosensitizing Agents / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D013056:Spectrophotometry, Ultraviolet; D013420:Sulfamethoxazole / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D014295:Trimethoprim / Q000737:chemistry / Q000494:pharmacology*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D005609:Free Radicals; D017319:Photosensitizing Agents; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D014295:Trimethoprim; D013420:Sulfamethoxazole; D010100:Oxygen