title: Photosensitization by drugs.
abstract: UV irradiation (365 nm) of air-saturated methanol solutions of 20 drugs absorbing in the 300--400 nm region gave rise to oxygen uptake, as determined with a polarographic oxygen electrode. The drugs were tested for photosensitizing capability by either a Type I (free radical) or a Type II (single molecular oxygen) mechanism. This testing was done by the inclusion of either acrylamide or 2,5-dimethylfuran in the irradiated drug solution, with observation of the subsequent polymerization or oxidation, respectively. Phenothiazine and thiazide derivatives appear capable of photosensitization by both mechanisms; promethazine, trifluoperazine, and furosemide show relatively high reactivity. Diazepam (weak), hexachlorophene, aminacrine, pyrilamine, tetracycline, demeclocycline, quinine, and anthracene (strong) react only by a Type II mechanism, with a photosensitizing efficiency increasing in the order given. A correlation appears to exist with reports of in vivo photosensitivity.
mesh_terms: D000178:Acrylamides / Q000528:radiation effects; D001581:Benzothiadiazines; D002626:Chemistry, Pharmaceutical; D004232:Diuretics; D005663:Furans / Q000528:radiation effects; D010084:Oxidation-Reduction; D004364:Pharmaceutical Preparations / Q000528:radiation effects*; D010640:Phenothiazines / Q000528:radiation effects; D010777:Photochemistry; D010787:Photosensitivity Disorders / Q000139:chemically induced*; D011108:Polymers / Q000528:radiation effects; D049993:Sodium Chloride Symporter Inhibitors / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D000178:Acrylamides; D001581:Benzothiadiazines; D004232:Diuretics; D005663:Furans; D004364:Pharmaceutical Preparations; D010640:Phenothiazines; D011108:Polymers; D049993:Sodium Chloride Symporter Inhibitors