MOLECULAR MECHANISM OF DRUG PHOTOSENSITIZATION–II. PHOTOHEMOLYSIS SENSITIZED BY KETOPROFEN

Abstract
Red blood cell lysis photosensitized by ketoprofen (KPF) was investigated. The photohem-olysis was inhibited by butylated hydroxyanisole, reduced glutathione, superoxide dismutase and mannitol, and was unaffected by sodium azide; the presence of oxygen markedly enhanced the lysis. Photohemolysis was also observed under anaerobic conditions. Ketoprofen, irradiated in aqueous buffer solution at pH 7.4, underwent a decarboxylation process via intermediate radicals, leading to the compounds (3-benzoylphenyl)ethane, (3-benzoylphenyl)ethyl hydroperoxide, (3-benzoylphenyl)-ethanol and (3-benzoylphenyl)ethanone under aerobic conditions and only to the compound (3-benzpylphenyl)ethane under anaerobic conditions. The four photoproducts showed lytic activity, particularly high for the alcohol and hydroperoxide. The overall results suggest for KPF-photosensitized hemolysis a molecular mechanism involving free radicals, superoxide anion and sensitizer photodegradation products.