Molecular Mechanism of Drug Photosensitization–ii. Photohemolysis Sensitized by Ketoprofen

Red blood cell lysis photosensitized by ketoprofen (KPF) was investigated. The photohemolysis 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-benzoylphenyl)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.