UV-dependent quinolone-induced human erythrocyte membrane lipid peroxidation: studies on the phototoxicity of Y-26611, a new quinolone derivative.

Quinolone antibacterial drugs are widely used as oral therapeutic agents. However, in some patients they cause ultraviolet (UV)-dependent dermatitis. Using lipid peroxidation as an index of phototoxicity, we studied the effects of a new quinolone derivative, Y-26611 together with ofloxacin, sparofloxicin and lomefloxacin on washed human erythrocyte suspensions. Irradiation of erythrocytes with UV-A or UV-B for 60 min. in the presence of Y-26611 (30-600 micrograms/ml) strong dose dependent lipid peroxidation, up to 17.01 nmoles/ml was induced. Under identical conditions, lipid peroxidation induced by up to 600 micrograms/ml ofloxacin, sparofloxacin or lomefloxacin were 0.94, 3.36 and 2.98 nmoles/ml respectively. The lipid peroxidation was entirely dependent on both UV as well as the drug. The lipid peroxidation responses to drug+UV could completely be inhibited by sodium azide (hydroxyl radical, HO. and single oxygen, 1O2 scavenger) or by phenyl N-tert-butylnitrone (PBN, HO. and superoxide anion radical, O2- scavenger). It is likely that reactive oxygen species generated by interaction between UV-sensitized drug molecules and oxygen molecules mediate erythrocyte membrane lipid peroxidation. The method used in this study is rapid and convenient for screening drugs for UV-dependent cytotoxicity.