Photohemolytic potency of oral antidiabetic drugs in vitro: effects of antioxidants and a nitrogen atmosphere.

The sulphonamide-derived oral antidiabetic drugs carbutamide, chlorpropamide, glibenclamide, glibornuride, gliclazide, glipizide, gliquidone, glisoxepide, glymidine, tolazamide and tolbutamide were investigated for photohemolytic properties in vitro. Irradiation with a SOL 3 apparatus (solar simulating irradiation) revealed hemolysis in the presence of chlorpropamide, glipizide, gliquidone, glymidine and tolbutamide (all in the concentration 10(-3) mol/l). Except for glymidine, which exerted photohemolysis in the concentration 10(-4) mol/l, no hemolytic effects were seen in the concentration of 10(-4) mol/l or 10(-5) mol/l. Irradiation with TL 12 light bulbs (UVB), a UVASUN 5000 apparatus (UVA) or an experimental lamp (visible light) did not induce phototoxic hemolysis with either of the test substances. Addition of the antioxidants ascorbic acid, alpha-tocopherol or superoxide dismutase significantly inhibited the phototoxic hemolysis. Investigations carried out in a nitrogen-rich atmosphere reduced the hemolysis as well. These findings indicate an involvement of reactive oxygen species in the mechanism of action of the hemolytic process in the presence of oral antidiabetic drugs.