Radiation-induced in vitro phototoxic potential of some fluoroquinolones.

Research paper by R S RS Ray, N N Agrawal, R B RB Misra, M M Farooq, R K RK Hans

Indexed on: 04 Feb '06Published on: 04 Feb '06Published in: Drug and chemical toxicology


Photosensitizing drugs that can damage cellular biomolecules is a matter of concern. Lomefloxacin, norfloxacin, ofloxacin, and enoxacin (broad-spectrum antibiotics of fluoroquinolone group) are used for the treatment of Gram-positive and Gram-negative bacterial infections. Phototoxicity and possible mechanism of their action was assessed under the exposure of ambient levels of UV-A, UV-B, and sunlight at a concentration generally used in the treatment of various diseases. Singlet oxygen (1O2), superoxide anion radical (O2.-) generation, DNA damage, and lipid peroxidation in human blood were studied. All the fluoroquinolones tested in this study produced 1O2 and O2.- under exposure to UV-A, UV-B, and sunlight depending on the concentrations (0 to 60 microg/mL) of the drugs. Enoxacin showed a higher yield of 1O2 and O2.- than other drugs. These materials also degraded deoxyguanosine and induced lipid peroxidation in vitro under exposure to UV-A, UV-B, and sunlight (depending on the dose of radiation). The formation of the reactive oxygen species (ROS) by the photoexcited drugs may be considered as a possible mechanism of their action.