Light induced changes in quinolone levels in rat serum and tissues.

Circadian rhythm may induce alterations of the pharmacokinetic properties of several drugs in clinical use. The aim of the study was to investigate whether lighting conditions alter the quinolone (pefloxacin) levels in serum and tissues and to determine any accumulation of the drug in the skin. Thirty male Wistar rats were divided into groups A, B, C, (n=10). The animals of group A were housed under 12h light/12h dark conditions, group B under 24h UV and group C was kept in complete darkness. All animals received 5 doses of 11mg/Kg pefloxacin every 8h for 48h.Pefloxacin levels were determined in serum, skin and femur by the inhibition zone in E.coli. in vitro. Pefloxacin concentrations in serum were increased in 24h darkness living status and decreased in 24h UV conditions as compared to group A animals. Additionally, both skin and femur pefloxacin levels were decreased under dark and UV conditions. In conclusion total light as well as total dark exposure may lead to pefloxacin pharmacokinetic changes which may have implications in the effectiveness of the drug in tissues.