Comparative pharmacokinetics of orbifloxacin following a single intravenous or oral administration to healthy and diabetic rats

The single-dose disposition kinetics of orbifloxacin was determined in clinically healthy and diabetic rats after intravenous or oral administration of 5 mg/kg body weight. Orbifloxacin concentrations were determined by HPLC with fluorescence detection. The HPLC method was sensitive, specific and repeatable. A systemic bioavailability of 99.1% and 108 %, and a C_max of 6.55 ± 1.09μg /mL and 8.63 ± 1.09 μg/mL were observed in healthy and diabetic rats, respectively. The terminal half-life after intravenous and oral administration was 4.17 ± 0.38 h and 4.03 ± 0.41 h for healthy and 2.31 ± 0.34 h and 3.03 ± 0.28 h for diabetic rats. Orbifloxacin was cleared more rapidly in diabetic rats (0.15 ± 0.01 L/kg.h) than healthy group (0.11 ± 0.01 L/kg.h), with longer mean resident time (MRT) values observed in the latter. Other kinetic parameters were almost the same between the healthy and diabetic groups. This investigation revealed that a dose of 5 mg/kg orbifloxacin can be safely and effectively used to combat infections in rats of either group associated with susceptible bacteria.