Comparative pharmacokinetic profiles of two norfloxacin formulations after oral administration in rabbits.

The pharmacokinetics and tissue distribution of two norfloxacin (NFLX) formulations, norfloxacin-glycine acetate (NFLXGA) and norfloxacin nicotinate (NFLXN), were compared after single oral administration with a dose of 5 mg equivalent NFLX base/kg of body weight in twenty rabbits. The pharmacokinetic characteristics of all formulations were fitted by a two-compartment open model. The elimination half-life (T1/2beta) of NFLX (3.37+/-1.37 hr) was not significant as compared with those of NFLXN (3.61+/-0.65 hr) and NFLXGA (3.93+/-1.54 hr). The absolute bioavailability (F) of NFLX, NFLXN and NFLXGA was calculated as 29%, 45% and 40%. In addition, tissue distribution of NFLXN and NFLXGA did not show any differences of NFLX concentrations in liver, kidney, serum and muscle. From the present results, it could be suggested that NFLXN and NFLXGA are considered to be bioequivalent when they use oral medication for rabbits.