Disposition kinetics of difloxacin in rabbit after intravenous and intramuscular injection of Dicural

Abstract

This study investigated the pharmacokinetic behaviour of difloxacin following a single intravenous (i.v.) bolus and intramuscular (i.m.) administration of 5 mg/kg body weight (bw) to rabbits (n = 6). Plasma concentrations were determined in triplicate by agar plate diffusion using E. coli (ATCC 25922) as the test organism. Difloxacin was assayed in plasma to determine its concentrations, kinetic behaviour and systemic availability. Plasma concentration-time data generated in the present study were analysed by non-compartmental methods based on statistical moment theory. Difloxacin was rapidly distributed to the tissues with a steady-state volume of distribution (Vdss) of 1.51 L/kg and the total body clearance (Cltot) was 0.59 L/kg/h. The elimination half-lives after i.v. and i.m. administration were 3.25 h and 3.82 h, respectively. After i.m. administration, difloxacin was rapidly absorbed, with mean peak plasma concentration (Cmax of 3.85 microg/ml achieved at 1.61 h (Tmax) post administration. The extent of plasma protein binding of difloxacin in rabbits was 21.45% and the systemic bioavailability was 95.29%.