pharmacokinetics, dosage regimen and in vitro plasma protein binding of intramuscular levofloxacin in buffalo calves

the pharmacokinetics of levofloxacin following its single intramuscular administration (3 mg/kg) was investigated in six male buffalo calves. peak plasma level of 2.95 ± 0.13μg/ml was observed at 1 h and the drug level above mic90  in plasma was detected up to 12 h of administration. the bioavailability was 68.1 ± 5.4% and levofloxacin was bound to the plasma proteins to the extent of 19.1 ± 1.5%. high values of auc (8.81 ± 0.37μg.h/ml) and vdarea (1.06 ± 0.04 l/kg) reflected a vast area of body covered by drug concentration and appropriate penetration of levofloxacin into various body fluids and tissues. the elimination half-life and mean residence time were 3.27 ± 0.31 h and 5.4 ± 0.59 h, respectively. the total body clearance was 343.2 ± 14.1 ml/kg/h. an appropriate intramuscular dosage regimen for levofloxacin in buffalo calves would be 1.7 mg/kg repeated at 12-h intervals.