Pharmacokinetics and dosage regimen of ceftriaxone in E. coli lipopolysaccharide induced fever in buffalo calves.

The present study was planned to investigate the pharmacokinetics of ceftriaxone in experimentally induced febrile buffalo calves (n=5). The fever was induced by intravenous injection of E.coli lipopolysaccaride (1 microgram/kg). To study the pharmacokinetics, ceftriaxone was administered at the dose rate of 10 mg/kg body wt. in all animals. At 1 min, the peak concentration of ceftriaxone was 79.4+/-2.37 microgram/ml and the drug was detected up to 6 h. The elimination rate constant was 0.35+/-0.02 /h and elimination half-life was 2.04+/-0.14 h. The apparent volume of distribution (Vd(area)) and total body clearance (Cl(B)) were 1.21+/-0.15 l/kg and 0.41+/-0.03 l/kg/h, respectively. To maintain a minimum therapeutic concentration of 1 microgram/kg, a satisfactory dosage regimen of cefriaxone in febrile buffalo calves is 19 mg/kg followed by 18 mg/kg at 8 h intervals.