Pharmacokinetics and Dosage Regimen of Cefepime following Single Dose Intravenous Administration in Calves

Pharmacokinetics of cefepime was studied after single dose intravenous administration at the dose rate of 5 mg/kg body weight in calves. Blood samples were collected from the jugular vein at predetermined time intervals before and after drug administration. Serum was harvested and analysed for cefepime con-centration by reverse-phase high performance liquid chromatography. Following intravenous administra-tion, the mean serum cefepime level of 44.93  5.47 g/mL was observed at 0.033 h (2 minutes). The therapeutically effective concentration of cefepime (≥ 1.00 g/mL) was maintained in serum up to 12 h. The distribution half-life (t1/2) and elimination half-life (t1/2β) were 0.09  0.01 h and 3.70  0.16 h, respec-tively. The mean values of apparent volume of distribution [Vd(area)] and volume of distribution of drug at steady-state (Vd (ss)) were calculated to be 0.57  0.03 and 0.43  0.03 L/kg, respectively. The mean value of total body clearance (ClB) was 1.81  0.16 mL/min/kg. The average values for area under serum drug concentration-time curve (AUC) and area under first moment of curve (AUMC) were 47.73  4.05 g h/mL and 190.3  19.9 g h2/mL. The average value of mean residence time (MRT) was 3.95  0.11 h. A satisfactory intravenous dosage regimen would be 4.20 mg/kg body weight as priming dose followed by 3.78 mg/kg repeated at 12 h intervals.