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 concentration by reverse-phase high performance liquid chromatography. Following intravenous administration the mean serum cefepime level of 44.93 ± 5.47 µg/mL was observed at 0.033 h (2 minutes). The therapeutically effective concentration of cefepime (≥ 1.00 mg/mL) was maintained in serum up to 12 h. The distribution half-life (t1/2α) and elimination half-life (t1/2β) were 0.09 ± 0.01 h and 3.70 ± 0.16 h, respectively. 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 µg h/mL and 190.3 ± 19.9 µg 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 interval.