Disposition kinetics, Bioavailability and renal clearance of cefepime in calves

The pharmacokinetics of cefepime were studied following intravenous and intramuscular administration of 6.5 mg/kg in four female Friesian calves. Following single intravenous administration, the serum concentration-time curves of cefepime were best fitted using a two-compartment open model. The elimination half-life (t(1/2) beta) was 2.38 +/- 0.16 h, volume of distribution at steady state (V-dss) was 0.21 +/- 0.01 L/kg, and total body clearance (Cl-B) was 1.1 +/- 0.08 ml/min per kg. Following intramuscular administration, the drug was rapidly absorbed with an absorption half-life (t(1/2 ab)) of 0.29 +/- 0.02 h; maximum serum concentration (C-max) of 21.7 +/- 1.1 mug/ml was attained after (T-max) 1.1 +/- 0.08 h; and the drug was eliminated with an elimination half-life (t(1/2 el)) of 3.02 +/- 0.18 h. The systemic bioavailability (F) after intramuscular administration of cefepime in calves was 95.7% +/- 7.44%. The in vitro serum protein-binding tendency was 10.5-16.7%. Following administration by both routes, the drug was excreted in high concentrations in urine for 24 h post administration.