Disposition kinetics and dosage regimen of cefepime in goats following single intravenous administration

The disposition kinetics of cefepime after a single intravenous administration of 10 mg.kg^-1 was investigated in goats and an appropriate dosage regimen was calculated. The blood samples were collected at different time intervals and the concentration of drug in plasma was estimated by microbiological assay technique. At 1 min after injection, the concentration of cefepime in the plasma was 60.6 ± 0.70 μg.ml^-1, which declined to 0.23 ± 0.01 μg.ml^-1 at 24 h. The plasma concentration time data of cefepime was best fitted to two-compartment open model. The cefepime was rapidly distributed from the blood to the tissue compartment as shown by the high values for the initial distribution rate constant (8.10 ± 0.24 h^-1) and the constant for the rate of transfer of drug from central to the peripheral compartment, K12 (5.20 ± 0.12 h^-1). The elimination half-life and volume of distribution were 3.00 ± 0.05 h and 0.52 ± 0.02 L.Kg^-1, respectively. The total body clearance (ClB) and the ratio of the drug present in the peripheral to that in the central compartment (T/P ratio) were 0.118 ± 0.01 L.Kg^-1.h^-1 and 2.53 ± 0.11, respectively. On the basis of the pharmacokinetic parameters obtained in the present study, an appropriate intravenous dosage regimen of cefepime in goats for most of the bacteria sensitive to it would be 8.46 mg.kg^-1 repeated at 12 h intervals.