PHARMACOKINETICS AND PENETRATION INTO TISSUE-FLUID OF CEFOTAXIME IN BOVINES

Concentrations of cefotaxime in serum and tissue fluid were studied in the bovine after intravenous and intramuscular administration at a dosage of 10 mg . kg(-1) body weight. Steers implanted subcutaneously with tissue cages were used. After intravenous bolus administration, profiles of mean concentrations in serum over time were described by a two-compartment open model. The rate constant of elimination was 1.4 +/- 0.3 h(-1) and the half-life 0.6 +/- 0.1 h. The rate constant of distribution was 11.5 +/- 1.9 h(-1), and the half-life was 0.06 +/- 0.01 h. The volume of distribution at steady state was 250.6 +/- 37.3 ml . kg(-1). The area under the curve was 31.8 +/- 7.4 mu g . ml(-1) . h. The penetration ratio into tissue fluid was 36.5 +/- 15.4%. After intramuscular injection, the half-life was 1.1 +/- 0.3 h, the area under the curve was 27.5 +/- 6.8 mu g . ml(-1) . h, and the penetration ratio into tissue fluid was 47.1 +/- 15.8%. The concentrations in tissue fluid after intravenous and intramuscular administration of cefotaxime were elevated during a 6-hour period after administration.