Pharmacokinetic Parameters of Ceftiofur Crystalline Free Acid in Non-Lactating Domestic Goats
The objective of this study was to describe the pharmacokinetics of ceftiofur crystalline free acid (CCFA) in the domestic goat (Capra aegagrus hircus) using the labelled cattle dosage of 6.6 mg/kg of CCFA after a single subcutaneous injection.
Six non-lactating yearling female goats were used in the study. The goat breeds included Saanen (n=4) and Toggenburg (n=2) and their body weights ranged from 66 to 78 kg. CCFA (Excede, Pfizer, New York, NY) containing 200 mg of ceftiofur/ml in a sterile oil suspension, was administered once subcutaneously in the skin fold behind the elbow at a dosage of 6.6 mg/kg. Blood was drawn from the jugular vein at 0, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, 72, 96, 120,144, 168, 192, 240 and 288 hours after CCFA administration. The blood was allowed to clot and serum was frozen at -80°C until analysis. Concentrations of ceftiofur and its metabolites were measured using high-performance liquid chromatography. Data were analyzed using compartmental and non-compartmental approaches using a commercial software program (WinNonLin, Pharsight Corporation, Mountain View, CA, USA). Preliminary analysis suggests that the kinetics of CCFA in the domestic goat is best described by a one compartment model. Average (± SD) pharmacokinetic parameters were as follows: area under the concentration time curve (159 h*μg/ml ± 19), maximum concentration (2.3 μg/ml ± 1.1), time of maximal concentration (26.7 h ± 16.5) and terminal elimination half life (42.2 h ± 16).