PHARMACOKINETICS OF OXYTETRACYCLINE IN RAINBOW-TROUT ONCORHYNCHUS-MYKISS FOLLOWING BOLUS INTRAVENOUS ADMINISTRATION

The present study examined the pharmacokinetics of oxytetracycline in rainbow trout Oncorhynchus mykiss. The pharmacokinetics of oxytetracyc line were determined after intravenous administration (50 mg/kg body w eight). Serum concentrations of oxytetracycline were determined using high performance liquid chromatography with direct injection. Serum le vels could be fitted to a two-compartment model. The calculated half-l ives for the distribution phase (T-1/2 alpha) and the elimination phas e (T-1/2 beta) were 0.5 and 52 h, respectively. The apparent volume of distribution (V-d beta) and total body clearance (Cl-B) were calculat ed to be 1.46 l/kg and 19.6 ml/kg/h, respectively. The area under the serum concentration-time curve was 2554 mu g . h/ml. Serum protein bin ding in vivo of oxytetracycline was 51.1 +/- 7.4%. As an application o f this pharmacokinetic study, the oral bioavailability and the dosage regimens of oxytetracycline in rainbow trout were briefly evaluated.