SINGLE-DOSE KINETIC-STUDY OF SARAFLOXACIN AFTER INTRAVENOUS AND ORAL-ADMINISTRATION OF DIFFERENT FORMULATIONS TO ATLANTIC SALMON (SALMO-SALAR) HELD IN SEA-WATER AT 8.5-DEGREES-C

The pharmacokinetics of sarafloxacin hydrochloride (Sarafin(TM)) following intravenous and oral administration were determined in Atlantic salmon (Salmo salar) weighing 163+/-36g (mean+/-s.d.). The study was performed at 8.5+/-0.7 degrees C. A Cose of 10 mg sarafloxacin/kg body weight was administered intravenously to one group and orally to four groups of 28 fish each. Two of the oral groups were given drug formulations prepared as medical:ed feeds, the other two oral groups being given formulations prepared using corn oil or capelin oil as the drug vehicle. At four time points, from 6 h to 48 h after administration, blood was sampled from each of five fish per group. The plasma was assayed for sarafloxacin using an HPLC method. Following intravenous administration, the plasma concentration-time data of sarafloxacin were best described by a one-compartment open model. The volume of distribution V-d(area), and the total body clearance Cl-T, were 4.1 1/kg and 0.18 1/h.kg, respectively. The elimination half-life, t(1/2), was estimated to be 15.9 h. Following oral administration, the peak plasma concentration, C-max, ranged from 0.08 to 0.70 mu g/ml, and the time to reach C-max(T-max) from 6 to 24 h, depending on the formulation used. The bioavailability, F, ranged from 3.6 to 23.9%. There were no significant differences in observed plasma concentrations between fish in the two medicated feed groups, but highly significant differences between fish in the two oil groups. After oral administration, the group using corn oil as the drug vehicle showed the highest plasma concentrations.