Pharmacokinetics of oxolinic acid in gilthead sea bream, Sparus aurata L.

This is the first study on the pharmacokinetic parameters of oxolinic acid (OA) in gilthead sea bream, Sparus aurata L. The kinetic profile of OA was studied after a single intravascular injection (20 mg kg(-1) ) in 100 g fish at 20 degreesC. The distribution half-life (t (1/2alpha) ) and the elimination half-life (t (1/2beta) ) of the drug were found to be short (0.51 and 12.60 h, respectively). The drug penetration from the plasma to the tissues was adequate as the apparent volume of distribution of the drug at steady-state (V (d(ss)) ) was found to be 2.11 L kg(-1) . The mean residence time (MRT ) of OA was short (14.25 h) and the total clearance rate (Cl (T) ) of the drug was low (0.15 L kg(-1) h(-1) ). The bioavailability (F %) of OA following oral administration (30 mg kg(-1) ) was also low (14%). Maximum values were observed for muscle at 0.5 h after injection, with levels declining as with subsequent sampling. At the first two time points (0.5 and 1 h) plasma levels of OA were higher than muscle, however, the reverse was evident for subsequent samples. Following oral administration, highest muscle levels were found at 16 h and, with the exception of the 24-h sampling, muscle OA concentrations were higher than plasma at all time points. The fast elimination of OA suggests short withdrawal times with reference to human consumption of treated fish.