Pharmacokinetics of Florfenicol after Oral Administration in Yellow Catfish, Pelteobagrus fulvidraco

The pharmacokinetics of florfenicol ( FF ) and its metabolite, florfenicol amine ( FFA ), were investigated after doses of 10 mg/kg/day were administered orally per os (p.o.) on a single day or on three consecutive days in yellow catfish, Pelteobagrus fulvidraco , raised in water temperatures of 25 C. After a single dose p.o. was administered, the apparent volume of distribution at steady state ( V dss ) of FF was computed to be 2.52 L/kg. The T max values were in the following order: liver (1.82 h) < kidney (2.26 h) < skin (6.15 h) < muscle (6.32 h) < plasma (7.25 h). These results show that FF and FFA accumulated rapidly in the kidney and liver. The t 1/2 β values in plasma, muscle, skin, liver, and kidney were 9.63, 15.75, 14.44, 11.55, and 15.75 h, respectively, for FF and 21.66, 15.07, 17.33, 26.65, and 30.13 h, respectively, for FFA . After a single p.o. dose was administered on three consecutive days, the t 1/2 β values of FF and FFA in skin‐on muscle were 17.12 and 13.55 h, respectively. The total concentrations of FF and FFA in skin‐on muscle 1, 3, and 5 d after the last administration were 3.39, 0.5, and 0.062 µg/g, respectively.