Comparative pharmacokinetics of enrofloxacin in healthy and Aeromonas hydrophila-infected crucian carp (Carassius auratus gibelio)

The comparative pharmacokinetics of enrofloxacin (ENR) and its metabolite ciprofloxacin (CIP) were investigated in healthy and Aeromonas hydrophila-infected crucian carp after a single oral (p.o.) administration at a dose of 10mg/kg at 25 degrees C. The plasma concentrations of ENR and of CIP were determined by HPLC. Pharmacokinetic parameters were calculated based on mean ENR concentrations by noncompartmental modeling. In healthy fish, the elimination half-life (T-1/2z), maximum plasma concentration (C-max), time to peak (T-max), and area under the concentration-time curve (AUC) values were 64.66h, 3.55g/mL, 0.5h, and 163.04g<bold>h</bold>/mL, respectively. In infected carp, by contrast, the corresponding values were 73.70h, 2.66g/mL, 0.75h, and 137.43g<bold>h</bold>/mL, and the absorption and elimination of ENR were slower following oral administration. Very low levels of CIP were detected, which indicates a low extent of deethylation of ENR in crucian carp.