Comparative pharmacokinetics and tissue distribution of quinocetone in crucian carp (Carassius auratus), common carp (Cyprinus carpio L.), and grass carp (Ctenopharyngodon idella) following the same experimental conditions.

The pharmacokinetics and tissue distribution of quinocetone (QCT) in crucian carp (Carassius auratus), common carp (Cyprinus carpio L.), and grass carp (Ctenopharyngodon idella) were compared after oral administration of QCT (50 mg/kg body weight) at water temperature of 24 ± 1 °C. Similar QCT plasma concentration-time profiles were found in the three species of cyprinid fish at the same dosage regimen and water temperature, which were all fitted two-compartment open pharmacokinetic model. However, different pharmacokinetic parameters were observed in crucian carp, common carp, and grass carp. The absorption rate constants (K(a)) of QCT were 1.65, 1.40 and 1.74/h, respectively and absorption half-lives (t(1/2kα)) were 0.42, 0.49, and 0.40/h, respectively. The distribution half-life (t(1/2α)) was 2.83, 0.67, and 0.88 h, respectively, and elimination half-lives (t(1/2β)) of QCT were 133.97, 63.55, and 40.76 h, respectively. The maximum concentrations (C(max)) of QCT in plasma were 0.315, 0.182, and 0.139 μg/mL and the time to peak concentrations (T(p)) were 1.45, 0.96, and 1.08 h, respectively. The area under the plasma concentration-time curves (AUC) were 12.35, 5.99, and 4.52 μg·h/mL, respectively. The distribution volumes (V(d)/F) of QCT were calculated as 117.81, 128.71, and 220.10 L/kg, respectively. The tissue analysis showed that a similar regularity was obtained in the three species of cyprinids with a single dose of 50 mg/kg body weight after oral administration at the same water temperature. The tissue concentration of QCT in each fish was in order of liver>kidney>muscle, while the residues of QCT in the three species of cyprinid fish were in order of crucian carp>common carp>grass carp.