PHARMACOKINETICS AND ELIMINATION REGULARITY OF ROBENIDINE HYDROCHLORIDE RESIDUES IN ICTALURUS PUNCTATUS

To assess tissues distribution and elimination of robenidine hydrochloride in Ictalurus punctatus, single and 5-day continuous oral administration (20 mg/kg) of robenidine hydrochloride has been conducted in healthy Ictalurus punctatus at (28±1)℃. The concentration-time curve of robenidine hydrochloride in plasma was a two-compartment model for the single oral administration with the kinetic equation: C= 7.69e^–0.02t + 0.13e^–0.01t–7.82e^–0.27t. The T_(peak) and C_max in the plasma, muscle, skin, gill, liver and kidney of channel catfish were 10.03, 15.79, 11.10, 2.61, 12.89, 7.87 and 5.76 μg/mL, 2.91, 2.90, 3.05, 3.04 and 0.42 mg/kg, respectively. The elimination half-life and drug-time curve AUC were 58.63, 23.57, 35.37, 19.74, 29.34, 43.30h and 326.74 (μg/mL)/h, 157.58, 183.72, 95.09, 174.82, 29.85 (mg/kg)/h, respectively. For the 5-day continuous oral administration at 20 mg/kg, the highest and lowest concentration of robenidine hydrochloride was the intestines and the muscle, respectively. The elimination rate of robenidine hydrochloride in each tissue from fast to slow was plasma, gill, brain, muscle, skin, liver, kidney and intestines. If the maxi-mum residue limit (MRL) of robenidine hydrochloride in edible tissue is 10 μg/kg, the withdraw period should not be less than 23 days under this experimental condition.