Studies On Pharmacokinetics And Residues Of Mebendazole In Carassius Auratus

A high performance liquid chromatography (HPLC) method was developed for determination of Mebendazole(MBZ) in the plasma and muscle of Carassius auratus. Plasma samples were extracted with ethyl acetate and detected with UV. Muscle samples were extracted with ethyl acetate, purified with n-hexane and detected with UV. The recovery of MBZ ranged from 86.45%⁹0.71% in plasma and 87.54%⁹3.48% in muscle,respectively. The coefficient of variation of MBZ ranged from 5.78%⁸.57% in plasma and 4.88%⁵.97% in muscle,respectively. The limit of detection of MBZ was 0.01mg/L in plasma,and 0.005mg/kg in muscle. The limit of quantitation of MBZ was 0.05mg/L in plasma, and 0.01mg/kg in muscle.Total 95 fishes with body weight of 130g to 170g were used. 55 fishes were used in plasma pharmacokinetics study,and 40 fishes were used in muscle residue elimination study. The groups of plasma pharmacokinetics were administrated orally via stomach tube at a single dose of 10mg/kg body weight and the plasma were collected at different intervals after administration of MBZ. The groups of muscle residue elimination were administrated orally via stomach tube at a dosage of 10mg/kg body weight per day for 5 days and the muscle were collected at different intervals after administration of MBZ.The concentration of MBZ in plasma and muscle was determined by HPLC. The concentration-time date of MBZ in plasma and muscle were analysed with 3p97 soft. The concentration-time data of MBZ in plasma were fitted to an one-compartment open model with first-order absorption after single oral adminstration in Carassius auratus.The main pharmacokinetic parameters of MBZ in Carassius auratus were as follows:t_1/2(ka)16.202±1.256h,t_1/2(ke)18.582±2.551h,T_(peak)32.058±0.883h,Ka0.043±0.003h^-1,Ke0.038±0.005h^-1,C_(max)0.336±0.012mg/L,AUC22.902±2.270mg/L·h.The results showed that MBZ was slowly absorpted and narrowly distributed in fish at 18±2℃water temperature. The half-life and lag time were long, and the concentration of MBZ in plasma was low.The result of residue elimination showed that concentrations of MBZ in muscle were 0.696mg/kg on the 4th day, and fell to 0.042mg/kg on the 16th day. The concentrations of MBZ in muscle were fell below limit of detection on the 24th day at 18±2℃water temperature.