| Ethanamizuril(EZL),a novel anti-coccidiosis triazine compound,was synthesized by the Shanghai Veterinary Research Institute of the Chinese Academy of Agricultural Sciences,which is characterized by broad spectrum and low toxicity.And the early pharmacodynamic studies showed that it has high anticoccidial activity,which is expected to become a new anticoccidial drugs,used in aquaculture widely.EZL was metabolized to 6 metabolites after administration to chickens.The concentration of one of the metabolites(M3)was very high and it remained in the body especially in kidney for long time,while the concentration of the parent drug(EZL)was very high in other tissues.Therefore,it is considered that EZL and its main metabolite M3 as the residual marker to study its detection methods and residual elimination in chicken tissues,aiming at providing a reliable theoretical basis for the listing of new drugs and ensuring the safety of animal food.Analytes were extracted using acetonitrile and 10%sodium carbonate solution,defatted by n-hexane,further purified by using an Oasis MCX cartridge and detected by UPLC-UV.The method showed a linear relationship in the range of 10~2000μg/kg for EZL,in the range of 10~2000μg/kg for M3,and the determination coefficients(R~2)were greater than 0.99.The limit of detection of EZL in chicken muscle,skin+fat,liver was 3,3,10μg/kg respectively.The limit of quantitation of EZL in chicken muscle,skin+fat,liver was 10,20,50μg/kg respectively.The limit of detection of M3 in chicken muscle,skin+fat,liver,kidney was 25,25,50,50μg/kg respectively.The limit of quantitation of M3 in chicken muscle,skin+fat,liver,kidney was 50,100,250,250μg/kg respectively.The average recoveries were 87.3~103.2%at different spiked levels in each tissues.The intra-day precision was less than 9.1%,and the inter-day precision was less than 15.5%.The chickens were administrated EZL of 10mg/L by water for 3 consecutive days according to the clinical recommended dose.And 6 chickens were killed at 0.5h,4h,8h,12h,24h,72h,96h,120h,6d,7d,8d,10d and 14d after administration.The concentration of EZL and M3 were detected by the method previously established.Then the withdrawal period was calculated by the WT1.4.The results showed that there was the highest concentration of residue makers in kidney tissue,the comparative low concentration in liver and skin+fat tissues,and the lowest concentration of residue makers was found in muscle tissues.The residues of EZL and M3 were less than the limit of quantitation of each tissue at96h after stopping administration.No residue was detected on the 5th day.The withdrawal time of EZL was advised as 4 days in chicken. |
