Determination Of Quinocetone And In Scophthahuns Maximus Metabolism

Quinocetone(QTC), a new Broad-spectrum antimicrobial durg which is used as medicinal feed additive and antibacterial growth promoters for swine,cow,and chicken. According to some paper that Quinocetone can promote growth rate, improve the survive ratio and water quality, so it has been used more and more widely in aquaculture. This article was designed to study analyrtical methods for quinocetone and its main metabolites 3-methylquinoxaline-2-carboxylic acid (MQCA) in Scophthalmus maximus muscle,liver and blood, and develop investigation of pharmacokinetics and residues of quinocetone in Scophthalmus maximus and its safety. These results would provide safe approval information of quinocetone for fish use.The first part reports the metabolite and residues of QTC in Scophthalmus maximus muscle,blood,liver after oral administration 50mg/kg dose at18℃。The concentrations were analyzed by DAS2.0 counted the pharmacokinetic parameters. The results indicated that the concentration -time course of QTC in three tissues can be described by two-compartment model. The main pharmacokinetics parameters were as follows: absorption half-life(t1/2ka)0.535h,0.692h,0.566h; the distribution half-lif(et1/2α)1.127h,1.214h,0.703h; the elimination half-life(t1/2β)2.427h,4.218h,6.826h; Tmax 8h,6h,4h ;Cmax 40.880μg/g,47.014μg/g,18.127μg/g. Base on those dates, we can conclude that the QTC distributed few and the absorption was slow in three tissues. After a metabolism time of 36h, the concentrations of QTC in three tissuese were below the safety concentration.The second part reports the metabolite and residues of MQCA in Scophthalmus maximus muscle,blood,liver after oral administration QTC 50mg/kg dose at 18℃。The results indicated that the concentration -time course of QTC in muscle and liver can be described by two-compartment model, in blood can be described by one- compartment model. The main pharmacokinetics parameters were as follows: absorption half-lif(et1/2ka)0.876h,1.695h,1.372h; the distribution half-life(t1/2α)1.233h,2.275h,0.703h; the elimination half-life(t1/2β)4.587h,10.871h,2.633h; Tmax 1.5h,4h,3h ;Cmax18.25μg/g,23.817μg/g,8.936μg/g. Base on those dates, we can conclude that the MQCA distributed fast and the absorption few in three tissues. After a metabolism time of 48h, the concentrations of MQCA in three tissuese have can not be detected. So the MQCA in Scophthalmus maximus is more safetAy.