Studies On The Pharmacokinetics And Residue Determination Of Furazolidonum In Grass Carp (Ctenopharyngodon Idellus)

A series of experiments were carried out for studies on pharmacokinetics and residues determination of furazolidonum .At first, in vitro, inhibitory efficacies of furazolidonum were tested on three strains pathogenic bacteria from grass carp (Ctenopharyngodon idellus) : 8X78-3-3 , 58-20-9 , 56-12-10. The minimum inhibitory concentration to the three strains was 8 g /ml, 128 g /ml, 128 g /ml respectively.Secondly, a sensitive, simple and accurate high performance liquid chromatograph (HPLC) method for the analysis of the concentration of furazolidonum in the grass carp in vivo had been set up. The average relative recoveries of furazolidonum in the plasma , muscle, liver and kidney were 89.2%, 85.7%, 70.9%, 72.1%, respectively. The within-a-day and interday cofficient of variations of the analytical method were (5.87 3.12)%, (6.12 4.18)% respectively,so the method can meet for the pharmacokinetics study.The limit of detection(LOD) which is calculated as two times the signal to noise ratio is 0.002 g /g, which can meet for the residue determination.Thirdly ,under 25 0.5 ,pharmacocinetics and residues of orally administered at single and multiple dose of furazolidonum (60mg/kg) were investigated in grass crap, concentration of furazolidonum in Tissues(plasma, muscle, liver, kidney) were measured using HPLC and processed with MILLEMNIUM32 work station. The plasma concentration-time data was analyzed with MCPKP practical pharmacokinetics software.The results showed that: 1) The plasma profiles of furazolidonum in grass carp were best described by a two-compartment open model with the first order absorption following single dosing administration . The main parameters in the blood of grass carp were: AUC 3.7569 g /ml, Cmax 0.5176 g /ml, T1/2 1.5249h, T1/2 22.8632h, Tpeak 2.2296h, K10 1.0158h-1,K12 0.1249h-1,K21 0.0654h-1. At seventy-two hours after administration ,the residues of furazolidonum in plasma and muscle can not be detected. 2) At multiple dosing administration , the Concentration-Time curve of furazolidonum in grass carp blood was in accordance with one-compartment open model with first order absorption . The main parameters were: AUC 2.3182 g.h/ml, Cmax 0.850 g /ml, Ka 0.5515h-1, K 0.0936 h-1, T1/2ka1.2565h, T1/2k 7.4308h, Tp 2.8732h. The depletion of furazolidonum from plasma .muscle, Liver and kidney took 3d, 15d, 20d, 20d, respectively .In conclusion , furazolidonum showed low efficiency in prohibition at the pathogenic bacteria from grass carp and long depletion time, which provided theoretical support for the ban of furazolidonum in aquaculture .