| The pharmacokinetics and residue of toltrazuril in chickens were studied in this paper.Determination of toltrazuril in solution by HPLC. In this section, the content of toltrazuril in its solution with a HPLC method was studied. C18 column was used as the stationary phase and the mobile phase was acetonitrile and phosphate buffered saline (53:47), the flow rate of mobile phase was 1.0ml/min, the detection wavelength was 240nm.The linear ranges of toltrazuril was 0.5-30 μg/mL. The RSD of intra-day and inter-day were 2.23% and 3.46%. This method could be used for the quality control..The content of toltrazuril solution was at the 98.6 percent of the signed content(2.5%), The result accorded with the regulation of veterinary drug criterion.Pharmacokinetics studies of toltrazuril in chickens. Avine broiler chickens followed single oral administration at the dosages of 4, 8, 24mg/kg ? bw of the 2.5% toltrazuril solution .Blood samples were collected at different intervals and toltrazuril concentrations were detected by HPLC. The concentration-time data were calculated with 3P97 and fitted to a two-compartment open model. The main pharmacokinetic parameters were as follows respectively. 4 mg/kg-bw dosage, t1/2α 4.10±0.33 h, t1/2β 26.86±3.32 h, V/F 0.33±0.06 L/kg, CL(s) 0.04±0.01 L/h, AUC 92.75±15.33 μg ·h/M1. 8 mg/kg-bw dosage, t(1/2α) 4.31±0.85 h, t1/2β 23.81±2.81 h, V/F 0.39±0.09 L/kg, CL(s) 0.05±0.01 L/h, AUC 174.15±34.09 μ g ? h/mL. 24 mg/kg-bw dosage, t1/2α 6.05±0.28 h, t1/2β 25.19±3.99 h, V/F 0.52±0.08 L/kg, CL(s) 0.05±0.01 L/h, AUC 307.15±41.47 μg·h/mL. Baycox was administrated as a reference agent at the dosage of 8mg/kg ·bw. The main pharmacokinetic parameters were as follows. t—1/2α 4.23±1.38h, t1/2β 23.73±3.48h, V/F 0.36±0.08 L/kg, CL(s) 0.05±0.01 L/h, AUC 183.10±29.88 μg?h/mL. The results showed that there was a good linear relationship between pharmacokinetic parameters and doses at 424mg/kg. The main pharmacokinetic parameters were not significantly different between 0.25% toltrazuril solution and Baycox in health chickens at the dosage of 8mg/kg ? bw. Comapred with Baycox, the relative bioavailability of toltrazuirl solution was 95.11%.Pharmacokinetics of 2.5% toltrazuril solution and Baycox were investigated in E.tenella coccidia-infected Avine broiler chickens following single oral administration atthe dosage of 8mg/kg ? bw. The toltrazuril concentration-time data were fitted to a two-compartment open model after single oral dosing in E.tenella coccidia-infected chickens. The main pharmacokinetic parameters of 2.5% toltrazuril solution and Baycox were as follows respectively, t1/2α4.29±1.03 and 4.44±0.66h, t1/2β 23.76±3.31 and 26.58±4.08h, V/F 0.40±0.07 and 0.38±0.09 L/kg, CL(s) 0.05±0.01 and 0.05±0.01 L/h, AUC 165.14±23.71 and 173.27±28.58 μg ? h/mL. The results showed that the main pharmacokinetic parameters were not significantly effected by E.tenella coccidian infection at the dose of 8mg/kg ? bw.Studies on determination of toltrazuril and toltrazuril sulfone in chicken plasma by HPLC/MS. In this section, a HPLC/MS method for the detetmination of toltrazuril and toltrazuril sulfone in chicken plasma were established. Plasma samples were dealed with acetonitrile, C18 column was used as the stationary phase, the mobile phase was acetonitrile and water(55:45). MS conditions were electrospray ionization (ESI), MS/MS , anion analysis, and the quantitative ions were molecule ions peak. This method could analyse the change of toltrazuril and the metabolite accurately. The linear range was 1-500 ng/mL and the limit of detection was 0.5 ng/mL. This method was more sensitive than HPLC. It could be used in further research of these kinds of drugs.Studies on residues of toltrazuril in broiler chicken tissues. A HPLC method was reported for the quantitative determination of residues of toltrazuril in broiler chicken muscles, livers and kidneys. Recoveries of toltrazuril added to blank chicken tissues at levels of 20, 200, 2000 μg/kg were high... |
