盐酸多西环素片在羔羊体内残留消除规律及休药期分析

旨在确定盐酸多西环素片按照给药说明给药后在羔羊体内的残留消除规律及休药期。将盐酸多西环素片根据体重以5 mg·kg^-1内服给药，间隔24 h，连续给药5次。在最后1次给药后，分别在第0（12小时）、1、2、3、5、7和9天时间点采集羔羊脂肪、肌肉、肝和肾，采用建立并验证的HPLC-VWD方法测定组织中多西环素的含量。结果显示：方法学考察结果表明，在50~5 000 ng·mL^-1添加的线性方程和相关系数为y=0.044x-0.414，R²=0.999。试验结果表明，多西环素在羔羊组织中代谢快速，最后1次给药后第9天，在肌肉、肝、肾和脂肪中均未检测到多西环素。本试验以5 mg·kg^-1体重内服给予羔羊盐酸多西环素片后，根据欧洲药品评估机构法规《EMEA/CVMP/036/95》，建议盐酸多西环素片在羔羊组织中的休药期为2 d。

Residues Depletion and Withdrawal Period Study of Doxycycline Hydrochloride Tablets in Sheep

This study was conducted to determine the elimination of doxycycline hydrochloride tablets in lambs after administration according to the administration instructions and the withdrawal period. Doxycycline hydrochloride tablets were administered orally at 5 mg·kg^-1 of body weight, at an interval of 24 hours, for 5 consecutive doses. After the last administration, fat, muscle, liver and kidney were collected at 12 h, 1 d, 2 d, 3 d, 5 d, 7 d and 9 d respectively, and the content of doxycycline hydrochloride tablets in tissues was determined by HPLC-VWD. The linear range of doxycycline hydrochloride tablets in sheep fat, muscle, liver and kidney tissues is 50-5 000 ng·mL^-1. The linear equation and correlation coefficient are y=0.044x-0.414, R²=0.999. The results showed that doxycycline metabolism in lamb tissue was rapid. Nine days after the last administration, doxycycline was not detected in muscle, liver, kidney and fat. The lamb was given doxycycline hydrochloride tablets at 5 mg·kg^-1 body weight in this study. The withdrawal time was calculated according to the recommendations of the European Agency for the Evaluation of Medicinal Products (EMEA/CVMP/036/95) and was set at 2 days.