大鼠颈静脉置管模型在咪达唑仑新制剂自身交叉实验药代动力学评价中的应用

Rat jugular vein catheterization model for the cross-over pharmacokinetic study of midazolam new formulation

目的建立和优化大鼠颈外静脉置管模型,应用大鼠双周期自身交叉实验,评价咪达唑仑自动注射针注射液与市售注射液的相对生物利用度及药代动力学特征。方法 SD大鼠6只,雌雄各半,麻醉后无菌条件下行颈静脉插管术,术后恢复1周用于咪达唑仑自动注射针制剂和市售注射液制剂双周期自身交叉实验。分别采用单剂量肌肉注射1.33 mg/kg的咪达唑仑自动注射针注射液及市售的咪达唑仑注射液对照制剂,交叉给药,间隔5 d,于给药后不同时间点从大鼠颈静脉插管中按时定量取血,血浆样品处理后,采用LC-MS/MS测定血浆中咪达唑仑原型的浓度,应用Win Nolin软件计算咪达唑仑的药动学参数及相对生物利用度。结果大鼠行颈静脉置管模型构建成功后,采血操作简单、对动物刺激小,满足药动学研究中少量、定时、连续取血的要求,解决了啮齿类动物在新制剂评价中应用自身交叉实验的操作瓶颈。咪达唑仑自动注射针制剂与市售注射液在大鼠体内的药代动力学参数无统计学差异,相对生物利用度为99%。结论大鼠颈静脉置管模型可作为应用自身交叉实验评价新制剂与参比制剂药动学特点的可推广模型。

Objective To establish and optimize the rat jugular vein catheterization model in our lab, and perform a cross-over study using this model to compare the pharmacokinetic characters of a newly developed midazolam formulation to the existing preparation. Methods Six SD rats （half male and half female） received the right jugular vein catheterization when the rats were sufficiently anesthetized. One week after the operation, all the rats were used to conduct a cross-over double period pharmacokinetic study. Totally1.33 mg/kg midazolam solutions from automatic needle and clinic available injection were adminisered to the jugular vein catheterization rats via im route. The washout period was 5 days. Exact volume of blood samples at designed time points were taken through the catheter. After preparation, the concentrations of midazolam in rat plasma were determined by using established LC-MS/MS method. The corresponding pharmacokinetic parameters were calculated by WinNolin software. Results The rat jugular vein catheterization model was successfully built. Blood was easily sampled and rats were well tolerated, meeting the requirement of repeated blooding. This model solved the bottleneck of cross-over study performed in rats. The pharmacokinetic behavior of newly developed midazolam formulation had no difference with that of clinic injections. The relative bioavailability was around 99%. Conclusion Rat jugular vein catheterization model is proved to be that of a propagating technique to do the cross-over study and to evaluate the pharmacokinetic characters of novel formulations.