¹²⁵I标记-萃取法研究大鼠血浆中PEG-Dipeptide-TNF-α的药代动力学

目的: 建立提取大鼠血浆中总PEG的方法,并研究PEG-Dipeptide-TNF-α结合物的在大鼠体内药代动力学。 方法: 采用¹²⁵I同位素标记PEG-Dipeptide-TNF-α,利用有机溶剂氯仿萃取血浆中总PEG量,两相体系分光光度法进行验证,放射免疫γ计数器检测萃取物放射性计数,并用3P87药动学软件进行曲线拟合并计算参数。 结果: 血浆样品冷冻干燥后用氯仿提取,两相体系分光光度法检测结果为高、中、低3个浓度样品的相对回收率在100%附近,日内精密度RSD均小于3%,空白血浆中的内源性物质不干扰已知放射数的样品。3P87药动学软件计算的结果显示,TNF-α和PEG-Dipeptide-TNF-α半衰期(t_1/2)分别为0.31和21.22h,表明新型的PEG修饰技术可以延长的TNF-α半衰期。 结论: 本方法建立了血浆中总PEG的提取方法,专属性高,分离完全,操作简单,成本低廉,符合生物等效性指导原则关于生物样品分析方法的基本要求。

Objective: To develop a method for extracting all of PEG in rat plasma and to study the pharmacokinetics profile of PEG-Dipeptide-TNF-α conjugates in rat.Method:PEG-Dipeptide-TNF-α labeled by ¹²⁵I isotopes,extracting general PEG was extracted from plasma by chloroform and validated by the method of two-phase spectrophotometry,then detecting radioactive counting of the substances extracted from rat plasma by radio-immunity Gamma counter and counting parameters by curve fitting with 3P87 pharmacokinetics software. Results: The plasma samples were extracted by chloroform after freeze drying,and the results of two-phase spectrophotometry were that the relative recoveries of the three samples were about 100% and the RSD less than 3%,that is to say,the samples possessing known radioactive counting were not influenced by endogenous substances in blank plasma.The result of counting with 3P87 pharmacokinetics software showed that the half-time (t_1/2) of TNF-α and PEG-Dipeptide-TNF-α was 0.31h and 21.22h,respectively,and indicated that the new-type PEG modification technology can extend the half-time of TNF-α. Conclusion: The method of extracting all of PEG from plasma was established,that was not only excellent in specificity,separability and operability,but also cheaper and was consonant with bioequiavailability guideline on basic requirements analyzing biological sample.