^(125)I标记的[Tyr^3]-Octreotide在小鼠体内的分布及其药代动力学研究

The Labeling of [Tyr^3]-Octreotide with ^(125)I and Its Biodistribution and Pharmacokinetic

目的探讨125I Ch-T法标记生长抑素类似物奥曲肽的方法,观察其在小鼠体内的生物学分布。方法用Ch-T法进行[Tyr3]-octreotide的125I标记,标记完成后加入NH4HAc以防止标记物的再氧化。Sephadex G-10分离纯化,纸层析测定放化纯,并行小鼠体内分布和药代实验。结果125I-[Tyr3]-octreotide比活度为5.92 TBq/mmol,标记率为76%,放化纯为95%。注射后1.0 h血液中放射性下降了90%,肠道、肝脏和肾脏中均有浓集,标记物24 h内排出体外。结论125I的Ch-T法标记[Tyr3]-octreotide放化纯高,方法简便,标记物的稳定性尚可1。25I-[Tyr3]-octreotide在小鼠体内血液清除快,药代动力学符合二室开放模型,T12α为5.28 min,T12β为141.3 min,经肠-肝途径和泌尿系统排除。

Objective To investigate labeling method of [ Tyr^3 ]-octreotide with ^125I and the biodistribution of ^125 I-[ Tyr^3 ]-octreotide in mice. Methods [ Tyr^3 ]-octreotide was labeled with ^125I using the method of Chloramine-T at room temperature. NH4HAc added to inhibit re-oxidation of ^125I- [Tyr^3 ]-octreotide. The radio-chemical purity was tested with XINHUA 1 chromatography paper. Its biodistribution in normal mice was analyzed. Results The specific activity of the labeling product was 5.92TBq/mmol, The labeled yield was76 % , the radiochemical purity was 95 %. At 1. 0h after injection, radioactivity in blood decreased by 90%. Obvious accumulation of ^125I in the intestinal-liver and kidney was observed. A great amount of radioactivity was detected within 24h. The pharmacokinetic characteristics of ^125I-[Tyr^3 ]-octreotide conformed to a two compartment open model, T1/2α was 5.28 rain, T1/2β was 141.3 min. Conclusions The method is simple and easy to perform. The radiochemical purity is high. Labeling of ^125I- [ Tyr^3 ]-octreotide is stabile. Blood clearance of ^125I- [ Tyr^3 ]-octreotide in normal mice is quiet fast. It is excreted through gastrointestinal-liver and kidney tract.