薄层色谱“一条”法检测~(99)Tc~m药物的放化纯度

临床注射99Tcm-MDP后,需等待2～3 h,至本底下降时才能进行骨显像。因怀疑系99Tcm-MDP的放化纯度偏低所致,于2002年试用上行薄层色谱"一条"法测定其放化纯度。该法的固定相为硅胶条,流动相为V(10%醋酸铵)∶V(甲醇)=1∶1,展开、干燥后进行放射性自显影。2008年用免洗胶片代替传统X光胶片进行自显影,检查99Tcm-MDP、99TcmO4-、99Tcm-EC、99Tcm-DTPA、99Tcm-MIBI和99Tcm-MAA6种药物"一条"法的分离效果,由自显影图像测得99Tcm-MDP的Rf为0.7,并定性估测其放化纯度高于2002年。2009年用同法测定99Tcm-DTPA、99Tcm-MIBI和99Tcm-MDP的放化纯度,前两种的自显影图像与2008年结果相同,其Rf分别为0.78±0.02和0.39±0.03。99Tcm-MDP的检测结果与2008年的相差较大,其Rf接近于零,这可能是由于99Tcm-MDP是一种具有锝锡胶体特性的复合物,其标记用药盒在贮存有效期(52周)内氯化亚锡含量下降而导致Rf的显著变化,该变化用两条法(一条测游离锝,另一条测锝锡胶体)难以测出。因此,建议生产厂家继续研究一种可用于测定多种锝药物的TLC,如将组分分离完全后,利用放射性曲线峰面积计算放化纯度或锝标记率,实现锝药物测定方法的规范化。

Experimental Study on"One-strip"Thin-layer Chromatography for Determining the Radiochemical Purity of 99Tcm Radiopharmaceuticals

The clinical skeletal imaging performed by injection of 99Tcm-MDP,has to wait for 2～3 h so as to reduce the background radiation,the low radiochemical purity of 99Tcm-MDP may be the major cause so that its radiochemical purity was assessed by so-called ＂one-strip method＂ in 2002,i.e.ascending thin-layer chromatography with one silica gel strip as the stationary phase and V（10% ammonium）∶V（acetate-methanol）=1∶1 as the mobile phase.After developing and drying this strip was tested by autoradiography.In 2008 99Tcm-MDP and the other five 99Tcm radiopharmaceuticals as 99TcmO4-,99Tcm-EC,99Tcm-DTPA,99Tcm-MIBI and 99Tcm-MAA were assessed by these methods as mentioned above,but the only difference was the self-developing film instead of traditional X ray film.The autoradiogram of 99Tcm-MDP was observed by naked eye and the results showed that the radiochemical purity of 99Tcm-MDP was higher than that in 2002,and the Rf values of 0.7 was assessed.Using these methods assessed 99Tcm-DTPA,99Tcm-MIBI and 99Tcm-MDP in 2009 respectively,the autoradiogram of former two drugs was as same as that in 2008,and the Rf average value was 0.78±0.02 and 0.39±0.03 separately.The Rf values of two 99Tcm-MDP samples were all closed to zero,which were rather different from those in 2008.It might be that 99Tcm-MDP was a composite compound of characteristics of 99Tcm-Sn colloid,in the storing effective time for 52 weeks,since the decrease of contents of stannous chloride in the box caused the significant change of Rf value,which could not be measured by two-strip method（one strip for free pertechtate,one strip for 99Tcm-Sn colloid）.It is suggested that the drug manufacturers should continue to study to find out the optimum TLC for testing the radiochemical purity of 99Tcm radiopharmaceuticals,after the components are separated completely,calculate the radiochemical purity or 99Tcm labeling efficiency by using these peak areas of the radioactive curve.The normalization of 99Tcm radiopharmaceuticals measuring method might be helpful for the further developing radiopharmacy.