125I-TOC和125I-F-PGA放射化学纯度的测定

为比较3种测定¹²⁵I标记的奥曲肽（TOC）和叶酸-青霉素酰化酶复合物（F-PGA）的放射化学纯度（RCP）的方法是否具有一致性，采用Iodogen法对TOC和F-PGA进行放射性碘标记，并用高效液相色谱法（HPLC）、三氯醋酸（TCA）沉淀法和纸层析法测定标记物的放射化学纯度（RCP），其中TCA沉淀法设4种蛋白浓度以观察其对RCP测定的影响。结果表明，HPLC和纸层析法均能有效分离标记物和游离碘，且HPLC测定这种标记物的RCP最为精确可信。在TCA沉淀法中，用0.2%的小牛血清白蛋白（BSA）测得的RCP最低,而用其它3个BSA浓度测得的RCP则无明显差异（P＞0.05）；当RCP＜10%时，TCA沉淀法与纸层析法测得的RCP间无明显差异（P＞0.05），而要高于HPLC（P＜0.01）；当RCP＞10%时，对¹²⁵I-TOC而言，TCA沉淀法要略低于HPLC和纸层析（P＜0.05），但后2种方法无明显差异（P＞0.05），且对¹²⁵I-F-PGA而言，3种方法无明显差异（P＞0.05）。3种方法两两之间显著相关（r=0.996～0.999，P＜0.001）。

Determination of Radiochemical Purity of 125 I-TOC and 125 I-F-PGA

To explore whether there is accordance among three determination methods of the radiochemical purity of \ octreotide(TOC) and folate-penicillin G amidase conjugate((F-PGA)),which are both labeled with ~(125)I by Iodogen method,the RCP of the labelings are (determined) by high performance liquid chromatography(HPLC),paper chromatography and trichloroacetic acid(TCA) precipitation,in which four different concentrations of proteins are used to investigate the effect of them on the determination of RCP.It is shown that both HPLC and paper chromatography can separate the labelings from free iodine efficiently,though HPLC is the most precise and reliable method to determinate RCP of such labelings.In TCA precipitation,the RCP measured with 0.2%BSA is the lowest,but those with three other concentrations of the BSA are similar(P>0.05).When RCP<10%,the RCP mea-(sured) with paper chromatography is not different from that with TCA precipitation((P>0.05)),whereas higher than that with HPLC(P<0.01).When RCP>10%,the RCP of ~(125)I-TOC obtained by TCA precipitation is a bit lower than those by two other methods((P<0.05)),but the latters are similar(P>(0.05)),and there are no significant differences to determinate the RCP of ~(125)I-F-PGA(P>(0.05)).The three methods are correlated each other(r=0.996-(0.999),P<0.001).