Astatine-211, a most promising α-particle emitter for targeted radiotherapy, is generally obtained by high-temperature distillation. However, a liquid–liquid extraction procedure (wet extraction) has also been described. The purpose of this study was to develop and optimize the labelling of the stannylated-activated ester N-hydroxysuccinimidyl-meta-trimethylstannylbenzoate ester (MeSTB) with astatine-211 extracted in di-isopropylether (DIPE) in the presence of the oxidant N-chlorosuccinimide (NCS). The effect of final volume, incubation duration and NCS amounts on radiolabelling yield was studied. The best yields (85–90%) of N-hydroxysuccinimidyl-meta-[211At]astatobenzoate ester (SAB) were obtained with 20 nmol of MeSTB, 100 nmol of NCS in 120 µL of DIPE after 15 min. The astatine-211-labelled-activated ester was then used to radiolabel a monoclonal antibody (mAb). The labelling yield was 20–25% and the radiochemical purity was 97–99%. These results show that mAbs may be efficiently labelled with astatine-211 obtained by wet extraction, a fully automatable technique that may prove to be a useful alternative to dry distillation for high activity labelling of radiopharmaceuticals. Copyright © 2008 John Wiley & Sons, Ltd.
Astatine-211是一种非常有前景的α粒子发射体,可用于靶向放射治疗,通常通过高温蒸馏获得。不过,也有文献描述了液-液萃取程序(湿法萃取)。本研究的目的是开发并优化N-羟基琥珀
酰亚胺基-间
三甲基锡苯甲酸酯(MeSTB)的标记,在氧化剂N-
氯代琥珀
酰亚胺(
NCS)的作用下,用二
异丙醚(DIPE)萃取astatine-211。研究了最终体积、孵育时间和
NCS量对放射性标记产率的影响。在120微升二
异丙醚中,用20毫摩尔MeSTB、100毫摩尔
NCS,经过15分钟,获得了N-羟基琥珀
酰亚胺基-间[211At]astatobenzoate酯(
SAB)的最佳产率(85-90%)。然后,用astatine-211标记的活性酯对单克隆
抗体(mAb)进行放射性标记。标记产率为20-25%,放射
化学纯度为97-99%。这些结果表明,mAbs可以用湿法萃取获得的astatine-211进行有效标记,这种全自动技术可能证明是干馏法的一种有用替代