State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Zhivopisnaya Str., bld. 46, 123098 Moscow, Russia.
Molecules. 2021 Oct 21;26(21):6371. doi: 10.3390/molecules26216371.
Today, Sc is an attractive radionuclide for molecular imaging with PET. In this work, we evaluated a Ti/Sc radionuclide generator based on TEVA resin as a source of Sc. The generator prototype (5 MBq) exhibits high Ti retention and stable yield of Sc (91 ± 6 %) in 1 mL of eluate (20 bed volumes, eluent-0.1 M oxalic acid/0.2 M HCl) during one year of monitoring (more than 120 elutions). The breakthrough of Ti did not exceed 1.5 × 10% (average value was 6.5 × 10%). Post-processing of the eluate for further use in radiopharmaceutical synthesis was proposed. The post-processing procedure using a combination of Presep PolyChelate and TK221 resins made it possible to obtain Sc-radioconjugates with high labeling yield (≥95%) while using small precursor amounts (5 nmol). The proposed method takes no more than 15 min and provides ≥90% yield relative to the Sc activity eluted from the generator. The labeling efficiency was demonstrated on the example of [Sc]Sc-PSMA-617 and [Sc]Sc-PSMA-I&T synthesis. Some superiority of PSMA-I&T over PSMA-617 in terms of Sc labeling efficiency was demonstrated (likely due to presence of DOTAGA chelator in the precursor structure). It was also shown that microwave heating of the reaction mixture considerably shortened the reaction time and improved radiolabeling yield and reproducibility of [Sc]Sc-PSMA-617 and [Sc]Sc-PSMA-I&T synthesis.
今天，Sc 是用于 PET 分子成像的有吸引力的放射性核素。在这项工作中，我们评估了一种基于 TEVA 树脂的 Ti/Sc 放射性核素发生器，作为 Sc 的来源。在一年的监测期间（超过 120 次洗脱），该发生器原型（5 MBq）在 1 mL 洗脱液（20 床体积，洗脱液-0.1 M 草酸/0.2 M HCl）中表现出高钛保留率和稳定的 Sc 产率（91±6%）。Ti 的突破不超过 1.5×10%（平均值为 6.5×10%）。提出了对洗脱液进行后处理以进一步用于放射性药物合成的方法。使用 Presep PolyChelate 和 TK221 树脂的组合进行后处理程序，可以在使用少量前体（5 nmol）的情况下获得具有高标记产率（≥95%）的 Sc 放射性缀合物。该方法不超过 15 分钟，与从发生器洗脱的 Sc 活性相比，提供≥90%的产率。通过[Sc]Sc-PSMA-617 和[Sc]Sc-PSMA-I&T 合成的实例证明了标记效率。在 Sc 标记效率方面，PSMA-I&T 相对于 PSMA-617 具有一些优势（可能是由于前体结构中存在 DOTAGA 螯合剂）。还表明，反应混合物的微波加热大大缩短了反应时间，并提高了[Sc]Sc-PSMA-617 和[Sc]Sc-PSMA-I&T 合成的放射性标记产率和重现性。
