Investigation on the influence of metal ion impurities on the complexation behavior of generator produced 90Y with different bifunctional chelators

Abstract

Abstract While the 90Sr/90Y generator is the exclusive source of obtaining `no carrier added' 90Y for targeted therapy, the presence of trace metals in the radiolabeling solutions poses a serious challenge owing to their ability to diminish the 90Y complexation yields with bifunctional chelators (BFCs). p-SCN-Bn-PCTA is a novel ligand having faster complexation kinetics with a number of radiometals. In this work, a systematic investigation was performed to evaluate the chelating ability of p-SCN-Bn-PCTA for 90Y and the influence of trace metal ions on it's complexation with 90Y in comparison to p-SCN-Bn-DTPA and p-SCN-Bn-DOTA using 90YCl3 obtained from an electrochemical generator. Results from our study indicate that while p-SCN-Bn-PCTA gave very good radiolabeling yields with 90Y when the reaction was carried out by heating for few minutes, it was most sensitive to the presence of trace metals, especially Fe(III). An independent and useful observation is that p-SCN-Bn-PCTA could be considered as the ligand of choice for assessing the chemical purity of generator derived 90Y.