Facile radiochemical separation of clinical-grade Y from Sr by selective precipitation for targeted radionuclide therapy.

INTRODUCTION

The widespread clinical utilization of Y for preparation of target specific radiopharmaceuticals demands development of a facile, efficient and cost-effective method for radiochemical separation of Y from Sr viaSr/Y generator. In this article, we describe an efficient and facile method for radiochemical separation of Y from Sr for preparation of radiopharmaceuticals by exploiting the large difference in the solubility product constants (K) of Y(OH) and Sr(OH).

METHODS

A two-step radiochemical separation procedure based on selective precipitation of Y under alkaline conditions from Sr/Y equilibrium mixture was developed. The Y(OH) colloid formed at pH ~ 10 was selectively trapped in 0.22 μm sterile filter and was subsequently retrieved by dissolution in HCl solution. Detailed quality control analyses of obtained Y were carried out and its utility towards preparation of different radiopharmaceuticals was assessed.

RESULTS

Using the same feed solution of Sr (3.7 GBq), consistent and repeated separation of Y could be achieved in different batches with >85% yield and >99.999% radionuclidic purity. Yttrium-90 obtained from this process was found suitable for preparation of therapeutically relevant doses of three different radiopharmaceutical formulations, namely, Y-DOTA-TATE, Y-PSMA-617 and Y-CHX-A″-DTPA-Cetuximab with >95% radiochemical purity.

CONCLUSIONS

The promising results obtained in this study would facilitate implementation of the developed technique for obtaining Y in adequate quantity and of required purity from a centralized radiopharmacy setup.