Facile radiochemical separation of clinical-grade 90Y from 90Sr by selective precipitation for targeted radionuclide therapy.

The widespread clinical utilization of 90Y for preparation of target specific radiopharmaceuticals demands development of a facile, efficient and cost-effective method for radiochemical separation of 90Y from 90Sr via90Sr/90Y generator. In this article, we describe an efficient and facile method for radiochemical separation of 90Y from 90Sr for preparation of radiopharmaceuticals by exploiting the large difference in the solubility product constants (Ksp) of Y(OH)3 and Sr(OH)2. A two-step radiochemical separation procedure based on selective precipitation of 90Y under alkaline conditions from 90Sr/90Y equilibrium mixture was developed. The 90Y(OH)3 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 90Y were carried out and its utility towards preparation of different radiopharmaceuticals was assessed. Using the same feed solution of 90Sr (3.7 GBq), consistent and repeated separation of 90Y 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, 90Y-DOTA-TATE, 90Y-PSMA-617 and 90Y-CHX-A″-DTPA-Cetuximab with >95% radiochemical purity. The promising results obtained in this study would facilitate implementation of the developed technique for obtaining 90Y in adequate quantity and of required purity from a centralized radiopharmacy setup.