Birnessite: A New‐Generation and Cost Effective Ion Exchange Material for Separation of Clinical‐Grade 90Y from 90Sr/90Y Mixture

Abstract

AbstractThe widespread clinical utilization of 90Y for preparation of target specific radiopharmaceuticals stipulates design of superior advanced materials for facile and cost effective separation of 90Y. We demonstrate for the first time potential of birnessite type phylomanganates for radiochemical separation of clinical grade 90Y from 90Sr/90Y mixture. Sodium birnessite was synthesized by controlled oxidation of MnCl2.4H2O in presence of excess of NaOH and characterized thoroughly for structure, microstructure and purity. Ion exchange experiments in the presence of 90Sr/90Y equilibrium mixture confirmed the exceptionally high selectivity of synthetic sodium birnessite for exchanging Sr2+ ions and the conditions have been optimized to achieve radiochemically pure 90Y (> 80% separation yield) meeting all the pharmaceutical requirements for its clinical use. Radionuclidic purity of 90Y could be achieved to < 1 × 10−4 % of 90Sr which is well below the limit set internationally (2 × 10−3 %). The separated 90Y has been used to prepare 90Y radiolabeled 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid coupled dimeric cyclic RGD peptide derivative [DOTA−E[c(RGDfK)]2] and the biological efficacy of the radiotracer was established in C57/BL6 mice bearing melanoma tumors. The results indicated highly target specific radiotherapy suggesting the potential of sodium birnessite for cost effective radiochemical separation of 90Y.