An Improved Method for the Production of Ac‐225/Bi‐213 from Th‐229 for Targeted Alpha Therapy

This work describes an improved method for radium/actinium separation as part of a process for the production of Ac‐225 from a Th‐229 source for targeted alpha therapy of cancer. The separation method is based on the use of a newly developed extraction chromatographic resin containing the diglycolamide (DGA) class of molecules. The weight distribution ratios of Ac(III) on the extraction chromatographic resins N,N,N′N′ tetraoctyldiglycolamide (TODGA) and N,N,N′N′ tetrakis‐2‐ethylhexyldiglycolamide (TEHDGA) (both Eichrom Inc.) were determined at varying nitric and hydrochloric acid concentrations by batch experiments to optimize conditions for the separation of Ac(III) from Ra(II). Consequently, a robust and rapid procedure based on the use of TEHDGA resin was developed yielding a carrier‐free, clinical‐grade Ac‐225 with an overall yield exceeding 98%.