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%.