The radio-europium impurities in [153Sm]-EDTMP production: a review of isolation methods

Many human cancers predominantly metastasize to the bone which causes bone pain and other symptoms. However, the management of bone metastases is challenging. Radionuclide therapy using low-energy beta-emitting radionuclides has yielded encouraging results. The aim of this therapy is to deliver the maximum dose to the metastatic sites but a minimal dose to the normal tissue. Samarium-153 [153Sm]Sm-Ethylenediamine tetramethylene phosphonate (EDTMP) is an FDA and European Medicine Agency approved (Quadramet) radionuclide and is widely used for bone pain palliation. 153Sm is reactor produced, and the presence of europium impurities is thus unavoidable. This in turn causes an increase in the hospital radioactive waste burden and in radiation absorbed doses to the patients, and therefore it is a concern. The effective removal of these impurities is thus highly desirable before its administration to the patients. In this article, we present a detailed review of the various methods described in the literature for separation of 153Sm and Eu, that is solvent extraction, ion-exchange chromatography, electrochromatography, electrochemical separation and supported ionic liquid phase.