Production, Quality Control and Biological Evaluation of (166)Ho-PDTMP as a Possible Bone Palliation Agent

Objective(s): In this study, (166)Ho-1,2-propylene di-amino tetra(methy1enephosphonicAcid) ((166)Ho-PDTMP) complex was prepared as a bone palliation agent. Materials and Methods: The complex was successfully prepared using an in-house synthesized EDTMP ligand and (166)HoCl(3). Ho-166 chloride was obtained by thermal neutron irradiation (1 × 1013 n.cm-2.s-1) of natural Ho(NO(3))(3) samples followed by radiolabeling and stability studies. Biodistribution in wild type rats was also peformed. Results: The complex was prepared with the specific activity of 278 GBq/mg and high radiochemical purity (>99%, checked by ITLC). (166)Ho-PDTMP complex was stabilized in the final preparation and in the presence of human serum (>90%) up to 72 hr. The biodistribution of (166)Ho-PDTMP in wild-type rats demonstrated significant bone uptake was up to 48 hr compared to (166)HoCl(3). Conclusion: The produced (166)Ho-PDTMP properties suggest a possible new bone palliative therapeutic to overcome the metastatic bone pains.