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

Objective(s):In this study, 166Ho-1,2-propylene di-amino tetra(methy1enephosphonicAcid) (166Ho-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 166HoCl3. Ho-166 chloride was obtained by thermal neutron irradiation (1 × 1013 n.cm-2.s-1) of natural Ho(NO3)3 samples  followed by radiolabeling and stability studies. Biodistribution in wild type rats was also peformed. Results: The complex was prepared with thespecific activity of 278 GBq/mg and high radiochemical purity (>99%, checked by ITLC). 166Ho-PDTMP complex was stabilized in the final preparation and in the presence of human serum (>90%) up to 72 hr. The biodistribution of 166Ho-PDTMP in wild-type rats demonstrated significant bone uptake was up to 48 hr compared to 166HoCl3. Conclusion: The produced 166Ho-PDTMP properties suggest a possible new bone palliative therapeutic to overcome the metastatic bone pains.