Sm-EDTMP in Wild-Type Rodents

Introduction: Nowadays various bone pain palliative therapeutic agents have been developed for bone metastases. Among those, Sm-ethylenediamine tetramethylene phosphonic acid (Sm-EDTMP) is the major therapeutic agent which is widely used in the world. In this study, production, quality control and biodistribution studies of this therapeutic radiopharmaceutical have been presented and followed by imaging studies in a wildtype rabbit for the first time in order to make preparations for this agent to be officially approved in the country. Methods: Sm-EDTMP was produced using Sm-SmCl3, prepared by neutron activation of an enriched Sm sample (purity >98%), and in-house synthesized EDTMP in 4h at 100°C. The analytical data for the structure determination and purity of the ligand was obtained and shown to be identical to an authentic sample from a European vendor. The Radiochemical purity of Sm-EDTMP was checked by RTLC and ITLC. The biodistribution of Sm-EDTMP in wild-type rodents was checked and SPECT imaging as well as following sacrificing the animal. Results: The radiolabeled Sm complex was prepared in high radiochemical purity (>99%, RTLC) followed by initial biodistribution data with the significant bone accumulation (>70%) of the tracer in 48h which is comparable with the reported methods. Conclusion: The produced Sm-EDTMP properties suggest good potential for efficient use of this radiopharmaceutical for bone pain palliation and as substitute for other agents, such as SrCl2 and P, currently used in the country.