Production, quality control, and bio-distribution studies of 159Gd-EDTMP as a palliative agent for bone pain

INTRODUCTION Particle-emitting, bone-seeking radiopharmaceuticals have attracted the attention of the nuclear medicine community over the last three decades for the treatment of the pain of osteoblastic metastases. The objectives of this research were to produce quality-controlled (159)Gd-EDTMP in order to provide a new therapeutic radiopharmaceutical for use in clinical applications. METHODS The investigation was an experimental study in which (159)Gd (T1/2=18.479 h, Eβ (max)=970.60 keV, Eγ=363.55 (11.4%) keV] was produced by thermal neutron bombardment of natural Gd2O3 at the Tehran Research Reactor (TRR) for a period of 7 d at a flux of 3-4×10(13) neutrons/cm(2).s. It was then quality-controlled and used to radio-label the in-house prepared ethylene diamine tetra acetic acid (EDTM). RESULTS Complexation parameters were optimized to achieve maximum yields (>99%). The radiochemical purity of (159)Gd-EDTMP was checked by radio thin layer chromatography RTLC. It was found to retain its stability at room temperature (>95%). Bio-distribution studies of the complexes conducted in wild rats showed significant bone uptake with rapid clearance from blood. CONCLUSION The properties of the (159)Gd-EDTMP that was produced suggest then use of a new, efficient, palliative therapeutic agent for metastatic bone pain instead of some other current radiopharmaceuticals.