Production of 177Lu and formulation of Ethylene diamine tetramethylene phosphonate [EDTMP] kits as a bone-seeking radiopharmaceutical

ABSTRACT

Owing to its favourable decay characteristics 177Lu [T1/2= 6.71 d, Ebeta[max]= 497 keV] is an attractive radionuclide for various therapeutic applications. Ethylene diamine tatramethylene phosphonate [EDTMP] is one of the most widely used ligands which form stable complexes with various radionuclides and all the complexes. Enriched 176Lu2O3 was dissolved in 0.1 N HCl and evaporated several times and 176LuCl3 target was irradiated at 2.6x1013 n.Cm- 2.S-1 thermal neutron flux for 14 days.177LuCl3 was dissolved in 1N HCl. EDTMP was dissolved in double distilled water at pH=7.5-8.5 and freeze-dried kits was radiolabeled with 177LuCl3. Distribution studies were done in healthy mice. The yield of 177Lu was [220 TBq/g; 6000 Ci/g], the radionuclidic purity was 99%.The radiolabeling yield of EDTMP kits at 37°C after 30 min and 4 hours was 98 +/- 0.5% and after 72 hours was 90 +/- 2.1%, the in vitro stability in human serum at 37°C up to 72 hours post radiolabeling was 85 +/- 1.8%.The biodistribution studies of 177Lu-EDTMP and 177LuCl3 in normal mice showed skeleton uptake and low soft-tissue concentration. In this study, we produce 220 TBq/g [6000 Ci/g] of 177Lu by neutron activation of 176Lu in the Tehran Research Reactor. Our results showed 177Lu-EDTMP as a bone-seeking radiopharmaceutical. Due to its suitable nuclear characteristics 177Lu appears to be worthwhile for palliative therapy of bone metastasis