Absorbed dose assessment of 177 Lu-zoledronate and 177 Lu-EDTMP for human based on biodistribution data in rats

Abstract

Over the past few decades, several bone-seeking radiopharmaceuticals including various bisphosphonate ligands and β-emitting radionuclides have been developed for bone pain palliation. Recently, 177 Lu was successfully labeled with zoledronic acid ( 177 Lu-ZLD) as a new generation potential bisphosphonate and demonstrated significant accumulation in bone tissue. In this work, the absorbed dose to each organ of human for 177 Lu-ZLD and 177 Lu-ethylenediaminetetramethylene phosphonic acid ( 177 Lu-EDTMP;as the only clinically bone pain palliation agent) was investigated based on biodistribution data in rats by medical internal radiation dosimetry (MIRD) method. 177 Lu-ZLD and 177 Lu-EDTMP were prepared in high radiochemical purity (>99%, instant thin layer chromatography (ITLC)) at the optimized condition. The biodistribution of the complexes demonstrated fast blood clearance and major accumulation in the bone tissue. The highest absorbed dose for both 177 Lu-ZLD and 177 Lu-EDTMP is observed in trabecular bone surface with 12.173 and 10.019 mSv/MBq, respectively. The results showed that 177 Lu-ZLD has better characteristics compared to 177 Lu-EDTMP and can be a good candidate for bone pain palliation.