An easy and effective method for synthesis and radiolabelling of risedronate as a model for bone imaging.

This study aimed to provide an easy method for synthesis of 1-hydroxy-2-(3-pyridyl) ethylidene bisphosphonic acid monosodium (sod. risedronate) with a high yield of 71%. The synthesized risedronate was labeled with technetium-99 m using two different reducing agents (SnCl2 .2H2 O and NaBH4 ) where NaBH4 gave stable complex and higher radiochemical yield more than SnCl2 .2H2 O. The results showed that, the radiochemical purity of (99m) Tc(NaBH4 )-risedronate was 99.2 ± 0.6% and its stability was up to 6 h. Biodistribution study showed high uptake and long retention of (99m) Tc(NaBH4 )-risedronate in bone starting from 15 min (29 ± 2.5% ID/organ) up to 4 h (35.1 ± 3.2 ID/organ) post injection. This research could introduce an easy and effective method for synthesis and labeling of risedrionate and affording a good tracer for bone imaging.