This study is focused on the synthesis of two bisphosphonate derivatives, 1-hydroxy-2-(3-pyridyl) ethylidene bisphosphonic acid monosodium (sod. risedronate) and 1-hydroxy-2-(2-pyridyl) ethylidene bisphosphonic acid monosodium (HPEBP) from corresponding nitrile. The labeling of two compounds was studied with technetium-99m using two different reducing agents (SnCl2.2H2O and NaBH4) where NaBH4 gave a stable complex and high radiochemical yield more than SnCl2.2H2O. The radiochemical yield of 99mTc-risedronate and 99mTc-HPEBP were 99.2 ± 0.6 and 95.5 ± 3.5%, respectively, which more than that...