Synthesis, characterization and biodistribution of 99m Tc(CO) 3 –ABP and comparison with 99m Tc–ABP

The (l‐hydroxy‐4‐amino‐butylidene‐l,l‐bisphosphate) (ABP) is a compound that inhibits bone resorption, and a highly effective drug in the treatment of metastatic bone disease. The fac‐[ 99m Tc(CO) 3 (H 2 O) 3 ] + precursor was reacted with ABP in saline (pH=3–4) at 45°C for 15 min to produce the 99m Tc(CO) 3 –ABP complex. The radiochemical purity (RCP) of the product was over 90% as measured by thin layer chromatography and high‐performance liquid chromatography. No decomposition of the complex at room temperature (25°C) was observed over a period of 6 h. Its partition coefficient indicated that it was a weak hydrophilic complex. The biodistribution in normal mice of 99m Tc(CO) 3 –ABP complex differed greatly from that of 99m Tc–ABP, and the former had a lower bone uptake as compared with that of the latter. The experiment results showed that the incorporation of the [ 99m Tc(CO) 3 ] + core into the ABP ligand may drastically change the characterization and biological features as compared with 99m Tc–ABP. Copyright © 2007 John Wiley & Sons, Ltd.