A novel (99m)Tc-labeled diphosphonic acid as potential bone seeking agent: synthesis and biological evaluation

A novel zoledronate derivative, 1-hydroxy-4-(2-butyl-1H-imidazol-1-yl)butane-1,1- diyldiphosphonic acid (BIBDP) was prepared and labeled with (99m)Tc successfully in a high radiochemical purity and good stability in vitro. The biodistribution in mice shows that (99m)Tc-BIBDP has high specificity and efficacy in bone uptake with a maximum of 12.14 ± 0.53 %ID/g at 120 min. Kinetics of blood clearance showed that distribution half life (T(1/2α)), elimination half life (T(1/2β)) and total clearance rate (CL) of (99m)Tc-BIBDP were 4.67 min, 91.9 min and 1.21 %ID/g·min(-1), respectively. Moreover, (99m)Tc-BIBDP has higher uptake in the bone and faster clearance from soft tissues than (99m)Tc-MDP and (99m)Tc-ZL. A plain and clear bone image was obtained at 1 h with SPECT bone imaging. The present findings indicate that (99m)Tc- BIBDP holds great potential for bone imaging.