Preparation and biodistribution of ^(99)Tc^m-PIDP as bone imaging agent

A novel zoledronic acid derivative,1-hydroxy-2-(2-propyl-1H-imidazol-1-yl)ethane-1,1-diyldiphosphonic acid (PIDP), was synthesized by three-step reactions from 2-propyl-1H-imidazole. It was labeled with 99Tcm in conditions of 0.1 mg SnCl2.2H2O at pH 6.0 and 99TcmO4? in aqueous solution for 20 min at room temperature. The labeling yield and radiochemical purity of 99Tcm-PIDP are both higher than 95%. The biodistribution results show that the bone uptake is up to 8.47% ID/g which is the maximum of bone uptake at 30 min after injection of 99Tcm-PIDP in mice. The pharmacokinetic parameters can be estimated from the exponential equation of C=59.565e-11.307t+2.069e-1.211t. The clear bone image of rabbit was obtained at 120 min after injection of 99Tcm-PIDP. The results indicate that 99Tcm-PIDP has highly selective uptake in the skeletal and low uptake, rapid clearance in soft tissues, so it would be a potential novel bone imaging agent.

A novel zoledronic acid derivative, 1-hydroxy-2-（2-propyl-lH-imidazol-1-yl）ethane-1,1-diyldiphosphonic acid （PIDP）, was synthesized by three-step reactions from 2-propyl-1H-imidazole. It was labeled with 99TCm in conditions of 0.1 mg SnC12-2H20 at pH 6.0 and ^99Tc^mO4^- in aqueous solution for 20 min at room temperature. The labeling yield and radiochemical purity of ^99Tc^m-PIDP are both higher than 95%. The biodistribution results show that the bone uptake is up to 8.47%ID/g which is the maximum of bone uptake at 30 rain after injection of ^99Tc^m-PIDP in mice. The pharmacokinetic parameters can be estimated from the exponential equation of C=59.565e^-11.307t ＋ 2.069e^-1.211t. The clear bone image of rabbit was obtained at 120 min after injection of ^99Tc^m-PIDP. The results indicate that ^99Tc^m-PIDP has highly selective uptake in the skeletal and low uptake, rapid clearance in soft tissues, so it would be a potential novel bone imaging agent.