(99) Of Tc ~ M-demdp, Preparation And Biodistribution Studies

Diethyl Methylenebisphosphnate(DEMDP) is an analogue of Methylene Diphosphonate(MDP),which is currently in wide use as bone imaging agent in nuclear medicine. The synthesis of DEMDP and the characterization of metal complex have been studied in literature. But the labeling of DEMDP with 99Tcm and the biodistribution of the labeled compound have not been studied yet.DEMDP has been characterized by IR,'H-NMR,31P-NMR and elemental analysis. Reduction of 99TcmO4- by stannous chloride in the presence of excess DEMDP leads to the product of 99Tcm-DEMDP complexes. The study indicates the best reaction conditions is:8mg DEMDP,0.4mg SnCl2PH:1.5-4.8,reacted temperature 100C,reacted time:30min.In this case,the labeling efficiency can go up to 95%.Furthermore 99Tcm-DEMDP can be kept stably at the room temperature in that the labeling percent is over 90% in six hours after being labeled. The biodistribution of 99Tcm-DEMDP in mice had been studied and It was found that the bone uptake of the labelld complex was quite high,but its blood clearance was slow.For the characterization of the multi-component bone-scan agent 99Tcm-diphosphonate we have analysed the complex mixture with reversed phase ion pair chromatography (RP-IPC). The optimal condition of RP-IPC for 99Tcm -DEMDP is as follows:the eluent of 0.1mol/L + 0.003mol/LTBA +1-2%EtAC+0.0065mol/L DEMDP + 0.005mol/LSn2+;the flow rate of 2mL/min.With RP-IPC more than one peak were found within a separation-time of 40 min. When prepared under different temperature,it appears that the composition of the complexes is not the same.