Synthesis, characterization and biodistribution of A 99mTc nitrido complex as a potential brain perfusion imaging agent

The bis(N-cyclohexyl-dithiocarbamato) nitrido technetium-99m, complex [(TcN)-Tc-99m(CHDTC)(2)] (CHDTC:N-cyclohexyl dithiocarbamato) has been synthesized through a ligand-exchange reaction. The two-step procedure involved the initial reaction of (TcO4-)-Tc-99m with succinic dihydrazide(SDH) in the presence of stannous chloride as reducing agent and propylenediamine tetraacetic acid(PDTA) as complexant, followed by the addition of sodium N-cyclohexyl dithiocarbamate dihydrate. The radiochemical purity of the complex was over 90% by thin layer chromatography. It was stable over 6h at room temperature, Its partition coefficient indicated that it was a good lipophilic complex. Biodistribution in mice demonstrated that the complex accumulated in brain with high uptake and good retention. The brain uptake(ID%/g) was 2.91,5.88 and 5.91 at 5,30 and 60min post-injection respectively. The ratio of brain/blood in mice was high, 2.10 at 1hr post-injection. The results for the complex suggested that it could be a potential brain perfusion imaging agent.