Synthesis and biodistribution of a new (99m)Tc nitrido complex for cerebral imaging

The bis(N-isopentyl dithiocarbamato) nitrido technetium-99m complex [(99m)TcN(IPEDTC)(2)] (IPEDTC: N-isopentyl dithiocarbamato) has been synthesized by the reduction of (99m)TcO(4)(-) into [(99m)TcN](2+) with stannous chloride in the presence of succinic dihydrazide and propylenediamine tetraacetic acid, followed by the addition of the sodium salt of N-isopentyl dithiocarbamate. The radiochemical purity of the complex was over 90% as measured by thin layer chromatography. In vitro studies showed that the complex possessed good stability under physiological conditions. Its partition coefficient indicated that it was a lipophilic complex. The electrophoresis results showed the complex was neutral. Biodistribution in mice showed that the complex accumulated in brain with high uptake and good retention. The brain uptake (ID%/g) was 2.22, 2.06 and 2.45 and the brain/blood ratio was 1.01, 2.34 and 3.22 at 5, 30 and 60 min post-injection, respectively. These results for the complex suggested that it could be a potential brain perfusion imaging agent.