Technetium-99m dithiocarbamates as potential brain agents: evaluation of aliphatic and amine-containing analogues

Technetium-99m forms a lipophilic complex with diethyldithiocarbamate (DDC) but this complex is not retained in the brain as is thallium-201 DDC. We therefore prepared a series of aliphatic and amine-containing analogues of DDC and evaluated the properties of their 99mTc complexes in vitro and in vivo. The ethyl acetate/buffer partition coefficients of the amine-containing derivatives showed a response to pH. Four of the five complexes were less stable than DDC in vitro and showed greater retention in rabbit brain. These agents warrant further investigation for cerebral perfusion imaging with SPECT.