Synthsis of a new ligand: 2-((2-((Dimethylamino)methyl)phenyl)thio)-5–iodophenylamine(125I-ADAM) as a serotonin imaging agent is reported. The radioiodinated ligand was prepared by iododestannylation reaction using hydrogen peroxide. The chemical structure of the labeling precursor (5-(tributylstannyl)-2-((2-((dimethylamino) methyl)phenyl)thio)phenylamine) and all intermediates were verified by IR
HNMR and MS. The radiochemical purity of 125I-ADAM was above 95% determined by TLC. Biodistribution studies in rats showed that the initial uptake of 125I-ADAM in the brain was high
and consistently the highest binding appeared in hypothalamus
a region with the highest density of SERT. The specific binding ((T/CB)-1) of 125I-ADAM in hypothalamus were 3.38
3.62 and 4.36 at 60 min
120 min and 240 min postinjection
respectively. These data suggest that 125I-ADAM may be useful for SPECT imaging of SERT binding sites in the brain.