Synthesis, characterization and biodistribution studies of a neutral-lipophilic Tc-99m N3S2 chelate

Diaminedithiols (DADT) are known to form neutral-lipophilic complexes with ^99mTc in aqueous solutions, where they are readily formed in high yields and demonstrate excellent stability. A new triaminedithiol (TADT) ligand was synthesized, characterized and shown to form a neutral-lipophilic ^99mTc-chelate. The biodistribution of this ^99mTc chelate in rats showed that its uptake in brain or heart following i.v. injection of the ^99mTc chelate was low, but activity taken up was retained over a long period of time. The in vivo and in vitro properties of this chelate indicate the possibility that chemical modification of this TADT ligand may produce ligand systems that form ^99mTc chelates with suitable diagnostic properties.