Abstract: In order to develop new tumor hypoxia imaging agent, two novel dithiocarbamate ligands, potassium 2-(2-methyl-5-nitro-1H-imidazolyl)-ethyl-carbamate(MNIE-DTC) and potassium 4-(2-methyl-5-nitro-1H-imidazolyl)-butyl-carbamate(MNIB-DTC), and the corresponding ⁹⁹mTcN-complexes were prepared. Both neutral complexes were stable in vitro. Biological evaluation in TA-2 mice bearing MA891 tumor showed that both [⁹⁹mTcN(MNIE-DTC)₂] and [⁹⁹mTcN(MNIB-DTC)₂] had certain tumor uptakes of (0.50±0.01)%ID/g and (0.64±0.10)%ID/g at 1 h post-injection, respectively. A significant increase in tumor uptakes of both complexes were produced by injection of hydralazine. The results indicated that the two complexes could be selectively accumulated in hypoxic tumors.

Key words: ⁹⁹mTc-nitrodo complexes, Tumor hypoxia imaging agent, Metronidazole