Evaluation of (99m)Tc-labeled tropanes with alkyl substituents on the 3beta-phenyl ring as potential dopamine transporter tracers

Nuclear Medicine and Biology
H P VanbilloenAlfons M Verbruggen

Abstract

Technetium(V)-oxo-3beta-(4-chlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-yl[N-(2-mercaptoethyl), N-(N'-(2-mercaptoethyl)-2-aminoethyl)]-aminomethyl ((99m)Tc-TRODAT-1) and three derivatives with one or two substituents on the 3beta-phenyl ring (4-methylphenyl, 4-ethylphenyl and 2,4-dimethylphenyl) were prepared and evaluated as potential imaging agents for the central nervous dopamine transporter (DAT). Labeling of the ligands with (99m)Tc yielded for each of them a mixture of two radiolabeled species, which were purified and isolated using reversed-phase high-performance liquid chromatography. Employing radio-LC-MS, we found both species to have the same molecular mass suggesting diastereoisomers. After intravenous injection in mice and rats, the compounds were stable in vivo and no important metabolites were found in plasma or urine. Replacement of the 4-chloro atom on the 3beta-phenyl ring by a methyl group causes no loss of affinity for the DAT system. However, substitution of an ethyl group for the 4-chloro atom or introduction of a second methyl group in the 2-position of the phenyl ring results in a serious reduction of the affinity for the DAT transporter. Ex vivo autoradiography on mice brain slices and biodistributio...Continue Reading

References

Nov 7, 1998·Journal of Medicinal Chemistry·A HoeppingB Johannsen
Apr 6, 2004·European Journal of Nuclear Medicine and Molecular Imaging·K Van LaereL Mortelmans
Jan 27, 2005·Bioorganic & Medicinal Chemistry·Bernard J CleynhensAlfons M Verbruggen
Jul 20, 2005·Nuclear Medicine and Biology·Hubert P VanbilloenAlfons M Verbruggen

❮ Previous
Next ❯

Related Concepts

Related Feeds

Basal Ganglia

Basal Ganglia are a group of subcortical nuclei in the brain associated with control of voluntary motor movements, procedural and habit learning, emotion, and cognition. Here is the latest research.