Monoamine Uptake Inhibitor, for PET Imaging Studies

Tetrabenazine (TBZ), a high affinity and specific inhibitor of the vesicular monoamine transporter, has been labeled with carbon-l 1 as a potential probe for in viva positron emission tomographic imaging of monoaminergic neuronal losses in neurodegenerative diseases. [“CITBZ was synthesized by O-[“Clmethylation of the 9-0-desmethylTBZ using [“C]methyl iodide in the presence of tetrabutylammonium hydroxide. The radiochemical yields were 35-55% (decay corrected) and the synthesis time 32-37 min from EOB. [“CITBZ was obtained with specific activities of 2000-2500 Ci/mmol (EOS) and radiochemical and chemical purities were ~95%. [“ClTetrabenazine is a promising new radioligand for the in viuo study of monoaminergic neurons using PET.