Radiosynthesis and biological evaluation of 123I-(±)-trans-2-hydroxy-5-((E)- -3-(iodo)allyloxy)-3-(4-phenyl-1-piperazinyl) tetralin

This work reports both the radiolabeling and preliminary biodistribution results in the rat brains of (±)-[123I]- -II. The novel benzovesamicol derivative (±)-[123I]-II was successfully labeled with iodine-123 from its corresponding n-tributyltin, with radiochemical purity greater than 97% and radiochemical yield in the range 50–55%. (±)-[123I]-II showed a higher accumulation in striatum than in the other regions studied. To determine if (±)-[123I]-II could provide an advantage compared to reference compound [125I]-IBVM a kinetic study was carried out, at each point of the kinetic study, (±)-[123I]-II showed a lower specific binding compared to [125I]-IBVM. Time activity curves of (±)-[123I]-II confirmed that this compound is inferior to [125I]-IBVM to explore the VAChT in vivo by SPECT. Moreover, it is well known that interaction at the VAChT binding site is enantioselective, and therefore, working with enantiomerically pure compounds, could improve the compound activity.