NUKLEONIKA 2013, 58(2):261-267

 


SYNTHESIS AND IN VIVO EVALUATION OF BOTH (2R,3R)-[123I]- AND (2S,3S)-[123I])-TRANS-2-HYDROXY-5-((E)-3-(IODO)ALLYLOXY)3-(4-PHENYL-1-PIPERAZINYL) TETRALIN AS SPECT RADIOTRACER



Thaer Assaad, Abdul H. Al Rayyes1

Department of Chemistry, Atomic Energy Commission of Syria (AECS),
P. O. Box 6091, Damascus, Syrian Arab Republic,

We report the synthesis of enantiopure benzovesamicol derivatives: (2R,3R)-[123I]-trans-2-hydroxy-5-((E)-3-(iodo)allyloxy)-3-(4-phenyl-1-piperazinyl) tetralin and (2S,3S)-[123I]-trans-2-hydroxy-5-((E)-3-(iodo)allyloxy)-3-(4-phenyl-1-piperazinyl) tetralin; [(2R,3R)-[123I]-1 and (2S,3S)-[123I]-1]. Both compounds were obtained with radiochemical and optical purities greater than 97% and with radiochemical yields in the range of 50–60%. To determine whether these compounds could have potential advantage compared to [125I]-iodo benzovesamicol (IBVM), IBVM was also labelled and used as the reference compound in all in vivo experiments. Both (2R,3R)-[123I]-1 and (-)-[125I]-IBVM showed similar time activity curves (TACs) with the highest accumulations in the striatum region followed by the cortex, hippocampus and then cerebellum. While (2S,3S)-[123I]-1 showed an overall homogeneous brain distribution. However, time activity curves of (2R,3R)-[123I]-1 confirmed that this compound could be used to visualize the vesicular acetylcholine transporter (VAChT) in vivo, at each point of the kinetic study. Also (2R,3R)-[123I]-1 showed lower specific bindings compared to [125I]-IBVM. These results suggested that (2R,3R)-[123I]-1 is inferior in comparison with [125I]-IBVM for in vivo VAChT exploration.

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