Synthesis and evaluation of technetium-99m labelled 1-(2-methoxyphenyl)piperazine derivative for single photon emission computed tomography imaging for targeting 5-HT.

Quantitative changes in expression level of 5HT are somewhere related to common neurological disorders such as anxiety, major depression and schizophrenia. We have designed EDTA conjugated SPECT imaging probe for localization of 5HT receptor in brain. For designing SPECT probe we have employed the concept of bivalent approach and a homodimeric system with desirable pharmacokinetics of 5HT imaging. Tc-EDHT was also evaluated for its stability through serum stability assay and glutathione challenge experiment. Biodistribution study showed the highest accumulation of radioactivity in kidney which depicted the renal mode of excretion from the body. However in brain the uptake of 1.21% ID per gram was observed in initial 5 min of drug administration. On blocking the receptor this percent get decreased to 0.97% ID per gram. The regional distribution in brain was also performed which showed the accumulation of drug in cerebellum, cortex and hippocampus part, which are already known for 5HT expression. Dynamic study in rabbit is also in support of results derived from biodistribution and blood kinetics experiment. These finding suggest that Tc-EDHT holds promising place for further optimization before nuclear medicine applications in different animal species.