Panel Disdussion

3rd International Congress of of Nuclear Medicine & & 15th 15th Iranian Annual Annual Congress of
Congress of Nuclear Medicine
Shahid Beheshti Shahid Beheshti University University of Medical of Medical Sciences Sciences 19-21 19-21 May May 2011
Synthesis and evaluation of 99mTc-carbonyl phenyl piperazin
dithiocarbamate as a 5-HT receptor imaging
Mostafa Erfani(Gandomkar) 1 , Leila Hassanzadeh 2 , Seyed Esmaeil
Sadat Ebrahimi 2 , Reza Najafi 1
1 Nuclear Science Research School
2 Department of Medicinal Chemistry
Introduction: serotonin receptors are associated with a variety of
neuropsychiatric disorder such as anxiety, depression, schizophrenia,
and Alzheimer disease. There is a considerable interest in developing
new 99mTc radiopharmaceuticals for imaging central neural system
receptors by using single photon emission computer tomography. The
goal of this study was to develop a novel 5-HT receptor imaging
agent.
Method: Phenyl piperazin dithiocarbamate was synthesized in the
presence of potassium hydroxide. The desired structure was
confirmed by IR and NMR analysis. 99mTc tricarbonyl precursor was
prepared and the labeling conditions were optimized in the aspect of
pH, reaction temperature, reaction time and the amount of ligand.
The final complex was obtained with high yield following the optimal
labeling procedure. The radiochemical purity of intermediate and final
complex were evaluated by ITLC and HPLC methods. Stability in
human serum, octanol/water partition coefficient and in vivo
biodistribution study of labeled compound in rat were carried out.
Results: Synthesized compound was labeled with 99mTc-tricarbonyl
core in high yield (>%90 by HPLC). The labeled compound was a
lipophilic complex, which was confirmed by octanol/water partition
coefficient (P = 2.50). In vivo biodistribution indicated that this
complex had moderate brain uptake (0.47 %ID/g at 5 min and 0.42
%ID/g at 30 min). The labeled compound was stable up to 6h in
saline.
Conclusion: This result indicates that labeled complex has brain
uptake and also has binding to receptor. Improvement of this
compound needs further ligand modification to obtain an ideal brain
receptor imaging agent.
Keywords: carbonyl, 5-HT, imaging agent
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