Preparation and in vivo evaluation of (99m)TcN-tertiary butyl xanthate as a potential myocardial agent

Abstract

(99m)Tc-tertiary butyl isonitrile (TBI), a complex structurally similar to (99m)Tc-sestamibi, has been reported to be taken up in the myocardium, albeit with significant retention in liver and lungs, thereby leading to obscure heart images when used for in vivo imaging. In the present study, tert-butyl xanthate, which is similar to TBI, but possesses two sulphur donors, has been synthesized in excellent yield by reacting tert-butanol with carbon disulphide and sodium hydroxide in dry ether. The prepared ligand was then labeled with [(99m)TcN]2+ core and the resultant complex was characterized by paper electrophoresis and HPLC. The complex was obtained in more than 95% yield and was found to be neutral. The preparation was evaluated in Swiss mice for its myocardial perfusion characteristics. The maximum heart uptake observed was 2.34%ID/g at 5 min p.i., which was cleared rapidly, with retention of 0.50%ID/g of the activity at 60 min p.i. However, owing to slow clearance from blood, liver and lungs, the heart/blood, heart/liver and heart/lung ratios at all the time points of study were not significantly high.