Synthesis and radiolabelling of a fatty acid xanthate with 99mTcN+2core for its possible use in myocardial imaging

摘要

Fatty acids and glucose are the major energy sources for the myocardium. A number of long chainfatty acids have been radiolabeled and evaluated for their potential to assess myocardial cellular viability. 123Iiodophenylpentadecanoicacid (IPPA) and 123I-beta-methyliodophenylpentadecanoic acid (BMIPPA) arecurrently being used for imaging the myocardial viability. Because of the limited accessibility of 123I, the searchfor a technetium-based agent for the above purpose has been on for long time. In line with this idea wesynthesized the xanthate derivative of 15-hydroxypentadecanoic acid (HPDA). Direct reaction of the HPDA withcarbondisulphide in presence of crushed sodium hydroxide in dry ether resulted in moderate yields of the desiredproduct. The prepared ligand was then labelled with [99mTcN]2+ core and the resultant complex was characterizedby paper electrophoresis and HPLC. The complex was obtained in more than 95% radiolabeling yield. Thelabelled preparation was evaluated in Swiss mice for its myocardial extraction and retention characteristics. Themaximum heart uptake observed was 3.10 %ID/g at 5 min p.I., which cleared out rapidly, with retention of 0.79%ID/g of the activity at 60 min p.I. However, owing to slow clearance from the blood, liver and lungs, theheart/blood, heart/liver and heart/lung ratios at all the time points of study were not significantly high