Preliminary studies of a novel cyclopentadienyl tricarbonyl technetium-99m fatty acid derivative for myocardical imaging

This study reports the synthesis and evaluation studies of 6′-cyclopentadienyl tricarbonyl technetium-99m 6′-oxo-11- (hexanamide)undecanoic acid (1). 1 was prepared with 26.5 ± 4.3% of radiochemical yield and more than 98% of radiochemical purity. Tissue distribution in mice showed that high radioactivity accumulated in the heart with moderate clearance. However, unfortunately, similar to those of other technetium-labeled fatty acid analogs, the biodistribution studies of 1 in mice showed poor heart-to-blood ratios, which suggested that 1 cannot be used as myocardial imaging agent, and it may provide a theoretical basis or a lab experience for corresponding fatty acid tracers studies. Tc-99m-labeled fatty acid is very important for the evaluation of myocardial metabolism. 1 was radiolabeled by a double ligand transfer reaction between ferrocene and 99mTc. Amidated 99mTc-labeling fatty acid is beneficial to prolonging retention in myocardium.