Synthesis and bio‐evaluation of Tc‐99 m‐labeled fatty acid derivatives for myocardial metabolism imaging

¹¹C, ¹⁸F and ¹²³I fatty acids are used for myocardial imaging, and ^99mTc‐labeled fatty acids are more desirable substitutes than other radiolabeled fatty acids. In the work reported, ^99mTc]‐CpTT‐10‐oxo‐FPA ( 1c ), ^99mTc]‐CpTT‐12‐oxo‐FPA ( 2c ), ^99mTc]‐CpTT‐14‐oxo‐FPA ( 3c ) and ^99mTc]‐CpTT‐16‐oxo‐FPA ( 4c ) were prepared with 60.76–70.92% of radiochemical yield and purity of more than 95%. These radiotracers ( 1c , 2c , 3c , 4c ) were chemically stable when incubated in Sprague Dawley rat serum for 3 h at 37 °C. Tissue distribution studies in female mice indicated that 2c had high initial heart uptake (8.84%ID g^?1 at 1 min post‐injection) and 4c had long retention in the heart (1.45%ID g^?1 at 30 min post‐injection). Metabolite analysis showed 4c could be metabolized to 5c via β‐oxidation with loss of two ? CH₂? in the myocardium, the radiometabolite being excreted via urine. However, low heart uptake suggested that 4c cannot be used as a diagnostic imaging agent. Copyright © 2016 John Wiley & Sons, Ltd.