Synthesis and Bio-distribution of Three Carbon-11-Labeled Phenylethylamine Derivatives

N-methylphenylethylamine, N-m-MeTyramine and N-P-MeTyramine were labeled with Carbon-11 by methylation of amino group. Biological distribution characteristics of the three radiolabeled compounds in Kunming mice were evaluated. Synthesis of ¹¹C-N-methylphenethylamine requires 30 minutes including HPLC separation time. The yield was 25% and the radiochemical purity was more than 98%. Synthesis of ¹¹C-m-MeTyramine required 25 minutes including HPLC separation time. The yield was 13% and the radiochemical purity was more than 97%. Synthesis of ¹¹C-P-MeTyramine required 25 minutes including HPLC separation time. The yield was 28% and the radiochemical purity was more than 98%. Distribution study showed that amount of the three marker uptaken by the target organism-myocardium, at each time point was smaller than that uptaken by non-target organs like lung, liver, spleen, kidney. Myocardial uptake was similar with that of muscle. After injection of the markers for 10 minutes, concentration of ¹¹C-N-methylphenethylamine in lung and liver was 2.08 and 2.94 times higher than that in heart, respectively. Concentration of ¹¹C-m-MeTyramine in lung and liver was 2.56, 2.76 higher than that in heart, respectively. Concentration of ¹¹C-P-MeTyramine in lung and liver was 1.85 and 5 higher than that in heart,respectively. Present results suggested that although synthetic methods of ¹¹C labeled N-methylphenylethylamine, N-m-MeTyramine and N-P-MeTyramine were simple, but the targeting in myocardium were poor and might not be suitable for myocardial perfusion imaging.