Rosenspire K C, Haka M S, Van Dort M E, Jewett D M, Gildersleeve D L, Schwaiger M, Wieland D M
Division of Nuclear Medicine, University of Michigan Medical Center, Ann Arbor 48109-0552.
J Nucl Med. 1990 Aug;31(8):1328-34.
Carbon-11-meta-hydroxyephedrine is a new radiotracer developed for mapping the sympathetic nerves of the heart. Carbon-11-meta-hydroxyephedrine is synthesized by direct N-methylation of metaraminol with [11C]methyl iodide in dimethyl formamide/dimethyl sulfoxide and purified by semi-preparative reversed-phase HPLC. Total synthesis time is 45 min from end-of-bombardment. Carbon-11-meta-hydroxyephedrine is produced in 40%-50% corrected radiochemical yield with a specific activity of 900 Ci/mmol. Routine radiochemical and chemical purity are 95% and 98%, respectively. Biodistribution studies in rats show high myocardial uptake. Pretreatment with desipramine, a drug known to selectively block neuronal uptake, results in a 92% decrease in tracer accumulation in the myocardium. Metabolic studies in guinea pigs show less than 5% metabolites in heart tissue 30 min after intravenous injection suggesting that [11C]meta-hydroxyephedrine is suitable for kinetic modeling. These preliminary results support this new tracer as a clinical agent for neuronal imaging of the heart.
碳-11-间羟基麻黄碱是一种新开发的用于绘制心脏交感神经的放射性示踪剂。碳-11-间羟基麻黄碱是通过在二甲基甲酰胺/二甲基亚砜中用[11C]甲基碘对间羟胺进行直接N-甲基化合成的，并通过半制备反相高效液相色谱法纯化。从轰击结束起，总合成时间为45分钟。碳-11-间羟基麻黄碱的校正放射化学产率为40%-50%，比活度为900 Ci/mmol。常规放射化学纯度和化学纯度分别为95%和98%。在大鼠身上进行的生物分布研究显示心肌摄取率很高。用已知能选择性阻断神经元摄取的药物地昔帕明预处理后，示踪剂在心肌中的积累减少了92%。在豚鼠身上进行的代谢研究表明，静脉注射后30分钟，心脏组织中的代谢物少于5%，这表明[11C]间羟基麻黄碱适用于动力学建模。这些初步结果支持这种新的示踪剂作为心脏神经元成像的临床试剂。
