Zhou Y G, Zhu T, Zhao H Y, Wu Z M, Shi Q X, Liang F H
Shanghai Medical University, China.
Int J Rad Appl Instrum B. 1987;14(5):467-73. doi: 10.1016/0883-2897(87)90111-5.
N-Pyridoxyl-5-methyltryptophan (5-PMT) was synthesized by a simplified method using sodium borohydride for the reduction of a Schiff base of pyridoxal and 5-methyltryptophan. Lyophilized kits containing 5-PMT, stannous chloride and L-(+)-ascorbic acid were prepared and labeled to afford 99mTc-5-PMT with 96% or higher radiochemical purity analysed by two thin-layer chromatographic solvent systems. 99mTc-5-PMT showed a rapid blood clearance, a faster hepatobiliary transit and a lower renal retention in comparison with 99mTc-5-EHIDA in rats. Eleven (61%) of 18 patients with histologically confirmed hepatocellular carcinoma showed positive images at 2 to 5 h after i.v. injection. The smallest tumor that could be identified was 2 cm in diameter with the best tumor/liver ratio of 4. In conclusion, 99mTc-5-PMT synthesized by sodium borohydride reduction shows great promise as a useful hepatoma imaging agent.
N-吡啶氧基-5-甲基色氨酸（5-PMT）通过一种简化方法合成，该方法使用硼氢化钠还原吡哆醛与5-甲基色氨酸的席夫碱。制备了含有5-PMT、氯化亚锡和L-(+)-抗坏血酸的冻干试剂盒，并进行标记，以获得放射化学纯度达96%或更高的99mTc-5-PMT，其通过两种薄层色谱溶剂系统进行分析。与大鼠体内的99mTc-5-EHIDA相比，99mTc-5-PMT显示出快速的血液清除、更快的肝胆转运和更低的肾脏滞留。18例经组织学确诊为肝细胞癌的患者中有11例（61%）在静脉注射后2至5小时显示阳性图像。能够识别的最小肿瘤直径为2厘米，最佳肿瘤/肝脏比值为4。总之，通过硼氢化钠还原法合成的99mTc-5-PMT作为一种有用的肝癌显像剂显示出巨大的前景。
