Preparation and biological evaluation of 99m TcN‐labeled pteroyl‐lys derivative as a potential folate receptor imaging agent

• Published in: Journal of labelled compounds & radiopharmaceuticals Vol. 57; no. 1; pp. 12 - 17
• Main Authors: Chen, Yuan, Guo, Hongjuan, Xie, Fang, Lu, Jie
• Format: Journal Article
• Language: English
• Published: 01.01.2014
• ISSN: 0362-4803; 1099-1344
• DOI: 10.1002/jlcr.3116

In order to develop a novel 99m Tc‐labeled folate receptor (FR) imaging agent, a dithiocarbamate derivative, pteroyl‐lys‐DTC, was synthesized and radiolabeled with 99m Tc through the [ 99m TcN] 2+ intermediate. The radiochemical purity of the corresponding 99m Tc‐complex, 99m TcN‐pteroyl‐lys‐DTC, was over 95% as measured by reversed‐phase HPLC. The 99m TcN complex was stable under physiological conditions. 99m TcN‐pteroyl‐lys‐DTC exhibited specific FR binding in FR‐positive KB cells in vitro . The biodistribution in tumor‐bearing mice showed that the 99m TcN‐labeled radiotracer had good uptake (3.56 ± 0.09%ID/g at 2 h postinjection) in FR‐positive KB tumors, as well as in the kidneys (30.34 ± 3.53%ID/g at 2 h postinjection). After coinjection with excess folic acid, the uptake in tumor and kidneys was significantly blocked. The results indicated that 99m TcN‐pteroyl‐lys‐DTC was able to target the FR‐positive tumor cells and tissues specifically both in vitro and in vivo . Copyright © 2013 John Wiley & Sons, Ltd.