Preparation and Evaluation of Novel Folate Isonitrile 99mTc Complexes as Potential Tumor Imaging Agents to Target Folate Receptors
Junhong Feng, Xuran Zhang, Qing Ruan, Yuhao Jiang, Junbo Zhang
Abstract
In order to seek novel technetium-99m folate receptor-targeting agents, two folate derivatives (CN5FA and CNPFA) were synthesized and radiolabeled to obtain [99mTc]Tc-CN5FA and [99mTc]Tc-CNPFA complexes, which exhibited high radiochemical purity (>95%) without purification, hydrophilicity, and good stability in vitro. The KB cell competitive binding experiments indicated that [99mTc]Tc-CN5FA and [99mTc]Tc-CNPFA had specificity to folate receptor. Biodistribution studies in KB tumor-bearing mice illustrated that [99mTc]Tc-CN5FA and [99mTc]Tc-CNPFA had specific tumor uptake. Compared with [99mTc]Tc-CN5FA, the tumor/muscle ratios of [99mTc]Tc-CNPFA were higher, resulting in a better SPECT/CT imaging background. According to the results, the two 99mTc complexes have potential as tumor imaging agents to target folate receptors.