ABSTRACT
Objective To prepare a novel radiolabeled FR?positive tumor targeting agent 99 Tcm?( HYNIC?NHHN?FA) ( EDDA) and evaluate its biological properties. Methods FA derivative FA?NHHN?HYNIC was synthesized and radiolabeled with 99 Tcm using EDDA as a coligand. The radiochemical purity, octanal/water partition coefficient and in vitro stabilities of the complex were studied after purified by HPLC. In vitro cellular uptakes were performed on FR?positive KB cells ( human oral epidermoid carcinoma cells) . Biodistribution and microSPECT/CT imaging were investigated on normal Kunming mice and nude mice bearing KB tumors, respectively. Results The radiochemical purity of the complex was over 95% after pu?rified by HPLC. It displayed high stability both in saline and in serum. It also exhibited high specific FR binding in FR?positive KB cells in vitro. The binding ratio was (6.76±0.60)%1 h after incubation, and de?creased to (0.24±0.02)% after adding excessive FA. The results of biodistribution showed high kidney up?take in normal mice, and the uptake reached (21.79±9.79) %ID/g 0.5 h after injection. Flank KB tumors were clearly visualized with 99 Tcm?( HYNIC?NHHN?FA ) ( EDDA ) by microSPECT/CT imaging at 2 h postinjection, and the uptake could be inhibited by excessive FA. Conclusions 99 Tcm?( HYNIC?NHHN?FA) ( EDDA) exhibits good pharmacokinetic properties, suggesting its potential as a promising FA targeting agent for tumor imaging.