The synthesis of pteroyl-lys conjugates and its application as Technetium-99m labeled radiotracer for folate receptor-positive tumor targeting

Aiming to develop a new 99mTc-labeled folate derivative for FR-positive tumor imaging, a simpler method has been established to synthesize the folate-drug conjugates with free α-carboxyl group. In this study, the conjugate pteroyl-lys-HYNIC was synthesized and labeled with 99mTc using tricine and TPPTS as co-ligands. The radiochemical purity of the final complex 99mTc(HYNIC-lys-pteroyl)(tricine/TPPTS), 5 was high (>98%), and it remained stable in saline and plasma over 6 h after preparation. The biologic evaluation results showed that the 99mTc labeled pteroyl-lys conjugate was able to specifically target the FR-positive tumor cells and tissues both in vitro and in vivo, highlighting its potential as an effective folate receptor targeted agent for tumor imaging.

Graphical abstractThe novel complex 99mTc(HYNIC-lys-pteroyl)(tricine/TPPTS) was able to specifically target the FR-positive tumor cells and tissues both in vitro and in vivo, highlighting its potential as an effective folate receptor targeted agent for tumor imaging.Figure optionsDownload full-size imageDownload as PowerPoint slide