Preparation and bioevaluation of [99mTcN]2+-labeled tetrameric complex of E-c(RGDfK)2 as a radiotracer for imaging αvβ3 integrins in tumors

Abstract

The objective of the present work is to radiolabel a dimeric RGD peptide namely, E-c(RGDfK)2 using [99mTcN]2+ core in order to obtain a 99mTc-labeled tetrameric RGD species, which is expected to have an enhanced tumor affinity. 99mTc-labeleld [E-c(RGDfK)2]2 complex was prepared with high radiochemical purity (>95 %). Pharmacokinetic evaluation of the radiolabeled agent, carried out in C57BL/6 mice bearing melanoma tumor, demonstrated good tumor uptake within 30 min of administration (3.94 ± 0.87 % IA/g) and retention therein till 3 h post-injection (2.65 ± 0.31 % IA/g). Blocking experiment revealed the specificity of the complex towards the αvβ3 receptors in the tumor model.