A99mTc-tricine-HYNIC-labeled peptide targeting the melanocortin-1 receptor for melanoma imaging

Melanocortin-1 (mc1) receptor is an attractive melanoma-specific target for the development of α-msh peptide based imaging and therapeutic agents. in this work a new lactam bridge α-msh analogue was synthesized and radiolabeled with99mtc via hynic chelator and tricine as co-ligand. also,stability in human serum,receptor bound internalization and tissue biodistribution in tumor bearing nude mice were thoroughly investigated. radiolabeling with99mtc was performed at high specific activities (163mbq/nmol) with an acceptable labeling yield (>98%). the radioligand showed specific internalization into b16/f10 cells (13.35 ± 0.9% at 4 h). in biodistribution studies,a receptor-specific uptake was observed in mc1 receptor positive organ so that after 4 h the tumor uptake was 4.51 ± 0.11 % id/g. predominant renal excretion pathway with a highest accumulation of activity in tumor was observed for this radiopeptide. obtained results show that the new designed labeled peptide conjugate can be a suitable candidate for diagnosis of metastatic melanomas. © 2016 by school of pharmacy.