BARC/PUB/2013/0030

 
 

A novel concept of radiosynthesis of a 99mTc-labeled dimeric RGD peptide as a potential radiotracer for tumor imaging

 
     
 
Author(s)

Mittal, S.; Bhadwal, M.; Chakraborty, S.; Sarma, H. D.; Banerjee, S.; Pillai, M. R. A.
(RPhD;RB&HSD)

Source

Bioorganic & Medicinal Chemistry Letters, 2013. Vol. 23 (6): pp. 1808-1812

ABSTRACT

Radiolabeled Arg-Gly-Asp (RGD) peptides are promising agents for non invasive imaging of αvβ3 expression in malignant tumors. The integrin αvβ3 binding affinity and consequent tumor uptake could be improved when a dimeric RGD peptide is used as the targeting moiety instead of a monomer. Towards this, a novel approach was envisaged to synthesize a 99mTc labeled dimeric RGD derivative using a RGD monomer and [99mTcN]+2 intermediate. The dithiocarbamate derivative of cyclic RGD peptide G3-c(RGDfK) (G3 = Gly-Gly-Gly, f = Phe, K = Lys) was synthesized and radiolabeled with [99mTcN]+2 intermediate to form the 99mTcN-[G3-c(RGDfK)]2 complex in high yield (˜98%). Biodistribution studies carried out in C57/BL6 mice bearing melanoma tumors showed good tumor uptake [4.61 ± 0.04% IA/g at 30 min post-injection] with fast clearance of the activity from non-target organs/tissue. Scintigraphic imaging studies showed visible accumulation of activity in the tumor with appreciable target to background ratio.

 
 
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