Synthesis, radiolabelling characteristics and biological evaluation of the derivatives of mercaptoacetyltriglycine

Abstract

Summary Several derivatives of MAG3, in which one or both of the first two amide bonds are inverted and contain an additional methyl or carboxyl-substituent on the ligand backbone, have been synthesized and evaluated. This was realized by substituting a glycyl with a D- or L-alanyl moiety or by replacing cysteamine with an L-cysteine to investigate the renal characteristics of the resulting derivatives versus the reference 99mTc-MAG3. Labelling with 99mTc resulted in two main radioactive species, which probably are the isomeric oxo-technetium complexes. These complexes were separated by HPLC and evaluated in mice. The data suggest that the substitution in the amide functions and addition of a methyl or carboxyl moiety results in poor renal handling of these compounds. However, one of the derivatives 99mTc-C-LB, exhibits renal characteristics comparable to 99mTc-MAG3.