The synthesis of cyclic Arg-Gly-Asp GP Ilb/IIIa receptor antagonists conjugated to 4,5-bis(S-1-ethoxyethyl-mercaptoacetamido)pentanoic acid is reported. The corresponding Tc-99m-labeled complexes were prepared by exchange labeling with Tc-99m-glucoheptonate. This indirect labeling approach is an alternative to the preformed chelate approach using mapt. Copyright (C) 1996 The DuPont Merck Pharmaceutical Company.