Tc-99m galactosyl-neoglycoalbumin: in vitro characterization of receptor-mediated binding

Hepatic binding protein (HBP) is a membrane receptor that binds and transports plasma glycoproteins from hepatic blood to hepatocellular lysosomes. The authors have characterized the in vitro binding of Tc-99m galactosyl-neoglycoalbumin (Tc-NGA), a synthetic HBP ligand, to liver membrane. Membrane displacement studies, using carrier ligands in contrast to previously bound Tc-NGA or I-NGA, correlated with the binding characteristics of a native HBP ligand, asialo-orosomucoid. They used computer simulation to study the detectibility of the changes in HBP concentration at different values of k/sub b/. The simulations indicated that radiopharmacokinetic sensitivity to alterations in [HBP] should be possible using a neoglycoalbumin preparation with a carbohydrate density within the range of 15 to 25 galactose units per albumin molecule