Advancement of drugs conjugated with GalNAc in the targeted delivery to hepatocytes based on asialoglycoprotein receptor

The asialoglycoprotein receptor (ASGPR) is specifically expressed in hepatocytes. Sugar molecules, such as asialoglycoprotein, galactose, galactosamine, and N-acetyl galactosamine (GalNAc), have a high affinity for ASGPR. This review summarizes the structure of ASGPR, the distribution of this molecule in different cells, and the factors influencing the binding of GalNAc to ASGPR. We introduce the application of GalNAc in targeted delivery into hepatocytes by forming conjugated compounds with RNAs and small molecules, and the standard methods for synthesizing GalNAc are also briefly presented. This is to provide an overview of the current research on GalNAc and to shed light on the design of the new GalNAc.