Design strategies for bivalent ligands targeting GPCRs

Specifically designed bivalent ligands targeting G protein-coupled receptor (GPCR) dimeric structures have become increasingly popular in recent literature. The advantages of the bivalent approach are numerous, including enhanced potency and receptor subtype specificity. However, the use of bivalent ligands as potential pharmacotherapeutics is limited by problematic molecular properties, such as high molecular weight and lipophilicity. This minireview focuses on the design of bivalent ligands recently described in the literature; discussing the choice of lead pharmacophore, the position and nature of the attachment point for linking the two pharmacophore units, and the length and composition of the spacer group. Furthermore, this minireview distils the molecular descriptors of the bivalent ligands that exhibit in vivo activity, as well as highlights their ability to access the central nervous system.