Residence time in drug discovery: current insights and future perspectives

The temporal stability of ligand-receptor complexes is increasingly acknowledged as a critical factor in drug discovery, influencing both efficacy and pharmacodynamics. Although the relationship between the duration of compound action and complex stability can be traced back to Paul Ehrlich's 19th-century doctrine Corpora non agunt nisi fixata, its significance has gained renewed attention in recent years. This review comprehensively examines the concept of residence time (RT). We first summarize key ligand binding models (lock-and-key, induced-fit, and conformational selection) and delve into various perspectives on how RT impacts functional outcomes. Furthermore, we discuss experimental methods for measuring RT, highlighting both radioligand and non-radioligand approaches. The growing interest in RT has spurred advancements in computational techniques, particularly molecular dynamics simulations, which utilize diverse strategies to observe dissociation events. We outline these molecular dynamics-based methods, their theoretical foundations, and provide examples of their application in assessing RT. Finally, we highlight molecular determinants of prolonged RT, focusing primarily on G protein-coupled receptors (GPCRs) while also incorporating relevant data from other receptor classes.