ADME Principles in Small Molecule Drug Discovery and Development: An Industrial Perspective

It is important to characterize the absorption, distribution, metabolism, and excretion parameters of new molecular entities (NMEs) during the drug development process. These "ADME" parameters are evaluated both in vitro and in vivo and are studied in both animal models and humans. In the discovery phase, NME properties are optimized in order to discover drugs with acceptable pharmacokinetic/exposure and metabolism profiles expected in man, all the while balancing the pharmacological and toxicological activities. In the development phase, the NME is more fully characterized to support clinical development and ultimately support registration and approval of the new drug by global regulatory agencies. In this chapter, important ADME concepts will be reviewed in the context of small molecule drug development. Additionally, the general types of ADME studies conducted in the discovery and development phases, along with the phase-specific goals of these studies, will be discussed.