Drug metabolism and pharmacokinetics in support of drug design

Pharmacokinetics has been recognized as one of the elements determining the probability of success in pharmaceutical research. As a result, compounds are routinely evaluated in drug discovery for their absorption, distribution, metabolism and elimination properties. The primary objective of these studies is to eliminate "flawed" molecules or a structural class based on preset selection criteria, while building a knowledge base for compilation of structure-activity relationships to guide chemistry synthesis efforts. This article is intended to provide a brief overview combined with critical evaluation on several strategies employed during lead optimization processes, and the analyses are supported by case studies. Future directions are discussed in the context of overcoming deficiencies in the current practice by developing tools enabling better prediction of clinical outcomes.