As a drug discovery program progresses, it becomes more
important to know the types of biotransformation and the
information on the metabolic site(s) that the lead compounds are
subject to, so that structures can be optimized to improve factors
such as bioavailability and pharmacokinetics. In addition, some
insight into the species specificity of metabolism may be obtained,
providing a basis for the selection of preclinical
toxicology species. Then, as compounds move from discovery to
development, the need for even more detailed and precise metabolite
data becomes increasingly important, both to understand the
characteristics of the candidate drug in humans and to fulfill the
regulatory requirements that will underpin a successful drug
registration.