Overview of pharmacokinetics.

In addition to having selective potency against the molecular target(s), a compound must be able to reach its intended site of action in vivo in sufficient quantity and for the appropriate duration of time to exert a biological effect. The fate of a compound after in vivo administration depends upon its absorption, distribution, metabolism, and excretion (ADME), as well as its target residence time. The concentration of the compound in the blood, plasma, and other tissues represents the sum of all of these processes. Described in this unit are protocols for administering a compound by various routes to rats and for collecting the appropriate samples to determine the pharmacokinetics profile. The basic terms used in pharmacokinetics studies are defined, and representative examples are given to illustrate important variables to consider.