The role of pharmacokinetics in veterinary drug residues.

This review provides a summary of those pharmacokinetic properties of veterinary drugs relevant to marker residues, marker tissues, and residue depletion rates. The scientific literature in this field is very extensive and there is also a wealth of data available on the websites of various regulatory jurisdictions. Therefore, this review is limited to selected examples, cited to illustrate general principles. The areas considered are: (1) the relationship of dose to plasma concentration through the pharmacokinetic properties, area under plasma concentration-time curve, bioavailability, and clearance; (2) the critical dependence of drug pharmacokinetics and residue depletion on product formulation; (3) disease state and population pharmacokinetics; and (4) the requirement for residue depletion studies for generic products shown to be bioequivalent to pioneer products.