Pharmacokinetic Principles and Concepts: An Overview

Summary Pharmacokinetics is defined as the study of the time course of a drug in the body. Pharmacokinetic studies can determine the concentration–time profile of drugs in the body. This approach is widely used in clinical settings and drug development. Parameters estimated in pharmacokinetic studies could be related to absorption, distribution, metabolism, and excretion. Absorption describes how drugs access circulation from the site of administration. Distribution highlights how drugs move from circulation in tissues. Metabolism primarily occurs in the liver, where drugs undergo biotransformation through enzymatic reactions to facilitate their elimination. Excretion refers to the removal of a drug from the body, either as the original compound or as a metabolite. Indeed, a number of pharmacokinetic models have been explored to aid in predicting drug disposition in different populations. Some of the models include compartmental, non-compartmental, and physiologically-based pharmacokinetic (PBPK) models. Understanding these pharmacokinetic principles and models allows healthcare providers to optimize drug therapy, manage drug interactions, and decrease the adverse effects of drugs on patients.