Pharmacokinetics is the quantitative study of the dynamic processes that govern the fate of exogenous substances, particularly pharmaceutical drugs, within a biological system. This academic field investigates the time course of absorption, distribution, metabolism, and excretion (ADME), characterizing the relationship between dose and drug concentration in various body compartments. Its significance lies in providing the scientific basis for optimizing drug dosing, predicting therapeutic and toxic responses, and informing drug development and regulatory science.