Pharmaceutical Biotechnology Research

Pharmacokinetics & Pharmacodynamics

Pharmacokinetics (PK) is the study of how the body interacts with administered substances for the entire duration of exposure (medications for the sake of this article). This is closely related to but distinctly different from pharmacodynamics, which examines the drug's effect on the body more closely. Pharmacokinetics may be defined as what the body does to a drug. It deals with the absorption, distribution, and elimination of drugs but also has utility in evaluating the time course of environmental (exogenous) toxicological agents as well as endogenous compounds. Think of pharmacokinetics as a drug's journey through the body, during which it passes through four different phases: absorption, distribution, metabolism, and excretion.

Pharmacodynamics (PD) is the study of the biochemical and physiologic effects of drugs (especially pharmaceutical drugs). The effects can include those manifested within animals (including humans), microorganisms, or combinations of organisms. Pharmacodynamics and pharmacokinetics are the main branches of pharmacology, being itself a topic of biology interested in the study of the interactions between both endogenous and exogenous chemical substances with living organisms. In particular, pharmacodynamics is the study of how a drug affects an organism, whereas pharmacokinetics is the study of how the organism affects the drug. Both together influence dosing, benefit, and adverse effects. Pharmacodynamics is sometimes abbreviated as PD and pharmacokinetics as PK, especially in combined reference