Pharmacokinetics, sometimes described as what the body does to a drug, refers to the movement of drug into, through, and out of the body—the time course of its absorption, bioavailability, distribution, metabolism, and excretion. Pharmacokinetics derived from the Greek words pharmakon (drug) and kinetikos (movement), is used to describe the absorption, distribution, metabolism, and excretion of a compound. Pharmacokinetics refers to the movement of drugs into, through and out of the body. The type of response of an individual to a particular drug depends on the inherent pharmacological properties of the drug at its site of action. Clinical pharmacokinetics is the application of pharmacokinetic principles to the safe and effective therapeutic management of drugs in an individual patient. Pharmacokinetics is an area of pharmacology concerned with the time course of absorption, distribution, metabolism and excretion (collectively ADME) of drugs from biological systems in order to understand the effect of the drug, or of the organism, on the drug's impact. Pharmacokinetic parameters can also include toxicology and a drug’s liberation from its medicinal formulation.