Pharmacokinetics, sometimes abbreviated as PK (from Ancient Greek pharmakon "drug" and kinetikos "moving, putting in motion"; see chemical kinetics), is a branch of pharmacology dedicated to determining the fate of substances administered externally to a living organism. The substances mainly depends on the pharmaceutical agents, hormones, nutrients, and toxins. Pharmacokinetics determines the fate of a drug from the administration point at which it is entirely excreted from the body. Pharmacokinetics also determines how the body affects after administration of a specific amount of drug through the mechanisms of absorption and distribution, as well as the chemical changes of the substance in the body such as metabolic enzymes such as cytochrome P450 or glucuronosyltransferaseenzymes, and the effects and routes of excretion of the metabolites of the drug. Pharmacokinetic properties of drugs is also influences by features such as the site of administration and the dose of administered drug. These may affect the absorption rate. Pharmacokinetics is generally studied in conjunction with pharmacodynamics, the study of a drug's pharmacological effect on the body. A number of model has been established to study the pharmacokinetics. Multi Compartment model method is widely used.