ADME stands for Absorption, Distribution, Metabolism, and Excretion. These four processes describe the movement of a drug into, through, and out of the body. Essentially, it's the process by which the body handles a drug.
Here's a breakdown of each component:
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Absorption: This is the process by which a drug enters the bloodstream. It involves the drug's movement from the site of administration (e.g., oral, intravenous, intramuscular) across biological membranes into the systemic circulation. Factors like the drug's formulation, route of administration, and physiological factors can influence absorption.
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Distribution: Once absorbed, the drug is distributed throughout the body via the bloodstream to various tissues and organs. Factors affecting distribution include blood flow, tissue binding, and the drug's ability to cross biological barriers like the blood-brain barrier.
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Metabolism: Also known as biotransformation, metabolism is the process by which the body chemically modifies a drug. This usually occurs in the liver but can also happen in other tissues. Metabolism often converts the drug into inactive metabolites, which are easier to excrete. However, some drugs are activated by metabolism (prodrugs).
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Excretion: This is the process by which the drug and its metabolites are removed from the body. The kidneys (via urine) are the primary route of excretion, but drugs can also be excreted through the bile (via feces), lungs (via exhaled air), sweat, and breast milk.
Understanding ADME is crucial in drug development and pharmacology because it determines the drug's concentration at its target site, and therefore its efficacy and safety. Differences in ADME between individuals can influence their response to a drug, leading to variability in therapeutic outcomes and adverse effects.
