What is Bioavailability - Meaning and definition

Published by Roberto Wenk. Reviewed by Alison Ramsey. Last updated date: September 13, 2018.

The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action.

DeCS. Health Sciences Descriptors. Internet. Accessed on May 25, 2016.

Published by Roberto Wenk. Reviewed by Alison Ramsey. Last updated date: September 13, 2018.

In pharmacology, bioavailability (BA) is a subcategory of absorption and is the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs.
By definition, when a medication is administered intravenously, its BA is 100%. However, when a medication is administered via other routes (such as orally), its BA generally decreases (due to incomplete absorption and first-pass metabolism) or may vary from patient to patient.

BA is one of the essential tools in pharmacokinetics, as bioavailability must be considered when calculating dosages for non-intravenous routes of administration.
It is a measurement of the rate and extent to which a drug reaches at the site of action. It is denoted by the letter f (or, if expressed as a percentage, by F).

Adapted from Wikipedia, the free encyclopedia. Internet. Accessed on January 18, 2016.

Bioavailability

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