Title: bioavailability
Long Title: IUPAC Gold Book - bioavailability
DOI: 10.1351/goldbook.BT06813
Status: current

Definition
Ratio of the systemic exposure from extravascular (ev) exposure to that following intravenous (iv) exposure as described by the equation: \[F=\frac{A_{\rm{ev}}\ D_{\rm{iv}}}{B_{\rm{iv}}\ D_{\rm{ev}}}\] where \(F\) is the bioavailabilty, \(A\) and \(B\) are areas under the (plasma) concentration-time curve following extravascular and intravenous administration, respectively, and \(D_{\rm{ev}}\) and \(D_{\rm{iv}}\) are the administered extravascular and intravenous doses.

Related Term
- exposure: https://goldbook.iupac.org//terms/view/ET06811

Source
- PAC, 2004, 76, 1033. 'Glossary of terms used in toxicokinetics (IUPAC Recommendations 2003)' on page 1041 (https://doi.org/10.1351/pac200476051033)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/BT06813/html
- json: https://goldbook.iupac.org/terms/view/BT06813/json
- xml: https://goldbook.iupac.org/terms/view/BT06813/xml

Citation: Citation: 'bioavailability' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.BT06813
License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.
Collection: If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .
Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.
Accessed: 2026-07-24T22:34:59+00:00