in pharmacokinetics
Ratio of the systemic exposure from extravascular (ev) exposure to that following intravenous (iv) exposure as described by the equation:
Math - e
where Math - ei is the bioavailabilty, Math - ei and Math - ei are areas under the (plasma) concentration-time curve following extravascular and intravenous administration, respectively, and Math - ei and Math - ei are the administered extravascular and intravenous doses.
PAC, 2004, 76, 1033 (Glossary of terms used in toxicokinetics (IUPAC Recommendations 2003)) on page 1041