- Bioavailability (F) is a pharmacokinetic parameter representing the fraction of a drug dose that reaches the systemic circulation unaltered.
- The greater the F, the greater the amount of drug that reaches the systemic circulation, and thus the greater the drug concentration in plasma and vice versa
- The route with the highest F (F=1) is via intravenous (I.V.) administration.
- The second highest F is achieved through inhalation.
- The parenteral routes of drug administration have low F because all the drug absorbed by the GIT, passes through the hepatic circulation undergoing first pass metabolism, prior entering to the systemic circulation.
- It is the comparison of the per os F to the intravenous F
- AUCP.O.: area under the curve for the oral route
- AUCI.V.: area under the curve for the intravenous route
- DP.O.: dose administered from oral route
- DI.V.: dose administers from intravenous route
- It is the comparison of the per os F to another administration route, other than intravenous.