2,851
edits
Bioavailability: Difference between revisions
→Measuring Bioavailability
No edit summary |
|||
| Line 18: | Line 18: | ||
Bioavailability is often assessed through specific pharmacokinetic studies, which evaluate the concentration of a drug in plasma over time. The two key metrics used are absolute and relative bioavailability. | Bioavailability is often assessed through specific pharmacokinetic studies, which evaluate the concentration of a drug in plasma over time. The two key metrics used are absolute and relative bioavailability. | ||
=== '''Absolute Bioavailability''' === | |||
This measures the bioavailability of a drug compared to its intravenous administration. The formula for calculating absolute bioavailability (F) is: | |||
<math>F = \frac{AUC_{\text{oral}} \times Dose_{\text{IV}}}{AUC_{\text{IV}} \times Dose_{\text{oral}}} \times 100\%</math> | <math>F = \frac{AUC_{\text{oral}} \times Dose_{\text{IV}}}{AUC_{\text{IV}} \times Dose_{\text{oral}}} \times 100\%</math> | ||
where AUC is the area under the plasma concentration-time curve for oral (AUC<sub>oral</sub>) and intravenous (AUC<sub>IV</sub>) administration, and Dose refers to the dose administered via each route. | where AUC is the area under the plasma concentration-time curve for oral (AUC<sub>oral</sub>) and intravenous (AUC<sub>IV</sub>) administration, and Dose refers to the dose administered via each route. | ||
=== '''Relative Bioavailability''': === | |||
This compares the bioavailability of a drug in different formulations, usually against a standard. The formula is: | |||
<math>F_{\text{rel}} = \frac{AUC_{\text{test}} \times Dose_{\text{ref}}}{AUC_{\text{ref}} \times Dose_{\text{test}}} \times 100\%</math> | <math>F_{\text{rel}} = \frac{AUC_{\text{test}} \times Dose_{\text{ref}}}{AUC_{\text{ref}} \times Dose_{\text{test}}} \times 100\%</math> | ||
where AUC<sub>test</sub> and AUC<sub>ref</sub> are the areas under the curve for the test and reference formulations, respectively, and Dose is the dose for each. | where AUC<sub>test</sub> and AUC<sub>ref</sub> are the areas under the curve for the test and reference formulations, respectively, and Dose is the dose for each. | ||