Bioavailability of Drug Calculator

Bioavailability Formula:

\[ f = \frac{AUC_{po} \times D_{iv}}{AUC_{iv} \times D_{po}} \]

Area under Curve Non-Intravenous (AUC_po):

Mole Second per Cubic Meter

Dose Intravenous (D_iv):

Mole

Area under Curve Intravenous (AUC_iv):

Mole Second per Cubic Meter

Dose Non-Intravenous (D_po):

Mole

Bioavailability of Drug (f):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Bioavailability of Drug?

The Bioavailability of Drug is defined as the systemically available fraction of a drug. It represents the proportion of a drug that enters the circulation when introduced into the body and is able to have an active effect.

2. How Does the Calculator Work?

The calculator uses the bioavailability formula:

\[ f = \frac{AUC_{po} \times D_{iv}}{AUC_{iv} \times D_{po}} \]

Where:

\( f \) — Bioavailability of Drug
\( AUC_{po} \) — Area under Curve Non-Intravenous (Mole Second per Cubic Meter)
\( D_{iv} \) — Dose Intravenous (Mole)
\( AUC_{iv} \) — Area under Curve Intravenous (Mole Second per Cubic Meter)
\( D_{po} \) — Dose Non-Intravenous (Mole)

Explanation: The formula compares the systemic exposure of a drug administered orally (non-intravenous) to that administered intravenously, which has 100% bioavailability by definition.

3. Importance of Bioavailability Calculation

Details: Bioavailability is a crucial pharmacokinetic parameter that determines the fraction of an administered dose that reaches systemic circulation. It helps in determining appropriate dosing regimens and comparing different formulations of the same drug.

4. Using the Calculator

Tips: Enter all values in the appropriate units. All values must be positive numbers greater than zero. The calculator will compute the bioavailability fraction (f) which typically ranges from 0 to 1.

5. Frequently Asked Questions (FAQ)

Q1: What does a bioavailability value of 1 mean?
A: A value of 1 indicates that 100% of the drug reaches systemic circulation, which is typical for intravenous administration.

Q2: Why is intravenous bioavailability always 1?
A: Intravenous administration delivers the drug directly into the bloodstream, bypassing absorption barriers, so the entire dose reaches systemic circulation.

Q3: What factors affect bioavailability?
A: Factors include drug formulation, gastrointestinal absorption, first-pass metabolism, food interactions, and individual patient factors.

Q4: What is considered good bioavailability?
A: Generally, bioavailability above 0.8 (80%) is considered excellent, while values below 0.3 (30%) may require special formulation strategies.

Q5: How is AUC measured?
A: AUC (Area Under the Curve) is calculated from plasma concentration-time data obtained through blood sampling at various time points after drug administration.