Use this pharmacokinetic calculation when dose, exposure, concentration, time, and route use compatible units and refer to the same analyte and study period.

Oral AUC

A finite measured or assumed value.

Intravenous AUC

A finite measured or assumed value.

Oral dose

A finite measured or assumed value.

Intravenous dose

A finite measured or assumed value.

The implementation follows this calculation rule: Compute oral bioavailability as a percentage from AUC and dose comparisons.

Bioavailability

The calculated bioavailability in %.

AUC segments, clearance, bioavailability, bioequivalence ratios, and concentration–response parameters depend on sampling design and model assumptions. Sparse sampling, extrapolation, nonlinear kinetics, active metabolites, and unaligned doses can invalidate a comparison. Ratios and percentages become unstable when their denominator is small, uncertain, or defined differently between samples.

Inspect the concentration–time data and calculate uncertainty with an appropriate pharmacokinetic model. Peak concentration, time to peak, terminal half-life, and dose-normalized exposure often provide complementary information.

• Clearance Rate

  Compute drug clearance from an administered dose and the plasma AUC.

• Apparent Vd

  Estimate volume of distribution as the systemically available dose (administered dose times bioavailability) divided by plasma concentration.

• Trapezoidal AUC

  Compute the trapezoidal area under a concentration-time segment as the average of the two concentrations multiplied by the elapsed time interval.