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

Test AUC

Area under the plasma concentration-time curve for the test product; must not be negative.

Reference AUC

Area under the plasma concentration-time curve for the reference product; must be greater than zero.

The implementation follows this calculation rule: Express bioequivalence as the test product area under the curve as a percentage of the reference product area under the curve.

Bioequivalence

Test-to-reference AUC ratio expressed as a percentage.

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.

• Trapezoidal AUC

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

• Bioavailability %

  Compute oral bioavailability as a percentage from AUC and dose comparisons.

• Clearance Rate

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