Calculation of Area Under the Curve (AUC)
Using the Trapeziodal Rule
The Approach
- First Segment - Extrapolate concentration back to y-axis to estimate Cp0. This is best done on semi-log graph paper. Calculate the first AUC segment using the trapezoidal rule.
- Middle segments. Calculate each segment according to the trapzezoidal rule. That is half height times width.
- Last segment. Calculate as last concentration divided by terminal rate constant (kel for a one compartment pharmacokinetic model)
Total AUC is calculated by adding all the segments together. Units of concentration times time. i.e. mg.hr/L.