Introduction To Pharmacokinetics
Area Under The Concentration-Time Curve (AUC)
HOW TO FIND AUC
To find the most accurate value for the area under the curve, you would find the integral of the curve from when the drug is first given to when the plasma drug concentration is negligible.
where Cpt = plasma drug concentration at time t dt = change in time
However, in practice, the area under the curve is estimated using the trapezoidal rule.
The concentration-time graph is divided into trapezoids.
The area for each trapezoid tells you the amount of drug eliminated during that particular time frame. The total area of all the trapezoids – the AUC – gives you the total amount of drug eliminated over the whole time period.
The following page shows an example of finding AUC using the trapezoidal rule.
