Introduction To Pharmacokinetics

Method Of Residuals

The major steps for the method of residuals are shown below.
Each step is covered in more detail in the next page.

Step 1
Extrapolate the linear part of the concentration-time curve back to time zero.

Step 2
For each existing time point, read off the corresponding concentration from the extrapolated line. This gives values of C*.

Step 3
For each time point, subtract the original concentration (C) from the extrapolated concentration (C*), giving C*-C.

Step 4
Plot the new concentrations (C*-C) on the same axes and draw the best fit line.