Validation of the robustness of an analytical method by design of experiments

The robustness of an analytical method is a measure of its ability to withstand, without consequence, small variations in the method's internal parameters (pH, flow rate, etc.). These variations are of the same order of magnitude as those which could occur during the application of the method under normal conditions of use. Robustness therefore assesses a method's reliability under routine conditions of use.

Several reference guides are available to quality control specialists for the validation of analytical methods. The work of the International Conference Harmonisation (ICH), with its Q2 (R1) guide, is one of the reference documents in this field. It should be noted that, although robustness validation is not listed in the mandatory criteria defined by the ICH for the validation of an analytical method, it is well known that the study of robustness should be considered at an appropriate stage in the development of the analytical procedure.