Robustness and System Suitability
The robustness of an analytical procedure is defined as a measure of its capacity to obtain comparable and acceptable results when perturbed by small but deliberate variations in procedural parameters listed in the documentation [1,2]. Robustness provides an indication of the method’s suitability and reliability during normal use and is the cornerstone of any good method validation process. One consequence of the evaluation of robustness is the establishment of system suitability parameters to ensure that the validity of the analytical procedure is maintained whenever used. Although not formally a part of method validation according to the USP, system suitability tests are an integral part of chromatographic methods . System suitability tests are used to verify that the resolution and precision of the system are adequate for the analysis to be performed. System suitability tests are based on the concept that the equipment, electronics, analytical operations, and samples constitute an integral system that can be evaluated as a whole, and in this way system suitability can be thought of as the test that pulls together the entire validation process. This chapter discusses both topics from an experimental design and specificationsetting standpoint. Both USP Chapter 1225: Validation of Compendial Methods, and the International Conference on Harmonization (ICH) Guideline: Validation of Analytical Procedures: Text and Methodology Q2 (R1), address robustness [1,2]. While the USP is the sole legal document in the eyes of the FDA, this chapter draws from both guidelines as appropriate for definitions and methodology.