Determination of system suitability limits with a robustness test

A robustness test was performed on a chromatographic method to identify and assay an active substance and two related compounds in film-coated tablet. For a number of responses the originally applied system suitability criteria were evaluated based on the results of the robustness test. Ambiguous situations can occur in situations where a method is found to be robust to assay the substances, as was the case here, but when system suitability criteria for some responses are violated. To avoid this, a proposal is made to define or re-define system suitability limits based on the results of the robustness test. From the effects found in the robustness test, the experimental conditions giving the worst result that still is acceptable and probable to occur are predicted and the system suitability limits are defined from replicated experiments in these conditions. (C) 1999 Elsevier Science B.V. All rights reserved.