Robustness testing of a reversed-phase high-performance liquid chromatographic assay: comparison of fractional and asymmetrical factorial designs

Robustness tests were performed on a reversed-phase HPLC assay for triadime nol. Different experimental designs were compared. Two-level fractional fac torial designs with different resolutions were used to study the influence of procedure-related factors. The factors chromatographic column manufactur er at four levels and instrument at three levels were stepwise included in the study using asymmetrical factorial designs. The significance of the fac tor effects was determined statistically, using two types of error estimate s in the calculation of critical effects, and graphically, by means of half -normal plots. The asymmetrical designs turned out to be an efficient and e conomic method to examine the influence of factors at different numbers of levels in the robustness testing of analytical methods. (C) 2000 Elsevier S cience B.V. All rights reserved.