Development and robustness testing of a nonaqueous capillary electrophoresis method for the analysis of nonsteroidal anti-inflammatory drugs

Nine non steroidal anti-inflammatory drugs were simultaneously separated by nonaqueous capillary electrophoresis with a methanol–acetonitrile (40:60, v/v) mixture containing 20 mM ammonium acetate. The effect of solvent composition, electrolyte nature and concentration on the electrophoretic behavior of the selected drugs was systematically studied. Investigated electrolytes were ammonium, lithium and sodium acetate. Modification of the solvent and/or the electrolyte composition was found to alter the migration order of the pharmaceutical drugs. Finally, to assess method robustness, three sensitive electrophoretic parameters as well as their interactions were evaluated using a full factorial design at two levels.