Determination of the enantiomeric purity of dexfenfluramine by capillary electrophoresis: Use of a Plackett-Burman design for the optimization of the separation

For the investigation of the stereochemical purity of the anorectic drug dexfenfluramine, a capillary electrophoretic method is presented using the chiral selector dimethyl beta-cyclodextrin (DMCD). A Plackett-Burman experimental design was used as a multivariate strategy for the evaluation of the effects of varying several operating conditions at once. The impact of concentration of DMCD, concentration of methanol added to the buffer, pH of the background electrolytes, temperature of the capillary and applied voltage, has been investigated on the resolution of the enantiomers, the analysis time and the peak symmetry. From these results, optimal values of the variables were selected for the development of a method capable of determining the levo-rotatory enantiomeric impurity of dexfenfluramine.