Enantioselective analysis of the antipsychotic 9-hydroxyrisperidone, main metabolite of risperidone, by chiral capillary EKC using dual CDs

An analytical method for the enantioseparation of the 9-hydroxyrisperidone, main metabolite of the antipsychotic risperidone (Risp), was developed by CD-EKC in the dual CDs mode using anionic and neutral CDs at acidic pH 2.5. Preliminary experiments allowed us to select the more suitable couple of CDs composed of sulfated-alpha-CD and hydroxypropylated-beta-CD. The optimization of the main experimental parameters (concentrations of both CDs and concentration of the phosphate buffer) was based on a central composite design through the response surface methodology. Then, the influence of the voltage and the temperature on the enantioseparation was studied using the classical univariate approach. The final method permits to resolve the enantiomers of the 9-hydroxyrisperidone with a resolution of 3.13 and an analysis time of about 13 min. Finally, this method was successfully applied for the simultaneous determination of Risp and the enantiomers of 9-hydroxyrisperidone (9-OHRisp).