Enantioseparation of meptazinol and its three intermediate enantiomers by capillary electrophoresis using a new cationic β-cyclodextrin derivative in single and dual cyclodextrin systems.

A new cationic β-cyclodextrin derivative, mono-6-deoxy-6-piperdine-β-cyclodextrin (PIP-β-CD), was synthesized and applied as a chiral selector for the enantioseparation of meptazinol and its three intermediate enantiomers (intermediates II-IV) in capillary electrophoresis. When PIP-β-CD was employed as the single CD system, intermediate II was baseline enantioseparated while the results for the other analytes were less satisfactory. In order to enhance the selectivity and resolution of meptazinol intermediate III and intermediate IV, dual CD systems of PIP-β-CD in combination with three different neutral CDs were synthesized and tested: β-cyclodextrin (β-CD), trimethyl-β-cyclodextrin (TM-β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD). After investigating the effect on the enantioseparation efficiency of the nature and the concentration of both CDs, the dual CD system consisting of PIP-β-CD and HP-β-CD was shown to be the most efficient for the simultaneous enantioseparation of meptazinol intermediates III and IV.