Chiral separation of deprenyl-N-oxide isomers by capillary electrophoresis using various cyclodextrin derivatives

Chiral separation of deprenyl-N-oxide isomers is presented using capillary electrophoresis in the presence of various cyclodextrin (CD) derivatives. This recently identified metabolite of R-(-)-deprenyl may possess desirable pharmacological activities. The effect of the cavity size and the substituents of the CD are examined on the enantiomer resolution of the compound having an asymmetric center on a heteroatom. The importance of hydrophilic or hydrogen bonding interaction, as well as the position of the interacting groups is demonstrated. Outstanding selectivity and resolution values are achieved using the chargeable carboxymethyl-beta-CD. 2-Hydroxypropyl-beta-CD is also suitable for the enantiomer separation of the analyte. Native beta-CD and carboxyethyl-beta-CD provide only poor enantioselectivity, whereas heptakis-(2,6-di-O-methyl)-beta-CD is capable of separating only the diastereomers. No chiral resolution can be observed in the presence of gamma-CD.