Resolution of Mephenytoin and Some Chiral Barbiturates into Enantiomers by Reversed Phase High Performance Liquid Chromatography via β-Cyclodextrin Inclusion Complexes

β-Cyclodextrin as the chiral mobile phase component was used for resolution of mephenytoin and some barbiturates (antidepressant drugs) into enantiomers on LiChrosorb RP 18 column. The effects of β-cyclodextrin concentration on the capacity factors were investigated and the stability constants as well as capacity factors of β-cyclodextrin complexes were calculated. It has been found that β-cyclodextrin complexation results in a distinct enantioselectivity in the case of mephenytoin and barbiturates containing a chiral center in the pyrimidine ring. Results are discussed in the light of two phenomena influencing resolution: adsorption of inclusion complexes on the stationary phase and complexation process in the mobile phase solution.