Evaluation of six chiral stationary phases in LC for their selectivity towards drug enantiomers.

Six chiral stationary phases (CSP) were evaluated for their enantioselectivity towards a series of 45 drugs with different acidic, basic or neutral properties. These CSPs were: a polyacrylamide phase, Chiraspher; two polysaccharide-based phases, cellulose tris-3,5-dimethyl phenylcarbamate (Chiralcel OD) and the S-naphthylethylcarbamate derivative of beta-cyclodextrin (SN-beta-CD; Cyclobond I SN); and three protein-based CSPs--alpha 1-acid glycoprotein (Chiral-AGP), ovomucoid (OVM) and cellulase. A total of 28 different mobile phases were involved. Chiral-AGP, OVM and Chiralcel OD appeared to be the most promising CSPs for the enantio separation of the series of structurally different compounds evaluated. Cellulase and Chiralcel OD show particularly high enantioselectivity towards the group of beta-blocker drugs. The different protein-based CSPs were used in their usual reversed-phase mode. The other phases were used in combination with apolar mobile phases, except for SN-beta-CD, which was evaluated in both modes. Formal optimization strategies were not adopted, although the effect of organic modifier and eluent pH on enantioselectivity was briefly examined for the protein-based phases.