Five arylpropionic acid nonsteroidal antiinflammatory drugs, i.e. ibuprofen, etodolac, fenoprofen calcium salt hydrate, ketoprofen and loxoprofen, were enantiomerically separated on a commercially available OJ cellulose chiral stationary phase by high performance liquid chromatography in a normal mode. The mechanism of enantioseparation was studied by stoichiometric displacement model for retention and thermodynamic study. It was found that the chromatographic retention and enantioseparation could be generated by the type of alcohol displacer and organic acid modifier, modification of the concentration of alcohol displacer and organic acid modifier, and change of column temperature.

Key words: HPLC, chiral stationary phase, enantioseparation, nonsteroidal anti-inflammatory drug