DISPLACEMENT CHROMATOGRAPHY ON CYCLODEXTRIN SILICAS .4. SEPARATION OFTHE ENANTIOMERS OF IBUPROFEN

A displacement chromatographic method has been developed for the prepa rative separation of the enantiomers of ibuprofen using a beta-cyclode xtrin silica stationary phase. The retention behavior of ibuprofen was studied in detail: the log k' vs. polar organic modifier concentratio n, the log k' vs. pH, the log k' vs. buffer concentration and the log k' vs, 1/T relationships; also, the alpha vs. polar organic modifier c oncentration, the alpha vs. pH, the alpha vs. buffer concentration and the log alpha vs. 1/T relationships have been determined in order to find the carrier solution composition which results in maximum chiral selectivity and sufficient, but not excessive solute retention (1 < k' < 30). 4-tert.-Butylcyclohexanol, a structurally similar but more ret ained compound than ibuprofen, was selected as displacer for the separ ation. Even with an a value as small as 1.08, good preparative chiral separations were observed both in the displacement mode and in the ove rloaded elution mode, up to a sample load of 0.5 mg.