INFLUENCE OF UNCHARGED MOBILE PHASE ADDITIVES ON RETENTION AND ENANTIOSELECTIVITY OF CHIRAL DRUGS USING AN ALPHA-1-ACID GLYCOPROTEIN COLUMN

The influence of uncharged mobile phase additives on retention and enantioselectivity on a chiral α1 acid glycoprotein (AGP) column was investigated. It was observed that it is possible to induce chiral selectivity for several drugs by adding to the mobile phase uncharged modifiers with different hydrophobicities and different hydrogen bonding properties. Modifiers with different hydrogen bonding properties affect the enantioselectivity in different ways. The solute enantiomers seem to compete with the modifier molecules for binding to the chiral stationary phase. The adsorption of 1-propanol and acetonitrile on the AGP column was measured. A monolayer was obtained at mobile phase concentrations of 1.3 M (10%) and 2.8 M (15%) for 1-propanol and acetonitrile, respectively. These concentrations are in the ranges usually used for chromatographic studies. The effect of 2-propanol on the protein conformation was studied using circular dichroism spectroscopy. It was not possible to detect any change in the conformation of AGP, even in the presence of 40% 2-propanol. © 1990.