Enantiomeric Separation Of Selected Pharmaceuticals On Chiral Stationary Phases By HPLC

Naproxen and its derivatives, four β2-acceptor analeptics, and eight other pharmaceuticals being widely used in clinic have been selected and tested on four chiral stationary phases(CSPs) including Whelk-O1, DNB-PG, DNB-Leucine and SH-1 by HPLC under different conditions. The effects of mobile phase composition and temperature on enantioselectivity have been investigated, and the chiral recognition mechanisms have also been discussed further according to the relative thermodynamic parameters.It was shown that the resolution of naproxen and its derivatives on Whelk-O1 CSP was very special. With the variation of mobile phase modifier's concentration , non-linear change of enantiomeric separation factor and maximal value of α corresponding to a very high mobile phase polarity (20%~50%VIPA) were found. This result indicated that the polar component of mobile phase effected the chiral recognition process by a particular way.At the same time, the linear plots of separation factor to mobile phase polarity of clenbuterol and procaterol enantiomers were found. To obtain more information about the discrimination process, the Gibbs-Helmholz parameters (??H and ??S) were examined. It was found that there were maximal ??H and ??S when the mobile phase of 5%VIPA being used. Obviously, the adsorption mechanisms in different conditions were different. The chiral recognition models of naproxen and clenbuterol enantiomers on Whelk-O1 CSP were predicted by the comparison research of enantioseparation thermodynamic data. In addition, ecanazol enantiomers have been directly separated by HPLC originally in this study.