The Design of Chiral Separations for β-Blocker Drugs on Pirkle High-Performance Liquid Chromatography Phases Using Achiral Derivatisation

Summary

The chromatographic performance of a series of isocyanate and isothiocyanate derivatives of (+/−)-propranolol on three Pirkle phases was investigated. For each phase the choice of urea or thiourea derivative had a consistent effect on retention although not on resolution. The relationship between structure and retention on π-acidic amino acid phases is explicable although this cannot be extended to separations observed. Inversion of elution order of the (+)- and (−)-enantiomers was observed for some derivatives on the covalent 1-leucine phase which further hinders the attempt to link structure to resolution for predictive method development purposes. The α-naphthyl and phenyl derivatives generally gave good resolution of enantiomers.