Macrocyclic Glycopeptide Chiral Stationary Phases

Abstract

The macrocyclic glycopeptide chiral selectors are an important class of Chiral Stationary Phases (CSPs) for liquid chromatography. They were introduced at the end of the last century. Three selectors are especially useful having a broad enantio-recognition capability: ristocetin, vancomycin and teicoplanin. The enantiomers best recognized by these three CSPs include amino-acids and peptides, but also a great number of ionizable chiral acids and bases and an impressive list of active pharmaceutical ingredients (API). This chapter describes in detail the physico-chemical properties of macrocyclic glycopeptides including insights in their three-dimensional structure and interaction possibilities. The unique chromatographic Polar Ionic Mode (PIM) works with waterless polar organic mobile phases (mainly methanol or ethanol) containing small amounts of acid and base so that the ionization state of the chiral selector is adjusted for the discrimination of enantiomers. This class of CSP is multimodal working with 100% polar solvents (PIM or polar organic mode) but also in reverse phase with aqueous buffer mobile phases, and normal phase with alkane/alcohol mixtures. A very large table lists the separation conditions of chiral APIs on macrocyclic glycopeptide CSPs including the recent developments with core–shell based CSPs.