Avoparcin, a new macrocyclic antibiotic chiral run buffer additive for capillary electrophoresis

Avoparcin, like vancomycin, teicoplanin, and ristocetin A, belongs to the f amily of macrocyclic glycopeptide antibiotics. These antibiotics have all b een used as effective chiral selectors for capillary electrophoresis (GE), thin-layer chromatography (TLC), and high performance liquid chromatography (HPLC). The present work focuses on avoparcin, which has been shown to be an excellent chiral selector for the CE enantioseparation of many N-blocked amino acids, as well as several anti-inflammatory drugs of pharmaceutical importance. The use of avoparcin as a chiral run buffer additive in CE is d iscussed, as well as the effects of changing experimental parameters, like avoparcin concentration, pH, organic modifiers, etc. Comparisons of enantio separations of some N-3,5-dinitrobenzoyl-derivatized amino acids, using eit her avoparcin, ristocetin A, teicoplanin, or vancomycin in the run buffer, are also made. In general, vancomycin had the longest migration times, and ristocetin A the shortest, while avoparcin was intermediate. Generally, at least one of the four chiral selectors produced an excellent separation, wh ile a different macrocyclic antibiotic produced a poor separation. Currentl y, we see no way to predict which chiral run buffer additive will be best o r worst for an individual solute.