Chiral separations using the macrocyclic antibiotics: a review

The macrocyclic antibiotics have recently gained popularity as chiral selec tors in CE, HPLC and TLC. The macrocyclic antibiotics used for chiral separ ations include the ansamycins, the glycopeptides, and the polypeptide antib iotic thiostrepton. Although not strictly considered macrocyclic antibiotic s, the aminoglycosides are antibiotics that have been used for chiral separ ations in CE. More chiral analytes have been resolved using the glycopeptid es than with the other macrocyclic antibiotics combined. The glycopeptides vancomycin, ristocetin A and teicoplanin have been used extensively as chir al selectors in CE, with ristocetin A appearing to be the most useful chira l selector followed by vancomycin and teicoplanin, respectively. The macroc yclic antibiotics have also been used as chiral bonded phases in HPLC, and HPLC stationary phases based on vancomycin, ristocetin A and teicoplanin ha ve been commercialized. Ristocetin A seems to be the most useful glycopepti de HPLC bonded phase, but its greater expense can be a drawback. The macroc yclic antibiotics have been used with micelles to improve efficiency, provi de unique selectivity, and extend the range of separations to neutral solut es. Changing the macrocyclic antibiotic used in CE or HPLC can significantl y alter the enantioselectivity of the separations. In fact, the glycopeptid e antibiotics are complementary to one another, where if a partial enantior esolution is obtained with one glycopeptide, there is a high probability th at a baseline or better separation can be obtained with another. (C) 2001 E lsevier Science B.V. All rights reserved.