Micellar electrokinetic capillary chromatography of macrolide antibiotics - Separation of tylosin, erythromycin and their related substances

The separation of tylosin by micellar electrokinetic capillary chromatograp hy with a mixed micelle system is described. Good selectivity was obtained with sodium phosphate buffer (80 mM, pH 7.5) containing 20 mM sodium cholat e and 7 mM cetyltrimethylammonium bromide (CTAB). This method permits tylos in to be separated from its closely related substances within 15 min. The i nfluences of type of buffer, buffer pH, the concentrations of sodium cholat e and CTAB were investigated. The robustness of the method was examined for tylosin by means of a full-fraction factorial design. Quantitative results are presented. Using a similar buffer system (80 mM sodium phosphate, pH 6 .0, 20 mM sodium cholate and 5 mM CTAB), separation of erythromycin and its main related substances was also obtained. However, detection sensitivity and resolution are not sufficient for analysis of related substances in ery thromycin commercial samples. (C) 1999 Elsevier Science B.V. All rights res erved.