Optimized methods for capillary electrophoresis of tetracyclines.

Optimized methods for the analysis of some tetracyclines by capillary electrophoresis are described. Different buffer systems were employed for the separation of tetracycline, oxytetracycline and demeclocycline from their respective major impurities, including the 2-acetyl-2-decarboxamido derivatives. The influence of buffer pH and buffer concentration was systematically investigated. Non-ionic surfactant Triton X-100 and methyl-beta-cyclodextrin were used to obtain improved selectivity in the case of oxytetracycline and demeclocycline. The results are compared with those of previously established liquid chromatography methods. Good correlations were obtained.