Improvement of chemical analysis of antibiotics. XV. Isocratic high-performance liquid chromatographic methods for the analysis and preparative separation of the components of bacitracin.

Isocratic high-performance liquid chromatographic (HPLC) systems were established for analytical and preparative separation of the components of the antibiotic preparation bacitracin (BC). The best analytical results were obtained using a C18 modified silica gel column (Capcell Pak C18) with a solvent system of 0.04 M disodium hydrogenphosphate buffer and methanol (4:6), pH 9-10. The calibration graphs showed good linear relationships between 50 and 1000 ng for BC-A and between 65 and 1000 ng for BC-F. With respect to the preparative HPLC, a Capcell Pak C18 column with methanol-0.05 M aqueous sodium sulphate solution (6:4) as a mobile phase gave satisfactory results. The isolation of BC-A and -F was readily achieved without decomposition of the components by using the present preparative HPLC followed by desalting on a prepacked C18 cartridge.