Liquid chromatographic method for separation of lincomycin from its related substances

Abstract

A reversed-phase ion-pair liquid chromatographic method with UV detection at 210 nm is described for the separation of lincomycin from 7-epilincomycin and lincomycin B. The method utilizes a base-deactivated Supelcosil LC-ABZ, C 12–18, 5 μm, 250×4.6 mm I.D. column maintained at 45°C. The mobile phase consists of 2.25% (v/v) acetonitrile, 5% (v/v) phosphate buffer (2.72%, m/v KH 2PO 4 adjusted to pH 5.0 with 3.48%, m/v K 2HPO 4), 0.067% (v/v) methanesulfonic acid and water to 100%. The flow-rate is 1.0 ml/min. The separation of lincomycin from 7-epilincomycin is only possible on base-deactivated (BDS) columns. Other octadecylsilyl columns examined showed insufficient selectivity. The method was also tested on other BDS columns (Spherisorb S5-ODS-B, 5 μm, Hypersil BDS, C 18, 5 μm and Supelcosil LC-ABZ, C 18, 5 μm, all 250×4.6 mm I.D.) and showed good robustness. Robustness was further evaluated by performing a full-factorial design experiment. The method showed good selectivity, repeatability, linearity and sensitivity. It is also suitable for analysis of lincomycin formulations.