Journal of liquid chromatography vol:16 issue:2 pages:421-445
A method for analysis of cefalexin by isocratic liquid chromatography is described. Cefalexin is separated from its related substances on a poly(styrene-divinylbenzene) stationary phase (PLRP-S, 250 x 4.6 mm I.D.) at 50-degrees-C. The mobile phase contains acetonitrile, 0.02 M sodium 1-octanesulphonate, 0.2 M phosphoric acid and water (15.5:10:5:up to 100). The flow rate is 1.0 ml/min, 30 mug samples are injected and UV-detection is at 254 nm. Results for official reference substances, a number of bulk samples and pharmaceutical dosage forms are reported.