A REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR DETERMINATION OF CEPHALEXIN IN HUMAN PLASMA

A reversed-phase HPLC method for the analysis of cephalexin o-5-thia-1 -azabicyclo[4.2.0]oct-2-ene-2-carboxglic acid) by isocratic separation is described. A comparison is made between the ultrafiltration and th e extraction procedure developed in our laboratory. The extraction pro cedure, based on the deproteinization of plasma with perchloric acid f ollowed by the extraction with dichloroethane and separation of cephal exin on a reversed phase column, gave better recovery, Quantitative va lidation of our method has been performed by an external standard tech nique, The relative standard deviations were between 1.1 and 1.9% in t he within-day assay and between 1.2 and 2.2% in the inter-day assay, T he limit of detection was 0.14 mu g/ml and the limit of quantification was 0.28 mu g/ml. This method is rapid, sensitive, simple, and reprod ucible, The LC MS/MS technique was successfully used for identificatio n and quantification of cephalexin in human plasma samples.