High-performance liquid chromatographic determination of xipamide in human plasma

A method for the determination of the diuretic xipamide in human plasma is described. It involves extraction of the drug and an internal standard, mephenesin, into diethyl ether-isopropanol (19 + 1), evaporation of the organic phase and analysis of the reconstituted residue on a C8 reversed-phase column, which is eluted with acetonitrile-acetate buffer (25 + 75). The drug and internal standard are detected by ultraviolet absorption at 225 nm. The method is precise with mean coefficients of variation of 4.1 and 4.3% for within-day (intra-assay) and between-day (inter-assay) runs, respectively. The recovery is 80% or greater at all concentrations and the method has a limit of determination of 100 ng ml–1 of xipamide in plasma.