Automated high-performance liquid chromatographic method for the determination of rifampicin in plasma

Due to the unstable nature of rifampicin, a rapid automated high-performance liquid chromatographic method had to be developed for the analysis of a large number of plasma samples generated during a bioavailability trial. Extraction and injection of the samples were automatically done by a sample preparation system using C2, 100 mg Bond Elut extraction columns. The extracts were chromatographed on a 4-microns reversed-phase C18 column with a citrate buffer and acetonitrile as mobile phase. The analytes were detected at 342 nm. Calibration curves were linear to at least 20 micrograms/ml and the limit of quantification was 0.16 micrograms/ml.