Rapid bioanalysis of vancomycin in serum and urine by high-performance liquid chromatography tandem mass spectrometry using on-line sample extractionand parallel analytical columns

A novel high-performance liquid chromatography tandem mass spectrometry (LC /MS/MS) method is described for the determination of vancomycin in serum an d urine. After the addition of internal standard (teicoplanin), serum and u rine samples were directly injected onto an HPLC system consisting of an ex traction column and dual analytical columns. The columns are plumbed throug h two switching valves. A six-port valve directs extraction column effluent either to waste or to an analytical column. A ten-port valve simultaneousl y permits equilibration of one analytical column while the other is used fo r sample analysis. Thus, off-line analytical column equilibration time does not require mass spectrometer time, freeing the detector for increased sam ple throughput. The online sample extraction step takes 15 seconds followed by gradient chromatography taking another 90 seconds. Having minimal sampl e pretreatment the method is both simple and fast. This system has been use d to successfully develop a validated positive-ion electrospray bioanalytic al method for the quantitation of vancomycin. Detection of vancomycin was a ccurate and precise, with a limit of detection of 1 ng/mL in serum and urin e. The calibration curves for vancomycin in rat, dog and primate were linea r in a concentration range of 0.001-10 mug/mL for serum and urine. This met hod has been successfully applied to determine the concentration of vancomy cin in rat, dog and primate serum and urine samples from pharmacokinetic an d urinary excretion studies. Copyright (C) 2001 John Wiley & Sons, Ltd.