Simple and rapid liquid chromatographic-turbo ion spray mass spectrometricdetermination of topiramate in human plasma

We present a simple and fast method for the determination of the novel anti epileptic drug topiramate in human plasma by high-performance liquid chroma tography coupled with turbo ion spray mass spectrometry. Plasma sample pre- treatment was based on simple deproteinization by acetonitrile. Liquid chro matographic analysis was carried out on a reversed-phase column (C-18, 125 x 4 mm I.D., 5 mum) using acetonitrile-ammonium acetate buffer, pH 6.3 as t he mobile phase, at a flow-rate of 0.8 ml/min. Retention time for topiramat e was 2.1 min. The detector was a single quadrupole mass spectrometer coupl ed to a turbo ion spray ion source and a heated nebulizer probe, operating in the positive ion mode. Ion source temperature was off; voltage was +5800 V, nebulizer and curtain gas flow-rates were 6 and 10 ml/min, respectively . Calibration curves for topiramate were linear over the range 1 to 20 mug/ ml. Absolute recovery ranged between 92 and 95%. Intra- and inter-assay pre cision was <4%. The present procedure, omitting extraction and drying steps , is faster and simpler than the previously reported analytical methods for topiramate and was demonstrated to possess adequate sensitivity for routin e therapeutic drug monitoring in plasma from patients with epilepsy. (C) 20 01 Elsevier Science B.V. All rights reserved.