Rapid and sensitive high-performance liquid chromatographic method, for busulfan assay in plasma

A reversed-phase liquid chromatographic method with ultraviolet detection has been developed to determine busulfan concentrations in plasma of children undergoing bone marrow transplantation Plasma samples (200 mu l) containing busulfan and 1,6-bis(methanesulfonyloxy)hexane as an internal standard were prepared by a simple derivatization method with diethyldithiocarbamate followed by extraction with ethyl acetate and solid-phase purification on C-8, columns conditioned with methanol and water and eluted with acetonitrile (recovery 99%). Chromatography was accomplished using a Hypersil octadecylsilyl column (10 cm x 4.6 mm I.D.) and a mobile phase of acetonitrile, tetrahydrofuran and distilled water (65:5:30, v/v), The limit of detection was 25 ng/ml (signal-to-noise ratio of 5). Calibration curves were linear up to 25 000 ng/ml. Intra-day and inter-day coefficients of variation of the assay were less than or equal to 5%. This method was used to analyse busulfan plasma concentrations after oral administration within the framework of therapeutic drug monitoring and pharmacokinetic studies in children. (C) 2000 Elsevier Science B.V. All rights reserved.