Determination of albendazole metabolites by direct injection of bovine plasma and multidimensional achiral–chiral high performance liquid chromatography

The development and validation of a fully automated achiral–chiral high performance liquid chromatography (HPLC) method for the simultaneous determination of albendazole metabolites: enantiomers of albendazole sulphoxide (ABZ-SO), albendazole sulphone (ABZ-SO2) and albendazole 2-aminosulphone (ABZ-SO2NH2) in bovine plasma are described. This method involves an octyl restricted access media bovine serum albumin column (C8-RAM-BSA) (50 mm × 4.6 mm I.D.) for sample clean-up, followed by enantioselective analysis on a column containing an amylose tris(3,5-dimethylphenylcarbamate) stationary phase (150 mm × 4.6 mm I.D.). The chromatographic separations of all target compounds were performed at 30 °C using a mobile phase composed of phosphate buffer (10 mmol L−1; pH 7.5):acetonitrile (60:40, v/v), flow rate of 0.5 mL min−1 and fluorescence detection at 290 nm and 320 nm, excitation and emission, respectively. The influence of different organic modifiers and chiral selector of the stationary phase on enantioseparation of ABZ-SO was investigated. The method developed was fully validated. The calibration curves were linear in the concentration range of 40.00–1280 ng mL−1 for each albendazole sulphoxide enantiomer, 10.0–320 ng mL−1 for albendazole sulphone and 20.0–320 ng mL−1 for albendazole 2-aminosulphone. The inter- and intra-day precision ranged from 0.760% to 7.79% relative standard deviation (R.S.D.), and the accuracy ranged 101% from 114% of the nominal values while the transfer efficiency was in the range of 84.4–103%. The method showed good linearity, precision, accuracy, sensitivity and selectivity allowing it to be appropriate for further pharmacokinetics and metabolism studies of albendazole.