Application of a high performance liquid chromatography–tandem mass spectrometry method for determination of buflomedil in human plasma for a bioequivalence study

A rapid, simple and sensitive method based on ultra fast liquid chromatography–tandem spectrometry for the determination of buflomedil in human plasma has been developed and validated using carbamazepine as internal standard. After the precipitation of plasma sample with methanol, the analyte and IS were separated on an Ultimate C18 column (5 μm, 2.1 mm × 50 mm, MD, USA) with an isocratic mobile phase composed of acetonitrile and 5 mM ammonium acetate in water (60:40, v/v) at a flow rate of 0.25 ml/min. The analyte and IS were detected with proton adducts at m/z 308.3–237.1 and m/z 237.2–194.2 in positive ion electrospray ionization and multiple reaction monitoring acquisition mode, respectively. The lower limit of quantification of the method was 23.64 ng/ml with a linear dynamic range of 23.64–1182 ng/ml for buflomedil. The intra- and inter-batch precisions were less than 5.8%. The developed method was successfully applied to a bioequivalence study of two buflomedil hydrochloride preparations (150 mg) in 22 healthy Chinese male volunteers.