Application of liquid chromatography atmospheric pressure chemical ionization tandem mass spectrometry in the quantitative analysis of glyburide (glibenclamide) in human plasma

Glyburide (glibenclamide) is widely prescribed in the treatment of Type II diabetes. A validated liquid chromatography atmospheric pressure chemical ionization tandem mass spectrometry (LC/APCI-MS/MS) method for the determination of glyburide is reported. The method uses a stable isotope labeled glyburide as the internal standard. Subsequent to acetonitrile protein precipitation, the supernatant was directly (unfiltered) injected onto the LC column (retention time approximately 3 min) for analysis. A lower limit of quantification (LLOQ) of 1.01 ng/mL was attained for the human plasma assay. The method was fast, specific, and exhibited excellent ruggedness. It was successfully applied to the analysis of clinical samples from patients dosed with glyburide.