Liquid chromatography-electrospray ionization mass spectrometric method for determination of gliclazide in human plasma

A rapid, sensitive, and specific liquid chromatography-electrospray ionization mass spectrometric (LC-ESI-MS) method has been developed for quantification of gliclazide in human plasma. The analyte and tolbutamide (internal standard, I.S.) were extracted from plasma samples with n-hexane-dichloromethane (1:1, v/v) and analyzed on a C-18 column. The chromatographic separation was achieved within 4.0 min by using methanol-0.5% formic acid (80:20, v/v) as mobile phase and the flow rate was 1.0 mL/min. Ion signals m/z 324.0 and 271.0 for gliclazide and internal standard were measured in the positive mode, respectively. The method was linear within the range of 2.5-2000 ng/mL. The lower limit of quantification (LLOQ) was 2.5 ng/mL. The intra- and inter-day precisions were lower than 2.8% in terms of relative standard deviation (RSD). The inter-day relative error (RE) as determined from quality control samples (QCs) ranged from -1.93% to 1.85%. This validated method was successfully applied for the evaluation of pharmacokinetic profiles of gliclazide modified-release tablets in 20 healthy volunteers.