A rapid, high sensitive and selective liquid chromatography-tandem mass spectrometric (LCMS/ MS) method has been developed and validated for the quantification of Zolpidem (Zol) in human EDTA plasma using Mirtazapine (IS) as an internal standard. Analyte and Internal standard were extracted from human plasma by Solid-phase extraction (SPE) using Oasis HLB cartridges. The eluted samples were chromatographed on a C18 column by using a 20:80 v/v mixture of ammonium formate buffer (20 mM, pH 5.00) and acetonitrile as an isocratic mobile phase at a flow rate of 0.4 mL/min and analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective [M+H] + ions, m/z 308.13 → 235.21 for Zolpidem and m/z 266.35 → 195.31 for the IS. The linearity of the response/concentration curve was established in human plasma over the concentration range 0.10-149.83 ng/mL. The lower detection limit (LOD, S/N > 3) was 0.04 ng/mL and the lower limit of quantization (LOQ, S/N > 10) was 0.10 ng/mL. This LC-MS/MS method was validated with Intra-batch and Inter-batch precision of 0.67-9.82.The Intra-batch and Inter-batch accuracy was 87.70-107.53 respectively. Recovery of Zolpidem in human plasma is 87.70% and ISTD recovery is 85.78%. The main pharmacokinetic parameters were Tmax (hr) = (1.50 ± 0.754), Cmax (ng/mL) (115.341 ± 34.741), AUC0®t, = (663.614 ± 370.888) and AUC0®¥, 694.020 ± 407.540 respectively. This method was successfully applied for the zolpidem 10 mg tablets bioequivalence study.
