title: Quantification of zolpidem in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry.
abstract: A simple and robust method for quantification of zolpidem in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI MS/MS). Es-citalopram was used as an internal standard. Zolpidem and internal standard in plasma sample were extracted using solid-phase extraction cartridges (Oasis HLB, 1 cm3/30 mg). The samples were injected into a C8 reversed-phase column and the mobile phase used was acetonitrile-ammonium acetate (pH 4.6; 10 mm) (80:20, v/v) at a flow rate of 0.7 mL/min. Using MS/MS in the selected reaction-monitoring (SRM) mode, zolpidem and Es-citalopram were detected without any interference from human plasma matrix. Zolpidem produced a protonated precursor ion ([M+H]+) at m/z 308.1 and a corresponding product ion at m/z 235.1. The internal standard produced a protonated precursor ion ([M+H]+) at m/z 325.1 and a corresponding product ion at m/z 262.1. Detection of zolpidem in human plasma by the LC-ESI MS/MS method was accurate and precise with a quantification limit of 2.5 ng/mL. The proposed method was validated in the linear range 2.5-300 ng/mL. Reproducibility, recovery and stability of the method were evaluated. The method has been successfully applied to bioequivalence studies of zolpidem.
authors.affiliation: Torrent Research Centre, Torrent Pharmaceuticals Limited, Village-Bhat, Gandhinagar-382428, Gujarat State, India. jigu_baroda@rediffmail.com
authors.forename: Jignesh
authors.initials: J
authors.lastname: Bhatt
authors.forename: Arvind
authors.initials: A
authors.lastname: Jangid
authors.forename: Raghavendra
authors.initials: R
authors.lastname: Shetty
authors.forename: Bhavin
authors.initials: B
authors.lastname: Shah
authors.forename: Sandeep
authors.initials: S
authors.lastname: Kambli
authors.forename: Gunta
authors.initials: G
authors.lastname: Subbaiah
authors.forename: Sadhana
authors.initials: S
authors.lastname: Singh
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D006801:Humans; D008297:Male; D011725:Pyridines / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D000077334:Zolpidem
chemical_list: D011725:Pyridines; D000077334:Zolpidem