title: High-performance liquid chromatography-atmospheric pressure chemical ionisation-mass spectrometry determination of zaleplon in human plasma.
abstract: A sensitive and specific liquid chromatography-atmospheric pressure chemical ionisation-mass spectrometry (LC-APCI-MS) method has been developed and validated for the identification and quantification of zaleplon in human plasma using estazolam as an internal standard (IS). After the addition of estazolam and 2.0 M sodium hydroxide solution, plasma samples were extracted with ethyl acetate and then the organic layer was evaporated to dryness. The reconstituted solution of the residue was injected onto a prepacked Shim-pack VP-ODS C18 (250 mm x 2.0 mm i.d.) column and chromatographed with a mobile phase comprised of methanol:water (70:30) at a flow-rate of 0.2 ml/min. Detection was performed on a single quadrupole mass spectrometer by selected ion monitoring (SIM) mode via atmospheric pressure chemical ionization (APCI) source. The mean standard curve was linear (r = 0.9991) over the concentration range of 0.2-100 ng/ml and had good back-calculated accuracy and precision. The intra-day and inter-day precisions were within 10% relative standard deviation and accuracy ranged from 85% to 115%. The limit of detection was 0.1 ng/ml. The validated LC-APCI-MS method has been used successfully to study zaleplon pharmacokinetic, bioavailability and bioequivalence in 18 adult volunteers.
authors.affiliation: Center for Instrumental Analysis, China Pharmaceutical University, Nanjing 210009, China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Zhang
authors.forename: Zunjian
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tian
authors.forename: Fengguo
authors.initials: F
authors.lastname: Xu
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000081:Acetamides / Q000097:blood*; D000328:Adult; D019540:Area Under Curve; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D005615:Freezing; D006801:Humans; D006993:Hypnotics and Sedatives / Q000097:blood*; D007202:Indicators and Reagents; D008297:Male; D013058:Mass Spectrometry; D011743:Pyrimidines / Q000097:blood*; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D012996:Solutions; D021241:Spectrometry, Mass, Electrospray Ionization; D013696:Temperature
chemical_list: D000081:Acetamides; D006993:Hypnotics and Sedatives; D007202:Indicators and Reagents; D011743:Pyrimidines; D012996:Solutions; C085665:zaleplon