title: Clonazepam quantification in human plasma by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry in a bioequivalence study.
abstract: A rapid, sensitive and specific method for quantifying clonazepam in human plasma using diazepam as the internal standard (IS) is described. The analyte and the IS were extracted from plasma by liquid-liquid extraction using a hexane/diethylether (20 : 80, v/v) solution. The extracts were analysed by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC-MS-MS). Chromatography was performed on a Jones Genesis C8 4 microm analytical column (100 x 2.1 mm i.d.). The method had a chromatographic run time of 3.0 min and a linear calibration curve over the range 0.5-50 ng/ml (r2 > 0.9965). The limit of quantification was 0.5 ng/ml. This HPLC/MS/MS procedure was used to assess the bioequivalence of two clonazepam 2 mg tablet formulations (clonazepam test formulation from Ranbaxy Laboratories Ltd and Rivotril from Roche Laboratórios Ltda as standard reference formulation).
authors.affiliation: Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas/SP, Brazil.
authors.forename: Luiz E
authors.initials: LE
authors.lastname: Cavedal
authors.forename: Fabiana D
authors.initials: FD
authors.lastname: Mendes
authors.forename: Claudia C
authors.initials: CC
authors.lastname: Domingues
authors.forename: Anil K
authors.initials: AK
authors.lastname: Patni
authors.forename: Tausif
authors.initials: T
authors.lastname: Monif
authors.forename: Simrit
authors.initials: S
authors.lastname: Reyar
authors.forename: Alberto Dos S
authors.initials: Ados S
authors.lastname: Pereira
authors.forename: Gustavo D
authors.initials: GD
authors.lastname: Mendes
authors.forename: Gilberto
authors.initials: G
authors.lastname: De Nucci
mesh_terms: D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000097:blood / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D002998:Clonazepam / Q000097:blood / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D004146:Dioxanes / Q000737:chemistry; D006586:Hexanes / Q000737:chemistry; D006801:Humans; D008875:Middle Aged; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D013810:Therapeutic Equivalency
chemical_list: D000927:Anticonvulsants; D004146:Dioxanes; D006586:Hexanes; D002998:Clonazepam; C025223:1,4-dioxane