title: Simultaneous quantitative analysis of oxcarbazepine and 10,11-dihydro-10-hydroxycarbamazepine in human plasma by liquid chromatography-electrospray tandem mass spectrometry.
abstract: A fast and sensitive method to quantify oxcarbazepine (OXC) and its active metabolite, 10,11-dihydro-10-hydroxycarbamazepine (MHD) in human plasma using HPLC-MS/MS has been developed. The method involved liquid-liquid extraction (LLE), with diethyl ether-diclhoromethane (60:40v/v) using deuterade carbamazepine (d10-carbamazepine) as internal standard (IS). The analytes and IS were separated using an isocratic mobile phase (acetonitrile/water (50:50v/v)+20 mM acetic acid) on the analytical column Phenomenex Luna C18 5 microm (150 mm x 4.6 mm) at room temperature. Detection was performed by a Micromass Quatro LC mass spectrometer in the reaction monitoring mode using positive electrospray ionization (ESI+). The MS-MS ion transition monitored were m/z 253>208 for OXC, m/z 255>194 for MHD and m/z 247>204 for IS. Over the range 20-5250 ng/ml for OXC and 40-10,500 ng/ml for MHD, the calibration curves were defined by the following equations: y = 0.00568 + 0.00296x -5.70e - 8x(2) and y = 0.00749 + 0.00178x - 5.70e - 8x(2) for OXC and MHD, respectively. All coefficient of determination (r(2)) were close to unity (0.9986-0.9994). The lower limits of quantification obtained as a result of the LLE procedure was 20 ng/ml for OXC and 40 ng/ml for MHD. The statistical evaluation of the developed method was conducted by examining within-batch and between-batch precision data, which were within the required limits. The suitability of the assay for pharmacokinetics studies was determined by measuring OXC and MHD concentration after administration of a single 10 ml of OXC oral suspension (6%) in plasma human of healthy volunteers.
authors.affiliation: Department of Physiology and Pharmacology, Federal University of Pernambuco, Av. Prof. Moraes Rêgo S/N, Cidade Universitária, 50670-901 Recife, Pernambuco, Brazil. mbsm@ufpe.br
authors.forename: Maria Bernadete
authors.initials: MB
authors.lastname: de Sousa Maia
authors.forename: Demétrius Fernandes
authors.initials: DF
authors.lastname: do Nascimento
authors.forename: Ismael Leite
authors.initials: IL
authors.lastname: Martins
authors.forename: Adriano Nunes
authors.initials: AN
authors.lastname: Cunha
authors.forename: Francisco Evanir Gonçalves
authors.initials: FE
authors.lastname: de Lima
authors.forename: Fernando Antônio Frota
authors.initials: FA
authors.lastname: Bezerra
authors.forename: Manoel Odorico
authors.initials: MO
authors.lastname: de Moraes
authors.forename: Maria Elisabete Amaral
authors.initials: ME
authors.lastname: de Moraes
mesh_terms: D000927:Anticonvulsants / Q000097:blood* / Q000737:chemistry / Q000378:metabolism*; D002220:Carbamazepine / Q000031:analogs & derivatives* / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D015394:Molecular Structure; D000078330:Oxcarbazepine; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013997:Time Factors
chemical_list: D000927:Anticonvulsants; D002220:Carbamazepine; D000078330:Oxcarbazepine