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Dalmora S.L.,Federal University of Santa Maria | Da Silva Sangoi M.,Federal University of Santa Maria | Nogueira D.R.,Federal University of Santa Maria | D'Avila F.B.,Federal University of Santa Maria | And 7 more authors.
Quimica Nova | Year: 2010

A liquid chromatography method was developed and validated for the determination of phenobarbital in human plasma using phenytoin as internal standard. The drugs were extracted from plasma by liquid-liquid extraction and separated isocratically on a C12 analytical column, maintained at 35 °C, with water:acetonitrile:methanol (58.8:15.2:26, v/v/v) as mobile phase, run at a flow rate of 1.2 mL/min with detection at 205 nm. The method was linear in the range of 0.1-4 μg/mL (r2=0.9999) and demonstrated acceptable results for the precision, accuracy and stability studies. The method was successfully applied for the bioequivalence study of two tablet formulations (test and reference) of phenobarbital 100 mg after single oral dose administration to healthy human volunteers. Source


Borges N.C.C.,Synchrophar Assessoria e Desenvolvimento de Projetos Clinicos S S Ltda | Borges N.C.C.,University of Campinas | Astigarraga R.B.,Magabi Pesquisas Clinicas e Farmaceuticas | Sverdloff C.E.,Synchrophar Assessoria e Desenvolvimento de Projetos Clinicos S S Ltda | And 5 more authors.
Current Clinical Pharmacology | Year: 2012

In the present study, a novel, fast, sensitive and robust method to quantify clozapine in human plasma using quetiapine as the internal standard (IS) is described. The analyte and the IS were extracted from plasma using a single protein precipitation extraction technique with methanol and analyzed by high performance liquid chromatography coupled to the electrospray ionization tandem mass spectrometric (HPLC-ESI-MS/MS). The method was linear over the range 20 to 1500 ng.mL-1. The intra-assay precisions ranged from 3.8 to 5.9%, while inter-assay precisions ranged from 4.2 to 6.0%. The intra-assay accuracies ranged from 99.3 to 107.5%, while the inter-assay accuracies ranged from 98.9 to 101.7%. This method agrees with the requirements proposed by the US Food and Drug Administration of high sensitivity, specificity and high sample throughput and was used to evaluate the pharmacokinetic profiles and bioequivalence of the two clozapine formulations in twenty six schizophrenic patients affected by refractory schizophrenia under steady-state conditions. During the hospitalization period the patients received the 100 mg clozapine formulation tablets corresponding to the same dose they were using 14 days before hospitalization. The clozapine pharmacokinetic did not differ significantly after administration of both test and the reference formulations. The Tmax and T1/2 for the test formulation were 2.26 and 10.92 h, respectively. In addition, the Tmax and T1/2 for the reference formulation were 2.44 and 11.08 h, respectively. The 90% confidence interval of the mean ratio of lnAUC0-t was within 0.80-1.25 range which indicates that the test formulation was bioequivalent to the reference formulation when orally administered to schizophrenic patients regarding both the rate and extent of absorption. © 2012 Bentham Science Publishers. Source


Borges N.C.,Synchrophar Assessoria e Desenvolvimento de Projetos Clinicos S S Ltda | Borges N.C.,University of Campinas | Barrientos-Astigarraga R.E.,Magabi Pesquisas Clinicas e Farmaceuticas | Sverdloff C.E.,Magabi Pesquisas Clinicas e Farmaceuticas | And 7 more authors.
Biomedical Chromatography | Year: 2012

In the present study a simple, fast, sensitive and robust method to quantify mirtazapine in human plasma using quetiapine as the internal standard (IS) is described. The analyte and the IS were extracted from human plasma by a simple protein precipitation with methanol and were analyzed by high-performance liquid chromatography coupled to an electrospray tandem triple quadrupole mass spectrometer (HPLC-ESI-MS/MS). Chromatography was performed isocratically on a C18, 5μm analytical column and the run time was 1.8min. The lower limit of quantitation was 0.5ng/mL and a linear calibration curve over the range 0.5-150ng/mL was obtained, showing acceptable accuracy and precision. This analytical method was applied in a relative bioavailability study in order to compare a test mirtazapine 30mg single-dose formulation vs a reference formulation in 31 volunteers of both sexes. The study was conducted in an open randomized two-period crossover design and with a 14day washout period. Since the 90% confidence interval for Cmax, AUClast and AUC0-inf were within the 80-125% interval proposed by the Food and Drug Administration and ANVISA (Brazilian Health Surveillance Agency), it was concluded that mirtazapine 30mg/dose is bioequivalent to the reference formulation, according to both the rate and extent of absorption. Copyright © 2012 John Wiley & Sons, Ltd. © 2012 John Wiley & Sons, Ltd. Source


Borges N.C.,Synchrophar Assessoria e Desenvolvimento de Projetos Clinicos S S Ltda | Borges N.C.,University of Campinas | Rezende V.M.,Synchrophar Analitica | Santana J.M.,Synchrophar Analitica | And 8 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2011

In the present study a method to quantify chlorpromazine in human plasma using cyclobenzaprine as the internal standard (IS) is described. The analyte and the IS were extracted from human plasma by a liquid-liquid extraction with diethyl ether/dichloromethane (70/30, v/v) and analyzed by an ultra performance liquid chromatography (UPLC) coupled to an electrospray tandem triple quadrupole mass spectrometer in positive mode (UPLC-ES +-MS/MS). Chromatography was performed isocratically on an Aquity UPLC BEH C18 1.7μm (50mm×2.1mm i.d.) operating at 40°C. The mobile phase was a mixture of 65% water+1% formic acid and 35% of acetonitrile at a flow-rate of 0.5mL/min. The lowest concentration quantified was 0.5ng/mL and a linear calibration curve over the range 0.5-200ng/mL was obtained, showing intra-assay precisions from 2.4 to 5.8%, and inter-assay precisions from 3.6 to 9.9%. The intra-assay accuracies ranged from 96.9 to 102.5%, while the inter-assay accuracies ranged from 94.1 to 100.3%. This analytical method was applied in a relative bioavailability study in order to compare a test chlorpromazine 100mg simple dose formulation versus a reference in 57 volunteers of both sexes. The study was conducted in an open randomized two-period crossover design and with a fourteen days washout period. Plasma samples were obtained over a 144-h interval. Since the 90% CI for both C max, AUC last and AUC 0-inf were within the 80-125% interval proposed by the Food and Drug Administration and ANVISA, it was concluded that chlorpromazine 100mg/dose was bioequivalent to the reference formulation, according to both the rate and extent of absorption. © 2011 Elsevier B.V. Source

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