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Development and Validation of a Simple and Rapid UPLC–MS Assay for Valproic Acid and Its Comparison With Immunoassay and HPLC Methods. Ther Drug Monit 2016; 38:246-52. [DOI: 10.1097/ftd.0000000000000256] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Determination of Magnesium Valproate and Its Process Related Impurities by Ultraperformance Liquid Chromatography. INTERNATIONAL SCHOLARLY RESEARCH NOTICES 2014; 2014:412704. [PMID: 27355082 PMCID: PMC4897345 DOI: 10.1155/2014/412704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 04/27/2014] [Accepted: 04/28/2014] [Indexed: 11/17/2022]
Abstract
A selective ultraperformance liquid chromatographic (UPLC) method for the determination of magnesium valproate and its process related impurities has been developed. The method includes reversed-phase Acquity BEH C18 column with 100 mm × 2.1 mm i.d. and 1.7 µ particle size. The mobile phase consists of acetonitrile and 5 mM ammonium dihydrogen orthophosphate with pH = 3.0 at 45 : 55 isocratic elution. The flow rate was set at 0.3 mL/min and UV detection was performed at 215 nm. A system suitability test (SST) was developed to govern the quality of the separation. The developed method has been validated further with respect to linearity, accuracy, precision, selectivity, LOD, LOQ, and robustness. Different batches of samples were examined using this method; the method proved to be successful when applied to analyze a marketed magnesium valproate formulation.
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Candidate reference method: Determination of valproic acid in serum by isotope-dilution mass spectrometry. Chromatographia 2014. [DOI: 10.1007/bf02688060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Nazeri A, Jalali M, Aliasgharpour M, Khosravie F. Comparison of Serum Valproic Acid Determination Through Gas and High Performance Liquid Chromatography Methods. HEALTH SCOPE 2014. [DOI: 10.17795/jhealthscope-12085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Fernández-Campos F, Calpena A, Soy D, Colom H. DETERMINATION OF TOTAL AND UNBOUND CONCENTRATIONS OF VALPROIC ACID IN HUMAN PLASMA BY LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY. J LIQ CHROMATOGR R T 2012. [DOI: 10.1080/10826076.2011.619027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- F. Fernández-Campos
- a Biopharmaceutics and Pharmacokinetics Unit, Department of Pharmacy and Pharmaceutical Technology , School of Pharmacy, University of Barcelona , Barcelona , Spain
| | - A. Calpena
- a Biopharmaceutics and Pharmacokinetics Unit, Department of Pharmacy and Pharmaceutical Technology , School of Pharmacy, University of Barcelona , Barcelona , Spain
| | - D. Soy
- b Pharmacy Service, Hospital Clínic , Barcelona , Spain
| | - H. Colom
- a Biopharmaceutics and Pharmacokinetics Unit, Department of Pharmacy and Pharmaceutical Technology , School of Pharmacy, University of Barcelona , Barcelona , Spain
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Kang J, Park YS, Kim SH, Kim SH, Jun MY. Modern methods for analysis of antiepileptic drugs in the biological fluids for pharmacokinetics, bioequivalence and therapeutic drug monitoring. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2011; 15:67-81. [PMID: 21660146 DOI: 10.4196/kjpp.2011.15.2.67] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 04/10/2011] [Accepted: 04/15/2011] [Indexed: 12/20/2022]
Abstract
Epilepsy is a chronic disease occurring in approximately 1.0% of the world's population. About 30% of the epileptic patients treated with availably antiepileptic drugs (AEDs) continue to have seizures and are considered therapy-resistant or refractory patients. The ultimate goal for the use of AEDs is complete cessation of seizures without side effects. Because of a narrow therapeutic index of AEDs, a complete understanding of its clinical pharmacokinetics is essential for understanding of the pharmacodynamics of these drugs. These drug concentrations in biological fluids serve as surrogate markers and can be used to guide or target drug dosing. Because early studies demonstrated clinical and/or electroencephalographic correlations with serum concentrations of several AEDs, It has been almost 50 years since clinicians started using plasma concentrations of AEDs to optimize pharmacotherapy in patients with epilepsy. Therefore, validated analytical method for concentrations of AEDs in biological fluids is a necessity in order to explore pharmacokinetics, bioequivalence and TDM in various clinical situations. There are hundreds of published articles on the analysis of specific AEDs by a wide variety of analytical methods in biological samples have appears over the past decade. This review intends to provide an updated, concise overview on the modern method development for monitoring AEDs for pharmacokinetic studies, bioequivalence and therapeutic drug monitoring.
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Affiliation(s)
- Juseop Kang
- Pharmacology & Clinical Pharmacology Lab, College of Medicine, Hanyang University, Seoul 133-791, Korea
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FARAJZADEH MA, FARHADI K, MATIN AA, HASHEMI P, JOUYBAN A. Headspace Solid-Phase Microextraction-Gas Chromatography Method for the Determination of Valproic Acid in Human Serum, and Formulations Using Hollow-Fiber Coated Wire. ANAL SCI 2009; 25:875-9. [DOI: 10.2116/analsci.25.875] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Mir Ali FARAJZADEH
- Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz
| | - Khalil FARHADI
- Department of Chemistry, Faculty of Science, Urmia University
| | - Amir A. MATIN
- Department of Chemistry, Faculty of Science, Urmia University
- Research Department of Chromatography, Iranian Academic Center for Education, Culture & Research (ACECR)
| | - Paria HASHEMI
- Department of Chemistry, Faculty of Science, Urmia University
| | - Abolghasem JOUYBAN
- School of Pharmacy & Drug Applied Research Center, Tabriz University of Medical Sciences
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Belin GK, Krähenbühl S, Hauser PC. Direct determination of valproic acid in biological fluids by capillary electrophoresis with contactless conductivity detection. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 847:205-9. [PMID: 17070114 DOI: 10.1016/j.jchromb.2006.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 09/25/2006] [Accepted: 10/07/2006] [Indexed: 01/08/2023]
Abstract
Capacitively coupled contactless conductivity detection (C(4)D) is a new technique providing high sensitivity in capillary electrophoresis (CE) especially for small ions that can otherwise only be determined with indirect methods. In this work, direct determination and validation of valproic acid (VPA) in biological fluids was achieved using CE with C(4)D. VPA is of pharmacological interest because of its use in epilepsy and bipolar disorder. The running electrolyte solution used consisted of 10mM 2-(N-morpholino)ethane sulfonic acid (MES)/dl-histidine (His) and 50microM hexadecyltrimethylammonium bromide (HTAB) at pH 6.0. Caproic acid (CA) was selected as internal standard (IS). Analyses of VPA in serum, plasma and urine samples were performed in less than 3min. The interference of the sample matrix was reduced by deproteinization of the sample with acetonitrile (ACN). The effect of the solvent type and ratio on interference was investigated. The limits of detection (LOD) and quantitation (LOQ) of VPA in plasma samples were determined as 24 and 80ng/ml, respectively. The method is linear between the 2 and 150microg/ml, covering well the therapeutic range of VPA (50-100microg/ml).
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Affiliation(s)
- Gamze Kavran Belin
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Geneva, Sciences I, Geneva 4, Switzerland.
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Bousquet E, Cavrini V, Gatti R, Spadaro A. Determination of Valproic Acid Salts in Pharmaceutical Preparations by High Performance Liquid Chromatography with Coulometric Electrochemical Detection. J LIQ CHROMATOGR R T 2006. [DOI: 10.1080/10826079808003450] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- E. Bousquet
- a Dipartimento di Scienze Farmaceutiche , Università di Catania , Viale A. Doria 6, 95125, Catania, Italy
| | - V. Cavrini
- a Dipartimento di Scienze Farmaceutiche , Università di Catania , Viale A. Doria 6, 95125, Catania, Italy
| | - R. Gatti
- a Dipartimento di Scienze Farmaceutiche , Università di Catania , Viale A. Doria 6, 95125, Catania, Italy
| | - A. Spadaro
- a Dipartimento di Scienze Farmaceutiche , Università di Catania , Viale A. Doria 6, 95125, Catania, Italy
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Lau-Cam CA, Roos RW. HPLC Method with Precolumn Phenacylation for the Assay of Valproic Acid and Its Salts in Pharmaceutical Dosage Forms. J LIQ CHROMATOGR R T 2006. [DOI: 10.1080/10826079708005566] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- C. A. Lau-Cam
- a College of Pharmacy and Allied Health Professions , St. John's University , Jamaica, New York, 11439
| | - R. W. Roos
- a College of Pharmacy and Allied Health Professions , St. John's University , Jamaica, New York, 11439
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11
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Rompotis S, Parissi-Poulou M, Gikas E, Kazanis M, Vavayannis A, Panderi I. DETERMINATION OF VALPROIC ACID IN HUMAN PLASMA BY HPLC WITH FLUORESCENCE DETECTION. J LIQ CHROMATOGR R T 2006. [DOI: 10.1081/jlc-120014953] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- S. Rompotis
- a Division of Pharmaceutical Chemistry , School of Pharmacy , University of Athens , Panepistimiopolis-Zografou, Athens, 157 71, Greece
| | - M. Parissi-Poulou
- a Division of Pharmaceutical Chemistry , School of Pharmacy , University of Athens , Panepistimiopolis-Zografou, Athens, 157 71, Greece
| | - E. Gikas
- a Division of Pharmaceutical Chemistry , School of Pharmacy , University of Athens , Panepistimiopolis-Zografou, Athens, 157 71, Greece
| | - M. Kazanis
- a Division of Pharmaceutical Chemistry , School of Pharmacy , University of Athens , Panepistimiopolis-Zografou, Athens, 157 71, Greece
| | - A. Vavayannis
- a Division of Pharmaceutical Chemistry , School of Pharmacy , University of Athens , Panepistimiopolis-Zografou, Athens, 157 71, Greece
| | - I. Panderi
- b Division of Pharmaceutical Chemistry , School of Pharmacy , University of Athens , Panepistimiopolis-Zografou, Athens, 157 71, Greece
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Zhong Y, Jiao Z, Yu Y. Simultaneous determination of mycophenolic acid and valproic acid based on derivatization by high-performance liquid chromatography with fluorescence detection. Biomed Chromatogr 2006; 20:319-26. [PMID: 16145659 DOI: 10.1002/bmc.566] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A reliable and validated reversed-phase high-performance liquid chromatography (HPLC) method using fluorescence detection is reported for the simultaneous quantitation of mycophenolic acid (MPA) and valproic acid (VPA) in human plasma. The method is based on the pre-column derivatization of valproic acid with 4-bromomethyl-6, 7-dimethoxycoumarin (BrMMC) and online solvatochromism of MPA by pH adjustment. The linear calibration range was 0.50-30 microg/mL for MPA and 5.00-150 microg/mL for VPA. The relative standard deviations of the method of intra- and inter-day analyses (n = 6) were below 6.5 and 6.7% for MPA, and 5.8 and 6.3% for VPA, respectively. Dichloromethane was used for the simultaneous extraction of MPA and VPA from acidified plasma. This reliable method can be applied in the analysis of MPA and VPA in human plasma using only a small volume (100 microL).
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Affiliation(s)
- Yan Zhong
- School of Pharmacy, Fudan University, Shanghai 200032, People's Republic of China
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Datta P, Dasgupta A. Analytical performance evaluation of a new turbidimetric immunoassay for valproic acid on the ADVIA 1650 analyzer: effect of gross hemolysis and high bilirubin. J Clin Lab Anal 2005; 19:31-5. [PMID: 15756706 PMCID: PMC6808112 DOI: 10.1002/jcla.20052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Valproic acid is an anticonvulsant that requires careful therapeutic drug monitoring. Valproic acid is also used in psychiatric patients. Bayer Diagnostics (Tarrytown, NY) recently marketed a turbidimetric immunoassay for monitoring valproic acid concentrations in serum or plasma using the ADVIA 1650 analyzer. We evaluated the performance of this new assay by comparing it with a widely used fluorescence polarization immunoassay (FPIA) on the AxSYM analyzer (Abbott Laboratories, Abbott Park, IL). The total coefficient of variation (CV) for the low control of this new assay was 6.8% (mean = 30.7, SD = 2.1 microg/mL, n = 44) while the corresponding CVs for the medium and high controls were 3.3% (mean = 81.0, SD = 2.7 microg/mL, n = 44) and 5.9% (mean = 142.9, SD = 8.4 microg/mL, n = 44), respectively. The assay is linear up to a serum valproic acid concentration of 170 microg/mL, and the detection limit is 4.4 microg/mL. We observed an excellent correlation between the FPIA of valproic acid and the turbidimetric assay using specimens from 52 different patients who were receiving valproic acid. Using the valproic acid concentrations obtained by the FPIA as the x-axis, and the corresponding valproic acid concentrations obtained by the turbidimetric assay as the y-axis, we developed the following regression equation: y = 1.03 x+1.55 (r = 0.98). With this new assay, high concentrations of bilirubin (unconjugated 30 mg/dL and conjugated 30 mg/dL) and gross hemolysis (4+, hemoglobin: 1,500 mg/dL) have no effect on measurements of valproic acid concentration. We conclude that the new turbidimetric assay for valproic acid can be used for routine therapeutic drug monitoring of valproic acid in clinical laboratories.
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Affiliation(s)
| | - Amitava Dasgupta
- Department of Pathology and Laboratory Medicine, University of Texas‐Houston Medical School, Houston, Texas
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Alsarra IA, Al-Omar M, Belal F. Valproic Acid and sodium valproate: comprehensive profile. PROFILES OF DRUG SUBSTANCES, EXCIPIENTS, AND RELATED METHODOLOGY 2005; 32:209-40. [PMID: 22469088 DOI: 10.1016/s0099-5428(05)32008-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Affiliation(s)
- Ibrahim A Alsarra
- Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Kingdom of Saudi Arabia
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Ramakrishna NVS, Vishwottam KN, Manoj S, Koteshwara M, Santosh M, Chidambara J, Kumar BR. Liquid chromatography/electrospray ionization mass spectrometry method for the quantification of valproic acid in human plasma. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:1970-8. [PMID: 15954179 DOI: 10.1002/rcm.2012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A simple, sensitive and rapid liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) method was developed and validated for the quantification of valproic acid, an antiepileptic drug, in human plasma using benzoic acid as internal standard (IS). Following solid-phase extraction, the analytes were separated using an isocratic mobile phase on a reversed-phase C18 column and analyzed by MS in the single ion monitoring mode using the respective [M-H]- ions, m/z 143 for valproic acid and m/z 121 for the IS. The assay exhibited a linear dynamic range of 0.5-60 microg/mL for valproic acid in human plasma. The lower limit of quantification was 500 ng/mL with a relative standard deviation of less than 10%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The average absolute recoveries of valproic acid and the IS from spiked plasma samples were 96.1+/-4.2 and 95.6+/-2.7%, respectively. A run time of 4.5 min for each sample made it possible to analyze more than 250 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability and bioequivalence studies.
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Affiliation(s)
- N V S Ramakrishna
- Biopharmaceutical Research, Suven Life Sciences Ltd., Serene Chambers, Road # 7, Banjara Hills, Hyderabad 500034, India.
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Bousquet E, Spadaro A, Santagati NA, Scalia S, Ronsisvalle G. Determination of undecylenic and sorbic acids in cosmetic preparations by high performance liquid chromatography with electrochemical detection. J Pharm Biomed Anal 2002; 30:947-54. [PMID: 12408884 DOI: 10.1016/s0731-7085(02)00472-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A highly sensitive and selective method for the determination of sorbic (SA) and undecylenic acid (UA) in cosmetic formulations by a high performance liquid chromatography method with electrochemical detection (ECD) is described. The pre-column derivatizations of SA and UA and the internal standard (cyclohexanoic acid (cHA)) were carried out using 1-(2,5-dihydroxyphenyl)-2-bromoethanone (2,5-DBE) as an electroactive labeling reagent previously synthesized in our lab. The resulting electroactive esters were separated by isocratic elution of a 5 micrometer Hypersil CN column with acetonitrile-acetate buffer eluent. The compounds were detected by a porous graphite electrode set at an oxidation potential of +0.45 V. The analytical method developed in this study is suitable for quality control assays of complex cosmetic formulations containing sorbic and/or UA.
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Affiliation(s)
- Ennio Bousquet
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Catania, Viale Andrea Doria 6, 95125, Catania, Italy.
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Murakami T, Okada M, Kawata Y, Zhu G, Kamata A, Kaneko S. Determination of effects of antiepileptic drugs on SNAREs-mediated hippocampal monoamine release using in vivo microdialysis. Br J Pharmacol 2001; 134:507-20. [PMID: 11588104 PMCID: PMC1572980 DOI: 10.1038/sj.bjp.0704285] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. To elucidate possible mechanisms underlying the effects of carbamazepine (CBZ), valproate (VPA) and zonisamide (ZNS) on neurotransmitter exocytosis, the interaction between these three antiepileptic drugs (AEDs) and botulinum toxins (BoNTs) on basal, Ca(2+)- and K(+)-evoked release of dopamine (DA) and serotonin (5-HT) were determined by microdialysis in the hippocampus of freely moving rats. 2. Basal release of monoamine was decreased by pre-microinjection of the syntaxin inhibitor, BoNT/C, but only weakly affected by the synaptobrevin inhibitor, BoNT/B. Ca(2+)-evoked release was inhibited by BoNT/C selectively. K(+)-evoked release was reduced by BoNT/B predominantly and BoNT/C weakly. 3. Perfusion with low and high concentrations of CBZ and ZNS increased and decreased basal monoamine release, respectively. Perfusion with VPA increased basal 5-HT release concentration-dependently, whereas basal DA release was affected by VPA biphasic concentration-dependently, similar to CBZ and ZNS. This stimulatory action of AEDs on basal release was inhibited by BoNT/C predominantly. 4. Ca(2+)-evoked monoamine release was increased by low concentrations of CBZ, ZNS and VPA, but decreased by high concentrations. These effects of the AEDs on Ca(2+)-evoked release were inhibited by BoNT/C, but not by BoNT/B. 5. K(+)-evoked monoamine release was reduced by AEDs concentration-dependently. The inhibitory effect of these three AEDs on K(+)-evoked release was inhibited by BoNT/B, but not by BoNT/C. 6. These findings suggest that the therapeutic-relevant concentration of CBZ, VPA and ZNS affects exocytosis of DA and 5-HT, the enhancement of syntaxin-mediated monoamine release during resting stage, and the inhibition of synaptobrevin-mediated release during depolarizing stage.
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Affiliation(s)
- Takuya Murakami
- Department of Neuropsychiatry, Hirosaki University, Hirosaki 036-8216, Japan
| | - Motohiro Okada
- Department of Neuropsychiatry, Hirosaki University, Hirosaki 036-8216, Japan
- Author for correspondence:
| | - Yuko Kawata
- Department of Neuropsychiatry, Hirosaki University, Hirosaki 036-8216, Japan
| | - Gan Zhu
- Department of Neuropsychiatry, Hirosaki University, Hirosaki 036-8216, Japan
| | - Akihisa Kamata
- Department of Neuropsychiatry, Hirosaki University, Hirosaki 036-8216, Japan
| | - Sunao Kaneko
- Department of Neuropsychiatry, Hirosaki University, Hirosaki 036-8216, Japan
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Nakajima M, Yamato S, Shimada K, Sato S, Kitagawa S, Honda A, Miyamoto J, Shoda J, Ohya M, Miyazaki H. Assessment of drug concentrations in tears in therapeutic drug monitoring: I. Determination of valproic acid in tears by gas chromatography/mass spectrometry with EC/NCI mode. Ther Drug Monit 2000; 22:716-22. [PMID: 11128240 DOI: 10.1097/00007691-200012000-00011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A rapid and sensitive method for the quantitation of valproic acid in tears has been developed using gas chromatography/electron capture negative chemical ionization/mass spectrometry. Valproic acid was converted directly into its pentafluorobenzyl ester derivative without the need to perform any extraction from the biologic fluid. The concentrations in tears [C]t correlated very well with those of the free form in the plasma [Cf]p and those of the total form in the plasma [Cb+f]p. The ratios between valproic acid concentrations in tears and plasma were as follows: [C]t/[Cb+f]p = 0.10 +/- 0.02; [C]t/[Cf]p = 0.57 +/- 0.11. Ratios of [C]t/[Cb+f]p were in good agreement with previously published data.
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Affiliation(s)
- M Nakajima
- Department of Anaytical Chemistry, Niigata College of Pharmacy, Japan
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Krogh M, Johansen K, Tønnesen F, Rasmussen KE. Solid-phase microextraction for the determination of the free concentration of valproic acid in human plasma by capillary gas chromatography. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1995; 673:299-305. [PMID: 8611965 DOI: 10.1016/0378-4347(95)00273-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The potential of solid-phase microextraction in the bioanalysis of drugs is demonstrated. The free concentration of valproic acid in human plasma was determined by equilibrium dialysis at room temperature. To the dialysate was added an internal standard and the pH was adjusted to 2.5. The polymethylsiloxane-coated fused-silica fibre of the solid-phase microextraction device was inserted into the dialysate for 3 min. The sorbed analytes were then thermally desorbed at 210 degrees C in the split-splitless injection port of the gas chromatograph, separated on a Nukol capillary column and detected with a flame ionization detector. The method was shown to be highly reproducible with a detection limit of 1 microgram/ml of free valproic acid in human plasma.
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Affiliation(s)
- M Krogh
- Institute of Pharmacy, University of Oslo, Norway
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20
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Susanto F, Reinauer H. Candidate reference method: Determination of valproic acid in serum by isotope-dilution mass spectrometry. Chromatographia 1995. [DOI: 10.1007/bf02318614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Krull IS, Deyl Z, Lingeman H. General strategies and selection of derivatization reactions for liquid chromatography and capillary electrophoresis. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1994; 659:1-17. [PMID: 7820271 DOI: 10.1016/0378-4347(94)00151-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The general strategies, reasons and the different possibilities for the derivatization of biomedically important compounds are reviewed. Different approaches apply for small versus large analyte molecules, different advantages and disadvantages are visualized with pre- and post-column arrangements. Particular interest is focused upon solid-phase derivatization reagents.
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Affiliation(s)
- I S Krull
- Department of Chemistry, Northeastern University, Boston, MA 02115
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