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Labat L, Goncalves A, Cleophax C, Megarbane B, Decleves X. Dosage du baclofène dans le plasma en chromatographie phase liquide couplée à de la spectrométrie de masse en tandem : à propos d’un cas de surdosage. TOXICOLOGIE ANALYTIQUE ET CLINIQUE 2016. [DOI: 10.1016/j.toxac.2016.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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2
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Nahar LK, Cordero RE, Nutt D, Lingford-Hughes A, Turton S, Durant C, Wilson S, Paterson S. Validated Method for the Quantification of Baclofen in Human Plasma Using Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry. J Anal Toxicol 2015; 40:117-23. [PMID: 26538544 DOI: 10.1093/jat/bkv125] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A highly sensitive and fully validated method was developed for the quantification of baclofen in human plasma. After adjusting the pH of the plasma samples using a phosphate buffer solution (pH 4), baclofen was purified using mixed mode (C8/cation exchange) solid-phase extraction (SPE) cartridges. Endogenous water-soluble compounds and lipids were removed from the cartridges before the samples were eluted and concentrated. The samples were analyzed using triple-quadrupole liquid chromatography-tandem mass spectrometry (LC-MS-MS) with triggered dynamic multiple reaction monitoring mode for simultaneous quantification and confirmation. The assay was linear from 25 to 1,000 ng/mL (r(2) > 0.999; n = 6). Intraday (n = 6) and interday (n = 15) imprecisions (% relative standard deviation) were <5%, and the average recovery was 30%. The limit of detection of the method was 5 ng/mL, and the limit of quantification was 25 ng/mL. Plasma samples from healthy male volunteers (n = 9, median age: 22) given two single oral doses of baclofen (10 and 60 mg) on nonconsecutive days were analyzed to demonstrate method applicability.
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Affiliation(s)
| | | | - David Nutt
- Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
| | - Anne Lingford-Hughes
- Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
| | - Samuel Turton
- Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
| | - Claire Durant
- Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
| | - Sue Wilson
- Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
| | - Sue Paterson
- Toxicology Unit, Imperial College London, London W6 8RP, UK
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Kim TH, Shin S, Shin JC, Choi JH, Seo WS, Park GY, Kwon DR, Yoo SD, Lee AR, Joo SH, Min BS, Yoo WY, Shin BS. Liquid chromatography–tandem mass spectrometry determination of baclofen in various biological samples and application to a pharmacokinetic study. J Chromatogr B Analyt Technol Biomed Life Sci 2013; 938:43-50. [DOI: 10.1016/j.jchromb.2013.08.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 07/26/2013] [Accepted: 08/21/2013] [Indexed: 11/27/2022]
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4
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Nazarov VA, Andronchik KA, Egorov VV, Belyaev SA, Yurkshtovich TL. Ion-selective electrode for quantitative determination of baclofen in pills. Pharm Chem J 2011. [DOI: 10.1007/s11094-011-0637-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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5
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Ban E, Park J, Kim C. Semi‐Microbore HPLC for the Determination of Baclofen in Human Plasma Using Column Switching. J LIQ CHROMATOGR R T 2009. [DOI: 10.1081/jlc-200032681] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Eunmi Ban
- a National Research Lab for Drug and Gene Delivery, College of Pharmacy , Seoul National University , San 56‐1, Shillim‐Dong, Kwanak‐Gu, Seoul , 151‐742 , Korea
| | - Jeong‐Sook Park
- a National Research Lab for Drug and Gene Delivery, College of Pharmacy , Seoul National University , San 56‐1, Shillim‐Dong, Kwanak‐Gu, Seoul , 151‐742 , Korea
| | - Chong‐Kook Kim
- a National Research Lab for Drug and Gene Delivery, College of Pharmacy , Seoul National University , San 56‐1, Shillim‐Dong, Kwanak‐Gu, Seoul , 151‐742 , Korea
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6
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Saleh HM, El-Henawee MM, Ragab GH, El-Hay SSA. Utility of NBD-Cl for the spectrophotometric determination of some skeletal muscle relaxant and antihistaminic drugs. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 67:1284-9. [PMID: 17223379 DOI: 10.1016/j.saa.2006.09.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 09/16/2006] [Indexed: 05/13/2023]
Abstract
A simple, accurate, precise and sensitive colorimetric method for the determination of some skeletal muscle relaxant drugs, namely orphenadrine citrate (I), baclofen (II), antihistaminic drugs as acrivastine (III) and fexofenadine hydrochloride (IV) is described. This method is based on the formation of charge transfer complex with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) in non-aqueous medium. The orange color products were measured at 472, 465, 475 and 469 nm for drugs I, II, III and IV, respectively. The optimization of various experimental conditions was described. Beer's Law was obeyed in the range (2.5-17.5), (5-70), (2.5-25) and (10-50)microg/ml for drugs I, II, III and IV, respectively. The molar absorptivity (epsilon), sandell sensitivity, detection((LOD)) and quantitation limits((LOQ)) are calculated. The procedure was favorably applied for determination of certain pharmaceutical dosage forms containing the studied drugs. The obtained results were compared with the official and reported methods. There were no significant differences between proposed, reported and the official methods.
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Affiliation(s)
- Hanaa M Saleh
- Department of Analytical Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
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7
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Sallerin-caute B, Monsarrat B, Lazorthes Y, Cros J, Bastide R. A Sensitive Method for the Determination of Baclofen in Human CSF by High Performance Liquid Chromatography. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/01483918808076735] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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8
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Kavran-Belin G, Rudaz S, Veuthey JL. Enantioseparation of baclofen with highly sulfated β-cyclodextrin by capillary electrophoresis with laser-induced fluorescence detection. J Sep Sci 2005; 28:2187-92. [PMID: 16318216 DOI: 10.1002/jssc.200500100] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The enantioseparation of baclofen (4-amino-3-p-chlorophenylbutyric acid) was achieved by CE-LIF with highly sulfated beta-CD (HS-beta-CD) as chiral selector. Naphthalene-2,3-dicarboxaldehyde was used for the derivatization of nonfluorescent baclofen. HS-beta-CD (2%) containing 50 mM borate buffer at pH 9.5 was chosen as the optimal running electrolyte and applied to the analysis of baclofen enantiomers in human plasma. The linearity of calibration curves (R2 > or = 0.998) for R-(-) and S-(+)-baclofen was in the 0.1-2.0 microM concentration range. After a simple ACN-protein precipitation, the LOD of baclofen in plasma sample was found as low as 50 nM.
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Affiliation(s)
- Gamze Kavran-Belin
- Laboratory of Mass Spectrometry, University of Geneva, Geneva, Switzerland.
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9
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Rat'ko AA, Stefan-van Staden RI. Determination of baclofen enantiomers in pharmaceutical formulations using maltodextrin-based enantioselective, potentiometric membrane electrodes. ACTA ACUST UNITED AC 2004; 59:993-7. [PMID: 15598435 DOI: 10.1016/j.farmac.2004.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Accepted: 08/07/2004] [Indexed: 10/26/2022]
Abstract
Two enantioselective, potentiometric membrane electrodes (EPMEs) based on maltodextrins with different value of dextrose equivalent (DE) (maltodextrin I: DE 4.0-7.0; maltodextrin II: DE 16.5-19.5) were proposed for the assay of baclofen enantiomers in baclofen raw materials and from its pharmaceutical formulation, Norton-Baclofen tablets. The slopes of the electrode function of the proposed electrodes were 55.0 mV/pS-baclofen for maltodextrin I-based electrode and 59.0 mV/pR-baclofen for maltodextrin II-based electrode and the detection limits were 1.34 x 10(-6) mol l(-1) (S-baclofen) and 2.52 x 10(-10) mol l(-1) (R-baclofen), respectively. The surfaces of the electrodes are stable and easily renewable by simply polishing on alumina paper.
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Affiliation(s)
- Alexander A Rat'ko
- Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa
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10
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Goda R, Murayama N, Fujimaki Y, Sudo K. Simple and sensitive liquid chromatography–tandem mass spectrometry method for determination of the S(+)- and R(−)-enantiomers of baclofen in human plasma and cerebrospinal fluid. J Chromatogr B Analyt Technol Biomed Life Sci 2004; 801:257-64. [PMID: 14751794 DOI: 10.1016/j.jchromb.2003.11.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A simple and sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) method to determine the enantiomers of the muscle relaxant baclofen in human plasma and cerebrospinal fluid (CSF) has been developed. A commercially available ultrafiltration membrane is used to prepare the sample. A chiral CROWNPAK CR(+) stationary phase column is then used to perform complete resolution of the S(+)- and R(-)-enantiomers of baclofen. This method was used to analyze human plasma and CSF spiked with baclofen, and the calibration curves for both biologic samples were linear over a concentration range of 0.15-150 ng enantiomer/ml. The lower limit of quantification was 0.15 ng enantiomer/ml in both fluids. Finally, the method was tested with an artificial CSF as an alternative to authentic human CSF. The results showed that no matrix effects and no interfering peaks were observed using this artificial CSF.
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Affiliation(s)
- R Goda
- Drug Metabolism and Physicochemical Property Research Laboratory, Daiichi Pharmaceutical Co. Ltd., 16-13 Kita-Kasai 1-Chome, Edogawa-ku, 134-8630 Tokyo, Japan.
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11
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Rat'ko AA, Stefan R. Teicoplanin‐Based Enantioselective, Potentiometric Membrane Electrodes for the Determination of R‐Baclofen in Pharmaceutical Formulations. ANAL LETT 2004. [DOI: 10.1081/al-200040315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Chang S, Yang H. Determination of baclofen by derivatization with anthracene-2,3-dicarboxaldehyde followed by capillary electrophoresis with laser-induced fluorescence detection. Chromatographia 2003. [DOI: 10.1007/bf02491772] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Gu YS, Whang CW. Capillary electrophoresis of baclofen with argon-ion laser-induced fluorescence detection. J Chromatogr A 2002; 972:289-93. [PMID: 12416888 DOI: 10.1016/s0021-9673(02)01083-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A capillary electrophoretic method with laser-induced fluorescence detection for baclofen (4-amino-3-p-chlorophenylbutyric acid) has been developed. 6-Carboxyfluorescein succinimidyl ester was used for precolumn derivatization of the non-fluorescent drug. Optimal separation and detection were obtained with an electrophoretic buffer of 50 mM sodium borate (pH 9.5) and an air-cooled argon-ion laser (excitation at 488 nm, emission at 520 nm). Linearity (r > or = 0.99) over three orders of magnitude was generally obtained and the lowest derivatizable concentration limit for baclofen in aqueous solution was 10 nM (2 ng baclofen/ml). Coupled with a simple clean up procedure, the method can be applied to the analysis of baclofen in human plasma at micromolar level. Recovery of spiked baclofen in plasma was 95%. The relative standard deviation values on peak size (0.5 microM level) and migration time were 8.2 and 1.0% (n=7), respectively. The limit of detection of baclofen in plasma was 0.1 microM (21 ng/ml).
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Affiliation(s)
- Yi-Sheng Gu
- Department of Chemistry, Tunghai University, Taichung, Taiwan
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14
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Abstract
A fatal suicidal intoxication with unusual drugs is reported. A 56-year-old man was found dead in his house; near by the corpse several empty drugs boxes were found. An autopsy was performed and the biological fluids were submitted to a full toxicological work-up. The analytical results supported the hypothesis of a death due to the acute baclofen (4-amino-3-(p-chlorophenyl)butyric acid) and dipyrone (sodium [N-(1,5-dimethyl-3-oxo-2-phenylpyrazolin-4-yl)-N-methylamino] methanesulfonate) intoxication.
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Affiliation(s)
- N De Giovanni
- Istituto di Medicina Legale e delle Assicurazioni, Università Cattolica del Sacro Cuore, L. gl.F. Vito 1, 00168 Rome, Italy
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15
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Chiang MT, Chang SY, Whang CW. Chiral analysis of baclofen by alpha-cyclodextrin-modified capillary electrophoresis and laser-induced fluorescence detection. Electrophoresis 2001; 22:123-7. [PMID: 11197160 DOI: 10.1002/1522-2683(200101)22:1<123::aid-elps123>3.0.co;2-4] [Citation(s) in RCA: 29] [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
An enantioselective method for baclofen (4-amino-3-p-chlorophenylbutyric acid) based on capillary electrophoresis (CE) separation and laser-induced fluorescence (LIF) detection has been developed. Naphthalene-2,3-dicarboxaldehyde (NDA) was used for precolumn derivatization of the nonfluorescent drug. alpha-Cyclodextrin (alpha-CD) was included in the buffer as a chiral selector for the separation of NDA-labeled S-(+)- and R-(-)-baclofen. Optimal resolution and detection were obtained with an electrophoretic buffer of 50 mM sodium borate (pH 9.5) containing 7 mM alpha-CD and a He-Cd laser (lambda ex = 442 nm, lambda em = 500 nm). Combined with a simple cleanup procedure, this method can be applied to the analysis of baclofen enantiomers in human plasma. The relative standard deviation (RSD) values on peak areas of a plasma sample containing 1.0 microM racemic baclofen were 6.4 and 4.9% (n = 8) for the S-(+)- and R-(-)-enantiomer, respectively. The RSD value on migration times of both enantiomers was 0.5% (n = 8). Calibration graphs for S-(+)- and R-(-)-baclofen in plasma showed a good linearity (r > or = 0.999) in the concentration range of 0.1-2.0 microM. The limit of detection of baclofen in plasma was about 10 ng/mL.
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Affiliation(s)
- M T Chiang
- Department of Chemistry, Tunghai University, Taichung, Taiwan
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16
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Chiang MT, Chang SY, Whang CW. Analysis of baclofen by capillary electrophoresis with laser-induced fluorescence detection. J Chromatogr A 2000; 877:233-7. [PMID: 10845802 DOI: 10.1016/s0021-9673(00)00168-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A new analytical method for baclofen (4-amino-3-p-chlorophenylbutyric acid) based on capillary electrophoretic separation and laser-induced fluorescence detection has been developed. Naphthalene-2,3-dicarboxaldehyde was used for precolumn derivatization of the non-fluorescent drug. Optimal separation and detection were obtained with an electrophoretic buffer of 50 mM sodium borate (pH 9.5) and a He-Cd laser (excitation at 442 nm, emission at 500 nm). Linearity (r > or = 0.99) over three orders of magnitude was generally obtained and the concentration limit of detection was in the nanomolar level. Coupled with a simple cleanup procedure, the method was successfully applied to the analysis of baclofen in human plasma. Recovery of spiked baclofen in plasma was 98%. The relative standard deviation values on peak size and migration time were 7.9% and 0.4%, respectively. The limit of detection of baclofen in plasma was 10 ng/ml.
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Affiliation(s)
- M T Chiang
- Department of Chemistry, Tunghai University, Taichung, Taiwan
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17
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Flärdh M, Jacobson BM. Sensitive method for the determination of baclofen in plasma by means of solid-phase extraction and liquid chromatography-tandem mass spectrometry. J Chromatogr A 1999; 846:169-73. [PMID: 10420608 DOI: 10.1016/s0021-9673(99)00013-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A simple and sensitive method for the determination of baclofen in plasma is described. Baclofen and the internal standard, KM 08205, were isolated from plasma by solid-phase extraction using C18 material. After separation by reversed-phase liquid chromatography, the analytes were detected with tandem mass spectrometry. The extraction procedure was optimised regarding the solid-phase extraction material, the pH in the conditioning solution and the washing volume. The method was proven to be selective and sensitive with an absolute recovery of about 95%, a relative standard deviation below 5% and a limit of quantification of 10 nmol/1.
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Affiliation(s)
- M Flärdh
- Astra Hässle AB, Mölndal, Sweden
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18
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Millerioux L, Brault M, Gualano V, Mignot A. High-performance liquid chromatographic determination of baclofen in human plasma. J Chromatogr A 1996; 729:309-14. [PMID: 9004955 DOI: 10.1016/0021-9673(95)00944-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A reversed-phase isocratic HPLC method is described for the determination of baclofen in human plasma. Solid-phase extraction using a SCX Bond Elut column is used followed by derivatization with o-phthalaldehyde-tert.-butanethiol and electrochemical detection. Both the within- and between-day R.S.D. and inaccuracy are less than 10% and 7%, respectively, even at the limit of quantification of the method, i.e., 10 ng/ml. The method was shown to give optimum performance in terms of sensitivity, precision and accuracy for the pharmacokinetic study of baclofen after a single oral administration to volunteers.
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Tosunoğlu S, Ersoy L. Determination of baclofen in human plasma and urine by high-performance liquid chromatography with fluorescence detection. Analyst 1995; 120:373-5. [PMID: 7710128 DOI: 10.1039/an9952000373] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An isocratic reversed-phase column liquid chromatographic assay for baclofen was developed. Prior to analysis, derivatization of urine or deproteinized plasma with 4-chloro-7-nitrobenzofurazan (NBD-CI) reagent was employed. After solid-phase extraction on a small silica gel column, the mixture was chromatographed on a 10 microns Bondapak C18 column using methanol-water (45 + 55 v/v) as the mobile phase. The NBD-baclofen derivative was detected spectrofluorimetrically by monitoring the emission at 524 nm with excitation at 463 nm. The method was tested for suitability in routine analysis. After a single oral dose of 20 mg of baclofen, the plasma concentration and the cumulative urinary excretion of the drug were determined. The average recoveries were 99.5 and 98.5% for plasma and urine, respectively.
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Affiliation(s)
- S Tosunoğlu
- Faculty of Pharmacy, Department of Analytical Chemistry, University of Istanbul, Turkey
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20
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Vaccher C, Berthelot P, Debaert M. Direct separation of 4-amino-3-(4-chlorophenyl)butyric acid and analogues, GABAB ligands, using a chiral crown ether stationary phase. J Chromatogr A 1993. [DOI: 10.1016/0021-9673(93)80622-f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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22
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Wall GM, Baker JK. Determination of baclofen and alpha-baclofen in rat liver homogenate and human urine using solid-phase extraction, o-phthalaldehyde-tert.-butyl thiol derivatization and high-performance liquid chromatography with amperometric detection. JOURNAL OF CHROMATOGRAPHY 1989; 491:151-62. [PMID: 2793970 DOI: 10.1016/s0378-4347(00)82828-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Methods were developed for the determination of the zwitterionic compounds baclofen and alpha-baclofen in complex biological samples (rat liver homogenates and human urine) in concentration ranges that would be suitable for pharmacokinetic studies of these compounds. In the procedure, the biological samples along with an internal standard were selectively concentrated using C18 solid-phase extraction cartridges, evaporated, derivatized with o-phthalaldehyde and tert.-butyl thiol at room temperature for 2 min, then subjected to high-performance liquid chromatographic analysis. The reversed-phase (C18) chromatographic analysis with amperometric detection (glassy carbon electrode in oxidative mode, +0.6 V vs. Ag/AgCl) was found to be useful for the measurement of both baclofen and alpha-baclofen from 10 ng/ml to 10 micrograms/ml in these complex biological samples. The primary advantage of the method was that the derivatives formed using tert.-butyl thiol were markedly more stable than the previously reported derivatives prepared using mercaptoethanol.
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Affiliation(s)
- G M Wall
- Department of Medicinal Chemistry, School of Pharmacy, University of Mississippi, University 38677
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23
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Rustum AM. Simple and rapid reversed-phase high-performance liquid chromatographic determination of baclofen in human plasma with ultraviolet detection. Application to a pharmacokinetic study. JOURNAL OF CHROMATOGRAPHY 1989; 487:107-15. [PMID: 2715253 DOI: 10.1016/s0378-4347(00)83012-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A sensitive, selective, and rapid reversed-phase high-performance liquid chromatographic method for separation and quantitation of intact racemic baclofen in human plasma has been described. Baclofen is very soluble in water and cannot be extracted efficiently by an organic solvent. Therefore, baclofen was isolated from plasma endogenous materials by adding 0.50 ml of acetonitrile and 50 mg of zinc sulfate to 1.0 ml of plasma. A 15 cm X 4.6 mm, 10-microns octyl (C8) column was slurry packed and used throughout the study. An isocratic mobile phase containing 0.01 M monobasic potassium phosphate (pH congruent to 3.5)-acetonitrile (80:20, v/v) was delivered at a flow-rate of 1.0 ml/min through the chromatographic system. Baclofen was detected with an ultraviolet-visible variable-wavelength detector at 220 nm and 0.50-0.005 a.u.f.s. The time needed to complete the analysis of one sample was approximately 15 min. The limit of detection for the assay of racemic baclofen was 35 ng/ml. After an oral dose of 20 mg of baclofen, blood samples were collected at several time points and plasma was analyzed using the method developed in this study. Various pharmacokinetics parameters were determined from the plasma concentration versus time profile of baclofen.
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Affiliation(s)
- A M Rustum
- Department of Metabolism and Environmental Fate, Hazleton Laboratories America, Inc., Madison, WI 53707
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24
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Tosuno??lu S, Büyüktimkin N. Spectrophotometric Determination of Baclofen.Spektrophotometrische Bestimmung von Baclofen. Arch Pharm (Weinheim) 1989. [DOI: 10.1002/ardp.19893220713] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Howe JR, Sutor B, Zieglgänsberger W. Baclofen reduces post-synaptic potentials of rat cortical neurones by an action other than its hyperpolarizing action. J Physiol 1987; 384:539-69. [PMID: 3309263 PMCID: PMC1192277 DOI: 10.1113/jphysiol.1987.sp016469] [Citation(s) in RCA: 137] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
1. Intracellular recordings were obtained from neurones in layers 2 and 3 of the rat frontal neocortex in an in vitro slice preparation. Three distinct types of stimulation-evoked post-synaptic potentials were recorded in these neurones: excitatory post-synaptic potentials (e.p.s.p.s); bicuculline-sensitive, chloride-dependent inhibitory post-synaptic potentials (i.p.s.p.s) with times to peak of 20-25 ms (fast(f)-i.p.s.p.s); bicuculline-insensitive, potassium-dependent i.p.s.p.s with bicuculline-insensitive, potassium-dependent i.p.s.p.s with times to peak of 150-250 ms (long(l)-i.p.s.p.s). 2. The effects of baclofen were investigated on seventy-one neurones. Baclofen was applied by ionophoresis or pressure ejection from micropipettes or was added to the superfusion medium. 3. Baclofen depressed stimulation-evoked e.p.s.p.s in fifty-seven of the sixty neurones tested. This effect was associated with an increase in the stimulation intensity required to produce a synaptically evoked action potential for thirty-nine of forty-four neurones. 4. Baclofen depressed f-i.p.s.p.s in thirty-seven of the thirty-nine neurones tested and l-i.p.s.p.s in each one of the seventeen neurones tested. Reversal potential values for each type of i.p.s.p. were not changed by baclofen and its depressions of each were independent of membrane potential (Em). Baclofen reduced the magnitude and the duration of the conductance increases that were associated with f- and l-i.p.s.p.s. 5. Baclofen hyperpolarized forty of seventy-one neurones and produced outward currents in three of four neurones recorded in voltage clamp at holding potentials between -55 and -65 mV. These actions were associated with 10-58% reductions of neuronal input resistance (RN) and 10-20% increases in neuronal input conductance (gN), respectively. Baclofen decreased the direct excitability of twenty-three of twenty-seven neurones tested. Determinations of the reversal potential for baclofen-induced changes of Em indicate that baclofen increases the conductance of rat neocortical neurones to potassium ions. 6. The EC50 for each action of DL-baclofen was approximately 1 microM. L-Baclofen was greater than 100 times more potent than D-baclofen. 7. Concentrations of bicuculline that blocked f-i.p.s.p.s and responses to ionophoretically applied gamma-aminobutyric acid (GABA) had no effect on the depressions of e.p.s.p.s or the hyperpolarizations and decreases in RN that baclofen produced. 8. Baclofen did not reduce the duration of action potentials that were prolonged with intracellular injections of caesium ions or by superfusions with medium that contained 10 mM-tetraethylammonium (TEA).(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J R Howe
- Clinical Neuropharmacology, Max Planck Institute for Psychiatry, Munich, F.R.G
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Harrison PM, Tonkin AM, McLean AJ. Determination of 4-amino-3-(p-chlorophenyl)butyric acid (baclofen) in plasma by high-performance liquid chromatography. JOURNAL OF CHROMATOGRAPHY 1985; 339:424-8. [PMID: 4008583 DOI: 10.1016/s0378-4347(00)84675-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Wuis EW, Dirks RJ, Vree TB, van der Kleyn E. High-performance liquid chromatographic analysis of baclofen in plasma and urine of man after precolumn extraction and derivatization with o-phthaldialdehyde. JOURNAL OF CHROMATOGRAPHY 1985; 337:341-50. [PMID: 3988864 DOI: 10.1016/0378-4347(85)80047-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A reversed-phase high-performance liquid chromatographic method for the determination of the skeletal muscle relaxant baclofen in human plasma and urine is described. Cation-exchange extraction, precolumn derivatization with o-phthaldialdehyde, and on-column concentration precede fluorimetric detection (excitation at 340 nm, emission at 460 nm). The precision of the assay was always better than 6%. Recoveries of standards added to plasma and urine were 92% and 93%, respectively. With a sample size of 0.5 ml, a detection limit of a few nanograms, and the possibility of analysing up to four samples per hour, this method is suitable for pharmacokinetic studies. An example is presented.
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Kochak G, Honc F. Improved gas-liquid chromatographic method for the determination of baclofen in plasma and urine. JOURNAL OF CHROMATOGRAPHY 1984; 310:319-26. [PMID: 6511850 DOI: 10.1016/0378-4347(84)80096-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A simple, rapid and sensitive assay for baclofen analysis has been developed. Baclofen and the internal standard are analyzed by gas-liquid chromatography with electron-capture detection after esterification of the carboxyl group to the butyl ester and acylation of the amino group to the pentafluoropropionylamide. Recovery from biological matrixes is accomplished by ion-pair extraction. The limit of quantitation of the entire assay as stated is about 10 ng/ml baclofen in plasma.
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Anderson P, Nohér H, Swahn CG. Pharmacokinetics in baclofen overdose. JOURNAL OF TOXICOLOGY. CLINICAL TOXICOLOGY 1984; 22:11-20. [PMID: 6492227 DOI: 10.3109/00099308409035078] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The pharmacokinetics of baclofen analyzed by gas chromatography mass spectrometry in a massive intoxication case (baclofen 1230 mg orally) is presented. In contrast to earlier reports, no increase in the plasma half-life of elimination of baclofen could be observed (t1/2 = 4.58 hours). On the contrary, we found an increased plasma clearance (Clpl = 0.368 l/kg) in this highly intoxicated patient compared to the kinetics usually found in healthy subjects.
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Eriksson G, Swahn CG. Concentrations of baclofen in serum and breast milk from a lactating woman. Scand J Clin Lab Invest 1981; 41:185-7. [PMID: 7313501 DOI: 10.3109/00365518109092032] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A lactating woman with spastic paraplegia was given 94 mumol (20 mg) of baclofen orally to study the transport of the drug into breast milk. The concentration of baclofen in serum and milk was determined with a gas chromatographic--mass spectrometric method. The elimination curves in serum and milk showed a similar course, the elimination from milk being delayed about 3 h relative to serum. The total amount of baclofen excreted in the milk during 24 h was about one thousandth of the ingested dose.
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