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Sawama Y, Park K, Yamada T, Sajiki H. New Gateways to the Platinum Group Metal-Catalyzed Direct Deuterium-Labeling Method Utilizing Hydrogen as a Catalyst Activator. Chem Pharm Bull (Tokyo) 2018; 66:21-28. [DOI: 10.1248/cpb.c17-00222] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Kwihwan Park
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University
| | - Tsuyoshi Yamada
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University
| | - Hironao Sajiki
- Laboratory of Organic Chemistry, Gifu Pharmaceutical University
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Yamada T, Park K, Yasukawa N, Morita K, Monguchi Y, Sawama Y, Sajiki H. Mild and Direct Multiple Deuterium-Labeling of Saturated Fatty Acids. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201600363] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Tsuyoshi Yamada
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Kwihwan Park
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Naoki Yasukawa
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Kosuke Morita
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Yasunari Monguchi
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Yoshinari Sawama
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Hironao Sajiki
- Laboratory of Organic Chemistry; Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
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Polepally AR, Remmel RP, Brundage RC, Leppik IE, Rarick JO, Ramsay RE, Birnbaum AK. Steady-state pharmacokinetics and bioavailability of immediate-release and extended-release formulations of lamotrigine in elderly epilepsy patients: Use of stable isotope methodology. J Clin Pharmacol 2015; 55:1101-8. [PMID: 25903807 DOI: 10.1002/jcph.522] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 04/14/2015] [Indexed: 11/06/2022]
Abstract
A classic 2-period crossover bioavailability study was conducted to evaluate the relative and absolute bioavailability of immediate-release (IR) and extended-release (XR) lamotrigine formulations under steady-state conditions in elderly patients with epilepsy. On treatment days, each subject's morning dose (IR or XR lamotrigine) was replaced with an intravenous 50-mg dose of stable-labeled lamotrigine. Lamotrigine concentrations were measured at 13 points between 0 and 96 hours. XR and IR lamotrigine formulations were similar with respect to steady-state area under the concentration-time curve from 0 to 24 hours (AUC0-24 h ss), average concentration (Cavg, ss), and trough concentration (Cτ, ss). A 33% lower fluctuation in concentrations with XR was observed relative to IR lamotrigine. The time to peak concentration (Tmax, ss) was delayed for XR lamotrigine (3.0 vs 1.3 hours) with lower peak concentration (15% lower). The absolute bioavailability for IR and XR formulations was 73% and 92%, respectively. The formulations were bioequivalent with respect to AUC0-24 h ss, Cτ, ss, and Cavg, ss indicating that it may be possible to switch directly from IR to XR lamotrigine without changes in the total daily dose.
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Affiliation(s)
- Akshanth R Polepally
- Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, USA
| | - Rory P Remmel
- Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN, USA
| | - Richard C Brundage
- Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, USA
| | - Ilo E Leppik
- Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, USA.,Department of Neurology, University of Minnesota, Minneapolis, MN, USA
| | - John O Rarick
- Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, USA
| | - R Eugene Ramsay
- Department of Neurology, Ochsner Baptist Medical Center, New Orleans, LA, USA.,University of Miami, Miami, FL, USA
| | - Angela K Birnbaum
- Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, USA
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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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Chapter 7 alternatives to mass spectrometry for quantitation of stable isotopes: High performance liquid chromatography with conventional ultraviolet detection. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0165-7208(97)80154-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Browne TR. Chapter 2 Isotope effect: Implications for pharmaceutical investigations. PHARMACOCHEMISTRY LIBRARY 1997. [DOI: 10.1016/s0165-7208(97)80149-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Abstract
The use of stable isotope-labeled compounds for pharmacologic studies requires careful consideration of the nature of the stable isotope label (2H, 13C, 15N, 18O) and its position of incorporation in the molecule. When deuterium is used, improper positioning can lead to significant primary isotope effects. Primary isotope effects occur when the breaking of the bond to the heavy isotope is the rate-limiting step in a reaction (or metabolic transformation). A reaction will proceed slower for the molecule with the heavy isotope label because of the mass difference between the light and the heavy isotope. In addition to these primary isotope effects, smaller but nevertheless important secondary isotope effects, physicochemical isotope effects, active hydrogen/deuterium exchange, or isotope effects associated with either the enzyme-catalyzed biotransformation or the mass spectrometric ionization and fragmentation can be operative. In mechanistic studies, isotope effects are used to their advantage; however, in pharmacokinetic studies, the occurrence of isotope effects can lead to grossly misleading biologic and analytic results: the metabolism of the drug will differ when 'in vivo' isotope effects are operative, and isotope effects occurring during the analysis procedure will obscure the true metabolic profile of the drug.
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Gaudry D, Wantiez D, Richard J, Metayer JP. Simultaneous determination of metoprolol and deuterium-labelled metoprolol in human plasma by gas chromatography-negative-ion mass spectrometry. JOURNAL OF CHROMATOGRAPHY 1985; 339:404-9. [PMID: 4008579 DOI: 10.1016/s0378-4347(00)84671-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Froescher W, Gugler R, Niesen M, Hoffmann F. Protein binding of valproic acid in maternal and umbilical cord serum. Epilepsia 1984; 25:244-9. [PMID: 6423379 DOI: 10.1111/j.1528-1157.1984.tb04183.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The serum valproic acid levels of 18 maternity patients at the time of delivery were compared with the valproic acid levels in the umbilical cord serum. The levels in the umbilical cord serum were 1.1-4.6 times higher than those in the maternal serum, with a mean value of 1.38. One explanation for this difference apparently is an increased protein binding of valproic acid in the infant's serum. Protein binding was determined in nine patients, in six by equilibrium dialysis and in three by ultrafiltration. The median value of the free fraction of valproic acid was 9.1% (range, 5.8-16.4%) in the umbilical cord serum (equilibrium dialysis) and 15% (range, 12.7-35.3%) in the maternal serum. The difference between the infant and the maternal serum is significant.
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Acheampong AA, Abbott FS, Orr JM, Ferguson SM, Burton RW. Use of hexadeuterated valproic acid and gas chromatography-mass spectrometry to determine the pharmacokinetics of valproic acid. J Pharm Sci 1984; 73:489-94. [PMID: 6427445 DOI: 10.1002/jps.2600730415] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Di-[( 3,3,3-2H3]propyl)acetic acid, a hexadeuterated analogue of valproic acid, was synthesized and its pharmacokinetic properties compared with valproic acid. Concentrations of valproic acid and [2H]valproic acid in serum and saliva were determined by GC-MS using selected-ion monitoring. Saliva drug levels were measured with good precision down to 0.1 microgram/mL. Kinetic equivalence of valproic acid and [2H]valproic acid was demonstrated in a single-dose study in a human volunteer. An isotope effect was observed for omega-oxidation, but the difference in metabolism was not sufficient to make [2H]valproic acid biologically nonequivalent. The application of [2H]valproic acid to determine the kinetics of valproic acid under steady-state concentrations was evaluated in the same volunteer. The kinetic data obtained with [2H]valproic acid was consistent with previously reported values for valproic acid including kinetic differences observed between single-dose and steady-state experiments. Saliva levels of valproic acid were found to give a good correlation (r = 0.953) with total serum valproic acid under multiple-dose conditions. A concentration dependence was found for the ratio of saliva valproic acid to free valproic acid in serum, low ratios being observed at high serum concentrations of valproic acid.
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Hoffman DJ, Porter WR. Resolution of valproic acid from deuterated analogues and their quantitation in plasma using capillary gas chromatography. JOURNAL OF CHROMATOGRAPHY 1983; 276:301-9. [PMID: 6415082 DOI: 10.1016/s0378-4347(00)85096-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Quantitation of valproic acid and a deuterated analogue in the same plasma sample by capillary gas chromatography without mass spectrometry was illustrated. Specificity was accomplished solely with a 60 m X 0.25 mm fused silica WCOT column coated with OV-351. A hexadeutero and two tetradeutero analogues of valproic acid had resolutions of at least 1.2 from valproic acid. Plasma samples were extracted with carbon tetrachloride following the addition of 2-ethylhexanoic acid as the internal standard. The method is sensitive to at least 0.5 microgram/ml and provides the capability of conducting absolute bioavailability and pulsed dosing studies with deuterated drug analogues without a mass spectrometer. The technique was applied to the analysis of plasma samples from dogs simultaneously administered valproic acid and a deuterated analogue.
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Vree TB, Tijhuis MW, Baakman M, Hekster CA. Analysis of N4-trideuteroacetylsulphamerazine and its metabolites sulphamerazine and N4-acetylsulphamerazine in man by means of high-performance liquid chromatography and mass spectrometry. BIOMEDICAL MASS SPECTROMETRY 1983; 10:114-9. [PMID: 6850064 DOI: 10.1002/bms.1200100303] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Browne TR, Van Langenhove A, Costello CE, Biemann K, Greenblatt DJ. Pharmacokinetic equivalence of stable-isotope-labeled and unlabeled drugs. Phenobarbital in man. J Clin Pharmacol 1982; 22:309-15. [PMID: 7107979 DOI: 10.1002/j.1552-4604.1982.tb02680.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Stable isotope labeling of drugs has been used in human metabolism studies because it eliminates the risk of radiation exposure accompanying use of radioactive tracers. The labeled drug can be measured by gas-chromatographic mass spectrometry (GCMS). However, if reliable pharmacokinetic data are to be obtained, one has to be certain the rate of metabolism of labeled and unlabeled drug is the same, i.e., there is no kinetic isotope effect. To evaluate this for phenobarbital (PB), three humans were infused with a 1:1 mixture of phenobarbital and 1,3-15N2-2-13C-PB. Serum was collected at regular intervals. Concentrations of labeled and unlabeled phenobarbital were determined by GCMS. Within each subject, there was no trend for concentrations of labeled phenobarbital to be higher or lower than concentrations of unlabeled phenobarbital (P greater than 0.90 for all three subjects). There was no difference in the zero time intercepts, distribution and elimination time constants and half-lives, volumes of distribution and central compartment, or clearance of the two forms of phenobarbital. Thus, no isotope effect was found. Published data on other labeled drugs and the likelihood of encountering an isotope effect based on type of isotope and its location in the molecule are discussed.
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Abbott FS, Burton R, Orr J, Wladichuk D, Ferguson S, Sun TH. Valproic acid analysis in saliva and serum using selected ion monitoring (electron ionization) of the tert.-butyldimethylsilyl derivatives. JOURNAL OF CHROMATOGRAPHY 1982; 227:433-44. [PMID: 6801067 DOI: 10.1016/s0378-4347(00)80396-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A highly sensitive ion monitoring method for the determination of valproic acid in saliva and in serum has been developed based on the gas chromatographic--mass spectrometric analysis of the tert.-butyldimethylsilyl derivatives. Extraction methods are simple and the techniques for derivatization are rapid and convenient. Selected ion monitoring was carried out using electron ionization conditions and a common ion m/z 201 (M+--57) present in valproic acid and the internal standard octanoic acid. The lower limit of sensitivity that has acceptable precision for assay purposes is 0.1 mg/l based on a 200-microliter sample size. The ion monitoring method (derivatized) was compared to a gas chromatographic method (underivatized) for serum valproate assays and found to be essentially identical. The assay methodology was used in a kinetic study of valproic acid in two normal subjects. Saliva levels of drug were found to give reasonably good correlations with serum total and with serum free concentrations of drug in both individuals.U
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Hoffmann F, von Unruh GE, Jancik BC. Valproic acid disposition in epileptic patients during combined antiepileptic maintenance therapy. Eur J Clin Pharmacol 1981; 19:383-5. [PMID: 6786896 DOI: 10.1007/bf00544590] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A previously developed mass spectrometric method was used to measure, in the presence of the unlabeled drug, the fate of pulse dose of tetradeuterated valproic acid given to epileptic patients. By this means the disposition of valproic acid (VPA) was studied in several epileptic patients on maintenance therapy with VPA and at least one other anti-epileptic drug. For 6 patients with 6 different anti-epileptic drug combinations, the mean VPA half-life was only 6.2 h, as compared to about 15 h after a single dose. The mean plasma clearance in those patients was 16.4 ml/min. The volume of distribution was 0.14 l/kg, which did not differ from values found in single dose studies. The clinical relevance of these findings is pointed out.
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