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  • 1
    Electronic Resource
    Electronic Resource
    Negative ion chemical ionization gas chromatography/mass spectrometry of valproic acid metabolites (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 918-926 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A negative ion chemical ionization (NICI) gas chromatographic/mass spectrometric method is described for the identification of 15 valproic acid (VPA) metabolites as their pentafluorobenzyl derivatives. Samples analyzed were serum, urine and saliva taken from a volunteer on VPA at steady state and also given selected doses of (2H6)VPA. Metabolite peaks were identified by comparison to synthetic standards. All the metabolites, like the parent drug, produced abundant [M - 181]- ions, except 3-keto VPA, which gave an [M - 181 - CO2]- ion. Using the NICI method, two new VPA metabolites were identified. One of these metabolites was characterized as 4′-keto-2-ene VPA by synthesis, while the second one appeared to be a positional isomer of 4′-keto-2-ene VPA. The sensitivity of the method was also sufficient to detect metabolites of VPA in saliva. The ratio of the levels of (Z)-2-ene VPA to (E)-2-ene VPA was much greater in saliva than in serum, suggesting stereoselective plasma protein binding or transport of these two metabolites. The lower limit of detection for the quantification of VPA in serum or saliva was 2 ng ml-1.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200181012
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and mass spectrometry of deuterated methadone and methadone metabolitesDDP = 1,5-dimethyl-3,3-diphenyl-2-pyrrolidone; EDDP = 2-ethylidene-1,5-dimethyl-3,3-diphenyl pyrrolidine; EMDP =2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline. (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1979), S. 179-186 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deuterated methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenyl pyrrolidine, 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline, 1,5-dimethyl-3,3-diphenyl-2-pyrrolidone and 4-dimethylamino-2,2-diphenylpentanoic acid have been synthesized for application to metabolic studies of methadone and as potential internal standards for selected ion monitoring methods. Mass fragmentation patterns are described based upon comparisons between labeled and unlabeled derivatives.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200060502
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Identification of valproic acid metabolites in human serum and urine using hexadeuterated valproic acid and gas chromatographic mass spectrometric analysis (1983)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 10 (1983), S. 586-595 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Valproic acid, an antiepileptic drug, is extensively metabolized in humans. A hexadeuterated valproic acid was used in this study to aid the identification of metabolites and their artifacts in serum and urine extracts. A 600 mg oral dose of hexadeuterated valproic acid was administered to a human volunteer at steady state serum concentrations of unlabelled valproic acid. By using gas chromatography mass spectrometry, metabolites were characterized as their methyl, tert -butyldimethylsilyl, or trimethylsilyl derivatives. A di-unsaturated metabolite with concentrations comparable to 2-ene valproic acid was identified in serum and urine. The presence of a molecular ion doublet in the mass spectrum corresponding to the unlabelled and hexadeuterated dienes reduces the possible structures for this metabolite. A new metabolite, 2-propyl-4-ketopentanoic acid was also identified in serum and in urine. The dicarboxylic acids, 2-propylsuccinic and 2-propylmalonic were identified in the urine extract as metabolites. Identification of isolated metabolites was aided by comparison of the retention times and mass spectra to those of synthesized reference compounds. Diagnostic fragment ions and ion doublets in the mass spectra of the derivatives of newly identified metabolites were compared to those of known metabolites.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200101103
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    Paper (German National Licenses)
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