Complete H-1 and C-13 assignments of fluorinated analogs of dehydroepiandrosterone
Science and Engineering Group, RTI International, Research Triangle Park NC 27709-2194, USA. Magnetic Resonance in Chemistry
(Impact Factor: 1.18).
11/2006; 44(11):1051-3. DOI: 10.1002/mrc.1874
The complete assignments of all H-1 and C-13 chemical shifts were made for the fluorinated dehydroepiandrosterone (DHEA) analog fluasterone, 2, and two potential in vivo metabolites 3 and 4. The assignments were made using a combination of one- and two-dimensional NMR techniques (H-1, C-13, gDQCOSY, gHSQC, gHMBC). Once the proton chemical shifts were assigned, the stereochemistry of the two hydroxylated analogs was determined using 2D ROESY experiments. Copyright (c) 2006 John Wiley & Sons, Ltd.
Available from: Dirk W Lachenmeier
- "(m) dihydrokavain in CD 3 OD/D 2 O, 600 MHz  (ethanol 40% vol) 9.Dehydroepiandrosterone (DHEA) 0.91 * --- 0.91 (s) * 1.02 suppressed 1.08 suppressed 1.17 suppressed 1.35 suppressed 1.48 - 1.56 1.52 (m) 1.60 1.60 (m) 1.65 1.68 (s) 1.86 1.87 (m) 1.99 1.92 (s) 2.06 2.00 (m) 5.15 - 5.29 5.38 (t) (500.13MHz, CDCl 3 )  "
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ABSTRACT: Dietary supplements and medicines are widely marketed over the Internet. Such products may be counterfeited and lack some or all of the labelled ingredients, or, in the case of lifestyle supplements, illegally contain pharmacologically active substances, such as anorectic or androgenic compounds. The market control - especially in the case of customs seizures - is complex, as reference substances necessary for identification and calibration in traditional high performance liquid chromatography (HPLC) or gas chromatography-mass spectrometry (GC-MS) analysis are often unavailable, or extremely expensive. In this study, we introduce a 400 MHz (1) H NMR methodology, which allows identification and quantitative estimation even without such pure compound standards. The identification can be based on literature spectra, or if these data are unavailable, by applying computational NMR spectra prediction. For standardless NMR determination, simple peak-area comparison of the target compound with the TSP reference was used. The applicability was demonstrated for a wide range of compounds, such as mesterolone, oxymetholone, sibutramine, monacolin K, vinpocetine, evodiamine, caffeine, kavain, and dehydroepiandrosterone. The average relative standard deviations were 5.0% for peak area comparison, and 3.3% for external calibration with standard substance. The method uncertainty is therefore higher in standardless determination, but acceptable for the purpose of proving the presence or absence of pharmacologically active substances. The limit of detection of 0.5-2 mg/kg is sufficient for the purpose. NMR is ideally suited to controlling dietary supplements or illegal medicines as it provides qualitative and at least semi-quantitative information more rapidly (measurement time 20 min) than with any other currently available spectroscopic or chromatographic method. Copyright © 2012 John Wiley & Sons, Ltd.
Drug Testing and Analysis 06/2013; 5:400-411. DOI:10.1002/dta.1367 · 2.51 Impact Factor
Available from: Brian Frazier Thomas
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ABSTRACT: The objective of this research was the identification of the metabolic profile of fluasterone, a synthetic derivative of dehydroepiandrosterone, in dogs treated orally or subcutaneously with [4-(14)C]fluasterone. Separation and characterization techniques used to identify the principal metabolites of fluasterone in urine and feces included high-performance liquid chromatography (HPLC), liquid scintillation spectrometry, HPLC/tandem mass spectrometry, and NMR. In urine, the majority of the radioactivity was present as two components that had apparent molecular weights consistent with their tentative identification as monoglucuronide conjugates of 4alpha-hydroxy-16alpha-fluoro-5-androsten-17beta-ol and X(alpha or beta)-4alpha-dihydroxy-16alpha-fluoro-5-androsten-17beta-ol. The identification of the monoglucuronide conjugate of 4alpha-hydroxy-16alpha-fluoro-5-androsten-17beta-ol was also supported by NMR data. In support of this identification, these metabolites were cleaved with glucuronidase enzyme treatment, which gave rise to components with molecular weights again consistent with the aglycones of a monohydroxylated, 17-keto reduced (dihydroxy) fluasterone metabolite and a dihydroxylated, 17-keto reduced (trihydroxy) fluasterone metabolite. In feces, nonconjugated material predominated. The primary metabolites eliminated in feces were the two hydroxy fluasterone metabolites arising from 17-reduction (16alpha-fluoro-5-androsten-17beta-ol and 16alpha-fluoro-5-androsten-17alpha-ol) and 4alpha-hydroxy-16alpha-fluoro-5-androsten-17beta-ol that was present in urine in glucuronide form.
Drug metabolism and disposition: the biological fate of chemicals 03/2009; 37(5):1089-97. DOI:10.1124/dmd.108.023614 · 3.25 Impact Factor
Available from: ncbi.nlm.nih.gov
Cancer Epidemiology Biomarkers & Prevention 03/2009; 18(3):698-700. DOI:10.1158/1055-9965.EPI-08-1007 · 4.13 Impact Factor
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