外文资料Standardless 1H NMR determination of pharmacologically active substances in dietary supplements and.pdfVIP

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外文资料Standardless 1H NMR determination of pharmacologically active substances in dietary supplements and.pdf

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Research article Drug Testing and Analysis Received: 11 January 2012 Revised: 30 March 2012 Accepted: 30 March 2012 Published online in Wiley Online Library: 1 May 2012 () DOI 10.1002/dta.1367 4 0 0Standardless 1H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the Internet Yulia B Monakhova,a,b,c Thomas Kuballa,a Sigrid L?bell-Behrends,a Sibylle Maixner,a Matthias Kohl-Himmelseher,a Winfried Rugea and Dirk W Lachenmeiera*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 1H 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 dehydroepiandros- terone. 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