Analysis of exemestane and 17ß-hydroxyexemestane in human urine by gas chromatography/mass spectrometry: development and validation of a method using MO-TMS derivatives.
Rapid Commun Mass Spectrom
; 24(22): 3297-302, 2010 Nov 30.
Article
en En
| MEDLINE
| ID: mdl-20973004
ABSTRACT
Trimethylsilylation of anabolic agents and their metabolites is frequently achieved by using the derivatization mixture N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA)/NH(4)I/2-mercaptoethanol. Nevertheless, artifacts were formed when this mixture was employed in the monitoring of exemestane and its main metabolite 17ß-hydroxyexemestane prior to GC-MS analysis. These artifacts were identified as the N-methyltrifluoroacetamide (MTFA) and trimethylsiloxyethylmercapto products of the respective trimethylsilyl (TMS) derivatives. Furthermore, artifact formation was evaluated taking the structure (1,4-diene-3-keto-6-exomethylene) of the compounds into account. Although these artifacts are relevant for investigations regarding the derivatization process and may be of interest in many fields, they are detrimental to cope with the requirements of the World Anti-Doping Agency (WADA) in terms of the limits of detection (LODs) required. To overcome this issue, a method using an alternative derivatization was proposed formation of methyloxime-TMS derivatives through double derivatization using O-methylhydroxylamine/pyridine and MSTFA/TMS imidazole after enzymatic hydrolysis and liquid-liquid extraction. Samples from an excretion study after administration of exemestane to healthy volunteers were analyzed by the proposed method and detection of both exemestane and its main metabolite was possible. This method showed excellent results for both analytes meeting the LODs required for antiestrogenic agents (50 ng/mL) established by WADA. The method was validated for the main metabolite, it was robust and cost-effective for qualitative and quantitative purposes, with LOD and LOQ of 10 ng/mL and 25 ng/mL, respectively.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Androstadienos
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Cromatografía de Gases y Espectrometría de Masas
Tipo de estudio:
Diagnostic_studies
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Prognostic_studies
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Qualitative_research
Límite:
Adult
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Humans
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Male
Idioma:
En
Año:
2010
Tipo del documento:
Article