Determination and excretion study of gestrinone in human urine by high performance liquid chromatography and gas chromatography/mass spectrometry

Mass spectrometric identification and characterization of new fluoxymesterone metabolites in human urine by liquid chromatography time-of-flight tandem mass spectrometry

In this study fluoxymesterone urinary profiles were investigated by liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC-QTOFMS) with accurate mass measurement. Twelve metabolites including the parent drug were detected in two fluoxymesterone positive control urine samples. Three parameters were employed for evaluation of the accuracy of the chemical formulae in positive full scan experiment, which contained error between actual and calculated mass weights of prontonated and isotopic molecules together with abundance match between prontonated and isotopic molecules. The 13 analytes were determined with mass accuracy less than 1.1 ppm and isotopic abundance match more than 94 marks. Based on the ionization, CID fragmentation, the accurate mass of the product ion and comparison of the accurate mass weight and retention time with reference standard, fluoxymesterone and its 12 metabolites containing three unreported ones were detected. The chemical structures of three unreported metabolites were identified as: 9-fluro-17β-ol-17-methyl-11-en-5α-androstan-3-one (F13), 9-fluro-17β-ol-17-methyl-11-en-5β-androstan-3-one (F8) and 9-fluro-17β-ol-17-methyl-5-androstan-3,6,11-trione, and meanwhile a dihydroxylated metabolite (F12), 6,16-dihydroxylated fluoxymesterone, was also detected in human urine, which was previously reported to be available only in equine urine.

Detection of new exemestane metabolites by liquid chromatography interfaced to electrospray-tandem mass spectrometry

Exemestane is an irreversible aromatase inhibitor used for anticancer therapy. Unfortunately, this drug is also misused in sports to avoid some adverse effects caused by steroids administration. For this reason exemestane has been included in World Anti-Doping Agency prohibited list. Usually, doping control laboratories monitor prohibited substances through their metabolites, because parent compounds are readily metabolized. Thus metabolism studies of these substances are very important. Metabolism of exemestane in humans is not clearly reported and this drug is detected indirectly through analysis of its only known metabolite: 17β-hydroxyexemestane using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and gas chromatography coupled to mass spectrometry (GC-MS). This drug is extensively metabolized to several unknown oxidized metabolites. For this purpose LC-MS/MS has been used to propose new urinary exemestane metabolites, mainly oxidized in C6-exomethylene and simultaneously reduced in 17-keto group. Urine samples from four volunteers obtained after administration of a 25mg dose of exemestane were analyzed separately by LC-MS/MS. Urine samples of each volunteer were hydrolyzed followed by liquid-liquid extraction and injected into a LC-MS/MS system. Three unreported metabolites were detected in all urine samples by LC-MS/MS. The postulated structures of the detected metabolites were based on molecular formulae composition obtained through high accuracy mass determination by liquid chromatography coupled to hybrid quadrupole-time of flight mass spectrometry (LC-QTOF MS) (all mass errors below 2ppm), electrospray (ESI) product ion spectra and chromatographic behavior.

Metabolism and excretion of anabolic steroids in doping control--new steroids and new insights

The use of anabolic steroids in sports is prohibited by the World Anti-Doping Agency. Until the 1990s, anabolic steroids were solely manufactured by pharmaceutical companies, albeit sometimes on demand from national sports agencies as part of their doping program. Recently the list of prohibited anabolic steroids in sports has grown due to the addition of numerous steroids that have been introduced on the market by non-pharmaceutical companies. Moreover, several designer steroids, specifically developed to circumvent doping control, have also been detected. Because anabolic steroids are most often intensively subjected to phase I metabolism and seldom excreted unchanged, excretion studies need to be performed in order to detect their misuse. This review attempts to summarise the results of excretion studies of recent additions to the list of prohibited steroids in sports. Additionally an update and insight on new aspects for "older" steroids with respect to doping control is given.

Determination of the metabolites of gestrinone in human urine by high performance liquid chromatography, liquid chromatography/mass spectrometry and gas chromatography/mass spectrometry

Gestrinone was studied by high performance liquid chromatography (HPLC) for screening and by gas chromatography/mass spectrometry (GC/MS) for confirmation. When the chromatograms of blank, spiked urine and dosed urine were compared by HPLC, two unknown metabolites were found and these were excreted as the conjugated forms. Metabolites 1 and 2 were tested by LC/MS and LC/MS/MS and both had parent ions at m/z 325. The fragment ion of metabolite 1 was at m/z 263 and ions for metabolite 2 were m/z 307 [MH - H(2)O](+), 289, 279 and 241. LC/MS/MS of m/z 263 as the parent ion of metabolite 1 gave fragment ions at m/z 245 and 217, which were assumed to be [263 - H(2)O](+) and [235 - H(2)O](+), respectively. The trimethylsilyl (TMS)-enol-TMS ether derivative of gestrinone displayed three peaks in its GC/MS chromatogram, formed by tautomerism.