Comparison of the analysis of beta-blockers by different techniques.

In this work we have compared three analytical techniques (ELISA, GC-MS, and LC-MS) for the analysis of 16 beta-blockers: acebutolol, alprenolol, atenolol, betaxolol, bisoprolol, carteolol, labetalol, metipranolol, metoprolol, nadolol, oxprenolol, pindolol, propranolol, sotalol, timolol, and bupranolol. Several sample-preparation methods were optimized for each technique and enabled compounds of interest to be extracted from small urine samples (1-2.5 mL). The results enabled us to assess the possibilities and the sensitivity of each technique for application to doping tests. ELISA, whose selectivity is very poor and sensitivity the lowest one, is, nevertheless, useful as a rapid screening method. GC/MS and LC/MS provide confirmation procedures with the identification and quantification of the beta-blockers with good sensitivity, accuracy, precision. The LC-MS analytical procedure allows the determination of the target analytes in the lower ng/mL range (0.53-2.23 ng/mL). The methodology was applied to the analysis of beta-blockers in different urines.

Quantitative analysis of DHEA and androsterone in female urine: investigating the effects of menstrual cycle, oral contraception and training on exercise-induced changes in young women.

Dehydroepiandrosterone (DHEA) and its metabolite androsterone (A) are natural steroids secreted in high quantities in human body. To assess the influence of oral contraceptives, menstrual cycle phase, and also physical exercise (acute and chronic such as training) on these metabolites excretions, a collection of 28 female urine specimens was organized. A three-extraction-step method was developed, and the analyses were performed by gas chromatography-mass spectrometry using deuterated 19-noretiocholanolone as the internal standard. Sample hydration state was found to be of great importance for kinetic studies, as it directly influenced the concentrations. No influence of menstrual cycle and training was found for androsterone and DHEA. However, oral contraceptive intake lowered DHEA excretion in urine and A seems to be slightly affected by exercise.

Comparison of the analysis of corticosteroids using different techniques.

In this work we have optimized the analysis of 18 human corticosteroids, some endogenous (tetrahydrocortisol, tetrahydrocortisone, cortisol, and cortisone) and others synthetic (betamethasone, budesonide, cortisone acetate, desonide, dexamethasone, dexamethasone acetate, flunisolide, fluocinolone acetonide, halcinonide, methylprednisolone, prednisolone, prednisone, triamcinolone, and triamcinolone acetonide). Three analytical techniques were developed: ELISA, gas chromatography coupled with mass spectrometry (GC-MS), and liquid chromatography coupled with mass spectrometry (LC-MS). Several sample-preparation methods were optimized for each technique and enabled compounds of interest to be extracted from small urine samples (several mL). The results enabled us to assess the possibilities and the sensitivity of each technique for application to doping tests.

Optimizing the extraction and analysis of DHEA sulfate, corticosteroids and androgens in urine: application to a study of the influence of corticosteroid intake on urinary steroid profiles.

A method of detecting and quantifying dehydroepiandrosterone (DHEA) sulfate, corticosteroids, and androgens has been developed. All of the compounds were first extracted from urine using solid phase extraction (SPE), enzymatically hydrolyzed, and separated into three samples using a second SPE. A DHEA sulfate sample was acetylated and re-extracted using SPE for purification before analysis. Corticosteroid samples were oxidized and re-extracted using liquid/liquid extraction for analysis. Androgen samples were acetylated and re-extracted using SPE prior to analysis. The extraction and analysis methods were investigated and optimized. Analyses were performed with gas chromatography/mass spectrometry (GC/MS) and gas chromatography/flame ionization detection (GC/FID). The entire procedure was then applied to the study of urine profiles of healthy volunteers and patients treated with corticosteroids. The results showed that the quantities of androgens found in patient urines were lower than in those of healthy volunteers. In addition, other metabolites were detected in patient urines.