Doping Control Analysis Research Articles

Comparison of reversed-phase and hydrophilic interaction liquid chromatography for the quantification of ephedrines using medium-resolution accurate mass spectrometry

The separation and quantification of hydrophilic basic compounds continues to challenge reversed-phase chromatography. Ephedrines are an example where the optimal separation of their isomers and related substances is complicated due to both their hydrophilicity and basic nature. Here we study two potential ultra-high pressure liquid chromatography (UHPLC) methods and present the merits and limitations of a high pH reversed-phase and a hydrophilic interaction liquid chromatography (HILIC) approach for the separation and quantification of ephedrines for doping control analysis. The study compares a hybrid silica material used for the HILIC separations with a C18 reversed-phase material produced from the same hybrid silica. While both analytical approaches provide good retention and resolution, HILIC offers benefits in terms of peak shape, sample loading capacity and enhanced sensitivity with electrospray ionisation-mass spectrometry (ESI-MS). HILIC permits favourable kinetic performance owing to the low viscosity mobile phase and hence better mass transfer characteristics. Common problems associated with HILIC including retention shifts and undesirable peak shapes are investigated and overcome using a suitable re-equilibration time and injection solvent. Validation data show both approaches provide good linearity (r>0.995), accuracy (RPLC<7.5% error, HILIC<7.6% error) and precision (RPLC<7.0% RSD, HILIC<10.3% RSD) for all analytes. Matrix effects were shown to have a negligible effect on ionisation variability in each mode, with inter-day retention times also being repeatable (<0.17% RSD). HILIC gave increased sensitivity with ESI-MS, giving a 6-fold increase in signal over the RPLC approach. In this application, we demonstrate the use of UHPLC technology coupled with a hybrid quadrupole time-of-flight (QToF) mass analyser. This approach provides fast scanning medium-resolution accurate mass detection for reliable identification and quantification purposes.

Novel pathway for the synthesis of arylpropionamide-derived selective androgen receptor modulator (SARM) metabolites of andarine and ostarine

O-Dephenylandarine and O-dephenylostarine, two SARM metabolites relevant for doping control analysis, were synthesized in their endogenous (S)-forms as well as in terms of their racemates. The enantiopure (S)-metabolites were obtained after six steps in 20% and 23% overall yield, the slightly modified racemic route provided the compounds in 28% and 31% total yield, respectively.

Doping control analysis of seven bioactive peptides in horse plasma by liquid chromatography–mass spectrometry

In recent years, there has been an ongoing focus for both human and equine doping control laboratories on developing detection methods to control the misuse of peptide therapeutics. Immunoaffinity purification is a common extraction method to isolate peptides from biological matrices and obtain sufficient detectability in subsequent instrumental analysis. However, monoclonal or polyclonal antibodies for immunoaffinity purification may not be commercially available, and even if available, such antibodies are usually very costly. In our study, a simple mixed-mode anion exchange solid-phase extraction cartridge was employed for the extraction of seven target peptides (GHRP-1, GHRP-2, GHRP-6, ipamorelin, hexarelin, CJC-1295, and N-acetylated LKKTETQ (active ingredient of TB-500)) and their in vitro metabolites from horse plasma. The final extract was subject to ultra-high-performance liquid chromatographic separation and analysed with a hybrid high-resolution mass spectrometer. The limits of detection for all seven peptides were estimated to be less than 50 pg/mL. Method validation was performed with respect to specificity, precision, and recovery. The applicability of this multi-analyte method was demonstrated by the detection of N-acetylated LKKTETQ and its metabolite N-acetylated LK from plasma samples obtained after subcutaneous administration of TB-500 (10 mg N-acetylated LKKTETQ) to two thoroughbred geldings. This method could easily be modified to cover more bioactive peptides, such as dermorphin, β-casomorphin, and desmopressin. With the use of high-resolution mass spectrometry, the full-scan data acquired can also be re-processed retrospectively to search for peptides and their metabolites that have not been targeted at the time of analysis. To our knowledge, this is the first identification of in vitro metabolites of all the studied peptides other than TB-500 in horses.

Evaluation of electrospun fibers as solid phase extraction sorbents for sample preparation in HPLC-MS/MS confirmatory doping control analysis of dexamethasone and betamethasone

The aim of the present work was to evaluate the possibility of a fast, simple, and greener sample preparation method using electrospun fibers as SPE sorbents and its application for doping control analysis. Electrospun polymer fibers of polystyrene with smooth morphology (1.3 μm average diameter) were used as sorbent materials for the fabrication of miniaturized solid phase extraction devices. A microcolumn SPE device (10 mg of electrospun fibers packed in a 200 μL pipette tip) and a SPE disk device (10 mg of electrospun fibers packed in a 500 μL polypropylene barrel) were used. Their performance was evaluated using dexamethasone and betamethasone as model analytes for the analysis of drug residues in biological samples. A qualitative confirmatory method for the detection of these glucocorticosteroids by HPLC-MS/MS in human urine was developed using electrospun microfibers for sample clean-up and pre-concentration. The limit of detection for both analytes was 10 ng mL−1 in urine matrix, and the resulting analytical method is at the same time fit for purpose (complying with strict requirements of doping control international organizations), simple (using tip-based microcolumns) and has a greener footprint (using very small amounts of organic solvents).

Ultra high performance liquid chromatography tandem mass spectrometry determination and profiling of prohibited steroids in human biological matrices. A review

The use of doping agents, once restricted to professional athletes, has nowadays become a problem of public health, since it also concerns young people and non-competing amateurs in different sports. The use is also diffused in social life for improving physical appearance and enhancing performance and even dietary supplements assumed to improve performance often contain anabolic steroids. While decades ago the so-called "classical doping agents" (like stimulants and narcotics) were used, to-day anabolic steroids are more widely diffused. Anabolic steroids are synthetic substances prepared by introducing modifications in the molecular structure of testosterone, the main natural androgenic anabolic steroid that forms in testes interstitial cells. The first report concerning the use of anabolic steroids by an athlete who searched for increased weight and power dates 1954. In 1974 the misuse of anabolic steroids in sports was banned by the International Olympic Committee and control tests were implemented in 1976 Montreal Olympic Games through radioimmunoassay analysis: the technique, however, only allows for unspecific detection of a limited number of exogenous steroids. Over the years, always new doping substances are synthesized and, as a consequence, the list of prohibited compounds is continuously updated and new suitable analytical methods for their detection and determination in biological matrices are continuously required. In doping control analysis the knowledge of steroid metabolism pathway in human body is of primary importance and the analytical methods must permit the simultaneous detection and determination not only of the forbidden precursor agents but also of their metabolites. In addition, the potential presence and amount in the biological samples of species that can interfere in the analysis should be evaluated. Also the several anabolic steroids, specifically designed to circumvent doping control, put on the market have been incorporated in the list of the prohibited substances of the World Anti-Doping Agency (WADA). In WADA list steroids figure in three main classes, namely anabolic steroids, corticosteroids and substances with anti-estrogenic properties. It must be strongly reminded that assumption of doping agents not only leads to athletes the possible failing of doping tests but causes important health risk and WADA prohibited list establishes criteria to highlight the alteration of the natural steroid profile caused by exogenous administration. Doping control analyses are generally performed in urine, a matrix that provides a prolonged detection time window, and less often in blood, serum, plasma, hair, saliva, and nails. To identify the chemical structures of anabolic steroids the use of mass spectrometry detection is very advantageous. Gas chromatography-mass spectrometry (GC-MS) techniques allowed for the development of comprehensive screening methods. GC-MS methods are sensitive and robust but present the disadvantages of time-consuming sample pretreatment, that is often based on hydrolysis and derivatisation reactions. Liquid chromatography-mass spectrometry (LC-MS) methods have been successfully used to identify and determinate steroids in different matrices, as well as to study their metabolisms. Nowadays, automatic rapid ultra high performance liquid chromatography (UHPLC) tandem mass spectrometry has become the technique of choice for steroid analysis. Due to its generally higher speed, sensitivity, reproducibility and specificity with respect to HPLC, it can be used to simultaneously separate and determinate multi component steroid mixtures. The technique is of huge interest to separate conjugates anabolic androgenic steroids, as it allows efficiency enhancement due to the small particle (sub-2μm) column packing, which provides high peak capacity within analysis times even 5-10 fold shorter than conventional HPLC methods. Modern multiplex instruments can analyze thousands of samples per month so that, notwithstanding the generally high instrumental costs, the cost of the individual assay is affordable. In addition, the improved specificity and resolution offered by time-of-flight or quadrupole time-of-flight mass spectrometry allow their application in doping control analysis or in steroid profiling for accurate and sensitive full mass range acquisition. Aim of the present review is to consider, compare and discuss the applications of the UHPLC/MS methods present in literature for the identification and determination of forbidden steroids and their metabolites in human biological matrices.

Metabolism of Growth Hormone Releasing Peptides

New, potentially performance enhancing compounds have frequently been introduced to licit and illicit markets and rapidly distributed via worldwide operating Internet platforms. Developing fast analytical strategies to follow these new trends is one the most challenging issues for modern doping control analysis. Even if reference compounds for the active drugs are readily obtained, their unknown metabolism complicates effective testing strategies. Recently, a new class of small C-terminally amidated peptides comprising four to seven amino acid residues received considerable attention of sports drug testing authorities due to their ability to stimulate growth hormone release from the pituitary. The most promising candidates are the growth hormone releasing peptide (GHRP)-1, -2, -4, -5, -6, hexarelin, alexamorelin, and ipamorelin. With the exemption of GHRP-2, the entity of these peptides represents nonapproved pharmaceuticals; however, via Internet providers, all compounds are readily available. To date, only limited information on the metabolism of these substances is available and merely one metabolite for GHRP-2 is established. Therefore, a comprehensive in vivo (po and iv administration in rats) and in vitro (with human serum and recombinant amidase) study was performed in order to generate information on urinary metabolites potentially useful for routine doping controls. The urine samples from the in vivo experiments were purified by mixed-mode cation-exchange solid-phase extraction and analyzed by ultrahigh-performance liquid chromatography (UHPLC) separation followed by high-resolution/high-accuracy mass spectrometry. Combining the high resolution power of a benchtop Orbitrap mass analyzer for the first metabolite screening and the speed of a quadrupole/time-of-flight (Q-TOF) instrument for identification, urinary metabolites were screened by means of a sensitive full scan analysis and subsequently confirmed by high-accuracy product ion scan experiments. Two deuterium-labeled internal standards (triply deuterated GHRP-4 and GHRP-2 metabolite) were used to optimize the extraction and analysis procedure. Overall, 28 metabolites (at least three for each GHRP) were identified from the in vivo samples and main metabolites were confirmed by the human in vitro model. All identified metabolites were formed due to exopeptidase- (amino- or carboxy-), amidase-, or endopeptidase activity.

Effect of changes in the deuterium content of drinking water on the hydrogen isotope ratio of urinary steroids in the context of sports drug testing

The hydrogen isotope ratio (HIR) of body water and, therefore, of all endogenously synthesized compounds in humans, is mainly affected by the HIR of ingested drinking water. As a consequence, the entire organism and all of its synthesized substrates will reflect alterations in the isotope ratio of drinking water, which depends on the duration of exposure. To investigate the effect of this change on endogenous urinary steroids relevant to doping-control analysis the hydrogen isotope composition of potable water was suddenly enriched from -50 to 200 ‰ and maintained at this level for two weeks for two individuals. The steroids under investigation were 5β-pregnane-3α,20α-diol, 5α-androst-16-en-3α-ol, 3α-hydroxy-5α-androstan-17-one (ANDRO), 3α-hydroxy-5β-androstan-17-one (ETIO), 5α-androstane-3α,17β-diol, and 5β-androstane-3α,17β-diol (excreted as glucuronides) and ETIO, ANDRO and 3β-hydroxyandrost-5-en-17-one (excreted as sulfates). The HIR of body water was estimated by determination of the HIR of total native urine, to trace the induced changes. The hydrogen in steroids is partly derived from the total amount of body water and cholesterol-enrichment could be calculated by use of these data. Although the sum of changes in the isotopic composition of body water was 150 ‰, shifts of approximately 30 ‰ were observed for urinary steroids. Parallel enrichment in their HIR was observed for most of the steroids, and none of the differences between the HIR of individual steroids was elevated beyond recently established thresholds. This finding is important to sports drug testing because it supports the intended use of this novel and complementary methodology even in cases where athletes have drunk water of different HIR, a plausible and, presumably, inevitable scenario while traveling.

Alternative long-term markers for the detection of methyltestosterone misuse

Methyltestosterone (MT) is one of the most frequently detected anabolic androgenic steroids in doping control analysis. MT misuse is commonly detected by the identification of its two main metabolites excreted as glucuronide conjugates, 17α-methyl-5α-androstan-3α,17β-diol and 17α-methyl-5β-androstan-3α,17β-diol. The detection of these metabolites is normally performed by gas chromatography–mass spectrometry, after previous hydrolysis with β-glucuronidase enzymes, extraction and derivatization steps. The aim of the present work was to study the sulphate fraction of MT and to evaluate their potential to improve the detection of the misuse of the drug in sports. MT was administered to healthy volunteers and urine samples were collected up to 30days after administration. After an extraction with ethyl acetate, urine extracts were analysed by liquid chromatography tandem mass spectrometry using electrospray ionisation in negative mode by monitoring the transition m/z 385 to m/z 97. Three diol sulphate metabolites (S1, S2 and S3) were detected. Potential structures for these metabolites were proposed after solvolysis and mass spectrometric experiments: S1, 17α-methyl-5β-androstan-3α,17β-diol 3α-sulphate; S2, 17β-methyl-5α-androstan-3α,17α-diol 3α-sulphate; and S3, 17β-methyl-5β-androstan-3α,17α-diol 3α-sulphate. Synthesis of reference compounds will be required in order to confirm the structures. The retrospectivity of these sulphate metabolites in the detection of MT misuse was compared with the obtained with previously described metabolites. Metabolite S2 was detected up to 21days after MT administration, improving between 2 and 3 times the retrospectivity of the detection compared to the last long-term metabolite of MT previously described, 17α-hydroxy-17β-methylandrostan-4,6-dien-3-one.

Quantitative approach to glucocorticosteroids analysis in human urine using LC-MS/MS

Glucocorticosteroids are included in the World Anti-Doping Agency (WADA) prohibited list as non-threshold analytes. Nevertheless, at least semi-quantitative approaches are necessary before reporting an adverse analytical finding for this class of substances. The liquid chromatography coupled to mass spectrometry (LC-MS) has been used with excellent selectivity and specificity in xenobiotic analysis in complex matrices. Real samples containing exogenous glucocorticosteroids from different administration routes were analyzed using the method proposed. Samples from systemic administration (oral route) presented levels of prednisolone or prednisone higher than 30 ng mL-1, the minimum requirement performance level used as diagnostic parameter. On the other hand, non-systemic routes seem to not have bioavailability to generate an adverse case in doping control analysis. Considering the low number of similar studies available in the literature, more urinary studies could be done using the method reported aiming to provide more information about the excretion profile of glucocorticosteroids administered by systemic and non-systemic routes.

Doping control analysis of TB-500, a synthetic version of an active region of thymosin β4, in equine urine and plasma by liquid chromatography–mass spectrometry

A veterinary preparation known as TB-500 and containing a synthetic version of the naturally occurring peptide LKKTETQ has emerged. The peptide segment 17LKKTETQ23 is the active site within the protein thymosin β4 responsible for actin binding, cell migration and wound healing. The key ingredient of TB-500 is the peptide LKKTETQ with artificial acetylation of the N-terminus. TB-500 is claimed to promote endothelial cell differentiation, angiogenesis in dermal tissues, keratinocyte migration, collagen deposition and decrease inflammation. In order to control the misuse of TB-500 in equine sports, a method to definitely identify its prior use in horses is required. This study describes a method for the simultaneous detection of N-acetylated LKKTETQ and its metabolites in equine urine and plasma samples. The possible metabolites of N-acetylated LKKTETQ were first identified from in vitro studies. The parent peptide and its metabolites were isolated from equine urine or plasma by solid-phase extraction using ion-exchange cartridges, and analysed by liquid chromatography–mass spectrometry (LC/MS). These analytes were identified according to their LC retention times and relative abundances of the major product ions. The peptide N-acetylated LKKTETQ could be detected and confirmed at 0.02ng/mL in equine plasma and 0.01ng/mL in equine urine. This method was successful in confirming the presence of N-acetylated LKKTETQ and its metabolites in equine urine and plasma collected from horses administered with a single dose of TB-500 (containing 10mg of N-acetylated LKKTETQ). To our knowledge, this is the first identification of TB-500 and its metabolites in post-administration samples from horses.

High resolution accurate mass screening of prohibited substances in equine plasma using liquid chromatography – Orbitrap mass spectrometry

A recent trend in the use of high resolution accurate mass screening (HRAMS) for doping control testing in both human and animal sports has emerged due to significant improvement in high resolution mass spectrometry in terms of sensitivity, mass accuracy, mass resolution, and mass stability. A number of HRAMS methods have been reported for the detection of multi-drug residues in human or equine urine. As blood has become a common matrix for doping control analysis, especially in equine sports, a sensitive, fast and wide coverage screening method for detecting a large number of drugs in equine blood samples would be desirable. This paper presents the development of a liquid chromatography-high resolution mass spectrometry (LC-HRMS) screening method for equine plasma samples to cover over 320 prohibited substances in a single analytical run. Plasma samples were diluted and processed by solid-phase extraction. The extracts were then analyzed with LC-HRMS in full-scan positive electrospray ionization mode. A mass resolution of 60 000 was employed. Benzyldimethylphenylammonium was used as an internal lock mass. Drug targets were identified by retention time and accurate mass, with a mass tolerance window of ±3 ppm. Over 320 drug targets could be detected in a 13-min run. Validation data including sensitivity, specificity, extraction recovery and precision are presented. As the method employs full-scan mass spectrometry, an unlimited number of drug targets can theoretically be incorporated. Moreover, the HRAMS data acquired can be re-processed retrospectively to search for drugs which have not been targeted at the time of analysis.

Mass spectrometric detection of peginesatide in human urine in doping control analysis

Erythropoiesis-stimulating agents (ESAs) have frequently been confessed to be illicitly used in elite sports due to their endurance enhancing effects. Recently, peginesatide, the first representative of a new generation of ESAs, referred to as Erythropoietin (EPO)-mimetic peptides, obtained approval in the USA under the trade name Omontys(®) for the treatment of anaemic patients. Lacking sequence homology with EPO, it consists of a pegylated homodimeric peptide of approximately 45 kDa, and thus, specific approaches for the determination of peginesatide in blood were developed as conventional detection assays for EPO do not allow for the analysis of the EPO-mimetic peptides. However, as urine specimens are the most frequently provided doping control samples and pharmacokinetic studies conducted in rats and monkeys revealed the excretion of the pegylated peptide into urine, a detection method for peginesatide in urine would be desirable. A mass spectrometric assay in human urine was developed consisting of protein precipitation with acetonitrile followed by proteolytic digestion after the removal of the acetonitrile fraction under reduced pressure. Purification and concentration of the resulting proteotypic target peptide was accomplished by means of solid-phase extraction on strong cation-exchange resin prior to liquid chromatographic-tandem mass spectrometric analysis. Method validation was performed for qualitative purposes and demonstrated specificity, precision, linearity as well as sufficient sensitivity (limit of detection: 0.5 ng/ml) while proof-of-concept for the applicability of the assay for the determination of peginesatide in authentic urine samples was obtained by analyzing animal in vivo specimens collected after a single i.v. administration of peginesatide over a period of 4 days.

Doping control analysis of desmopressin in human urine by LC‐ESI‐MS/MS after urine delipidation

The World Anti-Doping Agency (WADA) has recently added desmopressin, a synthetic analogue of the endogenous peptide hormone arginine vasopressin, to the Prohibited List, owing to the potential masking effects of this drug on hematic parameters useful to detect blood doping. A qualitative method for detection of desmopressin in human urine by high-performance liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) has been developed and validated. Desmopressin purification from urine was achieved by means of delipidation with a 60:40 di-isopropyl ether/n-butanol and solid-phase extraction with WCX cartridges. The lower limit of detection was 25 pg/mL. Extraction recovery was determined as 59.3% (SD 29.4), and signal reduction owing to ion suppression was estimated to be 42.7% (SD 12.9). The applicability of the method was proven by the analysis of real urine samples obtained after intravenous, oral and intranasal administration of desmopressin, achieving unambiguous detection of the peptide in all the cases.

New potential markers for the detection of boldenone misuse

Boldenone is one of the most frequently detected anabolic androgenic steroids in doping control analysis. Boldenone misuse is commonly detected by the identification of the active drug and its main metabolite, 5β-androst-1-en-17β-ol-3-one (BM1), by gas chromatography–mass spectrometry (GC–MS), after previous hydrolysis with β-glucuronidase enzymes, extraction and derivatization steps. However, some cases of endogenous boldenone and BM1 have been reported. Nowadays, when these compounds are detected in urine at low concentrations, isotope ratio mass spectrometry (IRMS) analysis is needed to confirm their exogenous origin. The aim of the present study was to identify boldenone metabolites conjugated with sulphate and to evaluate their potential to improve the detection of boldenone misuse in sports. Boldenone was administered to a healthy volunteer and urine samples were collected up to 56h after administration. After a liquid–liquid extraction with ethyl acetate, urine extracts were analysed by liquid chromatography tandem mass spectrometry (LC–MS/MS) using electrospray ionisation in negative mode by monitoring the transition of m/z 365–350, specific for boldenone sulphate. Boldenone sulphate was identified in the excretion study urine samples and, moreover, another peak with the same transition was observed. Based on the MS/MS behaviour the metabolite was identified as epiboldenone sulphate. The identity was confirmed by isolation of the LC peak, solvolysis and comparison of the retention time and MS/MS spectra with an epiboldenone standard. These sulphated metabolites have not been previously reported in humans and although they account for less than 1% of the administered dose, they were still present in urine when the concentrations of the major metabolites, boldenone and BM1, were at the level of endogenous origin. The sulphated metabolites were also detected in 10 urine samples tested positive to boldenone and BM1 by GC–MS.In order to verify the usefulness of these new metabolites to discriminate between endogenous and exogenous origin of boldenone, four samples containing endogenous boldenone and BM1, confirmed by IRMS, were analysed. In 3 of the 4 samples, neither boldenone sulphate nor epiboldenone sulphate were detected, confirming that these metabolites were mainly detected after exogenous administration of boldenone. In contrast, boldenone sulphate and, in some cases, epiboldenone sulphate were present in samples with low concentrations of exogenous boldenone and BM1. Thus, boldenone and epiboldenone sulphates are additional markers for the exogenous origin of boldenone and they can be used to reduce the number of samples to be analysed by IRMS. In samples with boldenone and BM1 at the concentrations suspicion for endogenous origin, only if boldenone and epiboldenone sulphates are present, further analysis by IRMS will be needed to confirm exogenous origin.

Characterization of In Vitro Synthesized Equine Metabolites of the Selective Androgen Receptor Modulators S24 and S4

Several selective androgen receptor modulators (SARMs) have been synthesized and investigated in humans, rats, and dogs in the past, but no data are yet available concerning the metabolism of SARMs in horses. The aryl-propionamide-derived drug candidates S24 and S4 (andarine) have a strong androgen receptor binding affinity and show distinctive specific cell answers. Although no SARM drug candidate (aiming for testosterone replacement therapy) has completed clinical trials yet, S4 has been illicitly available via the Internet. These facts led to the prohibition of SARMs by the German equestrian federation, and the (mis)use of such compounds would further represent a doping rule violation in horse racing. In this study, the drug candidates S24 and S4 were subjected to in vitro metabolism experiments with equine liver microsomal preparations from a female Quarter Horse to obtain information about potential target analytes in equine doping control analysis. The enzymatically synthesized metabolites were characterized by liquid chromatography–tandem mass spectrometry and –high-resolution/high-accuracy mass spectrometry. All observed S24 and S4 equine metabolites are in agreement with earlier in vitro and in vivo studies in humans and dogs. Nevertheless, the relative percentage of generated equine metabolites (as determined from the analytes’ response in full-scan chromatography–tandem mass spectrometry and –high-resolution/high-accuracy mass spectrometry measurements) differs considerably from the reported profiles. Although the S24 metabolite pattern is comparably balanced concerning glucuronidated and sulfonated conjugates, the major S4 metabolite was found to be the unconjugated dephenylated compound, with a proportion of more than 90%.

Quantitative detection of inhaled formoterol in human urine and relevance to doping control analysis

Formoterol is a frequently prescribed β(2)-agonist used for the treatment of asthma. Due to performance-enhancing effects of some β(2) -agonists, formoterol appears on the prohibited list, published by the World Anti-doping Agency (WADA). Its therapeutic use is allowed but restricted to inhalation. Since the data on urinary concentrations originating from therapeutic use is limited, no discrimination can be made between use and misuse when a routine sample is found to contain formoterol. Therefore the urinary excretion of six volunteers after inhalation of 18 µg of formoterol was investigated. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of formoterol in urine samples. Sample preparation consists of an enzymatic hydrolysis of the urine samples, followed by a liquid-liquid extraction at pH 9.5 with diethyl ether/isopropanol (5/1, v/v). Analysis was performed using selected reaction monitoring after electrospray ionization. The method was linear in the range of 0.5-50 ng/ml. The limit of quantification (LOQ) was 0.5 ng/ml. The bias ranged between -1.0 and -6.8 %. Results for the urinary excretion show that formoterol could be detected for 72 h. The maximum urinary concentration detected was 8.5 ng/ml without and 11.4 ng/ml after enzymatic hydrolysis. Cumulative data showed that maximum 11.5% and 23% of the administered dose is excreted as parent drug within the first 12 h, respectively, non-conjugated and conjugated. Analysis of 82 routine doping samples, declared positive for formoterol during routine analysis, did not exhibit concentrations which could be attributed to misuse.

Examination of the kinetic isotopic effect to the acetylation derivatization for the gas chromatographic‐combustion‐isotope ratio mass spectrometric doping control analysis of endogenous steroids

In gas chromatographic-combustion-isotope ratio mass spectrometry (GC-C-IRMS) doping control analysis, endogenous androgenic anabolic steroids and their metabolites are commonly acetylated using acetic anhydride reagent, thus incorporating exogenous carbon that contributes to the measured isotope ratio. Comparison of the endogenous δ(13)C of free, mono-, and di-acetylated steroids requires application of corrections, typically through straightforward use of the mass balance equation. Variability in kinetic isotope effects (KIE) due to steroid structures could cause fractionation of endogenous steroid carbon, resulting in inaccurate results. To test for possible KIE influence on δ(13)C, acetic anhydride of graded isotope ratio within the natural abundance range was used under normal derivatization conditions to test for linearity. In all cases, plots of measured steroid acetate δ(13)C versus acetic anhydride δ(13)C were linear and slopes were not significantly different. Regression analysis of the Δδ(13)C of enriched acetic anhydrides versus Δδ(13)C of derivatized steroids shows that KIE are similar in all cases. We conclude that δ(13)C calculated from the mass balance equation is independent of the δ(13)C of the acetic anhydride reagent, and that net KIE under normal derivatization conditions do not bias the final reported steroid δ(13)C.

Influences of β-HCG administration on carbon isotope ratios of endogenous urinary steroids

Several factors influencing the carbon isotope ratios (CIR) of endogenous urinary steroids have been identified in recent years. One of these should be the metabolism of steroids inside the body involving numerous different enzymes. A detailed look at this metabolism taking into account differences found between steroids excreted as glucuronides or as sulphates and hydrogen isotope ratios of different steroids pointed out possibility of unequal CIR at the main production sites inside the male body – the testes and the adrenal glands.By administration of β-HCG it is possible to strongly stimulate the steroid production within the testes without influencing the production at the adrenal glands. Therefore, this treatment should result in changed CIR of urinary androgens in contrast to the undisturbed pre-treatment values.Four male volunteers received three injections of β-HCG over a time course of 5days and collected their urine samples at defined intervals after the last administration. Those samples showing the largest response in contrast to the pre-administration urines were identified by steroid profile measurements and subsequent analysed by GC/C/IRMS. CIR of androsterone, etiocholanolone, testosterone, 5α- and 5β-androstanediol and pregnanediol were compared. While pregnanediol was not influenced, most of the investigated androgens showed depleted values after treatment. The majority of differences were found to be statistically significant and nearly all showed the expected trend towards more depleted δ13C-values.These results support the hypothesis of different CIR at different production sites inside the human body. The impact of these findings on doping control analysis will be discussed.

Recent Developments in Ms For Small Molecules: Application to Human Doping Control Analysis

Recent developments in MS for the detection of small molecules in the context of doping control analysis are reviewed. Doping control analysis is evolving together with MS, which is the technique of choice in order to accomplish the analytical requirements in this field. Since these analytical requirements for the detection of a doping agent depend on the substance, in the first section we review the different scenarios. The commonly established approaches, together with their achievements and drawbacks are described. New developments in hyphenated MS techniques (both GC-MS/MS and LC-MS/MS) concerning interfaces and analyzers are mentioned. The use (or potential use) of these developments in order to minimize the limitations of the commonly established approaches in the doping control field is discussed. Finally, a brief discussion about trends and remaining limitations is presented.

Two-Step Derivatization Procedures For The Ionization Enhancement of Anabolic Steroids in Lc–Esi-Ms For Doping Control Analysis

Two-step derivatization procedures were developed for the enhancement of the positive ESI in LC-MS detection of anabolic androgenic steroids, a class of prohibited substances with limited ionization efficiency in atmospheric pressure interfaces. The developed procedures are based on the esterification of hydroxyl groups of anabolic steroids with picolinic acid, followed by conversion of carbonyl groups to Schiff bases by either Girard's reagent T or 2-hydrazino pyridin. Ionization efficiency for the model derivatized compounds 19-norandrosterone (nandrolone main metabolite) and methasterone was higher by almost two orders of magnitude compared with the respective efficiency of the underivatized compounds. The obtained derivatives provided a significant improvement in the ESI sensitivity, compared with those of underivatized molecules in positive LC-ESI-ion trap-MS full-scan mode.