The Experts below are selected from a list of 109953 Experts worldwide ranked by ideXlab platform
Mario Thevis - One of the best experts on this subject based on the ideXlab platform.
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fully automated determination of nicotine and its major metabolites in whole blood by means of a dbs online spe lc hr ms ms approach for sports Drug Testing
Journal of Pharmaceutical and Biomedical Analysis, 2016Co-Authors: Laura Tretzel, Wilhelm Schanzer, Hans Geyer, Andreas Thomas, Thomas Piper, Mikael Hedeland, Mario ThevisAbstract:Dried blood spots (DBS) represent a sample matrix collected under minimal-invasive, straightforward and robust conditions. DBS specimens have been shown to provide appropriate test material for different analytical disciplines, e.g., preclinical Drug development, therapeutic Drug monitoring, forensic toxicology and diagnostic analysis of metabolic disorders in newborns. However, the sample preparation has occasionally been reported as laborious and time consuming. In order to minimize the manual workload and to substantiate the suitability of DBS for high sample-throughput, the automation of sample preparation processes is of paramount interest. In the current study, the development and validation of a fully automated DBS extraction method coupled to online solid-phase extraction using the example of nicotine, its major metabolites nornicotine, cotinine and trans-3'-hydroxycotinine and the tobacco alkaloids anabasine and anatabine is presented, based on the rationale that the use of nicotine-containing products for performance-enhancing purposes has been monitored by the World Anti-Doping Agency (WADA) for several years. Automation-derived DBS sample extracts were directed online to liquid chromatography high resolution/high mass accuracy tandem mass spectrometry, and target analytes were determined with support of four deuterated internal standards. Validation of the method yielded precise (CV 0.998) results. The limit of detection was established at 5 ng mL(-1) for all studied compounds, the extraction recovery ranged from 25 to 44%, and no matrix effects were observed. To exemplify the applicability of the DBS online-SPE LC-MS/MS approach for sports Drug Testing purposes, the method was applied to authentic DBS samples obtained from smokers, snus users, and e-cigarette users. Statistical evaluation of the obtained results indicated differences in metabolic behavior depending on the route of administration (inhalative versus buccal absorption) in terms of the ratio of nicotine and nornicotine.
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dilute and inject multi target screening assay for highly polar doping agents using hydrophilic interaction liquid chromatography high resolution high accuracy mass spectrometry for sports Drug Testing
Analytical and Bioanalytical Chemistry, 2015Co-Authors: Christian Gorgens, Mario Thevis, Andreas Thomas, Sven Guddat, Annekatrin Orlovius, Gerd Sigmund, Wilhelm SchanzerAbstract:In the field of LC-MS, reversed phase liquid chromatography is the predominant method of choice for the separation of prohibited substances from various classes in sports Drug Testing. However, highly polar and charged compounds still represent a challenging task in liquid chromatography due to their difficult chromatographic behavior using reversed phase materials. A very promising approach for the separation of hydrophilic compounds is hydrophilic interaction liquid chromatography (HILIC). Despite its great potential and versatile advantages for the separation of highly polar compounds, HILIC is up to now not very common in doping analysis, although most manufacturers offer a variety of HILIC columns in their portfolio. In this study, a novel multi-target approach based on HILIC high resolution/high accuracy mass spectrometry is presented to screen for various polar stimulants, stimulant sulfo-conjugates, glycerol, AICAR, ethyl glucuronide, morphine-3-glucuronide, and myo-inositol trispyrophosphate after direct injection of diluted urine specimens. The usage of an effective online sample cleanup and a zwitterionic HILIC analytical column in combination with a new generation Hybrid Quadrupol-Orbitrap® mass spectrometer enabled the detection of highly polar analytes without any time-consuming hydrolysis or further purification steps, far below the required detection limits. The methodology was fully validated for qualitative and quantitative (AICAR, glycerol) purposes considering the parameters specificity; robustness (rRT 0.99); intra- and inter-day precision at low, medium, and high concentration levels (CV < 20 %); limit of detection (stimulants and stimulant sulfo-conjugates < 10 ng/mL; norfenefrine; octopamine < 30 ng/mL; AICAR < 10 ng/mL; glycerol 100 μg/mL; ETG < 100 ng/mL); accuracy (AICAR 103.8–105.5 %, glycerol 85.1–98.3 % at three concentration levels) and ion suppression/enhancement effects.
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expanding analytical possibilities concerning the detection of stanozolol misuse by means of high resolution high accuracy mass spectrometric detection of stanozolol glucuronides in human sports Drug Testing
Drug Testing and Analysis, 2013Co-Authors: Wilhelm Schanzer, Hans Geyer, Andreas Thomas, Sven Guddat, Georg Opfermann, Mario ThevisAbstract:Anabolic-androgenic steroids (AAS) represent one of the most frequently detected classes of prohibited substances in doping controls. Due to their long-lasting beneficial effects on athletic performance, utmost retrospectivity via urine analysis is desirable and accomplished by targeting long-term metabolites of the respective Drugs. In case of stanozolol, a substantial variety of metabolites has enabled the identification of numerous adverse analytical findings in the past, and recent studies concerning complementary phase-I and phase-II metabolites has further expanded the windows of opportunity for detecting the abuse of stanozolol. In this study, the utility of liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry (LC-MS/MS) for the detection of 3’-OH-stanozolol glucuronide in sports Drug Testing is presented and the identification of two additional and so far unreported metabolites is shown. The structures of the complementary glucuronic acid conjugates were attributed to stanozolol-N-glucuronide and 17-epistanozolol-N-glucuronide. By means of chemical synthesis, stanozolol-N-glucuronide was prepared and used to corroborate the suggested structures. The 3’-OH-stanozolol glucuronide and the newly identified target compounds were implemented into routine sports Drug test assays consisting of direct injection LC-MS/MS or solid-phase extraction (SPE) followed by LC-MS/MS. A considerably expanded detection window for stanozolol abuse was demonstrated compared to the use of conventional phase-I metabolites and methodologies based on, for example, low resolution LC-MS/MS or gas chromatography-tandem mass spectrometry (GC-MS/MS). The commercial availability of 3’-OH-stanozolol glucuronide has been of great value for confirmatory purposes, and 17-epistanozolol-N-glucuronide was found to be a favourable long-term metabolite for doping controls as it was observed up to 28 days post-administration of the Drug. Applying the established methodology over a period of six months to 659 routine sports Drug Testing samples, a total of 85 adverse analytical findings was uncovered, 72 of which would have remained undetected using earlier employed GC-MS/MS approaches. Copyright © 2013 John Wiley & Sons, Ltd.
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trafficking of Drug candidates relevant for sports Drug Testing detection of non approved therapeutics categorized as anabolic and gene doping agents in products distributed via the internet
Drug Testing and Analysis, 2011Co-Authors: Mario Thevis, Hans Geyer, Andreas Thomas, Wilhelm SchanzerAbstract:Identifying the use of non-approved Drugs by cheating athletes has been a great challenge for doping control laboratories. This is due to the additional complexities associated with identifying relatively unknown and uncharacterized compounds and their metabolites as opposed to known and well-studied therapeutics. In 2010, the prohibited Drug candidates and gene doping substances AICAR and GW1516, together with the selective androgen receptor modulator (SARM) MK-2866 were obtained by the Cologne Doping Control Laboratory from Internet suppliers and their structure, quantity, and formulation elucidated. All three compounds proved authentic as determined by liquid chromatography—high resolution/high accuracy (tandem) mass spectrometry and comparison to reference material. While AICAR was provided as a colourless powder in 100 mg aliquots, GW1516 was obtained as an orange/yellow suspension in water/glycerol (150 mg/ml), and MK-2866 (25 mg/ml) was shipped dissolved in polyethylene glycol (PEG) 300. In all cases, the quantified amounts were considerably lower than indicated on the label. The substances were delivered via courier, with packaging identifying them as containing ‘amino acids’ and ‘green tea extract’, arguably to circumvent customs control. Although all of the substances were declared ‘for research only’, their potential misuse in illicit performance-enhancement cannot be excluded; moreover sports Drug Testing authorities should be aware of the facile availability of black market copies of these Drug candidates. Copyright © 2011 John Wiley & Sons, Ltd.
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annual banned substance review analytical approaches in human sports Drug Testing
Drug Testing and Analysis, 2010Co-Authors: Mario Thevis, Hans Geyer, Tiia Kuuranne, Wilhelm SchanzerAbstract:The aim of improving anti-doping efforts is predicated on several different pillars, including, amongst others, optimized analytical methods. These commonly result from exploiting most recent developments in analytical instrumentation as well as research data on elite athletes' physiology in general, and pharmacology, metabolism, elimination, and downstream effects of prohibited substances and methods of doping, in particular. The need for frequent and adequate adaptations of sports Drug Testing procedures has been incessant, largely due to the uninterrupted emergence of new chemical entities but also due to the apparent use of established or even obsolete Drugs for reasons other than therapeutic means, such as assumed beneficial effects on endurance, strength, and regeneration capacities. Continuing the series of annual banned-substance reviews, literature concerning human sports Drug Testing published between October 2014 and September 2015 is summarized and reviewed in reference to the content of the 2015 Prohibited List as issued by the World Anti-Doping Agency (WADA), with particular emphasis on analytical approaches and their contribution to enhanced doping controls.
Wilhelm Schanzer - One of the best experts on this subject based on the ideXlab platform.
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fully automated determination of nicotine and its major metabolites in whole blood by means of a dbs online spe lc hr ms ms approach for sports Drug Testing
Journal of Pharmaceutical and Biomedical Analysis, 2016Co-Authors: Laura Tretzel, Wilhelm Schanzer, Hans Geyer, Andreas Thomas, Thomas Piper, Mikael Hedeland, Mario ThevisAbstract:Dried blood spots (DBS) represent a sample matrix collected under minimal-invasive, straightforward and robust conditions. DBS specimens have been shown to provide appropriate test material for different analytical disciplines, e.g., preclinical Drug development, therapeutic Drug monitoring, forensic toxicology and diagnostic analysis of metabolic disorders in newborns. However, the sample preparation has occasionally been reported as laborious and time consuming. In order to minimize the manual workload and to substantiate the suitability of DBS for high sample-throughput, the automation of sample preparation processes is of paramount interest. In the current study, the development and validation of a fully automated DBS extraction method coupled to online solid-phase extraction using the example of nicotine, its major metabolites nornicotine, cotinine and trans-3'-hydroxycotinine and the tobacco alkaloids anabasine and anatabine is presented, based on the rationale that the use of nicotine-containing products for performance-enhancing purposes has been monitored by the World Anti-Doping Agency (WADA) for several years. Automation-derived DBS sample extracts were directed online to liquid chromatography high resolution/high mass accuracy tandem mass spectrometry, and target analytes were determined with support of four deuterated internal standards. Validation of the method yielded precise (CV 0.998) results. The limit of detection was established at 5 ng mL(-1) for all studied compounds, the extraction recovery ranged from 25 to 44%, and no matrix effects were observed. To exemplify the applicability of the DBS online-SPE LC-MS/MS approach for sports Drug Testing purposes, the method was applied to authentic DBS samples obtained from smokers, snus users, and e-cigarette users. Statistical evaluation of the obtained results indicated differences in metabolic behavior depending on the route of administration (inhalative versus buccal absorption) in terms of the ratio of nicotine and nornicotine.
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dilute and inject multi target screening assay for highly polar doping agents using hydrophilic interaction liquid chromatography high resolution high accuracy mass spectrometry for sports Drug Testing
Analytical and Bioanalytical Chemistry, 2015Co-Authors: Christian Gorgens, Mario Thevis, Andreas Thomas, Sven Guddat, Annekatrin Orlovius, Gerd Sigmund, Wilhelm SchanzerAbstract:In the field of LC-MS, reversed phase liquid chromatography is the predominant method of choice for the separation of prohibited substances from various classes in sports Drug Testing. However, highly polar and charged compounds still represent a challenging task in liquid chromatography due to their difficult chromatographic behavior using reversed phase materials. A very promising approach for the separation of hydrophilic compounds is hydrophilic interaction liquid chromatography (HILIC). Despite its great potential and versatile advantages for the separation of highly polar compounds, HILIC is up to now not very common in doping analysis, although most manufacturers offer a variety of HILIC columns in their portfolio. In this study, a novel multi-target approach based on HILIC high resolution/high accuracy mass spectrometry is presented to screen for various polar stimulants, stimulant sulfo-conjugates, glycerol, AICAR, ethyl glucuronide, morphine-3-glucuronide, and myo-inositol trispyrophosphate after direct injection of diluted urine specimens. The usage of an effective online sample cleanup and a zwitterionic HILIC analytical column in combination with a new generation Hybrid Quadrupol-Orbitrap® mass spectrometer enabled the detection of highly polar analytes without any time-consuming hydrolysis or further purification steps, far below the required detection limits. The methodology was fully validated for qualitative and quantitative (AICAR, glycerol) purposes considering the parameters specificity; robustness (rRT 0.99); intra- and inter-day precision at low, medium, and high concentration levels (CV < 20 %); limit of detection (stimulants and stimulant sulfo-conjugates < 10 ng/mL; norfenefrine; octopamine < 30 ng/mL; AICAR < 10 ng/mL; glycerol 100 μg/mL; ETG < 100 ng/mL); accuracy (AICAR 103.8–105.5 %, glycerol 85.1–98.3 % at three concentration levels) and ion suppression/enhancement effects.
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expanding analytical possibilities concerning the detection of stanozolol misuse by means of high resolution high accuracy mass spectrometric detection of stanozolol glucuronides in human sports Drug Testing
Drug Testing and Analysis, 2013Co-Authors: Wilhelm Schanzer, Hans Geyer, Andreas Thomas, Sven Guddat, Georg Opfermann, Mario ThevisAbstract:Anabolic-androgenic steroids (AAS) represent one of the most frequently detected classes of prohibited substances in doping controls. Due to their long-lasting beneficial effects on athletic performance, utmost retrospectivity via urine analysis is desirable and accomplished by targeting long-term metabolites of the respective Drugs. In case of stanozolol, a substantial variety of metabolites has enabled the identification of numerous adverse analytical findings in the past, and recent studies concerning complementary phase-I and phase-II metabolites has further expanded the windows of opportunity for detecting the abuse of stanozolol. In this study, the utility of liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry (LC-MS/MS) for the detection of 3’-OH-stanozolol glucuronide in sports Drug Testing is presented and the identification of two additional and so far unreported metabolites is shown. The structures of the complementary glucuronic acid conjugates were attributed to stanozolol-N-glucuronide and 17-epistanozolol-N-glucuronide. By means of chemical synthesis, stanozolol-N-glucuronide was prepared and used to corroborate the suggested structures. The 3’-OH-stanozolol glucuronide and the newly identified target compounds were implemented into routine sports Drug test assays consisting of direct injection LC-MS/MS or solid-phase extraction (SPE) followed by LC-MS/MS. A considerably expanded detection window for stanozolol abuse was demonstrated compared to the use of conventional phase-I metabolites and methodologies based on, for example, low resolution LC-MS/MS or gas chromatography-tandem mass spectrometry (GC-MS/MS). The commercial availability of 3’-OH-stanozolol glucuronide has been of great value for confirmatory purposes, and 17-epistanozolol-N-glucuronide was found to be a favourable long-term metabolite for doping controls as it was observed up to 28 days post-administration of the Drug. Applying the established methodology over a period of six months to 659 routine sports Drug Testing samples, a total of 85 adverse analytical findings was uncovered, 72 of which would have remained undetected using earlier employed GC-MS/MS approaches. Copyright © 2013 John Wiley & Sons, Ltd.
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trafficking of Drug candidates relevant for sports Drug Testing detection of non approved therapeutics categorized as anabolic and gene doping agents in products distributed via the internet
Drug Testing and Analysis, 2011Co-Authors: Mario Thevis, Hans Geyer, Andreas Thomas, Wilhelm SchanzerAbstract:Identifying the use of non-approved Drugs by cheating athletes has been a great challenge for doping control laboratories. This is due to the additional complexities associated with identifying relatively unknown and uncharacterized compounds and their metabolites as opposed to known and well-studied therapeutics. In 2010, the prohibited Drug candidates and gene doping substances AICAR and GW1516, together with the selective androgen receptor modulator (SARM) MK-2866 were obtained by the Cologne Doping Control Laboratory from Internet suppliers and their structure, quantity, and formulation elucidated. All three compounds proved authentic as determined by liquid chromatography—high resolution/high accuracy (tandem) mass spectrometry and comparison to reference material. While AICAR was provided as a colourless powder in 100 mg aliquots, GW1516 was obtained as an orange/yellow suspension in water/glycerol (150 mg/ml), and MK-2866 (25 mg/ml) was shipped dissolved in polyethylene glycol (PEG) 300. In all cases, the quantified amounts were considerably lower than indicated on the label. The substances were delivered via courier, with packaging identifying them as containing ‘amino acids’ and ‘green tea extract’, arguably to circumvent customs control. Although all of the substances were declared ‘for research only’, their potential misuse in illicit performance-enhancement cannot be excluded; moreover sports Drug Testing authorities should be aware of the facile availability of black market copies of these Drug candidates. Copyright © 2011 John Wiley & Sons, Ltd.
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annual banned substance review analytical approaches in human sports Drug Testing
Drug Testing and Analysis, 2010Co-Authors: Mario Thevis, Hans Geyer, Tiia Kuuranne, Wilhelm SchanzerAbstract:The aim of improving anti-doping efforts is predicated on several different pillars, including, amongst others, optimized analytical methods. These commonly result from exploiting most recent developments in analytical instrumentation as well as research data on elite athletes' physiology in general, and pharmacology, metabolism, elimination, and downstream effects of prohibited substances and methods of doping, in particular. The need for frequent and adequate adaptations of sports Drug Testing procedures has been incessant, largely due to the uninterrupted emergence of new chemical entities but also due to the apparent use of established or even obsolete Drugs for reasons other than therapeutic means, such as assumed beneficial effects on endurance, strength, and regeneration capacities. Continuing the series of annual banned-substance reviews, literature concerning human sports Drug Testing published between October 2014 and September 2015 is summarized and reviewed in reference to the content of the 2015 Prohibited List as issued by the World Anti-Doping Agency (WADA), with particular emphasis on analytical approaches and their contribution to enhanced doping controls.
Andreas Thomas - One of the best experts on this subject based on the ideXlab platform.
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fully automated determination of nicotine and its major metabolites in whole blood by means of a dbs online spe lc hr ms ms approach for sports Drug Testing
Journal of Pharmaceutical and Biomedical Analysis, 2016Co-Authors: Laura Tretzel, Wilhelm Schanzer, Hans Geyer, Andreas Thomas, Thomas Piper, Mikael Hedeland, Mario ThevisAbstract:Dried blood spots (DBS) represent a sample matrix collected under minimal-invasive, straightforward and robust conditions. DBS specimens have been shown to provide appropriate test material for different analytical disciplines, e.g., preclinical Drug development, therapeutic Drug monitoring, forensic toxicology and diagnostic analysis of metabolic disorders in newborns. However, the sample preparation has occasionally been reported as laborious and time consuming. In order to minimize the manual workload and to substantiate the suitability of DBS for high sample-throughput, the automation of sample preparation processes is of paramount interest. In the current study, the development and validation of a fully automated DBS extraction method coupled to online solid-phase extraction using the example of nicotine, its major metabolites nornicotine, cotinine and trans-3'-hydroxycotinine and the tobacco alkaloids anabasine and anatabine is presented, based on the rationale that the use of nicotine-containing products for performance-enhancing purposes has been monitored by the World Anti-Doping Agency (WADA) for several years. Automation-derived DBS sample extracts were directed online to liquid chromatography high resolution/high mass accuracy tandem mass spectrometry, and target analytes were determined with support of four deuterated internal standards. Validation of the method yielded precise (CV 0.998) results. The limit of detection was established at 5 ng mL(-1) for all studied compounds, the extraction recovery ranged from 25 to 44%, and no matrix effects were observed. To exemplify the applicability of the DBS online-SPE LC-MS/MS approach for sports Drug Testing purposes, the method was applied to authentic DBS samples obtained from smokers, snus users, and e-cigarette users. Statistical evaluation of the obtained results indicated differences in metabolic behavior depending on the route of administration (inhalative versus buccal absorption) in terms of the ratio of nicotine and nornicotine.
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dilute and inject multi target screening assay for highly polar doping agents using hydrophilic interaction liquid chromatography high resolution high accuracy mass spectrometry for sports Drug Testing
Analytical and Bioanalytical Chemistry, 2015Co-Authors: Christian Gorgens, Mario Thevis, Andreas Thomas, Sven Guddat, Annekatrin Orlovius, Gerd Sigmund, Wilhelm SchanzerAbstract:In the field of LC-MS, reversed phase liquid chromatography is the predominant method of choice for the separation of prohibited substances from various classes in sports Drug Testing. However, highly polar and charged compounds still represent a challenging task in liquid chromatography due to their difficult chromatographic behavior using reversed phase materials. A very promising approach for the separation of hydrophilic compounds is hydrophilic interaction liquid chromatography (HILIC). Despite its great potential and versatile advantages for the separation of highly polar compounds, HILIC is up to now not very common in doping analysis, although most manufacturers offer a variety of HILIC columns in their portfolio. In this study, a novel multi-target approach based on HILIC high resolution/high accuracy mass spectrometry is presented to screen for various polar stimulants, stimulant sulfo-conjugates, glycerol, AICAR, ethyl glucuronide, morphine-3-glucuronide, and myo-inositol trispyrophosphate after direct injection of diluted urine specimens. The usage of an effective online sample cleanup and a zwitterionic HILIC analytical column in combination with a new generation Hybrid Quadrupol-Orbitrap® mass spectrometer enabled the detection of highly polar analytes without any time-consuming hydrolysis or further purification steps, far below the required detection limits. The methodology was fully validated for qualitative and quantitative (AICAR, glycerol) purposes considering the parameters specificity; robustness (rRT 0.99); intra- and inter-day precision at low, medium, and high concentration levels (CV < 20 %); limit of detection (stimulants and stimulant sulfo-conjugates < 10 ng/mL; norfenefrine; octopamine < 30 ng/mL; AICAR < 10 ng/mL; glycerol 100 μg/mL; ETG < 100 ng/mL); accuracy (AICAR 103.8–105.5 %, glycerol 85.1–98.3 % at three concentration levels) and ion suppression/enhancement effects.
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expanding analytical possibilities concerning the detection of stanozolol misuse by means of high resolution high accuracy mass spectrometric detection of stanozolol glucuronides in human sports Drug Testing
Drug Testing and Analysis, 2013Co-Authors: Wilhelm Schanzer, Hans Geyer, Andreas Thomas, Sven Guddat, Georg Opfermann, Mario ThevisAbstract:Anabolic-androgenic steroids (AAS) represent one of the most frequently detected classes of prohibited substances in doping controls. Due to their long-lasting beneficial effects on athletic performance, utmost retrospectivity via urine analysis is desirable and accomplished by targeting long-term metabolites of the respective Drugs. In case of stanozolol, a substantial variety of metabolites has enabled the identification of numerous adverse analytical findings in the past, and recent studies concerning complementary phase-I and phase-II metabolites has further expanded the windows of opportunity for detecting the abuse of stanozolol. In this study, the utility of liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry (LC-MS/MS) for the detection of 3’-OH-stanozolol glucuronide in sports Drug Testing is presented and the identification of two additional and so far unreported metabolites is shown. The structures of the complementary glucuronic acid conjugates were attributed to stanozolol-N-glucuronide and 17-epistanozolol-N-glucuronide. By means of chemical synthesis, stanozolol-N-glucuronide was prepared and used to corroborate the suggested structures. The 3’-OH-stanozolol glucuronide and the newly identified target compounds were implemented into routine sports Drug test assays consisting of direct injection LC-MS/MS or solid-phase extraction (SPE) followed by LC-MS/MS. A considerably expanded detection window for stanozolol abuse was demonstrated compared to the use of conventional phase-I metabolites and methodologies based on, for example, low resolution LC-MS/MS or gas chromatography-tandem mass spectrometry (GC-MS/MS). The commercial availability of 3’-OH-stanozolol glucuronide has been of great value for confirmatory purposes, and 17-epistanozolol-N-glucuronide was found to be a favourable long-term metabolite for doping controls as it was observed up to 28 days post-administration of the Drug. Applying the established methodology over a period of six months to 659 routine sports Drug Testing samples, a total of 85 adverse analytical findings was uncovered, 72 of which would have remained undetected using earlier employed GC-MS/MS approaches. Copyright © 2013 John Wiley & Sons, Ltd.
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trafficking of Drug candidates relevant for sports Drug Testing detection of non approved therapeutics categorized as anabolic and gene doping agents in products distributed via the internet
Drug Testing and Analysis, 2011Co-Authors: Mario Thevis, Hans Geyer, Andreas Thomas, Wilhelm SchanzerAbstract:Identifying the use of non-approved Drugs by cheating athletes has been a great challenge for doping control laboratories. This is due to the additional complexities associated with identifying relatively unknown and uncharacterized compounds and their metabolites as opposed to known and well-studied therapeutics. In 2010, the prohibited Drug candidates and gene doping substances AICAR and GW1516, together with the selective androgen receptor modulator (SARM) MK-2866 were obtained by the Cologne Doping Control Laboratory from Internet suppliers and their structure, quantity, and formulation elucidated. All three compounds proved authentic as determined by liquid chromatography—high resolution/high accuracy (tandem) mass spectrometry and comparison to reference material. While AICAR was provided as a colourless powder in 100 mg aliquots, GW1516 was obtained as an orange/yellow suspension in water/glycerol (150 mg/ml), and MK-2866 (25 mg/ml) was shipped dissolved in polyethylene glycol (PEG) 300. In all cases, the quantified amounts were considerably lower than indicated on the label. The substances were delivered via courier, with packaging identifying them as containing ‘amino acids’ and ‘green tea extract’, arguably to circumvent customs control. Although all of the substances were declared ‘for research only’, their potential misuse in illicit performance-enhancement cannot be excluded; moreover sports Drug Testing authorities should be aware of the facile availability of black market copies of these Drug candidates. Copyright © 2011 John Wiley & Sons, Ltd.
Hans Geyer - One of the best experts on this subject based on the ideXlab platform.
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fully automated determination of nicotine and its major metabolites in whole blood by means of a dbs online spe lc hr ms ms approach for sports Drug Testing
Journal of Pharmaceutical and Biomedical Analysis, 2016Co-Authors: Laura Tretzel, Wilhelm Schanzer, Hans Geyer, Andreas Thomas, Thomas Piper, Mikael Hedeland, Mario ThevisAbstract:Dried blood spots (DBS) represent a sample matrix collected under minimal-invasive, straightforward and robust conditions. DBS specimens have been shown to provide appropriate test material for different analytical disciplines, e.g., preclinical Drug development, therapeutic Drug monitoring, forensic toxicology and diagnostic analysis of metabolic disorders in newborns. However, the sample preparation has occasionally been reported as laborious and time consuming. In order to minimize the manual workload and to substantiate the suitability of DBS for high sample-throughput, the automation of sample preparation processes is of paramount interest. In the current study, the development and validation of a fully automated DBS extraction method coupled to online solid-phase extraction using the example of nicotine, its major metabolites nornicotine, cotinine and trans-3'-hydroxycotinine and the tobacco alkaloids anabasine and anatabine is presented, based on the rationale that the use of nicotine-containing products for performance-enhancing purposes has been monitored by the World Anti-Doping Agency (WADA) for several years. Automation-derived DBS sample extracts were directed online to liquid chromatography high resolution/high mass accuracy tandem mass spectrometry, and target analytes were determined with support of four deuterated internal standards. Validation of the method yielded precise (CV 0.998) results. The limit of detection was established at 5 ng mL(-1) for all studied compounds, the extraction recovery ranged from 25 to 44%, and no matrix effects were observed. To exemplify the applicability of the DBS online-SPE LC-MS/MS approach for sports Drug Testing purposes, the method was applied to authentic DBS samples obtained from smokers, snus users, and e-cigarette users. Statistical evaluation of the obtained results indicated differences in metabolic behavior depending on the route of administration (inhalative versus buccal absorption) in terms of the ratio of nicotine and nornicotine.
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expanding analytical possibilities concerning the detection of stanozolol misuse by means of high resolution high accuracy mass spectrometric detection of stanozolol glucuronides in human sports Drug Testing
Drug Testing and Analysis, 2013Co-Authors: Wilhelm Schanzer, Hans Geyer, Andreas Thomas, Sven Guddat, Georg Opfermann, Mario ThevisAbstract:Anabolic-androgenic steroids (AAS) represent one of the most frequently detected classes of prohibited substances in doping controls. Due to their long-lasting beneficial effects on athletic performance, utmost retrospectivity via urine analysis is desirable and accomplished by targeting long-term metabolites of the respective Drugs. In case of stanozolol, a substantial variety of metabolites has enabled the identification of numerous adverse analytical findings in the past, and recent studies concerning complementary phase-I and phase-II metabolites has further expanded the windows of opportunity for detecting the abuse of stanozolol. In this study, the utility of liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry (LC-MS/MS) for the detection of 3’-OH-stanozolol glucuronide in sports Drug Testing is presented and the identification of two additional and so far unreported metabolites is shown. The structures of the complementary glucuronic acid conjugates were attributed to stanozolol-N-glucuronide and 17-epistanozolol-N-glucuronide. By means of chemical synthesis, stanozolol-N-glucuronide was prepared and used to corroborate the suggested structures. The 3’-OH-stanozolol glucuronide and the newly identified target compounds were implemented into routine sports Drug test assays consisting of direct injection LC-MS/MS or solid-phase extraction (SPE) followed by LC-MS/MS. A considerably expanded detection window for stanozolol abuse was demonstrated compared to the use of conventional phase-I metabolites and methodologies based on, for example, low resolution LC-MS/MS or gas chromatography-tandem mass spectrometry (GC-MS/MS). The commercial availability of 3’-OH-stanozolol glucuronide has been of great value for confirmatory purposes, and 17-epistanozolol-N-glucuronide was found to be a favourable long-term metabolite for doping controls as it was observed up to 28 days post-administration of the Drug. Applying the established methodology over a period of six months to 659 routine sports Drug Testing samples, a total of 85 adverse analytical findings was uncovered, 72 of which would have remained undetected using earlier employed GC-MS/MS approaches. Copyright © 2013 John Wiley & Sons, Ltd.
-
trafficking of Drug candidates relevant for sports Drug Testing detection of non approved therapeutics categorized as anabolic and gene doping agents in products distributed via the internet
Drug Testing and Analysis, 2011Co-Authors: Mario Thevis, Hans Geyer, Andreas Thomas, Wilhelm SchanzerAbstract:Identifying the use of non-approved Drugs by cheating athletes has been a great challenge for doping control laboratories. This is due to the additional complexities associated with identifying relatively unknown and uncharacterized compounds and their metabolites as opposed to known and well-studied therapeutics. In 2010, the prohibited Drug candidates and gene doping substances AICAR and GW1516, together with the selective androgen receptor modulator (SARM) MK-2866 were obtained by the Cologne Doping Control Laboratory from Internet suppliers and their structure, quantity, and formulation elucidated. All three compounds proved authentic as determined by liquid chromatography—high resolution/high accuracy (tandem) mass spectrometry and comparison to reference material. While AICAR was provided as a colourless powder in 100 mg aliquots, GW1516 was obtained as an orange/yellow suspension in water/glycerol (150 mg/ml), and MK-2866 (25 mg/ml) was shipped dissolved in polyethylene glycol (PEG) 300. In all cases, the quantified amounts were considerably lower than indicated on the label. The substances were delivered via courier, with packaging identifying them as containing ‘amino acids’ and ‘green tea extract’, arguably to circumvent customs control. Although all of the substances were declared ‘for research only’, their potential misuse in illicit performance-enhancement cannot be excluded; moreover sports Drug Testing authorities should be aware of the facile availability of black market copies of these Drug candidates. Copyright © 2011 John Wiley & Sons, Ltd.
-
annual banned substance review analytical approaches in human sports Drug Testing
Drug Testing and Analysis, 2010Co-Authors: Mario Thevis, Hans Geyer, Tiia Kuuranne, Wilhelm SchanzerAbstract:The aim of improving anti-doping efforts is predicated on several different pillars, including, amongst others, optimized analytical methods. These commonly result from exploiting most recent developments in analytical instrumentation as well as research data on elite athletes' physiology in general, and pharmacology, metabolism, elimination, and downstream effects of prohibited substances and methods of doping, in particular. The need for frequent and adequate adaptations of sports Drug Testing procedures has been incessant, largely due to the uninterrupted emergence of new chemical entities but also due to the apparent use of established or even obsolete Drugs for reasons other than therapeutic means, such as assumed beneficial effects on endurance, strength, and regeneration capacities. Continuing the series of annual banned-substance reviews, literature concerning human sports Drug Testing published between October 2014 and September 2015 is summarized and reviewed in reference to the content of the 2015 Prohibited List as issued by the World Anti-Doping Agency (WADA), with particular emphasis on analytical approaches and their contribution to enhanced doping controls.
Markus R Meyer - One of the best experts on this subject based on the ideXlab platform.
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paper spray ionization coupled to high resolution tandem mass spectrometry for comprehensive urine Drug Testing in comparison to liquid chromatography coupled techniques after urine precipitation or dried urine spot workup
Analytical Chemistry, 2017Co-Authors: Julian A Michely, Markus R Meyer, Hans H MaurerAbstract:Screening procedures using high resolution (HR)-mass spectrometry (MS) are getting more and more important, e.g., for Drug Testing or adherence monitoring. Approaches usually include time-consuming sample preparation and compound separation by liquid chromatography (LC). The paper spray ionization (PSI) technique coupled to MS might overcome these steps by direct analysis of complex mixtures without extraction and separation. In recent years, this technology proved its potential for quantification and/or qualitative screening in biofluids. However, so far, PSI-MS was only applied to procedures covering a limited number of targets. Therefore, a PSI-HR-MS/MS approach was developed and successfully validated for comprehensive urine screening. The procedure showed high matrix effects for most Drugs but still acceptable limits of identification. Applicability was tested by analyses of three proficiency tests for systematic toxicological analysis and of 103 authentic human urine samples. Its screening power was...
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identification of main human urinary metabolites of the designer nitrobenzodiazepines clonazolam meclonazepam and nifoxipam by nano liquid chromatography high resolution mass spectrometry for Drug Testing purposes
Analytical and Bioanalytical Chemistry, 2016Co-Authors: Markus R Meyer, Madeleine Pettersson Bergstrand, Anders Helander, Olof BeckAbstract:Among the new psychoactive substances (NPS), so-called designer benzodiazepines have become of particular importance over the last 2 years, due to their increasing availability on the internet Drug market. Therapeutically used nitrobenzodiazepines such as flunitrazepam are known to be extensively metabolized via N-dealkylation to active metabolites and via nitro reduction to the 7-amino compounds. The aim of the present work was to tentatively identify phase I and II metabolites of the latest members of this class appearing on the NPS market, clonazolam, meclonazepam, and nifoxipam, in human urine samples. Nano-liquid chromatography-high-resolution mass spectrometry was used to provide data about their detectability in urine. Data revealed that clonazolam and meclonazepam were extensively metabolized and mainly excreted as their amino and acetamino metabolites. Nifoxipam was also extensively metabolized, but instead mainly excreted as the acetamino metabolite and a glucuronic acid conjugate of the parent. Based on analysis of human urine samples collected in cases of acute intoxication within the Swedish STRIDA project, and samples submitted for routine Drug Testing, the most abundant metabolites and good targets for urine Drug Testing were 7-aminoclonazolam for clonazolam, 7-acetaminomeclonazepam for meclonazepam, and 7-acetaminonifoxipam for nifoxipam.
