Gas chromatographic-mass spectrometric identification of main metabolites of stanozolol in cattle after oral and subcutaneous administration

Anabolic steroids in livestock production: Background and implications for chemical food safety

The use of steroids in livestock animals is a source of concern for consumers because of the risks associated with the presence of their residues in foodstuffs of animal origin. Technological advances such as mass spectrometry have made it possible to play a fundamental role in controlling such practices, firstly for the discovery of marker metabolites but also for the monitoring of these compounds under the regulatory framework. Current control strategies rely on the monitoring of either the parent drug or its metabolites in various matrices of interest. As some of these steroids also have an endogenous status specific strategies have to be applied for control purposes. This review aims to provide a comprehensive and up-to-date knowledge of analytical strategies, whether targeted or non-targeted, and whether they focus on markers of exposure or effect in the specific context of chemical food safety regarding the use of anabolic steroids in livestock. The role of new approaches in data acquisition (e.g. ion mobility), processing and analysis, (e.g. molecular networking), is also discussed.

Liquid chromatographytandem mass spectrometry methods for determination of stanozolol and l6β-hydroxy-stanozolol in animal urine

Introduction

Because of the activities and effects they induce, hormones are prohibited for use for anabolic purposes in farm animals intended for slaughter, which is regulated in the European Union by relevant legal provisions. Therefore, there is an obligation to monitor residues of hormones in animals and food of animal origin to ensure consumer safety. A hormone banned but used formerly for fattening cattle, stanozolol, and its metabolite 16β-OH-stanozolol are synthetic compounds that belong to a large group of steroid hormones. This study investigates residues of these compounds in animal urine.

Material and Methods

From 2006-2022, 2,995 livestock urine samples were tested for stanozolol residues in Poland as part of the National Residue Monitoring Programme. A liquid chromatography-tandem mass spectrometry method to determine stanozolol and 16β-OH-stanozolol in animal urine was developed and validated according to the required criteria. Urine sample analysis was based on enzymatic hydrolysis of hormones potentially present in it to the free form, extraction of them from the sample with a mixture of n-hexane and butyl alcohol, purification of an extract on an NH2 amine column and finally, instrumental detection.

Results

The apparent recovery and precision parameters of the developed method were in line with the established criteria, while its decision limits CCα and detection capabilities CCβ were lower than the recommended concentration for analytical purposes set at 2 μg L-1 (valid until December 15, 2022; currently set as 0.5 μg L-1).

Conclusion

All examined samples were compliant with the evaluation criteria.

Anabolic Steroids in Fattening Food-Producing Animals—A Review

Simple Summary

Anabolic steroids significantly affect animal tissues and cause morphological and histological changes, which are often irreversible. This issue is currently a very hot topic, as the answers to the questions concerning the health of endangered animals and humans vary greatly from country to country. There is a need to further investigate whether the use of anabolic steroids in animal fattening threatens consumer health and to develop new tools for the detection of anabolic steroids in meat. One possibility for detection could be to observe histological changes in the tissues, which form a typical pattern of anabolic abuse. This review gathered information on the anabolic steroids most commonly used in animal fattening, the legislation governing this issue, and the main effects of anabolics on animal tissues.

Abstract

Anabolic steroids are chemically synthetic derivatives of the male sex hormone testosterone. They are used in medicine for their ability to support muscle growth and healing and by athletes for esthetic purposes and to increase sports performance, but another major use is in fattening animals to increase meat production. The more people there are on Earth, the greater the need for meat production and anabolic steroids accelerate the growth of animals and, most importantly, increase the amount of muscle mass. Anabolic steroids also have proven side effects that affect all organs and tissues, such as liver and kidney parenchymal damage, heart muscle degeneration, organ growth, coagulation disorders, and increased risk of muscle and tendon rupture. Anabolic steroids also have a number of harmful effects on the developing brain, such as brain atrophy and changes in gene expression with consequent changes in the neural circuits involved in cognitive functions. Behavioral changes such as aggression, irritability, anxiety and depression are related to changes in the brain. In terms of long-term toxicity, the greatest impact is on the reproductive system, i.e., testicular shrinkage and infertility. Therefore, their abuse can be considered a public health problem. In many countries around the world, such as the United States, Canada, China, Argentina, Australia, and other large meat producers, the use of steroids is permitted but in all countries of the European Union there is a strict ban on the use of anabolic steroids in fattening animals. Meat from a lot of countries must be carefully inspected and monitored for steroids before export to Europe. Gas or liquid chromatography methods in combination with mass spectrometry detectors and immunochemical methods are most often used for the analysis of these substances. These methods have been considered the most modern for decades, but can be completely ineffective if they face new synthetic steroid derivatives and want to meet meat safety requirements. The problem of last years is the application of “cocktails” of anabolic substances with very low concentrations, which are difficult to detect and are difficult to quantify using conventional detection methods. This is the reason why scientists are trying to find new methods of detection, mainly based on changes in the structure of tissues and cells and their metabolism. This review gathered this knowledge into a coherent form and its findings could help in finding such a combination of changes in tissues that would form a typical picture for evidence of anabolic misuse.

The application of in vitro technologies to study the metabolism of the androgenic/anabolic steroid stanozolol in the equine

In this study, the use of equine liver/lung microsomes and S9 tissue fractions were used to study the metabolism of the androgenic/anabolic steroid stanozolol as an example of the potential of in vitro technologies in sports drug surveillance. In vitro incubates were analysed qualitatively alongside urine samples originating from in vivo stanozolol administrations using LC-MS on a high-resolution accurate mass Thermo Orbitrap Discovery instrument, by LC-MS/MS on an Applied Biosystems Sciex 5500 Q Trap and by GC-MS/MS on an Agilent 7000A. Using high-resolution accurate mass full scan analysis on the Orbitrap, equine liver microsome and S9 in vitro fractions were found to generate all the major phase-1 metabolites observed following in vivo administrations. Additionally, analysis of the liver microsomal incubates using a shallower HPLC gradient combined with various MS/MS functions on the 5500 Q trap allowed the identification of a number of phase 1 metabolites previously unreported in the equine or any other species. Comparison between liver and lung S9 metabolism showed that the liver was the major site of metabolic activity in the equine. Furthermore, using chemical enzyme inhibitors that are known to be selective for particular isoforms in other species suggested that an enzyme related to CYP2C8 may be responsible the production of 16-hydroxy-stanozolol metabolites in the equine. In summary, the in vitro and in vivo phase 1 metabolism results reported herein compare well and demonstrate the potential of in vitro studies to compliment the existing in vivo paradigm and to benefit animal welfare through a reduction and refinement of animal experimentation.

Metabolism of stanozolol: chemical synthesis and identification of a major canine urinary metabolite by liquid chromatography-electrospray ionisation ion trap mass spectrometry

The canine phase I and phase II metabolism of the synthetic anabolic-androgenic steroid stanozolol was investigated following intramuscular injection into a male greyhound. The major phase I biotransformation was hydroxylation to give 6alpha-hydroxystanozolol which was excreted as a glucuronide conjugate and was identified by comparison with synthetically derived reference materials. An analytical procedure was developed for the detection of this stanozolol metabolite in canine urine using solid phase extraction, enzyme hydrolysis of glucuronide conjugates and analysis by positive ion electrospray ionisation ion trap LC-MS.

Detection and structural investigation of metabolites of stanozolol in human urine by liquid chromatography tandem mass spectrometry

The applicability of LC-MS/MS in precursor ion scan mode for the detection of urinary stanozolol metabolites has been studied. The product ion at m/z 81 has been selected as specific for stanozolol metabolites without a modification in A- or N-rings and the product ions at m/z 97 and 145 for the metabolites hydroxylated in the N-ring and 4-hydroxy-stanozolol metabolites, respectively. Under these conditions, the parent drug and up to 15 metabolites were found in a positive doping test sample. The study of a sample from a chimeric uPA-SCID mouse collected after the administration of stanozolol revealed the presence of 4 additional metabolites. The information obtained from the product ion spectra was used to develop a SRM method for the detection of 19 compounds. This SRM method was applied to several doping positive samples. All the metabolites were detected in both the uPA-SCID mouse sample and positive human samples and were not detected in none of the blank samples tested; confirming the metabolic nature of all the detected compounds. In addition, the application of the SRM method to a single human excretion study revealed that one of the metabolites (4xi,16xi-dihydroxy-stanozolol) could be detected in negative ionization mode for a longer period than those commonly used in the screening for stanozolol misuse (3'-hydroxy-stanozolol, 16beta-hydroxy-stanozolol and 4beta-hydroxy-stanozolol) in doping analysis. The application of the developed approach to several positive doping samples confirmed the usefulness of this metabolite for the screening of stanozolol misuse. Finally, a tentative structure for each detected metabolite has been proposed based on the product ion spectra measured with accurate masses using UPLC-QTOF MS.

Analysis of meat samples for anabolic steroids residues by liquid chromatography/tandem mass spectrometry

A rapid, specific and highly sensitive multi-residue method for the determination of anabolic steroid residues in bovine, pork and poultry muscle tissues was developed. The sample preparation involves enzymatic digestion followed by extraction with methanol. The crude extract was cleaned up by solid-phase extraction (SPE) combining C18 and NH2 columns. The detection was carried out by a highly sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method using both positive and negative ionization modes. Natural and synthetic steroids covering different polarities could be extracted, concentrated and purified using one single method. Mobile phase composition and additives were optimized to achieve the highest sensitivity. The linearity was not good enough for quantitative analysis but the method was well-suited for qualitative confirmation. The method was validated according to the European Commission Decision 2002/657/EC. Decision limits (CCalpha) and detection capabilities (CCbeta) were below 0.5 ng g(-1) for all the compounds in the three types of meat studied. The developed method is suitable for routine analysis in our laboratories.

Criteria to distinguish between natural situations and illegal use of boldenone, boldenone esters and boldione in cattle 1. Metabolite profiles of boldenone, boldenone esters and boldione in cattle urine

Boldenone is an androgenic steroid that improves the growth and food conversion in food producing animals. In most countries worldwide, this anabolic steroid is forbidden for meat production. Until recently, the control of its illegal use was based either on 17beta-boldenone or 17alpha-boldenone (its main metabolite in cattle) identification in edible tissues, hair, faeces or urine. Recent observations and data tend to demonstrate the natural occurrence (but not ubiquitous) in cattle of these steroids, making the analytical strategy of the control more complicated. We investigated the metabolism of boldenone in cattle after intramuscular and oral treatment of boldenone, boldenone esters and boldione. The central objective was to elucidate the structures of the main metabolites (phase I and phase II) in urine, with main objective to be further in position to compare boldenone urinary profiles of treated and non-treated animals. Nine metabolites have been identified, only four were present whatever the treatment and the administered boldenone source. Nevertheless, all of them have been detected at least once in non-treated animals which did not permit us to use them as biomarkers of an illegal treatment. At last, but not at least, all metabolites were found mainly glucuro-conjugated, and rarely sulfo-conjugated, with the only exception of 17beta-boldenone. Current investigations are showing the absence of 17beta-boldenone sulfoconjugate in non-treated animals; that would permit to distinguish non-treated from treated animals with boldione, boldenone and boldenone esters.

Quantitative detection of doping substances by a localised surface plasmon sensor

Within this communication, consistent evidence of a quantitative biosensing principle for steroidal residue analysis is presented. Our approach uses a simple method for the quantitative determination of an anabolic agent called stanozolol (Sz). Sz (Mw 328) is widely used in sports, horse racing and as a growth promoter in animals for human consumption. Through the use of localised surface plasmons (LSPs), sustained by three-dimensional noble metal nanostructures, we have developed a highly specific, label-less immunosensor for the detection of this small organic molecule to low levels (nM range). A main practical advantage over conventional flat extended film surface plasmon resonance (SPR) systems is the simplicity of the optical configuration, since there is no need for cumbersome total internal reflection illumination, thus making integration easier. In addition, the active area of the LSP-based sensor is smaller, decreasing the minimum detectable number of molecules involved in the binding event. Assay times are short and the set-up is comprised of relatively cheap instrumentation. Detection levels found here are comparable with SPR, even at this early stage of development and with further modifications, we envisage sensing down to pM (10(-12)) levels.

Mass spectrometry of stanozolol and its analogues using electrospray ionization and collision-induced dissociation with quadrupole-linear ion trap and linear ion trap-orbitrap hybrid mass analyzers

Mass spectrometric identification and characterization of growth-promoting anabolic-androgenic steroids in biological matrices has been a major task for doping control as well as food safety laboratories. The fragmentation behavior of stanozolol, its metabolites 17-epistanozolol, 3'-OH-stanozolol, 4alpha-OH-stanozolol, 4beta-OH-stanozolol, 17-epi-16alpha-OH-stanozolol, 16alpha-OH-stanozolol, 16beta-OH-stanozolol, as well as the synthetic analogues 4-dehydrostanozolol, 17-ketostanozolol, and N-methyl-3'-OH-stanozolol, was investigated after positive electrospray ionization and subsequent collision-induced dissociation utilizing a quadrupole-linear ion trap and a novel linear ion trap-orbitrap hybrid mass spectrometer. Stable isotope labeling, H/D-exchange experiments, MS3 analyses and high-resolution/high mass accuracy measurements of fragment ions were employed to allow proposals for charge-driven as well as charge-remote fragmentation pathways generating characteristic product ions of stanozolol at m/z 81, 91, 95, 105, 119, 135 and 297 and 4-hydroxylated stanozolol at m/z 145. Fragment ions were generated by dissociation of the steroidal A- and B-ring retaining the introduced charge within the pyrazole function of stanozolol and by elimination of A- and B-ring fractions including the pyrazole residue. In addition, a charge-remote fragmentation causing the neutral loss of methanol was observed, which was suggested to be composed by the methyl residue at C-18 and the hydroxyl function located at C-17.

Improvement in steroid screening for doping control with special emphasis on stanozolol

The Medical Commission of the International Olympic Committee forbids the use of anabolic androgenic steroids and beta2-agonists to improve athletic performance. In this work we have selected examples of anabolic androgenic compounds and their metabolites to evaluate the GC-MS analysis of some trimethylsilyl derivatives. The aim is to set the best GC conditions to improve the detection within the whole range of analyte elution temperatures. The initial column temperature was changed to 105 or 140 degrees C followed by 40 degrees C min(-1) to 200 degrees C and then 15 degrees C min(-1) to 300 degrees C. Using 140 degrees C as the initial oven temperature it was possible to obtain narrower initial analyte distributions for the compounds that elutes at the beginning of the chromatogram as clenbuterol, mabuterol, epimethylenediol and norandrosterone, without loss of derivatized metabolites signal. Later. eluting analytes, such as the stanozolol metabolites, furazabol and oxandrolone were not affected. Temperatures below 140 degrees C. resulted in partial derivatization for some analytes mainly stanozolol related structures. Therefore evaluation of derivatization conditions as occurring in three steps, the vial, vaporization chamber and capillary column, was thoroughly assessed. The new program temperature improves the signal-to-noise ratio for some compounds and shows adequate resolution for endogenous compounds. Some of the difficult key separations necessary for doping control enforcement were also obtained with the proposed method.

Development and validation of a multi-analyte method for the detection of anabolic steroids in bovine urine with liquid chromatography-tandem mass spectrometry

Detection of anabolic steroids in animal urine samples is currently performed with GC-MS in our lab. However we found that the detection of 17 alpha-trenbolone (17 alpha-TbOH), 4-chloroandrost-4-ene-3,17-dion (CLAD), 16- beta -OH-stanozolol (16OHstan) and alpha- and beta-boldenone (alpha -Bol, beta -Bol) was very difficult, if not impossible. Therefore a sensitive, specific and selective qualitative multi-analyte LC-MS-MS method was developed. The LC separation was achieved by using a Symmetry C(18) column and methanol-water-formic acid (54.7-44.7-0.6) as a mobile phase at a flow-rate of 0.3 ml/min. The mass spectrometer was operated in multiple reaction monitoring mode with positive electrospray interface. Validation of the method was done according to draft SANCO/1805/2000 Rev.1 and a CC beta smaller then 1 ng/ml was obtained for each compound.

Confirmatory analysis of residues of stanozolol and its major metabolite in bovine urine by liquid chromatography-tandem mass spectrometry

A reliable method for the confirmation of the synthetic hormone stanozolol and its major metabolite, 16beta-hydroxystanozolol, in bovine urine by liquid chromatography coupled with tandem mass spectrometry has been developed. [2H3]Stanozolol was used as internal standard. Sample preparation involved enzymatic hydrolysis, liquid-liquid extraction and purification on an amino solid-phase extraction column. The analytes were ionized using atmospheric pressure chemical ionization with a heated nebulizer interface operating in the positive ion mode, where only the protonated molecules, [M+H]+, at m/z 329 and m/z 345, for stanozolol and 16beta-hydroxystanozolol, respectively, were generated. These served as precursor ions for collision-induced dissociation and three diagnostic product ions for each analyte were identified for the unambiguous hormone confirmation by selected reaction monitoring liquid chromatography-tandem mass spectrometry. The accuracy ranged from 19.7 to 14.9% and from 18.9 to 13.2% for stanozolol and 16beta-hydroxystanozolol, respectively. The precision ranged from 12.4 to 2.4% and from 13.1 to 1.8% for stanozolol and 16beta-hydroxystanozolol, respectively. The limit of quantification of the method was 1 ng/ml in the bovine urine for both stanozolol and 16beta-hydroxystanozolol. The developed method fulfils the European Union requirements for confirmatory methods.

Measurement of testosterone and pregnenolone in nails using gas chromatography-mass spectrometry

An efficient method for the determination of testosterone and pregnenolone in human nails using gas chromatography-mass spectrometry (GC-MS) with d3-testosterone as an internal standard is described. The method involves alkaline digestion and liquid-liquid extraction, with subsequent conversion to mixed pentafluoropenyldimethylsilyl-trimethylsilyl (flophemesyl-TMS) derivatives for sensitive analysis in the selected-ion monitoring (SIM) mode. The limit of detection (LOD) and limit of quantification (LOQ) were lowered to 0.1 and 0.2 pg/g, respectively, when 100 mg of nail-clippings were used. The mean recoveries of testosterone and pregnenolone were 89.8 and 86.7%, respectively, while good overall precision (% C.V.; 4.5-9.5) and accuracy (% bias; 3.9-8.4) were demonstrated. Linearity as a correlation coefficient was 0.9913 (testosterone) and 0.9965 (pregnenolone). When applied to fingernail and toenail samples from seven healthy men and nine healthy women, testosterone and pregnenolone were positively detected in the concentration range of 0.24-5.80 ng/g. The levels of two steroids studied in the nails were found to be higher in the male subjects than in the female subjects, and except for the toenails of the females, the levels of testosterone were higher than those of pregnenolone.

Determination of 16beta-hydroxystanozolol in urine and faeces by liquid chromatography-multiple mass spectrometry

This paper describes the optimisation of the detection of stanozolol and its major metabolite 16beta-hydroxystanozolol in faeces and urine from cattle. Faeces are extracted directly with diisopropyl ether. Urine is first submitted to an enzymatic hydrolysis and then extracted over a modified diatomaceous earth column (Chem-Elut) with a mixture of diisopropyl ether-isooctane. In a final step an acidic back extraction is performed. For the LC-MS-MS detection two approaches are discussed. In a first approach the final extract is detected without derivatization, while the second approach makes use of a derivatization step for 16beta-hydroxystanozolol. While the MS-MS spectrum without derivatization exhibits extensive fragmentation, the spectrum of the derivative shows two abundant diagnostic ions with much more reproducible ion ratios. The derivatization method and the method without derivatization enable the detection of 16beta-hydroxystanozolol up to 0.03 microg l(-1) in urine and 0.07 microg kg(-1) in faeces. Until now there is no literature available for the detection of 16beta-hydroxystanozolol in faeces and urine at the ppt level.

Measurement of 19-nortestosterone and its esters in equine plasma by high-performance liquid chromatography with tandem mass spectrometry

A high-performance liquid chromatographic-tandem mass spectrometric (HPLC/MS/MS) method for the determination of 19-nortestosterone and its esters (cyclopentanepropionate, phenylpropionate, and decanoate) in equine plasma is achieved using an atmospheric pressure chemical ionization (APCI) interface in selected reaction monitoring (SRM) mode. The two internal standards used were 16,16, 17-(2)H(3)-19-nortestosterone for 19-nortestosterone and methenolone acetate for its esters. The steroids studied were extracted from plasma samples with a mixture of diethyl ether/n-hexane (9:1, v/v). The quantification limits for 19-nortestosterone, 19-nortestosterone cyclopentanepropionate, 19-nortestosterone phenylpropionate, and 19-nortestosterone decanoate were 0.16, 5.0, 0.1, and 2.0 ng/mL, respectively, when 2 mL of plasma were used. The recoveries of most of the steroids were 71.6-101.0% except for the decanoate, which could be recovered to about 39.8%. The responses were linear, with correlation coefficients varying from 0.9897 to 0.9999 in the concentration range of 0.1 to 50.0 ng/mL for the steroids studied. When applied to equine (mare) plasma samples, the present method allowed detection of 19-nortestosterone up to 23 days after an intra-muscular injection of 400 mg as the decanoate.