Determination of (13)C/(12)C ratios of urinary excreted boldenone and its main metabolite 5beta-androst-1-en-17beta-ol-3-one

Detection of boldenone in the urine of female horses-ex vivo formation versus administration

Boldenone is an anabolic-androgenic steroid (AAS) that is prohibited in equine sports. However, in certain situations, it is endogenous, potentially formed by the microbes in urine. An approach to the differentiation based on the detection of the biomarkers Δ1-progesterone, 20(S)-hydroxy-Δ1-progesterone and 20(S)-hydroxyprogesterone was assessed, and their concentrations were monitored in the urine of untreated female horses (n = 291) alongside boldenone, boldienone, testosterone and androstenedione. Using an ultra-sensitive analytical method, boldenone (256 ± 236 pg/mL, n = 290) and the biomarkers (Δ1-progesterone up to 57.6 pg/mL, n = 8; 20(S)-hydroxy-Δ1-progesterone 85.3 ± 181 pg/mL, n = 130; 20(S)-hydroxyprogesterone 43.5 ± 92.1 pg/mL, n = 158) were detected at low concentrations. The ex vivo production of Δ1-steroids was artificially induced following the storage of urine samples at room temperature for 7 days in order to assess the concentrations and ratios of the monitored steroids. The administration of inappropriately stored feed source also resulted in an increase in 20(S)-hydroxy-Δ1-progesterone concentrations and the biomarker ratios. Using the results from different datasets, an approach to differentiation was developed. In situations where the presence of boldenone exceeds a proposed action limit of 5 ng/mL, the presence of the biomarkers would be investigated. If Δ1-progesterone is above 50 pg/mL or if 20(S)-hydroxy-Δ1-progesterone is above 100 pg/mL with the ratio of 20(S)-hydroxy-Δ1-progesterone:20(S)-hydroxyprogesterone greater than 5:1, then this would indicate ex vivo transformation or consumption of altered feed rather than steroid administration. There remains a (small) possibility of a false negative result, but the model increases confidence that adverse analytical findings reported in female horses are caused by AAS administrations.

Addressing recent challenges in isotope ratio mass spectrometry: Development of a method applicable to 1-androstene-steroids, 6α-hydroxy-androstenedione and androstatrienedione

In 2020, the confirmation of the non-endogenous origin of several pseudo-endogenous steroids by means of isotope ratio mass spectrometry (IRMS) was recommended by the World Anti-Doping Agency (WADA), in addition to previously established target analytes for IRMS in sports drug testing. To date, however, IRMS-based methods validated in accordance with current WADA regulations have not been available. Therefore, the aim of this research project was the development and validation of a method to determine the carbon isotope ratios (CIR) of all newly considered pseudo-endogenous steroids, encompassing the anabolic androgenic steroids comprising a 1-ene-core structure (5α-androst-1-ene-3β,17β-diol, 5α-androst-1-ene-3,17-dione (1AD), 17β-hydroxy-5α-androst-1-en-3-one, 3α-hydroxy-5α-androst-1-ene-17-one (1AND), and 3β-hydroxy-5α-androst-1-ene-17-one (1EpiAND)), as well as steroids referred to as hormone and metabolic modulators (androsta-1,4,6-triene-3,17-dione (TRD) and its main metabolite 17β-hydroxy-androsta-1,4,6-triene-3-one) and 6α- and 6β-hydroxy-androst-4-ene-3,17-dione. With peak purity of target analytes being critical for IRMS analyses, a twofold high-performance liquid chromatography (HPLC)-based sample purification was employed, with all analytes being acetylated between the first and second HPLC fractionation. Using established gas chromatography/combustion/IRMS (GC/C/IRMS) instrumentation, limits of quantification were estimated at 10 ng/mL for a 20 mL urine aliquot for all analytes, except for 1AND (20 ng/mL), and combined measurement uncertainties were estimated between 0.4 and 0.9 ‰. For proof-of-concept, samples collected after the single oral administration of a nutritional supplement containing 1AD and 1EpiAND were analyzed as well as existing excretion study urine samples obtained after the administration of 4-androstenedione and TRD. Based on the obtained results, the developed method was considered to be fit-for-purpose.

Calibration and data processing in gas chromatography combustion isotope ratio mass spectrometry

Compound-specific isotope analysis (CSIA) by gas chromatography combustion isotope ratio mass spectrometry (GCC-IRMS) is a powerful technique for the sourcing of substances, such as determination of the geographic or chemical origin of drugs and food adulteration, and it is especially invaluable as a confirmatory tool for detection of the use of synthetic steroids in competitive sport. We review here principles and practices for data processing and calibration of GCC-IRMS data with consideration to anti-doping analyses, with a focus on carbon isotopic analysis ((13)C/(12)C). After a brief review of peak definition, the isotopologue signal reduction methods of summation, curve-fitting, and linear regression are described and reviewed. Principles for isotopic calibration are considered in the context of the Δ(13)C = δ(13)C(M) - δ(13)C(E) difference measurements required for establishing adverse analytical findings for metabolites (M) relative to endogenous (E) reference compounds. Considerations for the anti-doping analyst are reviewed.