Development and validation of a method to confirm the exogenous origin of prednisone and prednisolone by GC‐C‐IRMS

Two-dimensional high performance liquid chromatography purification of underivatized urinary prednisone and prednisolone for compound-specific stable carbon isotope analysis

The gas chromatography-combustion isotope ratio mass spectrometry (GC/C/IRMS) confirmation procedure for prednisone (PS) and prednisolone (PSL) is still a great challenge for the doping control laboratory due to the many structurally similar steroids present in urinary matrices. This study aims to establish an innovative online two-dimensional high performance liquid chromatography (2D-HPLC) purification method for measuring the carbon isotope ratios (CIRs) and achieving the identification of the synthetic forms of these two endogenous anabolic androgenic steroids (EAASs). Initially, the one-dimensional chromatographic column was used to separate and purify endogenous reference compounds (ERCs), and the co-elution fluids containing PS and PSL were switched to a two-dimensional chromatographic column for further purification through an online transfer system. Then the purified compounds were analyzed using GC/C/IRMS after sample pretreatments. The results showed that the minimum detection concentration of PS and PSL reached 30 ng mL-1, and no isotope fractionation occurred during the entire collection and preparation process. This method has been validated with the WADA technical document and showed good sensitivity and selectivity, demonstrating its practical applicability for urine samples in doping control laboratories.

Determination of selected glucocorticoids in healthy foods by ultra-performance convergence chromatography-triple quadrupole mass spectrometry

The presence of glucocorticoids in healthy foods has recently become a topic of concern because of their side effects. In this study, we developed a method based on ultra-performance convergence chromatography-triple quadrupole mass spectrometry (UPC²-MS/MS) to detect 63 glucocorticoids in healthy foods. The analysis conditions were optimized, and the method was validated. We further compared the results of this method with those of the RPLC-MS/MS method. Glucocorticoids were separated on an Acquity Torus 2-picolylamine column (100 mm × 3.0 mm, 1.7 µm) and detected via MS/MS. CO₂ and methanol (containing 0.1% formic acid) were used as mobile phases. The method demonstrated good linear relationships between 1 and 200 µg·L^-1 (R² ≥ 0.996). The limits of detection in different types of samples were 0.3-1.5 µg·kg^-1 (S/N = 3). The average recoveries (n = 9) and RSDs in different types of samples were 76.6-118.2% and 1.1-13.1%, respectively. The matrix effect, calculated as the ratio between calibration curves built in matrix and pure solvent, was less than 0.21 for both a fish oil and a protein powder. This method exhibited better selectivity and resolution than RPLC-MS/MS method. Lastly, it could realize the baseline separation of 31 isomers of 13 groups, including four groups of eight epimers. This study provides new technical support for assessing the risk of exposure to glucocorticoids in healthy foods.

Urinary excretion profile of prednisolone and prednisone after rectal administration: significance in antidoping analysis

The rectal administration of glucocorticoids, as well as any injectable, and oral ones, is currently prohibited by the World Anti-Doping Agency when occurs "in competition". A reporting level of 100 ng/mL for prednisolone and 300 ng/mL for prednisone was established to discriminate the allowed and the prohibited administration. Here, the urinary excretion profiles of prednisone and prednisolone were evaluated in five volunteers in therapy with glucocorticoid-based rectal formulations containing prednisone or prednisolone caproate. The urinary levels of the excreted target compounds were determined by LC-MS/MS following the procedure validated and currently in use in our laboratory to detect and quantitate glucocorticoids in urine. Predictably, the excretion trend of the analytes of interest were generally comparable to those obtained after oral administration, even if the excretion profile showed a broad inter-individual variability, with the absorption rate and the systemic bioavailability after rectal administration being strongly influenced by the type of formulations (suppository or rectal cream, in our case) as well as the physiological conditions of the absorption area. Results showed that the target compounds were detectable for at least 30 hours after drug administration. After suppository administration, prednisolone levels reached the maximum after 3 hours from drug administration, and then dropped below the reporting level after 15-21 hours; prednisone reached the maximum after 3 hours from drug administration, and then dropped below the reporting level after 12-15 hours. After cream administration both prednisone and prednisolone levels remained in a concentration below the reporting level throughout the entire monitored period.

Recent advances in identifying and utilizing metabolites of selected doping agents in human sports drug testing

Probing for evidence of the administration of prohibited therapeutics, drugs and/or drug candidates as well as the use of methods of doping in doping control samples is a central assignment of anti-doping laboratories. In order to accomplish the desired analytical sensitivity, retrospectivity, and comprehensiveness, a considerable portion of anti-doping research has been invested into studying metabolic biotransformation and elimination profiles of doping agents. As these doping agents include lower molecular mass drugs such as e.g. stimulants and anabolic androgenic steroids, some of which further necessitate the differentiation of their natural/endogenous or xenobiotic origin, but also higher molecular mass substances such as e.g. insulins, growth hormone, or siRNA/anti-sense oligonucleotides, a variety of different strategies towards the identification of employable and informative metabolites have been developed. In this review, approaches supporting the identification, characterization, and implementation of metabolites exemplified by means of selected doping agents into routine doping controls are presented, and challenges as well as solutions reported and published between 2010 and 2020 are discussed.

A novel approach to improve detection of glucocorticoid doping in sport with new guidance for physicians prescribing for athletes

The systemic effect of glucocorticoids (GCs) following injectable routes of administration presents a potential risk to both improving performance and causing harm to health in athletes. This review evaluates the current GC antidoping regulations defined by the World Anti-Doping Agency and presents a novel approach for defining permitted and prohibited use of glucocorticoids in sport based on the pharmacological potential for performance enhancement (PE) and risk of adverse effects on health. Known performance-enhancing doses of glucocorticoids are expressed in terms of cortisol-equivalent doses and thereby the dose associated with a high potential for PE for any GC and route of administration can be derived. Consequently, revised and substance-specific laboratory reporting values are presented to better distinguish between prohibited and permitted use in sport. In addition, washout periods are presented to enable clinicians to prescribe glucocorticoids safely and to avoid the risk of athletes testing positive for a doping test.

Annual banned-substance review: Analytical approaches in human sports drug testing 2019/2020

Analytical chemistry-based research in sports drug testing has been a dynamic endeavor for several decades, with technology-driven innovations continuously contributing to significant improvements in various regards including analytical sensitivity, comprehensiveness of target analytes, differentiation of natural/endogenous substances from structurally identical but synthetically derived compounds, assessment of alternative matrices for doping control purposes, and so forth. The resulting breadth of tools being investigated and developed by anti-doping researchers has allowed to substantially improve anti-doping programs and data interpretation in general. Additionally, these outcomes have been an extremely valuable pledge for routine doping controls during the unprecedented global health crisis that severely affected established sports drug testing strategies. In this edition of the annual banned-substance review, literature on recent developments in anti-doping published between October 2019 and September 2020 is summarized and discussed, particularly focusing on human doping controls and potential applications of new testing strategies to substances and methods of doping specified the World Anti-Doping Agency's 2020 Prohibited List.

Elimination profiles of prednisone and prednisolone after different administration routes: Evaluation of the reporting level and washout periods to ensure safe therapeutic administrations

Prednisolone (PRED) and prednisone (PSONE) are prohibited in sports competitions when administered by systemic routes, and they are allowed by other routes for therapeutic purposes. There is no restriction of use in out-of-competition periods. The present study aimed to evaluate the urinary excretion of PRED, PSONE, and their most important metabolites after systemic and nonsystemic treatments in order to verify the suitability of the current reporting level of 30 ng/ml used to distinguish allowed and prohibited administrations and to establish washout periods for oral treatments performed in out-of-competition periods. PRED was studied after dermatological administration (5 mg/day for 5 days, n = 6 males) and oral administration (5 mg, n = 6 males; 10 mg, n = 2 males). PSONE was studied after oral administration (10 mg, n = 2 males; 30 mg, n = 1 male and 1 female). Concentrations in urine were measured using an LC-MS/MS method. Concentrations after dermatological treatment were low for all metabolites. After oral administration, concentrations were very high during the first 24 h after administration ranging from 1.6 to 2261 ng/ml and from 4.6 to 908 ng/ml for PRED and PSONE, respectively. Concentrations of most of the metabolites measured were lower than 30 ng/ml from 24 h after all oral administrations. New reporting levels are proposed for PRED and PSONE considering data of our study and other information published after nonsystemic administrations of the compounds. Washout periods of at least 24 h are recommended to ensure no false positives when oral treatments need to be performed in out-of-competition periods.