Hair analysis to discriminate voluntary doping vs inadvertent ingestion of the aromatase inhibitor letrozole

Knowing the minimal detectable dose can facilitate the interpretation of a hair test result: Case example with chlortalidone

In case of an adverse analytical finding, a low (estimate) urine concentration can be the consequence of 2 very different situations: it can be the tail end of a drug voluntarily consumed to enhance athletic performance, even by microdosing (which is not effective for all drugs), or it can be the result of a contamination, irrespective of its source. For numerous doping agents, a hair test can allow discriminating doping from contamination based on the measured concentration or even the absence of the target drug. Given hair produces incremental concentrations, its analysis offers the possibility of establishing a pattern of drug use and thus, verifying self-reported histories of exposure. In order to provide a retrospective calendar of drug use, segmental analysis of the hair strand can be performed. In doping, the usual practice is to test the substance in short segments, such as 1 cm to avoid drug dilution when using larger segments. During the last months, seven athletes have returned an adverse analytical finding for the diuretic chlortalidone, with reported urine concentrations in the range 20 to 50 ng/mL. All these athletes submitted, via their legal team, their hair for establishing a pattern of exposure. Results were always consistent with incidental contamination (hair concentration lower than 5 pg/mg), although the source of contamination was never identified. The interpretation of the findings was established in the light of the limited literature, including hair tests after microdosing and therapeutic use.

Interest of hair tests to discriminate a tail end of a doping regimen from a possible contamination in case of challenging an anti-doping rule violation. V. Case reports involving trimetazidine, a drug where the concentration after a single 20 mg dose has been established

The identification of trimetazidine, a medicine used for treating stable angina pectoris and for preventing angina attacks, has been recently observed in doping cases involving high profile athletes from various countries over the world. In all the files where the authors have been involved, the urine concentration of trimetazidine was low (<2 ng/mL), and the athletes argued that contamination was the source of their adverse analytical finding. It is possible to challenge imposed sanctions in relation to an adverse analytical finding, but it is the responsibility of the athlete to demonstrate he/she is innocent and can qualify for no fault or negligence. When the delay between the urine collection and the notification of the violation was not too long (less than 6 months), these athletes requested a head hair test. Trimetazidine was analyzed by an original LC-MS/MS method involving pH 9.5 borate buffer overnight incubation of 20 mg and subsequent solvents extraction in presence of trimetazidine-D8 used as internal standard. Linearity was verified from 1 to 200 pg/mg (R2 = 0.9987). Limit of detection of the method was 0.1 pg/mg. The hair specimen of a male subject, collected 4 weeks after single oral ingestion of 20 mg trimetazidine, tested positive at 146 pg/mg in the corresponding segment. Concentrations of trimetazidine measured in several hair specimens (n = 5) collected from athletes challenging their anti-doping rule violation were below 1 pg/mg, which is consistent with incidental exposure due to contamination. This is the first evidence that trimetazidine is incorporated in human hair after a single therapeutic dose administration.

Probing the hair detectability of prohibited substances in sports: an in vivo-in silico-clinical approach and analytical implications compared with plasma, urine, and faeces

Hair analysis is a crucial method in forensic toxicology with potential applications in revealing doping histories in sports. Despite its widespread use, knowledge about detectable substances in hair is limited. This study systematically assessed the detectability of prohibited substances in sports using a multifaceted approach. Initially, an animal model received a subset of 17 model drugs to compare dose dependencies and detection windows across different matrices. Subsequently, hair incorporation data from the animal experiment were extrapolated to all substances on the World Anti-Doping Agency's List through in-silico prediction. The detectability of substances in hair was further validated in a proof-of-concept human study involving the consumption of diuretics and masking agents. Semi-quantitative analysis of substances in specimens was performed using ultra-performance liquid chromatography-tandem mass spectrometry. Results showed plasma had optimal dose dependencies with limited detection windows, while urine, faeces, and hair exhibited a reasonable relationship with the administered dose. Notably, hair displayed the highest detection probability (14 out of 17) for compounds, including anabolic agents, hormones, and diuretics, with beta-2 agonists undetected. Diuretics such as furosemide, canrenone, and hydrochlorothiazide showed the highest hair incorporation. Authentic human hair confirmed diuretic detectability, and their use duration was determined via segmental analysis. Noteworthy is the first-time reporting of canrenone in human hair. Anabolic agents were expected in hair, whereas undetectable compounds, such as peptide hormones and beta-2 agonists, were likely due to large molecular mass or high polarity. This study enhances understanding of hair analysis in doping investigations, providing insights into substance detectability.

Drug transfer during intimate moments: A key issue in doping control that can be documented by hair tests of the athlete and the partner

The presence of a prohibited substance or its metabolites or its markers in an athlete's sample constitutes the more frequent anti-doping rules violation. In the world anti-doping code, it is indicated (point 10.5) that if someone establishes in an individual case that the athlete bears no fault or negligence, then the otherwise applicable period of ineligibility shall be eliminated. The conditions that have to be met to fix the no fault or negligence evidence are described in several other points of the code. The following two points are of paramount importance: 1. the athlete or his/her legal representative must present verified circumstances of contamination and the source of contamination must be identified; and 
2. there must be verified claims by the athlete about the fact that he/she did not knowingly take the prohibited substance, i.e., that the violation was not intentional.In recent years, several cases of contamination involving drug transfer during intimate moments have been reported. This later situation was first reported in 2009 with the Richard Gasquet case. Since that time, several athletes have been allowed to return to competition with no charge based on strong evidence that the source of contamination was drug transfer during intimate moments. As some of these cases are public and because the author performed hair tests for the majority of the international athletes involved in such procedures, the strategy of the defence and the scientific bases of discussion are reviewed in this article.

Novel studies on Isolation, purification and characterization of dibenzonitro compound from Glycosmis pentaphylla (Retz.) DC. and effect in downregulating neuronal cancers

To isolate Letrozole from Glycosmis pentaphylla (Retz.) DC. and to determine its effect on regulating the proliferation, cell cycle distribution, apoptosis and key mechanisms in human neuroblastoma cell lines. Letrozole was isolated through column chromatographic technique and its effect was checked on human neuroblastoma cell lines, IMR 32. The effects of Letrozole on cell viability were measured by MTT assay, and the cell cycle distribution was determined by flow cytometry. The expression changes in mRNA of proliferating cell nuclear antigen (PCNA), cyclin D1 and Bcl-xL were taken from real-time PCR analysis and the protein levels were detected by Western blotting. The results of the present study showed that Letrozole, isolated from leaves of G. pentaphylla could cause significant inhibitory effect on proliferation of IMR 32 cells in a dose dependent manner. Cell arrest was obtained at S phase with the treatment of Letrozole. Apart from this, the expression of PCNA, cyclin D1 and Bcl-xL were decreased both at mRNA and protein levels for the same treatment. Letrozole can inhibit proliferation, induce cell arrest and cause apoptosis in IMR 32 cell lines. The decreased expression of PCNA, cyclin D1 and Bcl-xL induced by Letrozole contributes to the above effects in vitro. This is the first report on the isolation of Letrozole from G. pentaphylla.

Sports drug testing and the athletes' exposome

Similar to the general population, elite athletes are exposed to a complex set of environmental factors including chemicals and radiation and also biological and physical stressors, which constitute an exposome that is, unlike for the general population, subjected to specific scrutiny for athletes due to applicable antidoping regulations and associated (frequent) routine doping controls. Hence, investigations into the athlete's exposome and how to distinguish between deliberate drug use and different contamination scenarios has become a central topic of antidoping research, as a delicate balance is to be managed between the vital and continually evolving developments of sensitive analytical techniques on the one hand, and the risk of the athletes' exposome potentially causing adverse analytical findings on the other.

Characterization of letrozole in human hair using LC-MS/MS and confirmation by LC-HRMS: Application to a doping case

Letrozole is a reversible aromatase inhibitor, used in the treatment of hormone-dependent woman cancer. No indication for medical use is available for men. In recent years, several cases of doping with letrozole have been observed, especially among high level athletes. Aromatase inhibitors reverse the harmful effects (feminizing) of the abuse of anabolic androgenic steroids. Letrozole is included on the list of products prohibited in- and out-competition by the World Anti-Doping Agency, under section S4.1. The aim of the present work was to develop a specific method to identify letrozole in human hair of a male amateur athlete by LC-MS/MS and confirmation by LC-HRMS, after incubation of 20 mg of matrix in 1 mL of methanol. The chromatographic separation was performed using a reverse phase column HSS C18 with a gradient elution of 15 min (from 87% to 5% of formate buffer adjusted to pH 3). Linearity was observed from 1 to 1000 pg/mg (r² = 0.9999), after spiking blank hair with the corresponding amounts of letrozole. The limit of detection was estimated at 0.5 pg/mg and the lower limit of quantification was the first point of the calibration curve, i.e. 1 pg/mg. The precision was lower than 20% and there was no interference with the analytes by chemicals or any extractable endogenous materials present in hair. Letrozole was identified in the male amateur athlete hair at 310 pg/mg (segment 0-2 cm) and 245 pg/mg (segment 2-4 cm).

Identification of furosemide in hair in a post-mortem case by UHPLC-MS/MS with guidance on interpretation

Testing for drugs in hair raises several difficulties. Among them is the interpretation of the final concentration(s). In a post-mortem case, analyses revealed the presence of furosemide (12 ng/mL) in femoral blood, although it was not part of the victim's treatment. The prosecutor requested our laboratory to undertake an additional analysis in hair to obtain information about the use of furosemide. A specific method was therefore developed and validated to identify and quantify furosemide in hair by UHPLC-MS/MS. After decontamination of 30 mg of hair, incubation in acidic condition, extraction with ethyl acetate, the samples were analyzed by UHPLC-MS/MS. Furosemide was found in the victim's hair at 225 pg/mg. However, it was not possible to interpret this concentration due to the absence of data in the literature. Therefore, the authors performed a controlled study in two parts. In order to establish the basis of interpretation, several volunteers were tested (four after a single 20 mg administration and twenty-four under daily treatment). The first part indicated that a single dose is not detectable in hair using our method. The second part demonstrated concentrations ranging from 5 to 1110 pg/mg with no correlation between dosage and hair concentrations. The decedent's hair result was interpreted as repeated exposures. In the case of furosemide analysis, hair can provide information about its presence but cannot give information about dosage or frequency of use.