Characterization of growth hormone secretagogue small molecule ibutamoren (MK-0677) and its possible metabolites in thoroughbred horses for doping control

Pharmacokinetic evaluation of 24 representative components of Ling-Gui-Zhu-Gan decoction in acute myocardial infarction model rats via a validated ultrahigh-performance liquid chromatography-tandem mass spectrometry method

RATIONALE

Ling-Gui-Zhu-Gan decoction (LGZGD), one of the 100 herbal classic formulas, is clinically used to treat chronic heart failure with remarkable curative effect. However, LGZGD pharmacokinetic parameters in pathological model rats are poorly understood, in particular for special components. As physicochemical properties are specific to each representative component, no standard sample preparation is available for absolute quantification of representative components of LGZGD in rat plasma.

METHODS

A specific, sensitive and high-throughput ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS) method capturing 24 representative components was developed and applied to evaluate the pharmacokinetic parameters of LGZGD in acute myocardial infarction (AMI) rat plasma after intragastric administration (2.4, 4.8 and 9.6 g/kg). Precipitation and extraction were selected and optimized for plasma preparation, and isopropanol precipitation could offer higher recovery and broader coverage.

RESULTS

It was expected that AMI could cause less absorption and slower elimination of most of active components of LGZGD. Most of newly reported special components absorbed quickly and eliminated slowly. The average elimination half-life of the 24 representative components was 10.09 h, which is consistent with the dosage of LGZGD (twice daily).

CONCLUSIONS

The specificity, linearity, precision and accuracy, recovery, matrix effect and stability were validated according to Food and Drug Administration guidance. The validation results demonstrated that the method could be applied to evaluate the pharmacokinetic parameters of LGZGD in AMI rats. The pharmacokinetic parameters showed substantial improvement in quality research of LGZGD, thereby laying the groundwork for preclinical and clinical trials in chronic heart failure clinical efficacy.

Metabolic study of selective androgen receptor modulator LY2452473 in thoroughbred horses for doping control

RATIONALE

Since 2010, there has been an increasing number of adverse analytical findings related to selective androgen receptor modulators (SARMs) in competitive sports. It emphasizes the importance of comprehensive doping control analytical procedures that are capable of detecting SARM misuse.

METHODS

In this study, it is described how LY2452473, a SARM, was metabolized in thoroughbred horses after a single-dose oral administration and in vitro with equine liver microsome preparations. An investigation of the metabolism of LY2452473 in horses' urine, plasma, and hair matrices was carried out during the study. The plausible structures of the detected metabolites were postulated using high-performance liquid chromatography-high resolution mass spectrometry.

RESULTS

Under the experimental conditions 15 metabolites (12 phase I and three conjugates of phase I) were detected (M1-M15). The major phase I metabolites identified were formed by hydroxylation. Side-chain dissociated and methylated metabolites were also detected. In phase II, the glucuronic acid and sulfonic acid conjugates of hydroxy LY2452473 were detected as the major metabolites. In vitro analysis has confirmed the presence of all metabolites found in vivo except for the methylated analogs M11 and M12. A peak concentration of LY2452473 (0.5 pg/mg) in proximal hair segments was achieved 4 weeks after administration, according to hair analysis.

CONCLUSIONS

Data obtained will aid in identifying LY2452473 and related substances faster. Furthermore, the results will assist in checking for the illegal use of these substances in competitive sports.

Hydroxy levamisole and its phase II conjugates as potential indicators of levamisole doping in thoroughbred horses

RATIONALE

According to previous research, aminorex is the major metabolite of levamisole; however, in the screening of levamisole-positive racehorse urine and plasma samples, aminorex could only be detected in trace amounts or not at all. In forensic laboratories, hydroxy levamisole and its phase II conjugates make it easier to confirm levamisole misuse and to differentiate between the abuse of levamisole and aminorex. This study aimed to identify the major levamisole metabolites that can be detected along with the parent drug.

METHODS

The study describes levamisole and its metabolites in thoroughbred horses following oral administration and in vitro with equine liver microsomes. The plausible structures of the detected metabolites were postulated using liquid chromatography combined with high-resolution mass spectrometry.

RESULTS

Under the experimental conditions 26 metabolites (17 phase I, 2 phase II, and 7 conjugates of phase I metabolites) were detected (M1-M26). The major phase I metabolites identified were formed by hydroxylation. In phase II, the glucuronic acid conjugates of levamisole and hydroxy levamisole were detected as the major metabolites. In plasma, the parent drug and major metabolites are detectable for up to eight days, while in urine, they are detectable for up to twenty days. Levamisole levels rapidly increased at 45 min following administration, then declined gradually until detectable levels were reached approximately 8 days after administration, according to a pharmacokinetics study.

CONCLUSIONS

A prolonged elimination profile and relatively high concentration of hydroxy metabolites suggest that the detection of hydroxy metabolites is imperative for investigating levamisole doping in horses.

Processes in Doping System: Quantification Reports in Mixed Martial Arts Fighters

Mixed martial arts (MMA) has always been surrounded by controversy due to the unusual muscle development of its participants, so it is crucial to know the strategies that have been implemented to reduce doping cases. The main purpose of this paper is to describe the various cases of doping detected by USADA in UFC MMA participants. In addition, strategies that are being developed to reduce cases of positive doping are proposed. From the UFC USADA database, doping cases were extracted, obtaining the substance or substances involved; the formula, physiological effect and the athletes involved; the dates of the sampling; if it was out of competition or in-competition and the sanction time. The substances that were most involved were found to be Ostarine (22), Clomiphene (9), Diuretics (10) and Stanozolol (9). Some sanctions were diminished because they were treated with contamination of supplements (cases of Ostarine) and cases of contamination of meat (Clomiphene). When contaminated supplements were reported, they were added to the list of high-risk supplements maintained as part of USADA’s online dietary supplement safety education and awareness resource—Supplement 411. There were also cases in which positive doping could be avoided through the early report of therapeutic use exemptions. The methodology that the USADA has implemented allows us to register the athletes with positive doping, check the risk of the supplements before being bought and provide a teaching portal. These efforts are necessary to implement in all countries in which MMA is practiced, avoiding the participation of doped martial artists.