Detection of 6-halogenated steroids in antidoping analysis

Code: 22A05XT

Two halogenated steroids, 6-chloro-testosterone (6-Cl-T) and 6-bromo-androstenedione (6-Br-AED), may present equivalent or higher aromatase inhibition activity compared to those explicitly included in the list, acting as suicide aromatase inhibitors. 6-Cl-T is a synthetic derivative of testosterone and an isomer of clostebol (4-chloro-testosterone) another prohibited AAS. This compound is sold as a dietary supplement on the Internet, and it is claimed to have androgenic/anabolic activity, being more active than testosterone itself. Since some 6-halogenated steroids have been described as having anti-estrogenic activity, we cannot discard that some of the claimed effects may be related to this action.

Independently of the exact mechanism of action, this compound can be considered structurally and pharmacologically related to either Section S1. or S4.1 of the Prohibited List. No reports on the analysis of 6-Cl-T and 6-Br-AED in human urine exist. For 6-Br-AED, a bried indication of its degradation to androstenedione during the traditional sample preparation, suggest that an alternative approach may be needed.

Some micro-organisms can transform 6-halogenated steroids in their corresponding 6-oxo compounds, and this probably occurs through the formation of 6-dehydrated compounds. It appears necessary to verify if this may happen under in vivo conditions in humans, also considering the microbiota of the gut tract.

The metabolism of two 6-halogenated steroids will be described, improving the capacity of detecting their misuse in sports. These compounds are related to compounds explicitly mentioned in the WADA Prohibited List or, if our hypothees are confirmed, can be also considered as pro-drugs of prohibited substances (i.e. testosterone and androstenedione). The loss of chlorine would lead to the formation of pseudo-endogenous steroids. If the Hypotheses are confirmed, we expect that this behaviour will be amplified for 6-Br-androstenedione since the loss of the bromine from the original molecule is more favored in comparison with the chlorine.