Determination of ethylglucuronide and glucocorticoids in hair: an integrated strategy for the clinical and forensic investigation of alcohol abuse

Hair analysis has become a fundamental tool in forensic and clinical toxicology, owing to its ability to integrate substances from both endogenous and exogenous sources over extended periods. The unique features of hair, and its affinity for a large variety of compounds, make it an ideal biological matrix for retrospective evaluation of drug consumption, alcohol intake, and chronic stress conditions. This thesis comprises two experimental studies that emphasize the potential of hair as a matrix for evaluating both exogenous and endogenous exposure. Specifically, the first study explores the concurrent use of alcohol and cocaine by investigating two biomarkers in hair: ethyl glucuronide (hEtG), a marker of alcohol intake, and cocaethylene, a metabolite resulting from the simultaneous intake of alcohol and cocaine. This study was carried out on n = 209 hair samples, collected from cocaine users in the frame of re-issuing the driving license, with the purpose of analyzing the possible relationship between these biomarkers. The study reveals a lack of a sound correlation between hEtG and hCE, thus highlighting a potential advantage, in terms of improvement of diagnostic sensitivity, of an integrated use of the two metabolites. The second experimental study was focused on the development, optimization and validation of a liquid chromatography-mass spectrometry procedure to analyze hair cortisol and hair cortisone as biomarkers of chronic stress exposure. Particularly, the method could be suitable for the determination of alterations of long-term cumulative stress markers in chronic alcohol users. To this aim, the newly developed method was applied to a cohort of subjects under assessment for driving suitability, divided into three alcohol-related groups, namely abstinent (hEtG < 5 pg/mg), social drinkers (5<30 pg/mg) and abusers (hEtG>30 pg/mg), showing a significant increment of cortisol levels and cortisol/cortisone ratio in social drinkers and abusers compared abstinent. The findings of this study highlight a strong association between alcohol consumption and the cortisol/cortisone ratio.