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Hair is the matrix of choice for investigating a subject's drug history over time, usually with specific forensic applications (license renewal, workplace drug testing, toxicological evaluation), and it is generally considered difficult to be tampered with. Nevertheless, some treatments promising to lower drug concentrations in hair are described online as how to "pass" a drug test. We selected three of these practices, claiming to be effective in decreasing drug concentrations-Treatment 1: (A) baking soda, (B) salicylic acid, (C) bleach; Treatment 2: (A) bleaching and (B) dyeing; Treatment 3: (A) white vinegar, (B) salicylic acid moisturizer, (C) liquid cleanser, and (D) dyeing. Quantitative results were compared with those of untreated hair strands, used as reference. We evaluated the efficacy of the treatment on drugs of abuse and benzodiazepines. Treatment 1 proved to be the most effective, since drug concentrations in treated hair were significantly lower than in untreated ones, although methadone and tetrahydrocannabinol (THC) seemed to be less affected than cocaine and 6-monoacetylmorphine (MAM). The mean percentage values of treatment-induced decrease were up to 90% for cocaine, 81% for benzoylecgonine, 77% for morphine, 89% for MAM, 37% for methadone, 67% for ketamine, 80% for MDMA, 76% for methamphetamine, and 60% for THC, compared with the reference samples. There was no noticeable damage or discoloration of the keratin matrix, making it difficult for the technicians to determine if there was a treatment. This could be an issue for the application of cutoffs or when low concentrations of drugs are incorporated into the keratinic matrix., (© 2023 The Authors. Drug Testing and Analysis published by John Wiley & Sons Ltd.)

The quantitative determination of ethyl glucuronide (EtG) in hair samples is consistently used throughout the world to assess chronic excessive alcohol consumption. For administrative and legal purposes, the analytical results are compared with cut-off values recognised by regulatory authorities and scientific societies. However, it has been recently recognised that the analytical results depend on the hair sample pretreatment procedures, including the crumbling and extraction conditions. A systematic evaluation of the EtG extraction conditions from pulverised scalp hair was conducted by Design of Experiments (DoE) considering the extraction time, temperature, pH, and solvent composition as potential influencing factors. It was concluded that an overnight extraction at 60°C with pure water at neutral pH represents the most effective conditions to achieve high extraction yields. The absence of differential degradation of the internal standard (isotopically-labelled EtG) under such conditions was confirmed and the overall analytical method was validated according to SGWTOX and ISO17025 criteria. Twenty real hair samples with different EtG content were analysed with 3 commonly accepted procedures: (a) hair manually cut in snippets and extracted at room temperature; (b) pulverised hair extracted at room temperature; (c) hair treated with the optimised method. Average increments of EtG concentration around 69% (from a to c) and 29% (from b to c) were recorded. In light of these results, the authors urge the scientific community to undertake an inter-laboratory study with the aim of defining more in detail the optimal hair EtG detection method and verifying the corresponding cut-off level for legal enforcements., (Copyright © 2018 John Wiley & Sons, Ltd.)

The chronic intake of an excessive amount of alcohol is currently ascertained by determining the concentration of direct alcohol metabolites in the hair samples of the alleged abusers, including ethyl glucuronide (EtG) and, less frequently, fatty acid ethyl esters (FAEEs). Indirect blood biomarkers of alcohol abuse are still determined to support hair EtG results and diagnose a consequent liver impairment. In the present study, the supporting role of hair FAEEs is compared with indirect blood biomarkers with respect to the contexts in which hair EtG interpretation is uncertain. Receiver Operating Characteristics (ROC) curves and multivariate Principal Component Analysis (PCA) demonstrated much stronger correlation of EtG results with FAEEs than with any single indirect biomarker or their combinations. Partial Least Squares Discriminant Analysis (PLS-DA) models based on hair EtG and FAEEs were developed to maximize the biomarkers information content on a multivariate background. The final PLS-DA model yielded 100% correct classification on a training/evaluation dataset of 155 subjects, including both chronic alcohol abusers and social drinkers. Then, the PLS-DA model was validated on an external dataset of 81 individual providing optimal discrimination ability between chronic alcohol abusers and social drinkers, in terms of specificity and sensitivity. The PLS-DA scores obtained for each subject, with respect to the PLS-DA model threshold that separates the probabilistic distributions for the two classes, furnished a likelihood ratio value, which in turn conveys the strength of the experimental data support to the classification decision, within a Bayesian logic. Typical boundary real cases from daily work are discussed, too., (Copyright © 2017 Elsevier B.V. All rights reserved.)