Detection of drugs and metabolites in hair before and after treatment with freely available agents chosen to effectively remove drugs from the hair matrix – A case study

Abstract

Hair analysis is commonly used to control abstinence or provide evidence for drug use or drug exposure. While dyeing and coloration of hair have been proven to potentially reduce drug concentrations in hair, relatively little is known about the reduction of drug concentrations after extensive use of ‘household remedies’. In this study, a male subject with known past drug intake applied multiple washing procedures including the use of egg yolk, olive oil and vinegar in addition to common hair shampoo for one week in order to intentionally reduce drug concentrations in hair. Solutions with varying compositions were applied to the head for one hour per day. Hair samples were taken before and after the washing procedure from different parts of the skull. For drug analysis the samples were divided into two segments (0–3 cm and 3–6 cm). The analyses comprised methanol extraction and LC-MS/MS detection of cocaine and metabolites, designer stimulants, opioids and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) as well as alkaline hydrolysis followed by liquid-liquid extraction and GC MS/MS detection for Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN). The following drugs or drug metabolites were detected in the hair samples before the washing procedure in accordance with the information given by the subject: cocaine, benzoylecognine, cocaethylene, amphetamine, MDMA, nortilidine, 3-fluorophenmetrazine, ketamine, norketamine and the cannabinoids THC, CBD, CBN and THC-COOH. The concentrations differed depending on the location of hair sampling. After the washing procedure, drug concentrations in hair were significantly reduced (up to about 70%). In some cases, the drug concentrations fell below the values mentioned in the ‘CTU’ criteria for driving liability diagnostics. It is possible to significantly reduce drug concentrations in hair with products available for everyone. In cases with initial drug concentrations close to ‘cut-off’ values, such procedures might lead to ‘false negative’ results.