Analysis of cocaine adulterants in human brain in cases of drug-related death

•Cocaine, its metabolites and six adulterants were analyzed in brain tissue by GC–MS.•Post-mortem brain tissues of ten cocaine users were examined.•Levamisole, lidocaine, hydroxyzine and phenacetin were identified in these samples.•Interpretation of drug-related deaths should include the assessment of adulterants. For different reasons, street cocaine is often diluted with pharmacologically active substances, the so-called adulterants such as levamisole or hydroxyzine. A controversial debate exists currently on the uptake of adulterants from cocaine preparations and drug-related death. Previous research convincingly argues that serious adverse side effects that affect the central nervous and cardiovascular systems can be a consequence of adulterated cocaine. Having identified the presence of adulterants in lung tissue and blood, the concentrations of these substances in brain, an important target location, was of interest. This provides an opportunity to assess their role in cases of drug-related deaths. We developed and validated a method for the analysis of cocaine, two cocaine metabolites and six adulterants, which can typically be found in cocaine preparations, and one adulterant metabolite in brain tissue by gas chromatography–mass spectrometry (GC–MS)11Abbreviations: GC–MS, gas chromatography–mass spectrometry; SPE, solid-phase extraction; MSTFA, N-Methyl-N-(trimethylsilyl)trifluoroacetamide; COC, cocaine; BZE, benzoylecgonine; EME, ecgonine methyl ester; DIL, diltiazem; HYD, hydroxyzine; LEV, levamisole; CET, cetirizine; LID, lidocaine; PHE, phenacetin; PRO, procaine; COC-d3, cocaine-d3; BZE-d3, benzoylecgonine-d3; HYD-d8, hydroxyzine-d8; LEV-d5, levamisole-d5; EME-d3, ecgonine methyl ester-d3; SIM, selected ion monitoring; T, target; Q, qualifier ion; GTFCh, German Society of Toxicological and Forensic Chemistry; LoD, limit of detection; LoQ, limit of quantification; ULoQ, upper limit of quantification; RSD, relative standard deviation; ALC, alcohol; COD, codeine; FLU, fluoxetine; IBU, ibuprofen; 6-MAM, 6-monoacetylmorphine; MID, midazolam; MOR, morphine; NOS, noscapine; NRD, nordazepam; NRT, nortilidine; PAR, paracetamol; SIL, sildenafil; TIL, tilidine; THC, tetrahydrocannabinol; ZOP, zopiclone.. Ten brain samples which were tested positive for cocaine were analyzed. The homogenized brain tissue was embedded into drying paper for protein precipitation. During a subsequent solid-phase extraction (SPE), the eluate and one of the wash fractions were