title: Norcocaine and cocaethylene distribution patterns in hair samples from light, moderate, and heavy cocaine users.
abstract: Even though hair analysis often seems to be the best choice for retrospective monitoring of cocaine intake, differentiating between incorporated cocaine and external contamination is widely debated. In this study we report results obtained in 90 hair samples from addicts. All samples were analyzed for cocaine, benzoylecgonine, norcocaine, cocaethylene, and tropococaine by gas chromatography-mass spectrometry (GC-MS) techniques coupled with direct immersion solid-phase micro-extraction. Cocaine concentrations were stratified into three classes of usage: light (0.5-3 ng/mg), moderate (3.1-10 ng/mg) and heavy (10.1-40 ng/mg). The Substance Abuse and Mental Health Services Administration cut-off criteria for establishing active cocaine use were applied to the results. For all samples criteria were cocaine levels above 0.5 ng/mg (ranging from 1.63 to 39.29 ng/mg, mean 9.49 ng/mg), benzoylecgonine concentrations ≥ 0.05 ng/mg (ranging from 0.19 to 5.77 ng/mg, mean 1.40), and benzoylecgonine to cocaine % ratio ≥5% (from 6.43 to 26.09%). Norcocaine was present in 58.9% of samples (concentration range: 0.22-3.14 ng/mg) and was strongly predictive only of heavy cocaine use (sensitivity 100% for cocaine concentrations above 9.58 ng/mg). Twenty hair samples from moderate and heavy users tested positive for cocaethylene (concentration range: 0.22-1.98 ng/mg, mean 0.73 ng/mg). This study on hair samples with no chance of false positive cases highlights the very limited applications of testing minor cocaine metabolites for definitive proof of active cocaine consumption. © 2015 The Authors. Drug Testing and Analysis Published by John Wiley & Sons, Ltd.
authors.affiliation: Department of Surgical and Biomedical Science, Forensic Medicine, Forensic Science and Sports Medicine Section, University of Perugia, Via Gambuli-, 06132, Sant'Andrea delle Fratte-Perugia, Italy.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Gambelunghe
authors.affiliation: Public Health Institute, Forensic Medicine Section, Catholic University of the Sacred Heart, Largo Francesco Vito, 1-, 00168, Rome, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Rossi
authors.affiliation: Department of Surgical and Biomedical Science, Forensic Medicine, Forensic Science and Sports Medicine Section, University of Perugia, Via Gambuli-, 06132, Sant'Andrea delle Fratte-Perugia, Italy.
authors.forename: Kyriaki
authors.initials: K
authors.lastname: Aroni
authors.affiliation: Department of Experimental Medicine, Hygiene and Public Health Section, University of Perugia, Via del Giochetto, 06122, Perugia, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Gili
authors.affiliation: Department of Surgical and Biomedical Science, Forensic Medicine, Forensic Science and Sports Medicine Section, University of Perugia, Via Gambuli-, 06132, Sant'Andrea delle Fratte-Perugia, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Bacci
authors.affiliation: Public Health Institute, Forensic Medicine Section, Catholic University of the Sacred Heart, Largo Francesco Vito, 1-, 00168, Rome, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Pascali
authors.affiliation: Public Health Institute, Forensic Medicine Section, Catholic University of the Sacred Heart, Largo Francesco Vito, 1-, 00168, Rome, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Fucci
mesh_terms: D003042:Cocaine / Q000031:analogs & derivatives* / Q000032:analysis; D019970:Cocaine-Related Disorders / Q000175:diagnosis*; D018765:Dopamine Uptake Inhibitors / Q000032:analysis*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006197:Hair / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D008297:Male; D052616:Solid Phase Extraction / Q000379:methods; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: D018765:Dopamine Uptake Inhibitors; C008671:norcocaine; C066444:cocaethylene; D003042:Cocaine
keywords: DI-SPME, GC-MS; cocaethylene; cocaine; hair analysis; norcocaine