Duration of detection of cocaine and metabolites in hair after discontinuation of abuse

摘要

Researchers in hair analysis have known that abuse drugs test positive in results during a period of time, after subjects had declared the end of use. The objective of this study was to test hair samples from chronic cocaine addicts who had recently given up consuming. The study population (n = 15) is made up of patients in a drug rehabilitation program in Santiago de Compostela, Spain. Subjects provided hair samples at 2 months intervals after cocaine discontinuation for 6 months, with the first sample being collected on the admission day of the program. Cocaine and its metabolites benzoylecgonine (BZE) and cocaethylene (CE) were tested by GC/MS with a LOQ at 0.2 ng/mg for cocaine and BZE, and LOQ at 0.05 ng/mg for CE. The hair strands were cut into 1 cm segments and tested for the respective analyte. The older segment was considered as 100% of the response. After cessation of drug consumption, the presence of cocaine and its metabolites in new growing hair segments continued for a certain period. Negative results were obtained 6 months after discontinuation of cocaine abuse.