Fast and highly selective LC-MSMS screening for THC and 16 other abused drugs and metabolites in human hair to monitor patients for drug abuse.
To facilitate the monitoring of drug abuse by patients, a method was developed and validated for the analysis of amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylphenidate, cocaine, benzoylecgonine, morphine, codeine, heroin, 6-monoacteylmorphine, methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), delta-9-tetrahydrocannabinol (THC), nicotine, and cotinine in human hair. The hair preparation method contains a 3-step wash procedure with dichloromethane followed by a simultaneous hair pulverization and extraction procedure with disposable metal balls. The developed liquid chromatography tandem mass spectrometry method uses a single injection to detect and confirm all 17 abused drugs, including THC, within 4.8 minutes. Nicotine was validated with a linear range of 800-25,000 pgmg hair, and all other substances were validated with a linear range of 30.0-2500 pgmg hair. For inaccuracy and imprecision, the overall bias did not exceed -8.2% and the overall coefficient of variation did not exceed 17.7%. Autosampler stability was proven for 48 hours at 10°C for all substances. Analytical cutoff concentrations were defined for each substance at the lowest validated inaccuracy and imprecision concentration with a bias and coefficient of variation within 15% and qualifierquantifier ratios within 20% of the set ratio. The analytical cutoff concentrations were 200 pgmg for codeine and 80.0 pgmg for 6-MAM, heroin, EDDP, and THC. The analytical cutoff concentration for nicotine was 800 pgmg and for all other validated substances 30.0 pgmg. This method was successfully applied to analyze hair samples from patients who were monitored for drug abuse. Hair samples of 47 subjects (segmented into 129 samples) showed 3,4-methylenedioxymethamphetamine, methylphenidate, cocaine, benzoylecgonine, codeine, methadone, EDDP, THC, nicotine, and cotinine above the analytical cutoff. The method was fully validated, including the validation of the qualifierquantifier ratios. The analysis of real hair samples proved the efficacy of the developed method for monitoring drug abuse. The results obtained by this method provide the physician or health-care professional with extensive information about actual drug abuse or relapse and can be used for patient-specific therapy.