Determination of ketamine and norketamine in hair and evaluation of polydrug use in ketamine abusers using hair analysis in Korea
Abstract This study evaluated hair samples from 28 subjects who had measurable ketamine levels among the samples requested from 2016 to 2017 into Seoul Institute National Forensic Service in Korea. Ketamine in the hair was extracted by using a solution of 1% hydrochloric acid in methanol for 16 h. Extracts were analyzed using gas chromatography mass spectrometry (GC-MS) or liquid chromatography tandem mass spectrometry (LC-MS-MS). LC-MS-MS method was validated by determining the limit of detection (LOD), limit of quantitation (LOQ), linearity, intra- and inter-accuracy, precision, and matrix effects. In 59 ketamine-positive hair or hair segments from 28 ketamine abusers, the ketamine concentration was found to be in the range of 0.011-335.8 ng/mg (mean, 13.6; median, 1.8), and the norketamine concentration was found to be in the range of 0.001-35.7 ng/mg (mean, 7.5; median, 0.44). The ratio of norketamine to ketamine concentration in hair was in the range of 0.01-1.46 (mean, 0.34; median, 0.26). The distribution of ketamine concentration in hair samples was as follows: 0.01-0.1 ng/mg in 11 samples (18.6%), 0.1-5 ng/mg in 33 samples (55.9%), 5-10 ng/mg in 4 samples (6.8%), 10-15 ng/mg in 2 samples (3.4%), 15-20 ng/mg in 4 samples (6.8%), 40-45 ng/mg in 2 samples (3.4%), 45-50 ng/mg in 1 samples 1.7%) and >100 ng/mg in only 2 samples (3.4%). In the hair of ketamine-abusers, 26 of 28 subjects had simultaneously ketamine with detectable levels of other controlled drugs, including MDMA (n=9), MA (n=3), MDMA/MA (n=3), MDMA/PMA (n=3), MDMA/PMA/MA (n=2), cocaine (n=1), and other drugs (n=5, propofol, zolpidem or benzodiazepines). In most of the hair samples were detected ketamine with other controlled drugs: MDMA (60.7%), MA (28.6%), PMA(17.9%), zolpidem (17.9%), and propofol (14.3%) in the frequency of abuse. In conclusion, most of the ketamine-abusers (92.9%) would be polydrug abusers, who were concomitantly abusing other controlled substances.