Heesun Chung

Validation of a simultaneous analytical method for the detection of 27 benzodiazepines and metabolites and zolpidem in hair using LC-MS/MS and its application to human and rat hair.

Benzodiazepines and zolpidem are controlled in many countries due to their inherent adverse effects of a high degree of tolerance and dependence. Recently, as some of these drugs have become distributed illegally and available through media such as the Internet, their abuse is becoming a serious social problem. Hair is a useful specimen to prove chronic drug use. In the present study, a simultaneous analytical method for the detection of 27 benzodiazepines and metabolites and zolpidem in hair was established and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The drugs and their metabolites in hair were extracted using methanol, filtered and injected on the LC-MS/MS. The following validation parameters of the method were satisfactory: selectivity, linearity, matrix effect, recovery, process efficiency, intra- and inter-assay precision and accuracy and processed sample stability. The limit of detection (LOD) and the limit of quantification (LOQ) were the total drug detected from the sample. The LODs ranged from 0.005 ng (zolpidem) to 0.5 ng (bromazepam and chlordiazepoxide) and the LOQs were 0.25 ng in every analyte except for bromazepam and chlordiazepoxide, for which they were 0.5 ng. The developed method was successfully applied to five legal cases involving use of benzodiazepines and zolpidem and to an animal study on drug incorporation into hair. Diazepam and its three metabolites, as well as lorazepam, were detected in hair from both the multiple- and single-dose administration groups of lean Zucker rats. The concentration of diazepam was higher than those of its metabolites in both dark grey and white hair from the multiple-dose administration groups, with the mean concentration ranges from 0.16 to 0.51 ng/mg and from 0.10 to 0.24 ng/mg, respectively. The mean concentration ranges of lorazepam were from 0.05 to 0.37 ng/mg in dark grey hair and from 0.11 to 0.45 ng/mg in white hair from the multiple-dose administration groups. Hair pigmentation did not have any significant effect on the degree of the deposition of drugs and their metabolites in hair.

Recent Trends of Drug Abuse and Drug-Associated Deaths in Korea

Abstract: Methamphetamine is the most abused drug in Korea followed by cannabis and opiates. Recent characteristics of the drug problem in Korea include increased drug smuggling from abroad, drug trafficking by organized gangs, varieties of drug smuggling, foreigners engaged in drug smuggling, and spread among drug abusers and areas. New drugs such as MDMA, Yaba, and LSD are found in greater proportion in the seizure records, indicating diversification of smuggled drugs in Korea. In addition, there is a growing tendency for the abuse of common medicines among young people in Korea because they are easily available. Methamphetamine is so seriously abused that fatalities from its overdose have occurred; since 1985, 20 such fatalities have been reported. Many deaths from the abuse of noncontrolled substances, especially dextromethorphan, zipeprol, and carisoprodol, which are taken for their hallucinogenic effects, were also reported. Recently, there was even a fatality related to smuggling of cocaine by body‐packing.

Evaluation of postmortem redistribution phenomena for commonly encountered drugs

We described the findings of a study into the post-mortem redistribution (PMR) of 76 drugs found in 129 drug-related cases between 2006 and 2009. Seventy six drugs (psychotropic drugs (n=14), antidepressants (n=9), sedatives (n=6) and so on) were simultaneously quantified in cardiac and peripheral blood by gas chromatography-mass spectrometry (GC/MS) or liquid chromatography-tandem mass spectrometry (LC/MS/MS). The absence, possibility or presence of PMR of drugs was determined according to the ratios of cardiac to femoral blood concentrations (C/P ratios). Proxyphylline (C/P ratio: 0.85) showed no PMR; carbamazepine was not subject to PMR; a potential for PMR of lorazepam and mirtrazapine cannot be excluded; chlordiazepoxide is subject to PMR; acetaminophen and alprazolam exhibit minimal PMR; amitriptyline and benztropine exhibit PMR. Codeine (C/P ratio: 4.9), zolpidem (C/P ratio: 3.74), chlorpromazine (C/P ratio: 2.97), fluoxetine (C/P ratio: 2.83) and propranolol (C/P ratio: 2.72) had the largest C/P ratios. Postmortem drug concentrations showed variations depending on sampling sites and characteristics of the drugs. It is continuously necessary to analyze commonly used or abused drugs in simultaneously collected cardiac and peripheral blood to establish significant reference values for PMR. These findings can be used to reach a conclusion about the cause and manner of death.

Monitoring of urinary metabolites of JWH-018 and JWH-073 in legal cases

Due to their cannabis-like effects, synthetic cannabinoids have attracted much public attention since 2008. Thus, elucidation of the metabolic pattern and the detection of the intake of these drugs have been of major concern. In order to suggest appropriate urinary biomarkers to prove JWH-018 or JWH-073 intake, we selected the major metabolites of JWH-018 and JWH-073, namely (ω)-, (ω-1)-hydroxy, carboxy and 6-hydroxyindole metabolites, and validated a method for the quantification of these metabolites using solid-phase extraction based on LC-MS/MS analysis. Authentic urine specimens obtained from drug offenders were screened via a synthetic cannabinoid ELISA kit and were analyzed by LC-MS/MS for confirmation. Twenty-one out of a total of 52 samples (40%) were found positive for at least one metabolite of JWH-018 or JWH-073. N-pentyl hydroxy metabolites of JWH-018 and carboxy metabolites of JWH-018 and JWH-073 were detected in all positive samples. However, the rest of the metabolites were either not detected or only a small amount of them were found. A considerable variation was observed in the concentration ratio of (ω) and (ω-1)-hydroxy metabolites of JWH-018. Based on the results, it may have some pitfalls to determine the ingestion of specific synthetic cannabinoids by detecting a few metabolites, considering the continuous emergence of structurally related synthetic cannabinoids. Thus, use of synthetic cannabinoids should be proven carefully through comprehensive investigation of analytical results of biological specimens.

Hair analysis and self-report of methamphetamine use by methamphetamine dependent individuals

The questions of whether the dose of drug that is consumed corresponds to drug concentration levels in hair and how results of hair analyses can be interpreted are still debated. The aim of this study was to investigate (1) whether there is a correlation between doses of Methamphetamine (MA) use and MA concentration levels in hair and (2) whether results of hair analyses can be used to estimate dose, frequency, and patterns of MA use. In this study, segmental hair analysis was performed through consecutive 1cm as well as 1-4 cm (=3 cm) segmental hair lengths. MA dependent individuals (n=9) provided information on doses (0.25-4 g/day) of MA use as well as the frequency of MA use. The concentrations of MA and its metabolite amphetamine (AP) in hair were determined using gas chromatography/mass spectrometry (GC/MS). One-way analysis of variance (ANOVA) test was performed to evaluate whether MA and AP concentrations in consecutive 1cm length segmental hair were consistent with the history of MA use. The cumulative doses of MA use calculated from the daily dose and the frequency during 1-4 months were well correlated to the concentrations of MA and AP in 1-4 cm segmental hair length (correlation coefficient, r=0.87 for MA and r=0.77 for AP). The results from this study show the patterns and histories of MA use from MA dependent individuals and could assist in the interpretation of hair results in forensic toxicology as well as in rehabilitation and treatment programs.

Segmental Hair Analysis for 11-Nor-Δ9-Tetrahydrocannabinol-9-Carboxylic Acid and the Patterns of Cannabis Use

Cannabis is the most widely abused drug in the world. The purpose of this study is to detect 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THCCOOH) in segmental hair and to evaluate the patterns of cannabis use. We investigated the relationship between the concentrations of THCCOOH in hair and the self-reported use data and the route of administration. For this purpose, the hair samples were washed, digested with 1 mL of 1 M NaOH at 85°C for 30 min along with the internal standard, THCCOOH-d₃ (2.5 pg/mg) and extracted in 2 mL of n-hexane-ethyl acetate (9:1) twice after adding 1 mL of 0.1N sodium acetate buffer (pH = 4.5) and 200 µL of acetic acid. The organic extract was transferred and evaporated and the mixture was derivatized with 50 µL of pentafluoropropionic anhydride and 25 µL of pentafluoropropanol for 30 min at 70°C. Reconstituted final extract was injected into the gas chromatography-tandem mass spectrometer operating in the negative chemical ionization mode. In segmental hair analysis, the concentrations of THCCOOH decreased from the proximal to distal segments. The concentrations of THCCOOH in hair and the self-reported dose and frequency of administration from cannabis users were not well correlated because of the low accuracy and reliability of the self-reported data. However, this study provides preliminary information on the dose and frequency of administration among cannabis users in our country.

Simultaneous analysis of Δ9-tetrahydrocannabinol and 11-nor-9-carboxy-tetrahydrocannabinol in hair without different sample preparation and derivatization by gas chromatography–tandem mass spectrometry

The present study describes a gas chromatography/tandem mass spectrometry-negative ion chemical ionization assay (GC/MS/MS-NCI) for simultaneous analysis of Δ(9)-tetrahydrocannabinol (THC) and 11-nor-9-carboxy-tetrahydrocannabinol (THCCOOH) in hair. Each hair sample, of approximately 20mg, was weighed and the sample was dissolved in 1ml of 1M sodium hydroxide (30min at 85°C) in the presence of THC-d(3) and THCCOOH-d(3). For the analysis of THC, hair samples were extracted with n-hexane:ethyl acetate (9:1) two times; acetic acid and sodium acetate buffer were added for the analysis of THCCOOH, and hair samples were re-extracted with n-hexane:ethyl acetate (9:1) two times. The extracts were then derivatized with pentafluoropropionic anhydride (PFPA) and pentafluoropropanol (PFPOH). This method allowed the analysis of THC and THCCOOH using the GC/MS/MS-NCI assay. This method was also fully validated and applied to hair specimens (n=54) collected from known cannabis users whose urine test results were positive. The concentrations of THC and THCCOOH in hair ranged from 7.52 to 60.41ng/mg and from 0.10 to 11.68pg/mg, respectively. In this paper, we simultaneously measured THC and THCCOOH in human hair using GC/MS/MS-NCI without requiring different sample preparation and derivatization procedures. The analytical sensitivity for THCCOOH in hair was good, while that for THC in hair needs to be improved in further study.

Development of an LC–MS/MS method for the simultaneous determination of 25 benzodiazepines and zolpidem in oral fluid and its application to authentic samples from regular drug users

A simple and reliable analytical method was established and validated for the simultaneous determination of 25 benzodiazepines and zolpidem in oral fluid obtained using the Quantisal™ collection device. The samples were prepared by liquid-liquid extraction with ethyl acetate and analyzed using liquid chromatography-tandem mass spectrometry. The validation parameters included limits of detection and quantification (LOD and LOQ), linearity, accuracy and precision, selectivity, recovery, matrix effects and process efficiency. To investigate the variables associated with collection of oral fluid, drug stability and drug recovery in/from the collection device were also determined. The LOD ranged from 0.01 ng/ml to 0.5 ng/ml and the LOQ ranged from 0.1 ng/ml to 0.5 ng/ml. The results of the intra- and inter-day precision and accuracy were satisfactory, i.e., <10% for precision and within ± 10% for accuracy at a low (LOQ of each analyte) and high concentrations (5 ng/ml). In addition, all analytes were stable under the storage condition of below -20°C for 1 month. Drug recoveries from the collection device were more than 80% (81-95%) except those of clonazepam and flunitrazepam, which were unstable in oral fluid. The developed method was successfully applied to authentic oral fluid specimens obtained from psychiatric patients who take benzodiazepines or zolpidem regularly. As a result, alprazolam, clonazepam, diazepam, flunitrazepam, flurazepam, lorazepam, zolpidem and/or their metabolites were detected at 1-18 h after intake of these drugs. This study will be useful for the analysis of oral fluid samples collected in forensic toxicological cases.

Effect of α-tocopherol and deferoxamine on methamphetamine-induced neurotoxicity

Methamphetamine (MA)-induced dopaminergic neurotoxicity is believed to be associated with the increased formation of free radicals. This study examined the effect of alpha-tocopherol (alpha-TC), a scavenger of reactive oxygen species, and deferoxamine (DFO), an iron chelator, on the MA-induced neurotoxicity. Male rats were treated with MA (10 mg/kg, every 2 h for four injections). The rat received either alpha-TC (20 mg/kg) intraperitoneally for 3 days and 30 min prior to MA administration or DFO (50 mg/kg) subcutaneously 30 min before MA administration. The concentrations of dopamine (DA), serotonin and their metabolites decreased significantly after MA administration, which was inhibited by the alpha-TC and DFO pretreatment. alpha-TC and DFO attenuated the MA-induced hyperthermia as well as the alterations in the locomotor activity. The level of lipid peroxidation was higher and the reduced glutathione concentration was lower in the MA-treated rats. These changes were significantly attenuated by alpha-TC and DFO. This suggests that alpha-TC and DFO ameliorate the MA-induced neuronal damage by decreasing the level of oxidative stress.

Effects of repeated hair washing and a single hair dyeing on concentrations of methamphetamine and amphetamine in human hairs

The effects of repeated hair washing and a single hair dyeing on concentrations of methamphetamine (MA) and amphetamine (AM) in hair samples of MA addicts were studied. Thirty-one MA positive hair samples collected from male (n = 24, 24-51 yrs) and female abusers (n = 7, 17-46 yrs) were evaluated for MA and AM concentrations changes after repeated hair washing and a single hair dyeing. Thirty-one MA positive hair samples, no additional treatment hair sample group (NAT), were treated in vitro with liquid soap or three kinds of hair dyes which were black, brown and yellow color hair dye, respectively. Quantitation of AM and MA in hair samples was utilized GC-MS using selected ion monitoring. MA and AM concentrations in NAT were 10.41 ± 8.91 ng/mg (range 1.50-30.0 ng/mg) and 2.24 ± 2.75 ng/mg (range 0.41-12.90 ng/mg). And, their concentrations were decreased about 23.3 ± 4.5% (range 16.7-32.8%) in hair repeated washing group (WAS) and 32.6 ± 4.82 (22.2-41.9) in three kinds of a single hair dyeing groups in comparison to original concentrations of MA and AM in NAT. A statistically significant difference was found between NAT and WAS or three hair dyeing groups (p < 0.01), but not between WAS and three hair dyeing groups, and not between each hair dyeing groups with each three kinds of hair dyes (p > 0.05).