Targeted analysis of 116 drugs in hair by UHPLC-MS/MS and its application to forensic cases

Uncovering forensic evidence of drug-facilitated sexual assault: Toxicological findings from Eastern Denmark from 2015-2022

In drug-facilitated sexual assault (DFSA), the victim is unable to provide consent or resists sexual activity due to substance intoxication by voluntary or covert consumption. Obtaining forensic evidence of the assault is challenged by rapid drug metabolism and late sample collection. The objective of this study was to present toxicological findings and associated demographics from police reported sexual assault cases in Eastern Denmark from 2015 to 2022. A total of 369 sexual assault cases were submitted for analysis and a subgroup of 268 cases were categorized as suspected DFSA cases. The majority of the total sexual assault victims were women at the age 15-25 and the perpetrators were often unknown or an acquaintance. Time from assault to sample collection was slightly longer for suspected DFSA cases (12-24 h) compared to non-DFSA (<12 h). Positive toxicology was observed in 86 % of cases and the most common drug groups included alcohol (45 %), drugs of abuse (38 %), antidepressants (14 %), antihistamines (12 %), and benzodiazepines (11 %). Hypnotics were detected to a smaller extent (7 %). A total of 77 drugs were detected and the most commonly observed were cocaine, tetrahydrocannabinol (THC), cetirizine, amphetamine, diazepam and sertraline. The high level of observed alcohol and drugs of abuse indicated that most DFSA cases in Eastern Denmark were of an opportunistic approach rather than proactive.

Determination of ten antipsychotics in blood, hair and nails: Validation of a LC-MS/MS method and forensic application of keratinized matrix analysis

Determination of antipsychotics from biological samples is meaningful in the field of clinical and forensic medicine. Compared to blood, keratinized matrices such as hair and nails have attracted increasing attention in drug analysis for wider detection window. Nevertheless, the distribution and stability of antipsychotics in keratinized matrices are not clarified yet. Therefore, we developed a LC-MS/MS based method for simultaneous determination of 10 antipsychotics from blood, hair and nails, with high recovery (78.1-107.4%, 71.3-93.5% and 75.2-90.5%), low LOD (5-10 pg/mL, 5-10 pg/mg and 5 pg/mg) and high accuracy (96.0%-101.6%, 97.5%-102.5% and 97.6-101.7%). The method was applied to sets of blood, hair, and nail samples of 54 patients who received long-term therapy, and significant correlations between drug concentrations in blood and hair was found, while the correlation between nails and other matrices varied depending on the drug. Except for olanzapine, the concentrations of antipsychotics in segmental hair samples were consistent with drug exposure. Besides, the hair and nail samples of suspects in two forensic cases were analyzed and provided supporting evidence for the suspects' psychiatric state. Our research offered a deeper understanding of keratinized matrix as stable and retrospective bio-samples for antipsychotics detection in forensic practice.

Detection of scopolamine in urine and hair in a drug-facilitated sexual assault

The use of the drug scopolamine in drug-facilitated crimes is known. Nevertheless, given the high potency of the drug and its rapid metabolism, analysis in blood and urine may not be sufficient for drug detection in late crime declaration, especially following a single-dose administration in drug-facilitated sexual assault (DFSA) cases. Hair may constitute an essential supplemental matrix extending the drug detection window in such cases. This case report presents quantitative data on scopolamine findings in urine and hair in a DFSA case. A young female had consumed several alcoholic drinks at a party venue when her behaviour became noticeably peculiar. Later, she woke up next to an unknown man and had no recollection of the night's events. Blood and urine samples were collected 18 h after the incident. The initial toxicological target screening using UHPLC-TOF-MS detected scopolamine in the hydrolysed urine sample, and quantification yielded 41 µg/L scopolamine in urine, while blood was negative. Segmental hair analysis using multitarget UHPLC-MS/MS was performed on three washed 2-cm segments of hair collected five weeks after the incident, yielding 0.37 pg/mg scopolamine only in the relevant hair segment. This case report provides novel insight into the concentration in hair following a single exposure of scopolamine and the feasibility of detecting scopolamine in hair by comparison to published toxicological findings.

Concentrations of citalopram and escitalopram in postmortem hair segments

Hair analysis can provide information regarding previous drug intake and use patterns, as the drugs consumed are incorporated into the hair. Therefore, reference values for drugs in hair are valuable in forensic investigations, especially when evaluating drug intake and assessing drug tolerance. The aim of the study was to determine concentrations of citalopram, escitalopram, and their primary metabolites in hair segments from deceased individuals with mental illness. Concentrations in up to six months prior to death were evaluated and compared with the estimated daily doses. Hair samples collected from 47 deceased individuals, were segmented in one to six 1 cm segments, and extracted overnight in medium. The concentrations in hair were quantified via ultra-high-performance liquid chromatography-tandem mass spectrometry. Following this quantification, the extracts were reanalyzed qualitatively using a chiral method to distinguish between citalopram and escitalopram intake. We found hair concentrations (10-90 percentile (perc.)) of citalopram from 0.12 to 67 ng/mg with a median of 8.2 ng/mg (N = 40 individuals, n = 182 segments) and of escitalopram from 0.027 to 7.0 ng/mg with a median of 3.9 ng/mg (N = 4, n = 23). The metabolite-to-drug ratios in hair (10-90 perc.) of citalopram were 0.091-0.57 with a median of 0.30 (N = 39) and of escitalopram were 0.053-0.63 with a median of 0.41 (N = 3). No correlations were found between concentrations in the hair and the estimated daily dose. However, our results indicate higher concentrations in dark hair compared to light hair, given the estimated doses, and thus an influence of hair color on the results. A significant positive correlation was found between the concentration of citalopram in the proximal segment and the blood concentrations. The median R/S-ratio of citalopram in hair was 1.5 and was similar to previously reported ratios in blood. In the present study, we report concentrations of citalopram and escitalopram in postmortem hair and their relation to an estimated daily dose and thus contribute valuable information in forensic investigations.

A Systematic Review of Metabolite-to-Drug Ratios of Pharmaceuticals in Hair for Forensic Investigations

After ingestion, consumed drugs and their metabolites are incorporated into hair, which has a long detection window, ranging up to months. Therefore, in addition to conventional blood and urine analyses, hair analysis can provide useful information on long-term drug exposure. Meta-bolite-to-drug (MD) ratios are helpful in interpreting hair results, as they provide useful information on drug metabolism and can be used to distinguish drug use from external contamination, which is otherwise a limitation in hair analysis. Despite this, the MD ratios of a wide range of pharmaceuticals have scarcely been explored. This review aims to provide an overview of MD ratios in hair in a range of pharmaceuticals of interest to forensic toxicology, such as antipsychotic drugs, antidepressant drugs, benzodiazepines, common opiates/opioids, etc. The factors influencing the ratio were evaluated. MD ratios of 41 pharmaceuticals were reported from almost 100 studies. MD ratios below 1 were frequently reported, indicating higher concentrations of the parent pharmaceutical than of its metabolite in hair, but wide-ranging MD ratios of the majority of pharmaceuticals were found. Intra- and interindividual differences and compound properties were variables possibly contributing to this. This overview presents guidance for future comparison and evaluation of MD ratios of pharmaceuticals.

A Comprehensive Multi-Analyte Method for Hair Analysis: Substance-Specific Quantification Ranges and Tool for Task-Oriented Data Evaluation

The aim of the present study was to quantify a large number of analytes including opioids, stimulants, benzodiazepines, z-drugs, antidepressants and neuroleptics within a single sample workup followed by a single analytical measurement. Expected drug concentrations in hair are strongly substance dependent. Therefore, three different calibration ranges were implemented: 0.5 to 600 pg/mg (group 1), 10 to 12,000 pg/mg (group 2) and 50 to 60,000 pg/mg (group 3). In order to avoid saturation effects, different strategies were applied for selected transitions including the use of parent mass ions containing one or two 13C-isotopes and detuning of the declustering potential and/or collision energy. Drugs were extracted from pulverized hair by a two-step extraction protocol and measured by liquid chromatrography--tandem mass spectrometry (LC--MS-MS) using Scheduled MRM™ Algorithm Pro. In total, 275 MRM transitions including 43 deuterated standards were measured. The method has been fully validated according to international guidelines. A MultiQuant™ software based tool for task-oriented data evaluation was established, which allows extracting selected information from the measured data sets. The matrix effects and recoveries were within the allowed ranges for the majority of the analytes. The lower limits of quantification (LLOQs) were for ∼72% of the analytes in the low-pg/mg range (0.5-5 pg/mg) and for ∼24% of the analytes between 10 and 50 pg/mg. These LLOQs considered cut-offs by the Society of Hair Testing (SoHT), if recommended. The herein established multi-analyte approach meets the specific requirements of forensic hair testing and can be used for the rapid and robust measurement of a wide range of psychoactive substances. The analyte-specific wide concentration ranges open up a wide field of applications.

The development and validation of a sensitive HPLC-MS/MS method for the quantitative and pharmacokinetic study of the seven components of Buddleja lindleyana Fort

Buddleja lindleyana Fort., a traditional Chinese medicine, has demonstrated anti-inflammatory, immunomodulatory, antidementia, neuroprotective, antibacterial, and antioxidant effects. Its flowers, leaves, and roots have been used as traditional Chinese medicines. A simple and rapid high-performance liquid chromatography method coupled with mass spectrometry (HPLC-MS/MS) was applied in the multicomponent determination of Buddleja lindleyana Fort., and the discrepancies in the contents from ten different habitats were analyzed. The present study simultaneously determined the concentrations of seven chemical compounds of Buddleja lindleyana Fort. extract in rat plasma via HPLC-MS/MS, which was applied in the pharmacokinetic (PK) study of Buddleja lindleyana Fort. A C18 column was used for chromatographic separation, and ion acquisition was achieved by multiple-reaction monitoring (MRM) in negative ionization mode. The optimized mass transition ion-pairs (m/z) for quantization were 591.5/282.8 for linarin, 609.4/300.2 for rutin, 284.9/133.0 for luteolin, 300.6/151.0 for quercetin, 268.8/116.9 for apigenin, 283.0/267.9 for acacetin, 623.3/160.7 for acteoside, and 252.2/155.8 for sulfamethoxazole (IS). A double peak appeared in the drug–time curve of apigenin, which was associated with entero-hepatic recirculation. There were discrepancies in the contents of seven chemical compounds from 10 batches of Buddleja lindleyana Fort., which were associated with the growth environments. Herein, the pharmacokinetic parameters of seven analytes in Buddleja lindleyana Fort. extract are summarized. The maximum plasma concentration (C_max) of linarin, rutin, luteolin, quercetin, apigenin, acacetin and acteoside were 894.12 ± 9.34 ng mL⁻¹, 130.76 ± 18.33 ng mL⁻¹, 77.37 ± 25.72 ng mL⁻¹, 20.15 ± 24.85 ng mL⁻¹, 146.42 ± 14.88 ng mL⁻¹, 31.92 ± 17.58 ng mL⁻¹, and 649.78 ± 16.42 ng mL⁻¹, respectively. The time to reach C_max for linarin, rutin, luteolin, quercetin, apigenin, acacetin, and acteoside were 10, 5, 5, 5, 180, 10 and 10 min, respectively. This is the first report on the simultaneous determination of seven active components for 10 different growing environments and the pharmacokinetic studies of seven active components in rat plasma after the oral administration of Buddleja lindleyana Fort. extract. This study lays the foundation for a better understanding of the absorption mechanism of Buddleja lindleyana Fort., and the evaluation of its clinical application.

Quality control and pharmacokinetics of Buddleja lindleyana Fort by HPLC-MS/MS.

Incorporation of five common hypnotics into hair after a single dose and application to a forensic case of drug facilitated crimes

In order to obtain fundamental information on the disposition of hypnotics into hair after a single oral dose the quantitative hair analysis of triazolam (TZ), etizolam (EZ), flunitrazepam (FNZ), nitrazepam (NZ) and zolpidem (ZP) have been performed using a validated LC-MS/MS procedure. Hair specimens (straight, black) were collected from three subjects about one month and three months after a single 0.25 mg dose of TZ, 1 mg of EZ, 2 mg of FNZ, 5 mg of NZ and 10 mg of ZP tartrate. The subjects ingested just one out of five different hypnotics on each day, each of five days in turn. All ingested hypnotics have been detected in hair from each subject both one month and three months after intake, and their concentrations were in the range of 0.023-0.043 pg/hair strand (0.077-0.36 pg/mg) for TZ, 0.11-0.63 pg/hair strand (0.44-5.2 pg/mg) for EZ, 0.14-2.6 pg/hair strand (0.56-22 pg/mg) for FNZ, 0.33-1.7 pg/hair strand (1.3-17 pg/mg) for NZ and 20-40 pg/hair strand (120-270 pg/mg) for ZP. For FNZ and NZ, not only the parent drugs but also their metabolites, 7-amino-FNZ and 7-amino-NZ, were detected in the range of 2.3-9.2 pg/hair strand (9.2-82 pg/mg) and 2.4-9.1 pg/hair strand (8.0-55 pg/mg), respectively. The calculated incorporation ratios into hair against the dose were found to exhibit similarity between the four benzodiazepines. This finding suggests the ability to apply these quantitative data to approximately estimating the amounts of other benzodiazepines, which have similar chemical structures, in hair although it should be noted that the amounts of drugs in hair varies considerably depending on the hair color. On the other hand, the incorporation ratio of ZP showed 15-29 times higher than that of TZ, indicating that lipophilic ZP was more likely to incorporate into hair than benzodiazepines. In addition, the application of the present data to a drug-facilitated sexual assault was shown.

Segmental hair analysis for flunitrazepam and 7-aminoflunitrazepam in users: a comparison to existing literature

The availability of more quantitative data on flunitrazepam (FLU) and 7-aminoflunitrazepam (7AF) would aid in obtaining a better understanding of the interpretation of FLU concentrations in human hair. The purpose of this study was to provide concentrations of FLU and 7AF in hair segments of 22 FLU users. Quantitative data regarding hair concentrations of FLU and 7AF from various types of cases were also reviewed to give a comprehensive overview of the comparability of different studies. Three to six 1 cm segments of scalp hair from 22 FLU users were analyzed by a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method. FLU and its metabolite were confirmed in the hair segments from all cases. Concentrations of FLU and 7AF in the segments ranged from 0.01–0.16 ng/mg (median of 0.03) and 0.01–0.34 ng/mg (median of 0.09), respectively. Most cases had FLU and 7AF distributions along the hair segments that were suggestive of repeated drug use. A summary of the published concentrations gives valuable data and can assist forensic investigators in their estimations of drug use history and patterns.

Key points

A method using LC–MS/MS to quantify flunitrazepam and its metabolite was described.

Segmental analysis of flunitrazepam and its metabolite in human hair was reported.

A comprehensive overview of quantitative data was given.

Concentrations of aripiprazole and dehydroaripiprazole in hair segments from deceased individuals with mental disorders

Segmental hair analysis provides information regarding previous long-term drug exposure, which is useful in the evaluation of cause of death for individuals with mental disorders. The aim was to analyze postmortem concentrations of the antipsychotic drug aripiprazole and its active metabolite dehydroaripiprazole in hair segments from individuals with known aripiprazole intake. Hair samples were collected during autopsy. Each sample was segmented into one to six 1cm segments, depending on the length of the hair shaft. Pulverized hair was extracted and analyzed using a previously published ultra-high-performance liquid chromatography-tandem mass spectrometric method. The 10th-90th percentile of aripiprazole concentrations in all hair segments (n=78) from 17 individuals were 0.024ng/mg-11ng/mg with a median of 2.3ng/mg, and the 10th-90th percentile concentrations of dehydroaripiprazole were 0.020ng/mg-11ng/mg, with a median of 2.6ng/mg, in all hair segments (n=71). The metabolite-to-parent drug ratios ranged from 0.21 to 1.5, with a median of 0.72. The administered doses were calculated for each individual based on aripiprazole prescription data and pharmacy pickups, giving dose estimates of 1mg-32mg daily. A positive significant correlation was observed between concentrations in hair and blood, whereas no trends were observed between the concentrations in hair and the estimated doses. Besides aripiprazole, other antipsychotic drugs were found in several hair segments, indicating a high degree of polypharmacy among all subjects. The present study establishes concentrations of aripiprazole and dehydroaripiprazole in hair segments from 17 deceased individuals with long-term aripiprazole use. In addition, hair analysis demonstrates the possibility of evaluating polypharmacy.

Segmental hair analysis of olanzapine and N-desmethyl-olanzapine in postmortem hair from mentally ill patients by LC-MS/MS

Hair analysis is a useful tool for establishing long-term drug intake. Segmental analysis, in particular, where the hair is cut into defined segments, can potentially provide a calendar of patients' drug intake as drugs are incorporated into the growing hair through the bloodstream with an average growth rate of 1 cm per month. Forensic investigations of hair require knowledge of typical concentrations of common pharmaceuticals in hair, which are rarely reported. The aim of this study was to provide values for olanzapine and N-desmethyl-olanzapine concentrations in postmortem hair from chronic olanzapine consumers to contribute to the establishment of a reference interval for this drug. We analyzed postmortem head hair samples from 37 suspected mentally ill patients, who were part of the SURVIVE population, a Danish national autopsy-based study. Each sample was cut into 1 cm segments, and up to six segments, corresponding to up to six months of hair growth prior to death, were analyzed depending on the hair length. The hair extracts were analyzed by liquid chromatography tandem mass spectrometry. Olanzapine and N-desmethyl-olanzapine were added to a published and validated method. The 37 patients were 12 females and 25 males aged 25-81 years. Their hair colors varied from blond to black, with the majority brown, thus no trend could be discerned from the hair colors. Drugs other than olanzapine were found in all cases except one, and illicit drugs were found in the hair samples of 38 % of the cases. We report olanzapine concentrations ranging from 0.005-20.9 ng/mg (median 0.128 ng/mg) and N-desmethyl-olanzapine concentrations from 0.027 to 0.187 ng/mg (median 0.068 ng/mg) for all 141 analyzed segments. Metabolite-to-drug ratios ranged from 0.010 to 3.31 (median 0.590). Dose calculations based on prescription pick-up demonstrated no correlation with the concentrations in hair, but olanzapine concentrations in the proximal hair segment correlated significantly with olanzapine concentrations in postmortem blood. Olanzapine concentrations decreased considerably from the proximal to distal segments, emphasizing the importance of reporting the length of the measured hair when reporting drug concentrations in hair. This study can contribute to the establishment of a reference interval for olanzapine and N-desmethyl-olanzapine concentrations in hair by reporting concentrations in hair from chronic consumers.

Concentrations of Antidepressants, Antipsychotics, and Benzodiazepines in Hair Samples from Postmortem Cases

Certain postmortem case constellations require intensive investigation of the pattern of drug use over a long period before death. Hair analysis of illicit drugs has been investigated intensively over past decades, but there is a lack of comprehensive data on hair concentrations for antidepressants, antipsychotics, and benzodiazepines. This study aimed to obtain data for these substances. A LC-MS/MS method was developed and validated for detection of 52 antidepressants, antipsychotics, benzodiazepines, and metabolites in hair. Hair samples from 442 postmortem cases at the Institute of Legal Medicine of the Charité-University Medicine Berlin were analyzed. Postmortem hair concentrations of 49 analytes were obtained in 420 of the cases. Hair sample segmentation was possible in 258 cases, and the segments were compared to see if the concentrations decreased or increased. Descriptive statistical data are presented for the segmented and non-segmented cases combined (n = 420) and only the segmented cases (n = 258). An overview of published data for the target substances in hair is given. Metabolite/parent drug ratios were investigated for 10 metabolite/parent drug pairs. Cases were identified that had positive findings in hair, blood, urine, and organ tissue. The comprehensive data on postmortem hair concentrations for antidepressants, antipsychotics, and benzodiazepines may help other investigators in their casework. Postmortem hair analysis results provide valuable information on the drug intake history before death. Pattern changes can indicate if drug intake stopped or increased before death. Results should be interpreted carefully and preferably include segmental analysis and metabolite/parent drug ratios to exclude possible contamination.

Ketamine analogues: Comparative toxicokinetic in vitro-in vivo extrapolation and quantification of 2-fluorodeschloroketamine in forensic blood and hair samples

Recently, the new psychoactive substance (NPS) ketamine analogue 2-fluoro-deschloroketamine (2FDCK) was observed in driving-under-the-influence-of-drugs whole blood samples and in a forensic hair investigation case in Denmark. The molecular structure variations among the NPS subgroups may alter the metabolic fate and drug potency, thereby posing a threat for drug users. This study reports quantification of 2FDCK in whole blood samples and forensic hair and compares the following toxicokinetic parameters: unbound fraction (f_u) and in vitro-in vivo-extrapolation (IVIVE) of hepatic clearance for ketamine, norketamine, 2FDCK, methoxetamine and deschloroketamine. The f_u was investigated with ultrafiltration, while clearance studies were conducted at 1 μM with pooled human liver microsomes. Samples were analysed by liquid chromatography and mass spectrometry. For the first time, 2FDCK was determined in a concentration range between 0.005 and 0.48 mg/kg in blood samples. Segmental hair analysis demonstrated 2FDCK at concentrations from 0.007 to 0.034 ng/mg throughout the three investigated segments. Toxicokinetic comparison of the five compounds gave a f_u between 0.54 and 0.84, with ketamine being the most bound and deschloroketamine being the least bound, in accordance with the logP of the compounds. Conversely, a negative correlation was observed between the molecular weight of the halogen in the ortho-position and IVIVE hepatic clearance. The IVIVE of hepatic clearance, CL_{parallel-tube}, gave values from 18.1 to 5.44 mL/min/kg for ketamine and methoxetamine, respectively. The deschloroketamine IVIVE was disregarded due to low drug elimination under the experimental conditions used. This study provides a basis for toxicokinetic understanding of ketamine analogues.

Ultrahigh-performance liquid chromatography coupled with triple quadrupole and time-of-flight mass spectrometry for the screening and identification of the main flavonoids and their metabolites in rats after oral administration of Cirsium japonicum DC. extract

RATIONALE

Cirsium japonicum DC., a traditional Chinese medicine, has been shown to have anti-haemorrhagic and anti-tumour effects. Pharmacological studies have demonstrated that this curative effect may be related to flavonoids. The present work aimed to screen and identify the main flavonoids and their corresponding metabolites in rats after oral administration of Cirsium japonicum DC. extract.

METHODS

A rapid and simple method based on ultrahigh-performance liquid chromatography coupled with triple quadrupole and time-of-flight mass spectrometry (UHPLC/QTOF-MS) was developed for the identification of the primary absorbing components and metabolites of the principal flavonoids. The absorbing components were first characterized, followed by the selection of representative constituents. In this study, the main flavonoids, pectolinarin, linarin and pectolinarigenin, were selected as templates to identify possible metabolites.

RESULTS

A total of 27 metabolites were detected in rat blood, urine and bile samples. A hydrolysis reaction was the first step for pectolinarin and linarin, followed by oxidation and reduction reactions. However, phase II metabolites for pectolinarin and linarin were not detected. The primary biotransformation routes of pectolinarigenin were identified as oxidation, reduction, hydrolysis, and glucuronide and glucose conjugation.

CONCLUSIONS

The metabolic pathways of pectolinarin, linarin and pectolinarigenin were summarized. This study not only proposed a practical strategy for rapidly screening and identifying metabolites but also provided useful information for further pharmacological studies and the design of new drugs based on Cirsium japonicum DC.

Hair analysis in toxicological investigation of drug-facilitated crimes in Denmark over a 8-year period

Hair can serve as a specimen for identifying past drug exposure. Segmental hair analysis may differentiate a single exposure from chronic use. Consequently, segmental hair analysis is useful for disclosing a single drug ingestion, as well as for determining repeated exposures in drug-facilitated crimes (DFCs). This paper presents an overview of toxicological investigations that have used hair analysis in DFC cases from 2009 to 2016 in Denmark. Hair concentrations were determined for 24 DFC-related drugs and metabolites, including benzodiazepines and other hypnotics, antihistamines, opioid analgesics, antipsychotics, barbiturates, and illicit drugs from DFC cases. Drug detection in hair in DFC cases following a single or few intakes of chlorprothixene, codeine, diphenhydramine, oxazepam, oxycodone, promethazine, and phenobarbital is reported for the first time in forensic toxicology. A literature review on concentrations in the published DFC-related hair cases and on concentrations in hair of these substances after single and multiple doses is included. These cases demonstrate the value of segmental hair analysis in DFCs and facilitate future interpretations of results.

GC-MS/MS detects potential pregabalin abuse in susceptible subjects' hair

Pregabalin, a GABA analogue, binds to the alpha 2 delta subunit of voltage-dependent calcium channels. It is recognised as efficacious in pathologies such as epilepsy, neuropathic pain, and anxiety disorders. Since pregabalin prescriptions have increased worldwide, reports of its abuse have been accumulating, mainly in patients with opioid abuse disorders. The present study investigated potential pregabalin abuse by means of hair analysis, a matrix that provides valuable retrospective information. Half of the pool of 280 susceptible patients had been occasional drug users and were being monitored for driving licence renewals. The other 140 patients had a history of opiate dependency and were monitored to assess compliance with methadone therapy. In view of determining pregabalin in hair samples, it was extracted in methanol, successfully derivatised to give the ethyl chloroformate derivative, and finally pregabalin was analysed by gas chromatography-tandem mass spectrometry. Selectivity, linearity, limit of detection, limit of quantification, recovery, intra- and inter-day precision, and accuracy of the quantification procedure were appraised. Pregabalin limits of detection and quantification were 30 pg/mg and 50 pg/mg, respectively. We found 10.7% of hair samples from methadone patients and 4.29% from occasional drug users were positive to pregabalin without medical prescription. The mean pregabalin concentration in hair was higher than in consumers with medical indications (1.45 ng/mg vs 0.74 ng/mg). These results suggest that pregabalin possesses a significant abuse potential particularly among individuals attending opiate dependence services and that pregabalin abuse is a serious emerging issue, which should be carefully monitored.

Identification of metabolites of liquiritin in rats by UHPLC-Q-TOF-MS/MS: metabolic profiling and pathway comparisonin vitroandin vivo

Liquiritin (LQ), the main bioactive constituent of licorice, is a common flavoring and sweetening agent in food products and has a wide range of pharmacological properties, including antidepressant-like, neuroprotective, anti-cancer and anti-inflammatory properties. This study investigated the metabolic pathways of LQ in vitro (rat liver microsomes) and in vivo (rat model) using ultra high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). Moreover, supplementary tools such as key product ions (KPIs) were employed to search for and identify compounds. As a result, 56 in vivo metabolites and 15 in vitro metabolites were structurally characterized. Oxidation, reduction, hydrolysis, methylation, acetylation, and sulfate and glucuronide conjugation were determined to be the major metabolic pathways of LQ, and there were differences in LQ metabolism in vitro and in vivo. In addition, the in vitro and in vivo metabolic pathways were compared in this study.

Liquiritin (LQ), the main bioactive constituent of licorice, is a common flavoring and sweetening agent in food products and has a wide range of pharmacological properties, including antidepressant-like, neuroprotective and anti-cancer properties.