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The number of newly appearing benzodiazepine derivatives on the new psychoactive substances (NPS) drug market has increased over the last couple of years totaling 23 'designer benzodiazepines' monitored at the end of 2017 by the European Monitoring Centre for Drugs and Drug Addiction. In the present study, three benzodiazepines [flunitrazolam, norflurazepam, and 4'-chlorodiazepam (Ro5-4864)] offered as 'research chemicals' on the Internet were characterized and their main in vitro phase I metabolites tentatively identified after incubation with pooled human liver microsomes. For all compounds, the structural formula declared by the vendor was confirmed by gas chromatography-mass spectrometry (GC-MS), liquid chromatography-tandem mass spectrometry (LC MS/MS), liquid chromatography-quadrupole time of flight-mass spectrometry (LC-QTOF-MS) analysis and nuclear magnetic resonance (NMR) spectroscopy. The metabolic steps of flunitrazolam were monohydroxylation, dihydroxylation, and reduction of the nitro function. The detected in vitro phase I metabolites of norflurazepam were hydroxynorflurazepam and dihydroxynorflurazepam. 4'-Chlorodiazepam biotransformation consisted of N-dealkylation and hydroxylation. It has to be noted that 4'-chlorodiazepam and its metabolites show almost identical LC-MS/MS fragmentation patterns to diclazepam and its metabolites (delorazepam, lormetazepam, and lorazepam), making a sufficient chromatographic separation inevitable. Sale of norflurazepam, the metabolite of the prescribed benzodiazepines flurazepam and fludiazepam, presents the risk of incorrect interpretation of analytical findings., (© 2018 John Wiley & Sons, Ltd.)

Benzodiazepines have been introduced as medical drugs in the 1960s. They replaced the more toxic barbiturates, which were commonly used for treatment of anxiety or sleep disorders at the time. However, benzodiazepines show a high potential of misuse and dependence. Although being of great value as medicines, dependence to these drugs is a concern worldwide, in part due to overprescription and easy availability. Therefore, the phenomenon of benzodiazepines sold via Internet shops without restrictions at low prices is alarming and poses a serious threat to public health. Most of these compounds (with the exception of, e.g., phenazepam and etizolam) have never been licensed as medical drugs in any part of the world and are structurally derived from medically used benzodiazepines. Strategies of clandestine producers to generate new compounds include typical structural variations of medically used 1,4-benzodiazepines based on structure-activity relationships as well as synthesis of active metabolites and triazolo analogs of these compounds. As they were obviously designed to circumvent national narcotics laws or international control, they can be referred to as "designer benzodiazepines." The majority of these compounds, such as diclazepam, clonazolam, and nitrazolam, have been described in scientific or patent literature. However, little is known about their pharmacological properties and specific risks related to their use. This chapter describes the phenomenon of designer benzodiazepines and summarizes the available data on pharmacokinetics and pharmacodynamics as well as analytical approaches for their detection.

Since their first appearance on the Internet in 2012, designer benzodiazepines established as an additional, quickly growing compound class among new psychoactive substances. Data regarding pharmacokinetic parameters, metabolism, and detectability for new compounds are limited or often not available. One of these compounds, flubromazolam (8-bromo-6-(2-fluorophenyl)-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine), the triazolo-analogue of flubromazepam, has been offered on the Internet from 2014 on. The purpose of the present study was to assess the period of detectability in biological samples along with preliminary basic pharmacokinetic parameters of the designer benzodiazepine flubromazolam. To investigate these, one of the authors ingested a capsule containing 0.5 mg of the drug. Metabolism studies and suitability tests for the detection with immunochemical assays were performed with the samples obtained from the self-experiment and five authentic case samples. Flubromazolam and its mono-hydroxylated metabolite were detectable by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in urine for up to 6.5 and 8 days, respectively (lower limit of quantification (LLOQ) flubromazolam: 0.1 ng/mL). Peak serum concentrations were as low as 8 ng/mL (8 h post ingestion). Glucuronides were also detected. The terminal elimination half-life could be estimated in the range of 10-20 h. Immunochemical assays yielded negative results for serum samples and positive results for urine samples for up to five days post ingestion. The presented data demonstrate the detectability of a single uptake of 0.5 mg of flubromazolam in hair samples collected two weeks after drug uptake by LC-MS 3 (c max 0.6 pg/mg; LOD 0.01 pg/mg). The detected metabolites were in good agreement with those described in other studies. Copyright © 2017 John Wiley & Sons, Ltd., (Copyright © 2017 John Wiley & Sons, Ltd.)

Designer benzodiazepines represent an emerging class of new psychoactive substances. While other classes of new psychoactive substances such as cannabinoid receptor agonists and designer stimulants are mainly consumed for hedonistic reasons, designer benzodiazepines may also be consumed as 'self-medication' by persons suffering from anxiety or other psychiatric disorders or as stand-by 'antidote' by users of stimulant and hallucinogenic drugs. In the present study, five benzodiazepines (adinazolam, cloniprazepam, fonazepam, 3-hydroxyphenazepam and nitrazolam) and one thienodiazepine (metizolam) offered as 'research chemicals' on the Internet were characterized and their main in vitro phase I metabolites tentatively identified after incubation with pooled human liver microsomes. For all compounds, the structural formula declared by the vendor was confirmed by nuclear magnetic resonance spectroscopy, gas chromatography-mass spectrometry (MS), liquid chromatography MS/MS and liquid chromatography quadrupole time-of-flight MS analysis. The detected in vitro phase I metabolites of adinazolam were N-desmethyladinazolam and N-didesmethyladinazolam. Metizolam showed a similar metabolism to other thienodiazepines comprising monohydroxylations and dihydroxylation. Cloniprazepam was metabolized to numerous metabolites with the main metabolic steps being N-dealkylation, hydroxylation and reduction of the nitro function. It has to be noted that clonazepam is a metabolite of cloniprazepam, which may lead to difficulties when interpreting analytical findings. Nitrazolam and fonazepam both underwent monohydroxylation and reduction of the nitro function. In the case of 3-OH-phenazepam, no in vitro phase I metabolites were detected. Formation of licensed benzodiazepines (clonazepam after uptake of cloniprazepam) and the sale of metabolites of prescribed benzodiazepines (fonazepam, identical to norflunitrazepam, and 3-hydroxyphenazepam) present the risk of incorrect interpretation of analytical findings. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

Designer benzodiazepines, first offered in online shops selling 'research chemicals' in 2012, provide an attractive alternative to prescription-only benzodiazepines as they are readily available over the Internet at a low price. However, as data regarding pharmacokinetic parameters, metabolism, and detectability in biological fluids are limited, they present a challenge for forensic laboratories. Most recently, diclazepam (other names: 2-chlorodiazepam, Ro 5-3448 or 7-chloro-5-(2-chlorophenyl)-1-methyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one) emerged as a new compound in this class of drugs. In this paper, this new designer benzodiazepine was characterized utilizing nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS) as well as liquid chromatography tandem mass spectrometry (LC-MS/MS) techniques. Furthermore, a self-experiment was performed to gain preliminary data on pharmacokinetic properties and to identify the main metabolites. For this purpose, one tablet of diclazepam (declared amount: 1 mg) was ingested by one of the authors, and serum as well as urine samples were collected for 14 and 21 days, respectively. Based on this study, diclazepam has an approximate elimination half-life of 42 h and is metabolized into the pharmacologically active benzodiazepines delorazepam, lorazepam, and lormetazepam which can be detected in urine for 6, 19, and 11 days, respectively, when applying the presented LC-MS/MS method. In serum, the consumption could be proven between 99 h post-intake targeting the parent compound and up to 10 days targeting the metabolite delorazepam. As immunochemical assays are applied for screening purposes quite often, detectability using this technique was assessed, especially since detection of low-dosed benzodiazepines can be sometimes problematic. However, only one of the utilized immunochemical assays was capable of detecting the intake of one tablet diclazepam, and the positive results were restricted to a few urine samples showing relatively high creatinine concentrations., (Copyright © 2014 John Wiley & Sons, Ltd.)

The appearance of pyrazolam in Internet shops selling 'research chemicals' in 2012 marked the beginning of designer benzodiazepines being sold as recreational drugs or 'self medication'. With recent changes in national narcotics laws in many countries, where two uncontrolled benzodiazepines (phenazepam and etizolam), which were marketed by pharmaceutical companies in some countries, were scheduled, clandestine laboratories seem to turn to poorly characterized research drug candidates as legal substitutes. Following the appearance of pyrazolam, it comes with no surprise that recently, flubromazepam (7-bromo-5-(2-fluorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one), a second designer benzodiazepine, was offered on the market. In this article, this new compound was characterized using nuclear magnetic resonance, gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS/MS) and liquid chromatography quadrupole time-of-flight MS (LC-Q-ToF-MS). Additionally, a study was carried out, in which one of the authors consumed 4 mg of flubromazepam to gain preliminary data on the pharmacokinetic properties and the metabolism of this compound. For this purpose, serum as well as urine samples were collected for up to 31 days post-ingestion and analyzed applying LC-MS/MS and LC-Q-ToF-MS techniques. On the basis of this study, flubromazepam appears to have an extremely long elimination half-life of more than 100 h. One monohydroxylated compound and the debrominated compound could be identified as the predominant metabolites, the first allowing a detection of a consumption for up to 28 days post-ingestion when analyzing urine samples in our case. Additionally, various immunochemical assays were evaluated, showing that the cross-reactivity of the used assay seems not to be sufficient for safe detection of the applied dose in urine samples, bearing the risk that it could be misused in drug-withdrawal settings or in other circumstances requiring regular drug testing. Furthermore, it may be used in drug-facilitated crimes without being detected., (Copyright © 2013 John Wiley & Sons, Ltd.)

Aminoalkylindoles, a subclass of synthetic cannabinoid receptor agonists, show an extensive and complex metabolism in vivo, and due to their structural similarity, they can be challenging in terms of unambiguous assignment of metabolic patterns in urine samples to consumed substances. The situation may even be more complicated as these drugs are usually smoked, and the high temperature exposure may lead to formation of artifacts. Typical metabolites of JWH-018 (Naphthalen-1-yl(1-pentyl-1H-indol-3-yl)methanone) were reportedly detected not only in urine samples collected after consumption of JWH-018 but also after AM-2201 (1-(5-fluoropentyl-1H-indol-3-yl)-(naphthalene-1-yl)methanone) use. The aim of the presented study was to evaluate if typical JWH-018 metabolites can be formed metabolically in humans and if JWH-018 may be formed artifactually during smoking of AM-2201. Therefore, one of the authors ingested 5 mg of pure AM-2201, and serum as well as urine samples were analyzed subsequently. Additionally, the smoke condensate from a cigarette laced with pure AM-2201 was investigated. In addition, urine samples of patients after known consumption of AM-2201 or JWH-018 were evaluated. The results of the study prove that typical metabolites of JWH-018 and JWH-073 are built in humans after ingestion of AM-2201. However, the N-(4-hydroxypentyl) metabolite of JWH-018, which is the major metabolite after JWH-018 use, was not detected after the self-experiment. In the smoke condensate, small amounts of JWH-018 and JWH-022 (Naphthalen-1-yl[1-(pent-4-en-1-yl)-1H-indol-3-yl]methanone) were detected. Nevertheless, the results of our study suggest that the amounts absorbed by smoking do not significantly influence the metabolic pattern in urine samples. Therefore, the N-(4-hydroxypentyl) metabolite of JWH-018 can serve as a valuable marker to distinguish consume of products containing AM-2201 from JWH-018 use., (Copyright © 2013 John Wiley & Sons, Ltd.)

In the age of the Internet, the variety of drugs offered online is constantly increasing, and new drugs emerge every month. One group of drugs showing such an enormous increase is that of synthetic cannabinoids. Since their first identification in 'herbal mixtures', new structural modifications continue to appear on the market. In order to keep up with this process, toxicological screening methods need to be up to date. This can become extremely difficult if no reference material is available. In this article, a fast and effective way to extract and purify synthetic cannabinoids from 'herbal mixtures' is presented. This method opens a new opportunity for a timely reaction by obtaining reference material straight out of the 'herbal mixtures' ordered via the Internet. Isolation was carried out on a flash chromatography system with gradient elution on a C18 column using methanol and 0.55 % formic acid as mobile phases. The obtained purity of all compounds exceeded 99 %. In addition to the isolation of single compounds, the method proved to be suitable for the separation of various synthetic cannabinoids in one mixture, including the diastereomers cis- and trans-CP-47,497-C8. This approach for obtaining pure standards of new drugs proved to be effective, inexpensive and much quicker than waiting for the substances to be commercially available as reference material.