Benzodiazepines in complex biological matrices: Recent updates on pretreatment and detection methods

Benzodiazepines(BDZs)are used in clinics for anxiolysis,anticonvulsants,sedative hypnosis,and muscle relaxation.They have high consumptions worldwide because of their easy availability and potential addiction.They are often used for suicide or criminal practices such as abduction and drug-facilitated sexual assault.The pharmacological effects of using small doses of BDZs and their detections from complex biological matrices are challenging.Efficient pretreatment methods followed by accurate and sensitive detections are necessary.Herein,pretreatment methods for the extraction,enrichment,and preconcentration of BDZs as well as the strategies for their screening,identification,and quantitation developed in the past five years have been reviewed.Moreover,recent advances in various methods are summarized.Characteristics and advantages of each method are encompassed.Future directions of the pretreatment and detection methods for BDZs are also reviewed.

Pilot Studies on the Novel Hypothesis that TSPO (Peripheral Benzodiazepine Receptor) Is Involved in Benzodiazepine/“Z-Drug” Physical Dependence and/or Withdrawal

Benzodiazepines and other benzodiazepine receptor agonists, such as the “Z” drugs, are widely prescribed medications mainly used for treating anxiety and seizures, and for inducing sedation. Unfortunately, despite their popularity, benzodiazepine prescribing often exceeds recommendations and the consequences can be severe. On September 23, 2020, the United States FDA announced a new requirement for a Boxed Warning for benzodiazepines prescribing. Along with this announcement, the FDA stated that relevant information regarding the initiation, continuation, and discontinuation of benzodiazepines is lacking. Here, we describe initial pilot studies intended to investigate the questions 1) can animal models be developed that demonstrate benzodiazepine physical dependence and/or withdrawal symptoms, and 2) determine whether translocator protein (TSPO) plays a role in benzodiazepine dependence and/or withdrawal processes. The former was demonstrated, methodological limitations prevented the latter.

NEW HETEROCYCLIC SYSTEM SYNTHESIS VI． THE CYCLOADDITION DERIVATIVES OF 1，5－BENZOTHIAZEPINE AND 1，5－BENZODIAZEPINE

Dihydro-1H-1, 5-benzodiazepines and 1-benzoy1-2, 3-dihydro-1H-1H-1,5-benzodiazepines react with .α-carbonylkelenes, generated from 2-diazo-1,3-diphenyl-1,3-propandione or 2-diazo-1-phenyl-1,3-butandione by heating, to give 4a,5, 6, 12-letralydro- 1H,7H-1,3-oxazino[3,2-d][1,5]-benzodiazepine-1-ones,a new ring system. 2, 3-Dihydro-1H-1,5-benzodiazepines also afford,dducts of H-N bond,with a carbonylketenes, 2-aryt-1-(2-benzoyl-phenylacelyl)-4-phenyl-2,3-dihydro-1H-1,5-benzodiazepines. Addition of henzonitrile N-phenylimine,yielde in situ from the N-phenyl benzenecarbohydrazic chloride,to 2, 4-diaryl-2, 3-dihydro-1,5-benzothiazepines and 1H-1,5-benzodiazepine gave 3a, 5-diaryl-1, 3-diphenyl-3a, 4, 5, 11 tetralydro-3H-1, 2, 4-triazolo [4, 3-d][1. 5]benzothiazepine and 3H,6H-1, 2, 4 triazolo[4, 3-d][1, 5] benzodiazpine, respectively.

The FDA Mandate to Reassess Benzodiazepines: Alprazolam Induces a Positive Conditioned Place-Preference in Male Rats

On September 23, 2020, in order “To address the serious risks of abuse, addiction, physical dependence, and withdrawal reactions, the U.S. Food and Drug Administration (FDA) is requiring the Boxed Warning be updated for all benzodiazepine medicines”. With this announcement, the FDA proclaimed that much more needs to be known about the initiation, continuation, and discontinuation of these widely-used drugs. Unfortunately, relevant information is lacking, since for many years, there has been a notable sparsity in the funding and conduct of basic and clinical research on these drugs. In order to begin to fill the void, it is valuable to (re)examine animal models. We here describe a model of conditioned place-preference (CPP) for rats and for the first time, to our knowledge, show that the representative benzodiazepine alprazolam induces positive place-preference in male rats.

Novel,efficient,and green procedure for the synthesis of 1,5-benzodiazepines catalyzed by MgBr_2 in aqueous media

MgBr2 performs as a novel catalyst for the synthesis of various 1,5-benzodiazepine derivatives from wide range of substituted o- phenylenediamines and various ketones in good to excellent isolated yields （93-98%） using water as solvent at ambient temperature. Several solvents were examined for this reaction; however, in terms of reaction yield and time, water was found to be the optimum solvent. The remarkable advantages offered by this method are easily and inexpensive available catalyst, simple procedure, mild conditions, much faster （40-60 man） reactions and good to excellent yields of products.

Fast Determination of Benzodiazepines in Human Urine via Liquid-Liquid Extraction with Low Temperature Partitioning and LC-HRMS

A simple and high-throughput method to simultaneously determine selected benzodiazepines (i.e., diazepam, lorazepam, clonazepam, and bromazepam) in urine was developed and validated. The entire methodology consisted of the application of an innovative extraction/cleanup procedure, namely liquid-liquid extraction with low-temperature partitioning (LLE-LTP), and analysis by liquid chromatography combined with high-resolution mass spectrometry (LC-HRMS). The LLE-LTP procedure was optimized via factorial design and by evaluating crucial variables, specifically the freezing mode (either slow or fast), the urine/acetonitrile volume ratio, and the sample ionic strength. The benzodiazepines were quantified using matrix-matched calibration curves where the following parameters were assessed by validation protocol: in general, linearity range of 17 - 200 μg?L–1 (r > 0.9957);limits of detection lower than 5 μg?L–1;relative standard deviations (RSD) lower than 12.5%;and accuracy ranging from 72.3 to 117%. To test this procedure’s performance, the method was applied to determine the content of diazepam in actual urine samples. The validation results obtained for the method demonstrated that the present methodology could be potentially applied in proficient laboratories as a routine approach for determining benzodiazepines compounds content in urine.

Involvement of flumazenil-insensitive benzodiazepine binding site in benzodiazepine-induced anesthesia in zebrafish larvae

OBJECTIVE To identify the involvement of flumazenil-insensitive benzodiazepine(BZD) binding site in mediating BZD-induced immobility.The distribution of this nonclassical binding site and its key amino acid residues in GABAAreceptors(GABAARs) were also investigated.METHODS Using a zebrafish larvae locomotion model,we investigated the detailed dose-dependent effects of diazepam and other BZDs on zebrafish larvae behaviors,with a focus on their high-dose effects.We then evaluated the influence of the classical BZD antagonist flumazenil,GABAARs antagonist bicuculline,and the antagonist of a proposed BZD binding site in α4/6β3δ subtype receptor Ro15-4513 on BZDs induced immobility.Using wholecell patch clamp electrophysiological recordings on recombinant GABAARs,we investigated the modulation of diazepam alone or combined with flumazenil on GABA-elicited current in wildtype and mutated receptors.RESULTS Diazepam dose-dependently decreased the locomotor activities of zebrafish larvae at doses of 0.4,2,10,20,30,50 and 75 mg·L^(-1).The hypolocomotion(sedation-like state) induced by diazepam at10 and 20 mg·L^(-1) were effectively antagonized by flumazenil with EC150 of 0.086 mg·L-and1.295 mg·L^(-1),while the immobility(anesthesialike state) induced by diazepam at 30 mg·L^(-1) was abolished by bicuculline(3 mg·L^(-1)),but not affected by flumazenil(even at concentration up to150 mg·L^(-1)) or Ro15-4513(100 mg·L^(-1)).The immobility induced by clonazepam and lorazepam(100 mg·L^(-1)) was also resistant to flumazenil(100 mg·L^(-1)).In the α1β2γ2 subtype receptor expressed in HEK293 T cells,diazepam dose-dependently potentiated GABA-elicited current,and this potentiation was effectively antagonized by flumazenil(100 μmol·L^(-1)).However,in α1β2 subtype receptor,diazepam(150 μmol·L^(-1)) induced potentiation was insensitive to flumazenil(100 μmol·L^(-1)),but was abolished by the mutation of β2 N265 I.CONCLUSION These results provide direct in vivo evidence for the nonclassical binding sites,which may be located at the second transmembrane domain of GABAAR,mediate BZD-induced anesthesia.

Crystal Structure of 1,1-Dichloro-3-Dichloromethyl-1a-3-Dipenyl-1a,2,3,4-Tetrahydro-1 H-Azirino〔1,2-a〕〔1,5〕benzodiazepine(C_(23)H_(18)Cl_4N_2)

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The Role of Ca^(2+) and Cyclic AMP in the Modulation of BenzodiazepineReceptor on Aldosterone Secretion

PK11195, a ligand of peripheral-type benzodiazepine receptor can stimulate thealdosterone secretion of isolated adrenal glomerulosa cell: this effect could be abolished by nifedipinewhich mainly blocks the calcium channel in plasma membrane, but could not be abolished bydantrolene, a selective blocker of mitochondria calcium channel. Even under the condition of themaximum stimulative effects on aldosterone secretion, PK11195 could not change the cyclic AMP（cAMP） content in isolated glomerulosa cells. These results indicated that in the modulatory mecha-nism of benzodiazepine receptor on aldosterone secretion, the intracellular messenger might be theCa2+ from extracellular Ca2+ pool, but not the Ca2+ from mitochondria Ca2+ pool or cAMP.

New Approach to Synthesis of Tetrahydroisoquino[2,l-c] [1,3]-benzodiazepine

A concise and efficient synthesis of the new compounds tetrahydroisoquino [2,1-c] [1,3] benzodiazepine 5 and 7 is reported.

Synthesis and Evaluation of 8-[^(131)I]Iodo-substituted Imidazopyridine Derivative as Single Photon Emission Computed Tomography Tracer for Peripheral Benzodiazepine Receptors

A novel N-methyl, N-phenyl-[6-chloro-2-（4-chlorophenyl）-8-iodoimidazo[1, 2-a]- pyridine-3-yl]acetamide （compound Ⅴ） was synthesized, radiolabelled with 131I and evaluated in vitro. In vitro cell uptake studies showed that MDA-MB-231 cells yield four-fold higher specific uptake of [^131I]-compound Ⅵ than MCF-7 cells, corresponding to the increased expression of PBR in MDA-MB-231 cells. Blocking studies significantly reduced the MDA-MB-231 cells uptake of [^131I]-compound Ⅵ. It indicated that [^131I]-compound Ⅵ might be a potential SPECT radioligand for imaging of PBR.

Synthesis of 3, 7-Disubstituted 1, 4-Benzodiazepin-2-one

A series of 3-methoxycarbonylpropoxy-7-(imidazol-4-ylpropinamide)-1, 3-dihydrogen- 1-methyl-5-phenyl-2H-1, 4-benzodiazepin-2-ones, as farnesyltransferase(Ftase) inhibitors, were synthesized. The preparation of the key intermediate, 7-amino-3-methoxycabonylpropoxy-1- methyl-5-phenyl-2H-1,4-benzodiazepin-2-one, was improved.

Flumazenil-insensitive benzodiazepine effects in vitro and in vivo

OBJECTIVE To identify benzodi⁃azepine(BZD)effects that are insensitive to the classical BZD binding site antagonist,flumazenil.Whether the flumazenil-insensitive BZD effects have selectivity on different GABAA receptor sub⁃types was also investigated.METHODS The high-concentration effects of BZDs and their sensitivity to flumazenil were determined on recombi⁃nant synaptic(α1β2γ2,α2β2γ2,α5β2γ2)and extra-synaptic(α4β2δ)GABAA receptors using the voltage-clamp electrophysiology technique.The in vivo evaluation of flumazenil-insensitive BZD effects was conducted in mice loss of right reflex(LORR)test.RESULTS Diazepam induced a biphasic potentiation for theα1β2γ2,α2β2γ2 andα5β2γ2 receptor channels,but did not affect theα4β2δreceptor.In contrast to the nanomolar com⁃ponent of potentiation,the second potentiation elicited by micromolar diazepam was insensitive to flumazenil.Midazolam,clonazepam,and loraz⁃epam at 200μmol·L-1 exhibited similar flumaze⁃nil-insensitive effects onα1β2γ2,α2β2γ2 andα5β2γ2 receptors,whereas the potentiation induced by 200μmol·L-1 zolpidem or triazolam was abol⁃ished by flumazenil.Consistent with the in vitro results,flumazenil antagonized the zolpidem(50 mg·kg-1)-induced LORR,but not those induced by 50 mg·kg-1 diazepam or 100 mg·kg-1 midazolam.CONCLUSION The existence of non-classical BZD binding sites on certain GABAA receptor subtypes and the flumazenil-insensitive effects depend on the chemical structures of the allosteric modulators.

Purkinje-neuron-specific down-regulation of p38 protects motoric function from the repeated use of benzodiazepine

Benzodiazepine (BZD) is the most prescribed CNS depressant in America to treat hyper-excitatory disorders such as anxiety and insomnia. However, the chronic use of BZD often creates adverse effects including psychomotor deficit. In this study, we investigated a novel mechanism by which chronic BZD impedes motoric function in female mice. We used female mice because BZD use is much more prevalent in female than male populations. We tested the hypothesis that the accumulation of p38 (stress-activated protein) in cerebellar Purkinje neurons mediates motoric deficit induced by chronic BZD. To test this hypothesis, we generated transgenic mice that lack p38 incerebellar Purkinje neurons by crossing Pcp2 (Purkinje cell protein 2)-Cre mice with p38loxP/loxP mice. p38-knockdown mice and wild-type mice received BZD (lorazepam, 0.5 mg/kg) for 14 days. During this period, they were tested for motoric performance using Rotarod assay in which a quicker fall from rotating rod indicates poorer motoric performance. Cerebellum was then collected to detect p38 inPurkinje neurons and to measure mitochondrial respiration using immunohistochemistry and real-time XF respirometry, respectively. Compared to vehicletreated mice, BZD-treated mice showed poorer motoric performance, a higher number of Purkinje neurons containing p38, and lower mitochondrial respiration. These effects of BZD were much smaller in p38-knockdown mice. These results suggest that the excessive accumulation of p38 incerebellar Purkinje neurons contributes to motoric deficit associated with chronic BZD. They also suggest that Purkinje neuronal p38 mediates BZD-induced mitochondrial respiratory inhibition in cerebellum. Our findings may provide a new mechanistic insight into chronic BZD-induced motoric deficit.

Intranasal Delivery of Two Benzodiazepines, Midazolam and Diazepam, by a Microemulsion System

Nasal application of benzodiazepines might be an alternative to intravenous administration in acute clinical situations such as seizures emergencies. However, irritation and pain as well as symptoms like teary eyes, dizziness, discomfort, nasal drainage and bad taste usually accompany subject received midazolam and diazepam via the nasal route. The purpose of this study was to evaluate the use of a new alcohol-free microemulsion system as a carrier for diazepam or midazolam given intranasally. Midazolam (base) or diazepam was solubilized in the microemulsion to obtain a high drug concentration of 25 mg/g (2.5% by weight), to provide 2.5 mg drug in 100 μl spray (d ≈ 1.00 g/ml). The nasal absorption of both drugs from the same microemulsion formulation (containing 20% aqueous phase) was found to be fairly rapid after administration of 0.4 mg/kg to rabbits. The absolute bioavailability of diazepam after intranasal administration using this formulation was 33.45% ± 12.36% and the tmax was 18.33 ± 23.09 min, which was twice longer than the tmax obtained after midazolam administration, 9.25 ± 6.75 min. The pharmacokinetic parameters of midazolam in W/O (20% water) microemulsion and their comparison with midazolam in O/W (50% water) microemulsion have shown that both formulations resulted in a relatively short time to reach the peak plasma level (tmax), that is, 9.25 ± 6.75 min and 6.75 ± 5.67 min, respectively. However, the peak plasma levels (Cmax) and the absolute bioavailability (FA) of midazolam were significantly higher after administration of the W/O formulation than those obtained after application of O/W formulation, i.e., 46.62 ± 17.38 μg/ml vs. 15.44 ± 4.00 μg/ml, and 35.19% ± 11.83% vs. 19.83% ± 16.32%, respectively. Our results suggest that the new microemulsion system may be useful for getting rapid-onset of midazolam and diazepam following intranasal administration, resulting in reasonable peak plasma levels and bioavailability, but most importantly, providing a high measure of tolerability and comfort.

Treating Insomnia in Older Adult Patients: Limiting Benzodiazepine Use

As aging comes, an increased prevalence of medical maladies and chronic pain independently or interactively disrupt sleep, which in turn can exacerbate either one. Furthermore, anxiety about pain can further negatively impact sleep. Fortunately, good quality sleep can improve pain management. Because benzodiazepine receptor agonists (including the “Z” drugs) can reduce anxiety and improve sleep, they seem a convenient choice. However, their use in this population, particularly for more than short-term (guidelines range from 2 to 6 weeks max), is not recommended because of increased likelihood of falls, further disruption of sleep, dependence, and problems with discontinuation (withdrawal). Besides, this population is often likely to take concomitant medication for pain or other central nervous system depressants leading to potentially serious and even life-threatening interactions involving synergistic amplification of respiratory depression (opioids being a particularly dangerous interaction). Therefore, insomnia in older adults should ideally be treated with a non-benzodiazepine receptor agonist;if indicated, they may be used, but should be closely monitored and tapered to avoid long-term adverse problems (direct or from withdrawal). Older adult patients with insomnia may be more optimally treated with sleep aids that do not interact with the GABAA receptor.

<i>Commentary</i>: Benzodiazepine (BZD) and Related BZD-Receptor Agonists: Basic Science Reasons to Limit to Four Weeks or Less

Benzodiazepines and related benzodiazepine-receptor agonists such as the pyrazolopyrimidinezalepl -on;?the imidazopyridine zolpidem;and the cyclopyrroloneszopiclone and eszopiclone, are among the most widely prescribed drugs, and for a variety of conditions. Surprisingly: 1) there are only a few conditions for which there is a good evidence basis, 2) efficacy has only been well demonstrated for short-term use (i.e., less than 4 weeks), and 3) much less is known about the basic science of these drugs than is widely believed. We suggest that the use of these drugs beyond four or less weeks exceeds the available knowledge base, so best-practice use suggests that the prescribing of these drugs for most patients should be limited to only short-term use until more is known about the basic pharmacology of their actions in the brain and in the periphery.

A New Approach to 2,3-Dihydro-1H-1,5-Benzodiazepines from the Reaction of o-Nitrophenylazide with

o-Nitrophenylazide was reduced by SmI2 in anhydrous THF at room temperature to produce active intermediate 2 (samarium amide), "living" double-anion in situ which reacted smoothly with α，β-unsaturated ketones to afford 2,3-dihydro-1H-1,5-benzodiazepines in good yields under mild and neutral conditions.

Novel Efficient Method for Synthesis of N_(1,4)-Disubstituted-1,4-benzodiazepine-2,5-diones

A novel and efficient method was developed for the liquid-phase synthesis of Nj,4-disubstitutedbenzodiazepine-2,5-diones with 2-chloro-5-nitrobenzoic acid as initiating material via 4 step reactions containing esterifieation, ＂Ulmn reaction＂, acylation, alkylation and cyclization. The reaction conditions were mild and the overall yields of the products ranged from 45% to 71%.

Psychoactive Chemical Constituents of Carissa edulis (Forssk.) Vahl Roots and Its Safety Limits in Folk Treatment: Benzodiazepines Analogous

Carissa edulis Vahl is well known in Sudanese herbal medicine,commonly used for treatment of epilepsy,headache,chest pains,rheumatism,skin lesions,mania and other psychoactive diseases.The investigations of the safety use for psychoactive purposes in Sudanese healing traditions and identifying secondary metabolites of the plant extracts are the key steps towards determination of appropriate medicinal doses.Therefore,one of the chemical constituents was isolated and structurally identified by 1H-NMR and LC-MS.With the aim of evaluating Carissa edulis folk random uses,the isolated compound was compared with reference artificial drugs Lormetazepam,a potentially toxic compound.Structure investigations confirm that the isolated product was benzodiazepines analogous 7-chloro 1,4-benzodiazepine-2-ones.It is important to know the potential toxicity of certain plant in order to assess the therapeutic effect of it,as these are slight distinctions between the medicinal and toxic doses.In general the results obtained justify the use of the roots of Carissa edulis in traditional medicine for the treatment of some psychiatric diseases.