GABAA receptors (GABAARs) play a crucial inhibitory role in the CNS. Benzodiazepines (BDZs) are positive modulators of specific subtypes of GABAARs, but the underlying mechanism remains obscure. Early studies demonstrated the major impact of BDZs on binding and more recent investigations indicated gating, but it is unclear which transitions are affected. Moreover, the upregulation of GABAAR spontaneous activity by BDZs indicates their impact on receptor gating but the underlying mechanisms remain unknown. Herein, we investigated the effect of a BDZ (flurazepam) on the spontaneous and GABA-induced activity for wild-type (WT, α1β2γ2) and mutated (at the orthosteric binding site α1F64) GABAARs. Surprisingly, in spite of the localization at the binding site, these mutations increased the spontaneous activity. Flurazepam (FLU) upregulated this activity for mutants and WT receptors to a similar extent by affecting opening/closing transitions. Spontaneous activity affected GABA-evoked currents and is manifested as an overshoot after agonist removal that depended on the modulation by BDZs. We explain the mechanism of this phenomenon as a cross-desensitization of ligand-activated and spontaneously active receptors. Moreover, due to spontaneous activity, FLU-pretreatment and co-application (agonist + FLU) protocols yielded distinct results. We provide also the first evidence that GABAAR may enter the desensitized state in the absence of GABA in a FLU-dependent manner. Based on our data and model simulations, we propose that FLU affects agonist-induced gating by modifying primarily preactivation and desensitization. We conclude that the mechanisms of modulation of spontaneous and ligand-activated GABAAR activity concerns gating but distinct transitions are affected in spontaneous and agonist-evoked activity.

No information is available on the excretion of flurazepam into breastmilk. One case of infant sedation was reported in a woman taking flurazepam along with other sedating drugs during breastfeeding. Because of the long duration of action of flurazepam, an alternate hypnotic is preferred, especially while nursing a newborn or preterm infant.

A method was developed for the analysis of stimulant drugs, opiates, synthetic opiates, PCP, and benzodiazepines in wastewater samples using liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS). A total of 33 compounds (stimulant-type drugs and metabolites of opiates, synthetic opiates, PCP, and benzodiazepines) were analyzed. These drugs included amphetamine (Amp) (1), methamphetamine (Meth) (2), methylenedioxyamphetamine (MDA) (3), methylenedioxymethamphetamine (MDMA) (4), methylenedioxyethylamphetamine (MDEA) (5), benzoylecgonine (BE, the major metabolite of Coc) (6), cocaine (Coc) (7), 6-monoacetylmorphine (6-MAM, the primary urinary metabolite of heroin) (8), codeine (9), hydrocodone (10), hydromorphone (11), morphine (12), norhydrocodone (the primary urinary metabolite of hydrocodone) (13), oxycodone (14), oxymorphone (15), 2-ethylidine-1,5-dimethyl-3,3-diphenylpyrolidine (EDDP, the primary urinary metabolite of methadone) (16), fentanyl (17), meperidine (18), methadone (19), norfentanyl (the primary urinary metabolite of fentanyl) (20), normeperidine (the primary urinary metabolite of meperidine) (21), phencyclidine (PCP) (22), tramadol (23), alprazolam (24), temazepam (25), nordiazepam (26), chlordiazepoxide (27), flurazepam (28), oxazepam (29), α-OH-alprazolam (the primary urinary metabolite of alprazolam) (30), α-OH-triazolam (the primary urinary metabolite of triazolam) (31), 2-OH-ethylflurazepam (the primary urinary metabolite of flurazepam) (32), and 7-NH2-flunitrazepam (the primary urinary metabolite of flunitrazepam) (33). These drugs were chosen because of their widespread abuse. Wastewater samples were collected at both the Oxford Wastewater Treatment Plant in Oxford, Mississippi (MS), and the University Wastewater Treatment Plant in University, MS. Samples were collected on weekends on which the Ole Miss Rebel football team held home games (Vaught-Hemingway Stadium, University, MS 38677). The collected samples were analyzed using a validated method and found to contain Amp, Meth, MDMA, MDA, Coc, BE, codeine, hydrocodone, hydromorphone, morphine, norhydrocodone, oxycodone, oxymorphone, tramadol, EDDP, meperidine, normeperidine, methadone, alprazolam, α-OH-alprazolam, nordiazepam, oxazepam, and temazepam. None of the samples contained MDEA, 6-MAM, fentanyl, norfentanyl, PCP, chlordiazepoxide, flurazepam, 2-OH-ethylflurazepam, 7-NH2-flunitrazepam, and α-OH-triazolam.

Dispersive liquid-liquid microextraction with and without ultrasound assistance (DLLME, UA-DLLME) and microextraction with packed sorbent (MEPS) methods for the extraction and determination of eight different benzodiazepines (BDZ) (chlordiazepoxide, flurazepam, bromazepam, oxazepam, lorazepam, clobazam, clonazepam, and flunitrazepam) in three commercial non-alcoholic and light alcoholic beverages were optimized and compared. Benzodiazepines are frequently used for their extensive diffusion and strong numbing effect in drug-facilitated crimes (DFC). The tiny small amount of sample required for DLLME and MEPS extraction makes them very suitable for specimens collected at the crime scene of DFCs. Microextraction techniques are of increasing interest thanks to their accordance to green analytical chemistry (GAC) guidelines providing good recovery values. Ultrasound assistance (UA-DLLME) was used to investigate whether this type of energy can improve the recoveries of the analytes. Analyses of the extracts were performed with reverse-phase capillary high-performance liquid chromatography with UV detection (HPLC - UV), thanks to low environmental impact, robustness, diffusion, and affordability. Recovery percentages at three different concentrations in the three beverages were between 14.30% and 103.28% with intraday and interday RSD lower than ±2.78%. The same samples were extracted using a MEPS protocol, and the results were compared with those obtained with DLLME. MEPS gave recoveries between 20.90% and 101.88% for all matrices showing a better performance than DLLME at higher concentrations, though lower recoveries were observed with diluted samples.

Sample preparation is rapidly improving to fulfill the need for faster and more environmentally friendly alternatives. In this respect, ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) is an interesting technique. However, it has not yet been evaluated for the analysis of postmortem samples, which are frequently analyzed in forensic toxicology. This study investigates the applicability of IL-DLLME coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS), for the analysis of benzodiazepines in postmortem blood of 11 forensic cases. The method was compared with a validated solid-phase extraction (SPE) method. Bland-Altman analysis was performed on 24 benzodiazepine measurements. Both methods gave comparable results, except for flurazepam and temazepam (>55% difference). A feasible explanation is high postmortem matrix variability that was not considered during IL-DLLME validation experiments. Another issue could be the use of a single nondeuterated SPE internal standard. Overall, IL-DLLME has proven its usability for the analysis of postmortem blood.

Reuse of treated wastewater for irrigation of crops is growing in arid and semi-arid regions, whilst increasing amounts of biosolids are being applied to fields to improve agricultural outputs. Due to incomplete removal in the wastewater treatment processes, pharmaceuticals present in treated wastewater and biosolids can contaminate soil systems. Benzodiazepines are a widely used class of pharmaceuticals that are released following wastewater treatment. Benzodiazepines are represented by a class of compounds with a range of physicochemical properties and this study was therefore designed to evaluate the influence of soil properties on the sorption behaviour and subsequent uptake of seven benzodiazepines (chlordiazepoxide, clonazepam, diazepam, flurazepam, oxazepam, temazepam and triazolam) in two plant species. The sorption and desorption behaviour of benzodiazepines was strongly influenced by soil type and hydrophobicity of the chemical. The partitioning behaviour of these chemicals in soil was a key controller of the uptake and accumulation of benzodiazepines by radish (Raphanus sativus) and silverbeet (Beta vulgaris). Benzodiazepines such as oxazepam that were neutral, had low sorption coefficients (Kd) or had pH-adjusted log octanol-water partition coefficients (log Dow, pH6.3) values close to 2 had the greatest extent of uptake. Conversely, benzodiazepines such as flurazepam that had an ionised functional groups and greater Kd values had comparatively limited accumulation in the selected plant species. Results also revealed active in-plant metabolism of benzodiazepines, potentially analogous to the known metabolic transformation pathway of benzodiazepines in humans. Along with this observed biological transformation of benzodiazepines in exposed plants, previously work has established the widespread presence of the plant signalling molecule γ-amino butyric acid (GABA), which is specifically modulated by benzodiazepines in humans. This highlights the need for further assessment of the potential for biological activity of benzodiazepines following their plant uptake.

In this communication, we describe a flow-through optical absorption detector for HPLC using for the first time a deep-UV light-emitting diode with an emission band at 235nm as light source. The detector is also comprised of a UV-sensitive photodiode positioned to enable measurement of radiation through a flow-through cuvette with round aperture of 1mm diameter and optical path length of 10mm, and a second one positioned as reference photodiode; a beam splitter and a power supply. The absorbance was measured and related to the analyte concentration by emulating the Lambert-Beer law with a log-ratio amplifier circuitry. This detector showed noise levels of 0.30mAU, which is comparable with our previous LED-based detectors employing LEDs at 280 and 255nm. The detector was coupled to a HPLC system and successfully evaluated for the determination of the anti-diabetic drugs pioglitazone and glimepiride in an isocratic separation and the benzodiazepines flurazepam, oxazepam and clobazam in a gradient elution. Good linearities (r>0.99), a precision better than 0.85% and limits of detection at sub-ppm levels were achieved.

To date, thorough clean-up of complex biological samples remains an essential part of the analytical process. The solid phase extraction (SPE) technique is the well-known standard, however, its main weaknesses are the labor-intensive and time-consuming protocols. In this respect, dispersive liquid-liquid microextractions (DLLME) seem to offer less complex and more efficient extraction procedures. Furthermore, ionic liquids (ILs) - liquid salts - are emerging as new promising extraction solvents, thanks to their non-flammable nature, negligible vapor pressure and easily adaptable physiochemical properties. In this study, we investigated whether ILs can be used as an extraction solvent in a DLLME procedure for the extraction of a broad range of benzodiazepines and benzodiazepine-like hypnotics in whole blood samples. 1.0mL whole blood was extracted using an optimized 30-min IL-based DLLME procedure, followed by LC-ESI(+)-MS/MS analysis in scheduled MRM scan mode. The optimized analytical method was successfully validated for 7-aminoflunitrazepam, alprazolam, bromazepam, clobazam, clonazepam, clotiazepam, diazepam, estazolam, ethyl loflazepate, etizolam, flurazepam, lormetazepam, midazolam, oxazepam, prazepam, temazepam, triazolam, zolpidem and zopiclone. The method showed good selectivity for endogenous interferences based on 12 sources of blank whole blood. No benzodiazepine interferences were observed, except for clorazepate and nordiazepam, which were excluded from the quantitative method. Matrix-matched calibration curves were constructed covering the whole therapeutic range, including low toxic plasma concentrations. Accuracy and precision results met the proposed acceptance criteria for the vast majority of compounds, except for brotizolam, chlordiazepoxide, cloxazolam, flunitrazepam, loprazolam, lorazepam and nitrazepam, which can only be determined in a semi-quantitative way. Recoveries were within the range of 24.7%-127.2% and matrix effects were within 20.0%-92.6%. Both parameters were tested using 5 sources of whole blood and coefficients of variance were below 20%. Overall, the applicability of ILs as promising solvents for the extraction of benzodiazepines in whole blood samples has been proven. Moreover, a fast and easy IL-based DLLME procedure was developed for the quantification of 19 benzodiazepines and benzodiazepine-like hypnotics.

In this review, we discuss the management of chronic orofacial pain (COFP) patients with insomnia. Diagnostic work-up and follow-up routines of COFP patients should include assessment of sleep problems. Management is based on a multidisciplinary approach, addressing the factors that modulate the pain experience as well as insomnia and including both non-pharmacological and pharmacological modalities. Parallel to treatment, patients should receive therapy for comorbid medical and psychiatric disorders, and possible substance abuse that may be that may trigger or worsen the COFP and/or their insomnia. Insomnia treatment should begin with non-pharmacological therapy, to minimize potential side effects, drug interactions, and risk of substance abuse associated with pharmacological therapy. Behavioral therapies for insomnia include the following: sleep hygiene, cognitive behavioral therapy for insomnia, multicomponent behavioral therapy or brief behavioral therapy for insomnia, relaxation strategies, stimulus control, and sleep restriction. Approved U.S. Food and Drug Administration medications to treat insomnia include the following: benzodiazepines (estazolam, flurazepam, temazepam, triazolam, and quazepam), non-benzodiazepine hypnotics (eszopiclone, zaleplon, zolpidem), the melatonin receptor agonist ramelteon, the antidepressant doxepin, and the orexin receptor antagonist suvorexant. Chronic orofacial pain can greatly improve following treatment of the underlying insomnia, and therefore, re-evaluation of COFP is advised after 1 month of treatment.