High-throughput and trace analysis of diazepam in plasma using DART-MS/MS and its pharmacokinetic application.

A high-throughput quantitative analytical method based on Direct Analysis in Real Time tandem mass spectrometry (DART-MS/MS) has been developed and validated for the determination of diazepam in rat plasma, whereby analyzing of each sample needs merely 25 µL plasma, simple solid phase extraction sample preparation and 15 s acquisition time. The multiple reaction monitoring (MRM) transitions at m/z 285.2 â†’ 193.1 and 316.0 â†’ 270.0 were selected for the monitoring of diazepam and its internal standard clonazepam respectively. A good linearity within the range of 10-2000 ng/mL, an intra- and inter-day precisions within <7.78% as to an accuracy ranging from 1.04% to 7.92% have been achieved. The method has been successfully applied to the pharmacokinetic study of diazepam in rats' plasma after a single intragastric administration at a dose of 10 mg/kg. The results indicate that this method fulfills the requirements of the bioanalysis in sensitivity and accuracy. It shows considerable promise for application of DART-MS to the quantitative investigation of other drugs.

Precisely adjusting the hepatic clearance of highly extracted drugs using the modified well-stirred model.

Hepatic clearance has been widely studied for over 50 yr. Many models have been developed using either theoretical or empirical tests to predict drug metabolism. The well-stirred, parallel-tube, and dispersion metabolic models have been extensively discussed. However, to our knowledge, these models cannot fully describe all relevant scenarios in hepatic clearance. We addressed this issue using the isolated perfused rat liver technique with minor modifications. Diazepam was selected to illustrate different levels of drug plasma-protein binding by changing the added concentration of human serum albumin. The free fractions of diazepam at different albumin concentrations were assayed by rapid equilibrium dialysis. The experimental data provide new insights concerning an accepted formula used to describe hepatic clearance. Regarding drug concentrations passing through the liver, the driving force concentration (CH,ss) in terms of Cin (influx in the liver) or Cout (efflux from the liver) needs to be carefully considered when determining drug hepatic and intrinsic clearances. The newly established model, termed the modified well-stirred model, which was derived from the original formula, successfully estimated hepatic drug metabolism. Using the modified well-stirred model, a theoretical driving force concentration of diazepam passing through the liver was evaluated. The model was further used to assess the predictability of in vitro to in vivo extrapolation. This study was not intended to refute the existing models, but rather to augment them using experimental data. The results stress the importance of proper calculation of dose when the drug clearance deviates from the prediction of the well-stirred model.

Femoral blood concentrations of the designer benzodiazepine etizolam in post-mortem cases.

Etizolam is a thienodiazepine that although licensed for clinical usage in Japan, India and South Korea is commonly abused and detected in post-mortem cases around the world. To date, there are limited data in the literature to allow for the interpretation of blood concentrations of etizolam in post-mortem cases. A liquid chromatography with tandem mass spectrometry method was used to quantitate etizolam concentrations in 28 post-mortem cases where etizolam was detected. The median concentration of etizolam in femoral blood was 8.5 ng/mL (range 1.0-172.0 ng/mL; n = 24); in antemortem plasma, the etizolam concentration range was 4-44 ng/mL (n = 4). The mean age of the individuals abusing etizolam was 38.5 ± 8.4 years (median 39 years), with the majority being male (86%). In all of the cases, multiple drugs were detected, with the most common being pregabalin (61%) followed by morphine/heroin (54%), diazepam (54%) and benzoylecgonine (21%), illustrating the increasing problem of poly-substance use in drug abusers. The cause of death in the cases in which etizolam was detected was multi-drug toxicity in 87.5% of the cases, with 12.5% unrelated to drug use (hangings and blunt-force trauma). These data will further help forensic practitioners with the interpretation of post-mortem etizolam concentrations.

Point-of-care diagnostics for drugs of abuse in biological fluids: application of a microfabricated disposable copper potentiometric sensor.

The major objective of this work was to develop a portable, disposable, cost-effective, and reliable POC solid-state electrochemical sensor based on potentiometric transduction to detect benzodiazepine abuse, mainly diazepam (DZP), in biological fluids. To achieve that, microfabricated Cu electrodes on a printed circuit board modified with the conducting polymer poly(3-octylthiophene) (POT) have been employed as a substrate. This polymer was introduced to enhance the stability of the potential drift (0.9 mV/h) and improve the limit of detection (0.126 nmol mL-1). Nernstian potentiometric response was achieved for DZP over the concentration range 1.0 × 10-2 to 5.0 × 10-7 mol L-1 with a slope of 55.0 ± 0.4 mV/decade and E0 ~ 478.9 ± 0.9. Intrinsic merits of the proposed sensor include rapid response time (11 ± 2 s) and long life time (3 months). In order to enhance the selectivity of the potentiometric sensor towards the target drug and minimize any false positive results, calix[4]arene (CX4) was impregnated as an ionophore within the PVC plastic ion-sensing membrane. The performance of the POC sensors was assessed using electrochemical methods of analysis and electrochemical impedance spectroscopy as a surface characterization tool. The studied sensors were applied to the potentiometric determination of DZP in different biological fluids (plasma, urine, saliva, and human milk) in the presence of its metabolite with an average recovery of 100.9 ± 1.3%, 99.4 ± 1.0%, 101.8 ± 1.2%, and 99.0 ± 2.0%, respectively. Graphical abstract.

Predicted values for human total clearance of a variety of typical compounds with differently humanized-liver mouse plasma data.

Prediction of human pharmacokinetics is important in the preclinical stage. Values for total clearance of compounds from plasma should be one of the most important pharmacokinetic parameters for predictions. Although several physiological and empirical methods including single-species allometry for prediction of values for human clearance of compounds using humanized-liver mice have been reported, further improvement of prediction accuracies would be still expected. To optimize these approaches, we proposed methods for unbound intrinsic clearance in virtually 100% humanized-liver mouse by incorporating unbound plasma fractions of compounds in differently humanized-liver mice. Comparisons of prediction accuracies of values for human clearance of 15 model compounds were performed among our current physiological and previously reported models and single-species allometry using humanized-liver mice. Incorporation of the actual unbound plasma fractions of compounds and correction of residual mice hepatocyte in humanized-liver mice showed comparable prediction accuracy to that by single-species allometry. After exclusion of 3 compounds with large species differences in values of clearance and unbound plasma fractions between mice and humans out of 15 compounds, prediction accuracies were improved in the methods investigated. The previously and present reported physiological methods could show the good prediction accuracy of values for clearance of drugs from plasma.

How do CYP2C19*2 and CYP2C19*17 genetic polymorphisms affect the efficacy and safety of diazepam in patients with alcohol withdrawal syndrome?

Background Diazepam is one of the most commonly prescribed tranquilizers for therapy of alcohol withdrawal syndrome (AWS). Despite its popularity, there is currently no precise information on the effect of genetic polymorphisms on its efficacy and safety. The objective of our study was to investigate the effect of CYP2C19*2 and CYP2C19*17 genetic polymorphisms on the efficacy and safety of diazepam in patients with AWS. Methods The study was conducted on 30 Russian male patients suffering from the AWS who received diazepam in injections at a dosage of 30.0 mg/day for 5 days. The efficacy and safety assessment was performed using psychometric scales and scales for assessing the severity of adverse drug reactions. Results Based on the results of the study, we revealed the differences in the efficacy of therapy in patients with different CYP2C19 681G>A (CYP2C19*2, rs4244285) genotypes: (CYP2C19*1/*1) -8.5 [-15.0; -5.0], (CYP2C19*1/*2 and CYP2C19*2/*2) -12.0 [-13.0; -9.0], p = 0.021. The UKU scale scores, which were used to evaluate the safety of therapy, were also different: (CYP2C19*1/*1) 7.0 [6.0; 12.0], (CYP2C19*1/*2 and CYP2C19*2/*2) 9.5 [8.0; 11.0], p = 0.009. Patients carrying different CYP2C19 -806C>T (CYP2C19*17, rs12248560) genotypes also demonstrated differences in therapy efficacy and safety rates. Conclusions Thus, the effects of CYP2C19*2 and CYP2C19*17 genetic polymorphisms on the efficacy of diazepam were demonstrated.

Study on the Pharmacokinetics of Diazepam and Its Metabolites in Blood of Chinese People.

BACKGROUND AND OBJECTIVES: Driving under the influence of diazepam is increasing in China. The pharmacokinetics of diazepam and its metabolites, especially the glucuronide metabolites, are helpful in the identification of diazepam use by drivers. This study aimed to investigate the pharmacokinetics of diazepam and its metabolites (nordazepam, oxazepam, oxazepam glucuronide and temazepam glucuronide) in the blood of Chinese people, and to provide basic data for identifying diazepam use and estimating the time of last diazepam ingestion. METHODS: A total of 28 participants (14 men, 14 women) were recruited and each person received 5 mg diazepam orally. Whole blood was collected at 0 h (pre-dose), and 1 h, 2 h, 4 h, 8 h, 12 h, and 24 h, and at 2 days, 3 days, 6 days, 12 days, and 15 days post-dose. Analytes of interest were extracted via solid-phase extraction and analyzed by a liquid chromatography tandem mass spectrometry method operated in a positive multiple response monitoring mode. Pharmacokinetic parameters were analyzed by a pharmacokinetic software DAS according to the non-compartment model. The time of last diazepam use was estimated using the concentration ratios of diazepam to metabolites and metabolites to metabolites from controlled drug administration studies. RESULTS: The respective time of maximum concentration, the maximum concentration and the elimination half-life of diazepam were 1.04 ± 1.00 h, 87.37 ± 31.92 ng/mL and 129.07 ± 75.00 h; of nordazepam were 133.14 ± 109.63 h, 3.80 ± 1.75 ng/mL, and 229.73 ± 236.83 h; of oxazepam were 100.29 ± 87.16 h, 1.62 ± 2.64 ng/mL, and 382.86 ± 324.58 h; of temazepam glucuronide were 44.43 ± 55.41 h, 2.08 ± 0.88 ng/mL, and 130.53 ± 72.11 h; and of oxazepam glucuronide were 66.86 ± 56.33 h, 1.10 ± 0.41 ng/mL, and 240.66 ± 170.12 h. A good correlation model was obtained from the concentration ratio of diazepam to nordazepam and the time of diazepam use, and the prediction errors were less than 20%. CONCLUSIONS: This study provides a sensitive method to identify diazepam ingestion by monitoring diazepam and its metabolites including glucuronides, as well as to infer the time following oral consumption.

Diagnostic evaluation and management of seizures and status epilepticus in children with known epilepsy or new-onset seizures: A retrospective and comparative analysis.

OBJECTIVES: The purpose of this study was to describe and compare the initial management, including clinical/biological investigation and treatment, of new-onset seizures and status epilepticus (SE) in children versus seizures and SE in those with known epilepsy. METHODS: This was a retrospective, single-center, observational study conducted in an urban pediatric hospital in Paris. All patients, aged from 1 month to 18 years, admitted to the pediatric intensive care unit, the high-dependency care unit, and those who required hospitalization in the short-term unit of the emergency department between January 1 and December 31, 2014 for seizures and/or SE were included. RESULTS: We analyzed the data of 190 children: new-onset seizures (N=118; group A) versus those with known epilepsy (N=72; group B). At least one diagnostic test was performed on 156 patients (82.1%) (group A, N=104, 88.1%; group B, N=52, 72.2%; P=0.05). In group B, blood levels of antiepileptic drugs were measured in 14 of the 38 patients with SE, of whom six were under dosed. Treatments were: first line, diazepam (group A, 80%; group B, 46%; P<0.001); second line, diazepam (group A, 56%; group B, 34%; P=0.02) or clonazepam (group A, 24%; group B, 46%; P=0.001); third line, phenytoin (group A, 54%; group B, 22%; P<0.001) or clonazepam (group A, 18%; group B, 61%; P<0.001). CONCLUSION: Diagnostic evaluation and treatment should be individualized for children with known epilepsy.

Microsampling with cotton thread: Storage and ultra-sensitive analysis by thread spray mass Spectrometry.

Storage and quantitative analysis of small volumes of biofluids are challenging, especially when low concentrations of analytes are to be detected in the presence of complex matrices. In this study, we describe an integrated thread-based approach for stabilizing small blood volumes in the dry-state at room temperature, while also offering direct analysis capabilities via thread spray mass spectrometry. The analytical merits of this novel microsampling platform was demonstrated via the direct analysis of diazepam and cocaine in dried blood samples stored for 42 days. In-situ in-capillary blood processing from hydrophobic threads enabled limits of detection as low as parts-per-quadrillion to be reached. We validated this ultra-sensitivity by analyzing small tissue-like residues collected after pushing a thread through the sample once. The implications of this sample collection, storage, and analysis platform can be extensive with direct applications in forensics and clinical studies.

Dried blood spots sampling in case samples deprived of hematocrit level information - Investigation and calculation strategy.

The application of a new calculation strategy for the psychotropic drug concentration in blood and bone marrow samples in the form of dried blood spots (DBS) was the main aim of the study. The standard DBS method consists of the deposition of the capillary blood onto the dedicated paper cards. Nowadays, the DBS technique is seen as a fast and partly superior microsampling alternative methodology replacing the conventional venous blood and plasma collection. The calculation approach to drug concentration in the limited volume of the case sample, where the hematocrit level cannot be determined, constitutes an important step of this method. The method has been validated and the results of the determination of alprazolam and diazepam previously spiked in the post-mortem blood and bone marrow sample have been satisfactory.

Direct analysis from dried blood spot card surfaces with direct probe mass spectrometry - Evaluation study.

RATIONALE: The Direct Probe Mass Spectrometry (DIPMS) method allows successful analysis of powders, solid and liquid samples. The potential of direct surface analysis could find further application in the examination of surfaces with good absorption properties such as Dried Blood Spot (DBS) cards that constitute a great alternative to the classical blood collection method directly from veins. METHODS: DIPMS was performed with the ionization carried out under atmospheric pressure in an Atmospheric Pressure Chemical Ionization source. Direct analysis of diazepam solutions in methanol and after their deposition onto a DBS card was conducted. Subsequently, images of the DBS cards with and without blood samples were acquired using Scanning Electron Microscopy (SEM). RESULTS: Direct quantitative analysis of diazepam liquid samples by DIPMS was successfully performed. Linear correlation between the concentration of diazepam and the peak intensity with a R2 coefficient of 0.937 was obtained. However, the method failed when the analysis was conducted directly from the surface of the DBS cards and no diazepam peak was observed in the mass spectrum. The SEM images confirmed the good absorption properties of DBS cards and the absence of blood components on the surface. CONCLUSIONS: DIPMS is an excellent technique for the rapid, direct analysis of powders, solid and liquid samples; however, the potential of the method is limited when samples are deposited on surfaces with good absorption properties such as DBS cards.

A Liquid-Chromatography High-Resolution Mass Spectrometry Method for Non-FDA Approved Benzodiazepines.

Benzodiazepines (BZDs) are widely used for treatment of anxiety and insomnia, however, this class of drugs is also commonly abused. Many different BZDs and analogs have been produced that are not FDA-approved. We tested 15 of these with the ThermoFisher CEDIA® BZD-immunoassay. With the exception of ketazolam, all compounds showed significant reactivity, highlighting the need for mass spectrometry confirmation assays. We developed a liquid-chromatography high-resolution mass spectrometry method for the detection of these 15 non-FDA approved BZDs. The limit of detection for most compounds ranged from 1 to 50 ng/mL, with mostly positive matrix effects observed in urine and negative matrix effects in serum. In a clinical research case, clonazolam and etizolam were detected in serum at 10.2 and 281 ng/mL, with an apparent elimination half-life of 3.6 and 4.8 hours, respectively. Although we did not detect non-FDA approved BZDs in 211 urine samples that were previously determined to be BZD-positive by immunoassay, abuse of these drugs is on the rise and clinical and forensic toxicology laboratories should consider developing methods to detect them.

Dried Blood Spheroids for Dry-State Room Temperature Stabilization of Microliter Blood Samples.

It is well-known that 2D dried blood spots on paper offer a facile sample collection, storage, and transportation of blood. However, large volume requirements, possible analyte instability, and difficult sample recovery plague this method, lowering confidence in analyte quantification. For the first time, we demonstrate a new approach using 3D dried blood spheroids for stabilization of small volume blood samples, mitigating these effects without cold storage. Blood spheroids form on hydrophobic paper, preventing interaction between the sample and paper substrate, eliminating all chromatographic effects. Stability of the enzyme alanine transaminase and labile organic compounds such as cocaine and diazepam were also shown to increase in the spheroid by providing a critical radius of insulation. On-surface analysis of the dried blood spheroids using paper spray mass spectrometry resulted in sub-ng/mL limits of detection for all illicit drugs tested, representing 1 order of magnitude improvement compared with analysis from 2D dried blood spots.

A Case Study Involving U-47700, Diclazepam and Flubromazepam-Application of Retrospective Analysis of HRMS Data.

The number of new psychoactive substances (NPS) available is constantly increasing, making it difficult for toxicology laboratories to keep screening methods up to date. Full scan high-resolution mass spectrometry (HRMS) is a versatile technique which allows for progressive updating of spectral databases to increase the scope of screening. It also allows for retrospective screening of data-specifically, reprocessing of data files using an updated spectral database without the need for re-extraction or reanalysis.The coronial case reported here illustrates the application of retrospective processing of HRMS data in the detection of emerging NPS. A 28-year-old male with a history of illicit drug use was found deceased at home. Initial routine screening of the post-mortem peripheral blood identified only methylamphetamine, amphetamine and trace amounts of lorazepam. A compound with an accurate mass and isotope ratio consistent with the opioid AH-7921 was also detected in the liquid chromatography (LC)-HRMS screen; however; the retention time and mass spectrum did not match the library. Further investigation confirmed the compound to be U-47700, another opioid and structural isomer of AH-7921. Several months later, after additional NPS had been added to the in-house HRMS database, retrospective screening of the HRMS data was performed, revealing the presence of designer benzodiazepines, diclazepam and flubromazepam as well as the psychedelic drug 2,5-dimethoxy-4-chloroamphetamine (DOC). Quantitative analysis gave the following results in peripheral post-mortem blood: U-47700 (330 µg/L), diclazepam (70 µg/L), flubromazepam (10 µg/L), methylamphetamine (290 µg/L) and amphetamine (150 µg/L) (DOC not quantitated). These substances, along with lorazepam and etizolam, were also confirmed in the post-mortem urine and an investigation into blood and urinary metabolites was carried out. All analyses were performed using the same LC-quadrupole-time of flight method. The cause of death was aspiration (of gastric content into airways and lungs) due to mixed drug toxicity.

Repeated diazepam administration reversed working memory impairments and glucocorticoid alterations in the prefrontal cortex after short but not long alcohol-withdrawal periods.

The study was designed to assess whether repeated administration of diazepam (Valium®, Roche)-a benzodiazepine exerting an agonist action on GABAA receptors-may alleviate both the short (1 week, 1W) and long-term (6 weeks, 6W) deleterious effects of alcohol withdrawal occurring after chronic alcohol consumption (6 months; 12% v/v) in C57/BL6 male mice. More pointedly, we first evidenced that 1W and 6W alcohol-withdrawn mice exhibited working memory deficits in a sequential alternation task, associated with sustained exaggerated corticosterone rise and decreased pCREB levels in the prefrontal cortex (PFC). In a subsequent experiment, diazepam was administered i.p. for 9 consecutive days (1 injection/day) during the alcohol withdrawal period at decreasing doses ranging from 1.0 mg/kg to 0.25 mg/kg. Diazepam was not detected in the blood of withdrawn mice at the time of memory testing, occurring 24 hours after the last diazepam injection. Repeated diazepam administration significantly improved alternation rates and normalized levels of glucocorticoids and pCREB activity in the PFC in 1W but not in 6W withdrawn mice. Thus, repeated diazepam administration during the alcohol-withdrawal period only transitorily canceled out the working memory impairments and glucocorticoid alterations in the PFC of alcohol-withdrawn animals.

Determination of minimal steady-state plasma level of diazepam causing seizure threshold elevation in rats.

OBJECTIVE: Diazepam, administered by the intravenous, oral, or rectal routes, is widely used for the management of acute seizures. Dosage forms for delivery of diazepam by other routes of administration, including intranasal, intramuscular, and transbuccal, are under investigation. In predicting what dosages are necessary to terminate seizures, the minimal exposure required to confer seizure protection must be known. Here we administered diazepam by continuous intravenous infusion to obtain near-steady-state levels, which allowed an assessment of the minimal levels that elevate seizure threshold. METHODS: The thresholds for various behavioral seizure signs (myoclonic jerk, clonus, and tonus) were determined with the timed intravenous pentylenetetrazol seizure threshold test in rats. Diazepam was administered to freely moving animals by continuous intravenous infusion via an indwelling jugular vein cannula. Blood samples for assay of plasma levels of diazepam and metabolites were recovered via an indwelling cannula in the contralateral jugular vein. RESULTS: The pharmacokinetic parameters of diazepam following a single 80-µg/kg intravenous bolus injection were determined using a noncompartmental pharmacokinetic approach. The derived parameters Vd , CL, t1/2α (distribution half-life) and t1/2ß (terminal half-life) for diazepam were, respectively, 608 mL, 22.1 mL/min, 13.7 minutes, and 76.8 minutes, respectively. Various doses of diazepam were continuously infused without or with an initial loading dose. At the end of the infusions, the thresholds for various behavioral seizure signs were determined. The minimal plasma diazepam concentration associated with threshold elevations was estimated at approximately 70 ng/mL. The active metabolites nordiazepam, oxazepam, and temazepam achieved levels that are expected to make only minor contributions to the threshold elevations. SIGNIFICANCE: Diazepam elevates seizure threshold at steady-state plasma concentrations lower than previously recognized. The minimally effective plasma concentration provides a reference that may be considered when estimating the diazepam exposure required for acute seizure treatment.

The Constraints, Construction, and Verification of a Strain-Specific Physiologically Based Pharmacokinetic Rat Model.

The use of in vitro-in vivo extrapolation (IVIVE) techniques, mechanistically incorporated within physiologically based pharmacokinetic (PBPK) models, can harness in vitro drug data and enhance understanding of in vivo pharmacokinetics. This study's objective was to develop a user-friendly rat (250 g, male Sprague-Dawley) IVIVE-linked PBPK model. A 13-compartment PBPK model including mechanistic absorption models was developed, with required system data (anatomical, physiological, and relevant IVIVE scaling factors) collated from literature and analyzed. Overall, 178 system parameter values for the model are provided. This study also highlights gaps in available system data required for strain-specific rat PBPK model development. The model's functionality and performance were assessed using previous literature-sourced in vitro properties for diazepam, metoprolol, and midazolam. The results of simulations were compared against observed pharmacokinetic rat data. Predicted and observed concentration profiles in 10 tissues for diazepam after a single intravenous (i.v.) dose making use of either observed i.v. clearance (CLiv) or in vitro hepatocyte intrinsic clearance (CLint) for simulations generally led to good predictions in various tissue compartments. Overall, all i.v. plasma concentration profiles were successfully predicted. However, there were challenges in predicting oral plasma concentration profiles for metoprolol and midazolam, and the potential reasons and according solutions are discussed.

Site-, Technique-, and Time-Related Aspects of the Postmortem Redistribution of Diazepam, Methadone, Morphine, and their Metabolites: Interest of Popliteal Vein Blood Sampling.

Sampling site, technique, and time influence postmortem drug concentrations. In 57 cases, we studied drug concentration differences as follows: subclavian vein-dissection/clamping versus blind stick, femoral vein-dissection/clamping versus blind stick, right cardiac chamber, and popliteal vein-dissection and clamping only. Cases were distributed in group #1 (all cases with both techniques), group #2 (dissection/clamping), and group #3 (blind stick). Sampled drugs were diazepam, methadone, morphine, and their metabolites. To assess PMR, mean concentrations and ratios were calculated for each group. Time-dependent variations of blood concentrations and ratios were also assessed. Results indicate that site, method, and time may influence postmortem distribution interpretation in different ways. Popliteal blood seems less subject to PMR. In conclusion, our study is the first to evaluate concurrently three main aspects of PMR and confirms that the popliteal vein may represent a site that is more resistant to the changes seen as a result of PMR.

High Performance Liquid Chromatographic Method for Direct Determination of Diazepam in Whole Blood and Serum - Optimization of Solid-Phase Extraction Method.

Herein, we present a simple and rapid high performance liquid chromatographic (HPLC) method with UV-detection for the direct determination of diazepam in whole blood and serum that can be used for monitoring diazepam levels in clinical samples analysis. The isolation of diazepam and the internal standard bromazepam from serum and whole blood samples was performed using solid phase extraction method with RP select B cartridges. The analytes were separated employing a reversed phase C8 column with a mobile phase composed of 0.1 % (V/V) triethylamine in water (pH 3.5) and acetonitrile (63:37, V/V). UV detection was carried out at 240 nm. Linearity was achieved in the range from 10.0-1000.0 ng/ml for serum and whole blood. The method was applied to spiked and real biological samples after an oral administration of 10 mg diazepam. In conclusion, the proposed method is simple, rapid and provides efficient clean-up of the complex biological matrix and high recovery of diazepam.

Lack of Effect of Vortioxetine on the Pharmacokinetics and Pharmacodynamics of Ethanol, Diazepam, and Lithium.

INTRODUCTION: Because the multimodal antidepressant vortioxetine is likely to be coadministered with other central nervous system (CNS)-active drugs, potential drug-drug interactions warrant examination. OBJECTIVE: These studies evaluated whether there are pharmacokinetic and/or pharmacodynamic interactions between vortioxetine and ethanol, diazepam, or lithium. METHODS: This series of phase I studies included healthy men and women (only men in the lithium study) aged 18-45 years. The ethanol study was a randomized, double-blind, two-parallel group, four-period crossover study in which subjects received a single dose of vortioxetine (20 or 40 mg) or placebo with or without ethanol, and the diazepam study was a randomized, double-blind, placebo-controlled, two-sequence, two-period crossover study in which subjects received a single dose of diazepam following multiple doses of vortioxetine 10 mg/day or placebo. These two studies evaluated the effect of coadministration on standardized psychomotor parameters and on selected pharmacokinetic parameters of each drug. The lithium study was a single-blind, single-sequence study evaluating the effect of multiple doses of vortioxetine 10 mg/day on the steady-state pharmacokinetics of lithium. RESULTS: Concomitant administration of vortioxetine and single doses of either ethanol or diazepam had no significant effect on the psychomotor performance of subjects compared with administration of ethanol or diazepam alone. Vortioxetine had no significant effect on the pharmacokinetics of ethanol, diazepam, or lithium, and ethanol had no significant effect on the pharmacokinetics of vortioxetine. CONCLUSIONS: Concomitant administration of these agents with vortioxetine was generally well tolerated, with no clinically relevant drug-drug pharmacokinetic or pharmacodynamic interactions identified.