Synthesis and Pharmacological Evaluation of Novel 2,3,4,5-tetrahydro[1,3]diazepino[1,2-a]benzimidazole Derivatives as Promising Anxiolytic and Analgesic Agents.

A number of novel 2,3,4,5-tetrahydro[1,3]diazepino[1,2-a]benzimidazole derivatives 2 were obtained by alkylation mainly in the 1H-tautomeric form of 2,3,4,5-tetrahydro[1,3]diazepino[1,2-a]benzimidazole or its 8,9-dimethyl-substituted analog 4-chlorobenzyl bromide, 4-chloroacetic acid fluoroanilide, and 4-tert-butylphenacyl bromide in neutral medium. Compounds 3 were cyclized and synthesized earlier with 11-phenacyl-substituted diazepino[1,2-a]benzimidazoles upon heating in conc. HBr. The chemical structures of the compounds were clarified by using the 1H Nuclear Magnetic Resonance Spectroscopy (1H-NMR) technique. Anxiolytic properties were evaluated using the elevated plus maze (EPM) and open field (OF) tests. The analgesic effect of compounds was estimated with the tail flick (TF) and hot plate (HP) methods. Besides, possible the influence of the test compounds on motor activities of the animals was examined by the Grid, Wire, and Rotarod tests. Compounds 2d and 3b were the most active due to their prominent analgesic and anxiolytic potentials, respectively. The results of the performed in silico analysis showed that the high anxiolytic activity of compound 3b is explained by the combination of a pronounced interaction mainly with the benzodiazepine site of the GABAA receptor with a prominent interaction with both the specific and allosteric sites of the 5-HT2A receptor.

Leveraging Physiologically Based Pharmacokinetic Modeling and Experimental Data to Guide Dosing Modification of CYP3A-Mediated Drug-Drug Interactions in the Pediatric Population.

Solithromycin is a novel fluoroketolide antibiotic that is both a substrate and time-dependent inhibitor of CYP3A. Solithromycin has demonstrated efficacy in adults with community-acquired bacterial pneumonia and has also been investigated in pediatric patients. The objective of this study was to develop a framework for leveraging physiologically based pharmacokinetic (PBPK) modeling to predict CYP3A-mediated drug-drug interaction (DDI) potential in the pediatric population using solithromycin as a case study. To account for age, we performed in vitro metabolism and time-dependent inhibition studies for solithromycin for CYP3A4, CYP3A5, and CYP3A7. The PBPK model included CYP3A4 and CYP3A5 metabolism and time-dependent inhibition, glomerular filtration, P-glycoprotein transport, and enterohepatic recirculation. The average fold error of simulated and observed plasma concentrations of solithromycin in both adults (1966 plasma samples) and pediatric patients from 4 days to 17.9 years (684 plasma samples) were within 0.5- to 2.0-fold. The geometric mean ratios for the simulated area under the concentration versus time curve (AUC) extrapolated to infinity were within 0.75- to 1.25-fold of observed values in healthy adults receiving solithromycin with midazolam or ketoconazole. DDI potential was simulated in pediatric patients (1 month to 17 years of age) and adults. Solithromycin increased the simulated midazolam AUC 4- to 6-fold, and ketoconazole increased the simulated solithromycin AUC 1- to 2-fold in virtual subjects ranging from 1 month to 65 years of age. This study presents a systematic approach for incorporating CYP3A in vitro data into adult and pediatric PBPK models to predict pediatric CYP3A-mediated DDI potential. SIGNIFICANCE STATEMENT: Using solithromycin, this study presents a framework for investigating and incorporating CYP3A4, CYP3A5, and CYP3A7 in vitro data into adult and pediatric physiologically based pharmacokinetic models to predict CYP3A-mediated DDI potential in adult and pediatric subjects during drug development. In this study, minor age-related differences in inhibitor concentration resulted in differences in the magnitude of the DDI. Therefore, age-related differences in DDI potential for substrates metabolized primarily by CYP3A4 can be minimized by closely matching adult and pediatric inhibitor concentrations.

Citalopram and Cannabidiol: In Vitro and In Vivo Evidence of Pharmacokinetic Interactions Relevant to the Treatment of Anxiety Disorders in Young People.

BACKGROUND: Cannabidiol (CBD), a major nonintoxicating constituent of cannabis, exhibits anxiolytic properties in preclinical and human studies and is of interest as a novel intervention for treating anxiety disorders. Existing first-line pharmacotherapies for these disorders include selective serotonin reuptake inhibitor and other antidepressants. Cannabidiol has well-described inhibitory action on cytochrome P450 (CYP450) drug-metabolizing enzymes and significant drug-drug interactions (DDIs) between CBD and various anticonvulsant medications (eg, clobazam) have been described in the treatment of epilepsy. Here, we examined the likelihood of DDIs when CBD is added to medications prescribed in the treatment of anxiety. METHODS: The effect of CBD on CYP450-mediated metabolism of the commonly used antidepressants fluoxetine, sertraline, citalopram, and mirtazapine were examined in vitro. Cannabidiol-citalopram interactions were also examined in vivo in patients (n = 6) with anxiety disorders on stable treatment with citalopram or escitalopram who received ascending daily doses of adjunctive CBD (200-800 mg) over 12 weeks in a recent clinical trial. RESULTS: Cannabidiol minimally affected the metabolism of sertraline, fluoxetine, and mirtazapine in vitro. However, CBD significantly inhibited CYP3A4 and CYP2C19-mediated metabolism of citalopram and its stereoisomer escitalopram at physiologically relevant concentrations, suggesting a possible in vivo DDI. In patients on citalopram or escitalopram, the addition of CBD significantly increased citalopram plasma concentrations, although it was uncertain whether this also increased selective serotonin reuptake inhibitor-mediated adverse events. CONCLUSIONS: Further pharmacokinetic examination of the interaction between CBD and citalopram/escitalopram is clearly warranted, and clinicians should be vigilant around the possibility of treatment-emergent adverse effects when CBD is introduced to patients taking these antidepressants.

PHARMACOKINETICS AND CLINICAL EFFECTS OF A SINGLE ORAL DOSE OF TRAZODONE IN THE DOMESTIC GOAT (CAPRA HIRCUS) AS A MODEL FOR WILD RUMINANTS.

Trazodone is an antianxiety medication commonly used in human and veterinary medicine. Stress-related trauma is the leading cause of morbidity and mortality in wild ruminant species. Trazodone could reduce stress and allow safer capture and handling, thus having a positive effect on their welfare. The objective of this study was to describe the clinical effects and pharmacokinetic profile of an oral dose of trazodone in domestic goats (Capra hircus) as a model for wild ruminants. A pilot study using ethograms and accelerometers identified an oral dose of 10 mg/kg as optimal to reduce activity levels. This dose resulted in a 502% increase in time spent sleeping (P=0.0016) and a 623% increase in time spent lying down (P=0.01). Additionally, there were reductions of 72% in time spent grooming (P=0.02), 49% in time spent moving (P=0.01), and 87% in time spent observing (P=0.0002). Activity levels were significantly decreased by 31% for 4 hr following administration (P=0.049). There were no observed adverse effects. Time spent eating or ruminating was not affected by trazodone administration (P > 0.05). The pharmacokinetics of trazodone following a single oral dose of 10 mg/kg in 7 goats was assessed. All animals achieved plasma concentrations over 130 ng/ml, a level considered therapeutic in humans and dogs, for a mean of 6.4 ± 5.0 hr. Mean terminal half-life was 10.55 ± 6.80 hr. All goats achieved maximum concentration within 5-15 min and still had detectable plasma levels at 24 hr. Trazodone appears promising to decrease stress in exotic ruminant species. Further research is warranted to establish its efficacy in other ruminant species and clinical situations.

Pharmacological and pharmacokinetic effect of a polyherbal combination with Withania somnifera (L.) Dunal for the management of anxiety.

ETHNOPHARMACOLOGICAL RELEVANCE: In the Indian system of medicine, Withania somnifera (L.) Dunal, Hemidesmus indicus (R.Br.), Aegle marmelos (L.) Correa, Emblica officinalis Gaertn, Ocimum sanctum (L.) has been mentioned as a remedy for the treatment of anxiety related disorders. Based on their folklore use, a polyherbal combination was derived for the management of anxiety. AIM OF THE STUDY: The present study is aimed to find the best polyherbal combination (PHC), in terms of its pharmacological action, out of two PHC, namely PHC1 and PHC3, prepared based on the previous studies conducted and to carry out the pharmacokinetic (PK) study of the best combination (PHC3). MATERIALS AND METHODS: Pharmacological activities include elevated plus maze model and hole-board test for anti-anxiety screening, gamma amino-butyric acid (GABAA) measurement in brain tissues and superoxide dismutase, lipid peroxidation and reduced glutathione measurement for anti-oxidant screening. RESULTS: PHC3 (100 mg/kg) produced statistically significant (p < 0.05) effect on all the pharmacological outcome measures when compared to alprazolam standard. Therefore, it was chosen for PK study. PK study was carried out using Liquid Chromatography Mass Spectroscopy technique with respect to Withaferin-A. PK parameters such as maximum plasma concentration (Cmax), 16.78 ± 5.32 ng/mL; time of maximum concentration (Tmax), 18 ± 0.12min; half-life (T1/2) 61.20 ± 9.87min; mean residual time (MRT), 7.53 h s; area under the concentration versus time curve (AUC0-1), 1678 ± 34.13 ng/mL; area under the concentration versus time curve from zero to infinity (AUC0-∞), 1705 ± 28.87 ng/mL; total clearance (CL), 290.67 ± 15.89 mL/min and volume of distribution (Vd) 0.054 L were calculated. CONCLUSIONS: The results of the studies revealed that PHC3 possessed significant anxiolytic, anti-oxidant activities and enhanced expression of GABAA mediated inhibition when compared to PHC1. Withaferin-A in PHC3 exhibited a rapid oral absorption in rat plasma. The findings of this study greatly help to provide useful evidence for the development of suitable formulation using PHC3.

Slow Accumulation and Elimination of Diazepam and Its Active Metabolite With Extended Treatment in the Elderly.

Age-related changes in disposition of diazepam and its principal active metabolite, desmethyldiazepam (DMDZ), during and after extended dosage with diazepam were studied in healthy volunteers. Eight elderly subjects (ages 61-78 years) and 7 young subjects (21-33 years) received 2.5 mg of diazepam twice daily for 15 days. Predose (trough) concentrations of diazepam and DMDZ were measured during the 15 days of dosing, and in the postdosage washout period. Kinetic properties were determined by nonlinear regression using a sequential drug-to-metabolite pharmacokinetic model. Steady-state plasma concentrations of diazepam and DMDZ were 30% to 35% higher in elderly subjects compared to young volunteers, and steady-state clearances correspondingly lower, though differences did not reach significance. Large and significant differences were found between young and elderly groups in mean half-life of diazepam (31 vs 86 hours; P < .005) and DMDZ (40 vs 80 hours; P < .02). Half-life values from the multiple-dose study were closely correlated with values from previous single-dose studies of diazepam (R2 = 0.85) and DMDZ (R2 = 0.94) in the same subjects. With extended dosing of diazepam in the elderly, slow accumulation and delayed washout of diazepam and DMDZ is probable. After discontinuation, withdrawal or rebound effects are reduced in likelihood, but delayed recovery from sedative effects is possible due to slow elimination of active compounds. Safe treatment of elderly patients with diazepam is supported by understanding of age-related changes in pharmacologic and pharmacokinetic properties.

Flavonoids as therapeutic candidates for emotional disorders such as anxiety and depression.

Emotional disorders such as anxiety and depression are widespread psychological diseases that affect up to 20% of the world's population. There are many approaches to the discovery of novel agents for the treatment of depressive- and anxiety-like symptoms. However, the efficacy of existing drugs for emotional disorders is only exerted after a few weeks of treatment and have serious side effects. Due to this, new strategies to find suitable and safe options are being sought by many researchers. Among them, a lot of interest has been attracted by plant-derived natural compounds due to their wide range of beneficial effects for new agent development. Flavonoids are natural polyphenol-like compounds found commonly in plants, fruits, vegetables, and medicinal herbs. A diverse range of flavonoids have been studied to investigate their potential therapeutic activities for the treatment of brain-associated disorders, including anxiety and depression. The main aim of this review is to understand the associations between the various flavonoids and the emotional disorders and discuss the therapeutic effects of these natural compounds that were demonstrated during the conduction of recent studies. The current work shows advances in the latest research of some flavonoids as a potential candidate for the treatment of emotional disorders. We summarize their behavioral, molecular, physiological, and neurochemical effects in various in vitro and in vivo models. Therefore, in the present work, the latest studies were collected on the most important flavonoid compounds and their underlying mechanisms of action in emotion-related disorders were discussed.

Effects of the monoacylglycerol lipase inhibitor JZL184 on chickens infected with avian pathogenic Escherichia coli O78: A preliminary pharmacokinetic and infection study.

The endocannabinoid (eCB) system modulates the degree of injury caused by inflammation, while enhancing the activity of phagocytes that promote resolution of inflammation and tissue repair. In-vitro studies with the monoacylglycerol lipase (MAGL) inhibitor JZL184 have suggested that increased eCB signaling might enhance the ability of the host immune system to clear invading pathogens. Although the neurochemical effects of JZL184 on the eCB system in rodents are well-known, its immuneregulating effects are less clear, especially in chickens. The primary objective of this study was to explore whether modulating the eCB system affects immune responses in chickens. To do this, we administered JZL184 [10 and 40 mg/kg body weight (BW), intraperitoneal injection] into chickens prior to a challenge with avian pathogenic Escherichia coli (APEC) O78. Bacteria were isolated from livers, blood, air sacs, and hearts at 8, 28, and 56 h post-infection and the gross lesions in air sacs, livers, and hearts were also examined. Serum levels of JZL184 were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), which indicated that the drug was distributed systemically. The number of birds positive for airsacculitis after APEC O78 challenge was marginally higher in groups treated with JZL184 than in the control group (P = 0.064). Rather than augmenting host defense and enhancing pathogen clearance, these results suggested that JZL184 might have immunosuppressive effects that exacerbated APEC O78 infection in chickens.

Le système de l'endocannabinoïde (eCB) module le degré de blessure causé par une inflammation, tout en augmentant l'activité des phagocytes qui favorise la résolution de l'inflammation et la réparation tissulaire. Des études in vitro avec l'inhibiteur de la monoacylglycérol lipase (MAGL) JZL184 suggèrent qu'une augmentation du signal d'eCB pourrait augmenter la capacité du système immunitaire de l'hôte à éliminer les agents pathogènes envahisseurs. Bien que les effets neurochimiques du JZL184 sur le système eCB des rongeurs est bien connu, ses effets immuno-régulateurs sont moins clairs, spécialement chez les poulets. L'objectif primaire de la présente étude était d'explorer si une modulation du système eCB affecte les réponses immunitaires des poulets. Pour se faire, nous avons administré JZL184 [10 et 40 mg/kg de poids corporel (BW), par injection intrapéritonéale] à des poulets avant une infection défi avec l'agent pathogène aviaire Escherichia coli (APEC) O78. Des bactéries furent isolées du foie, du sang, des sacs aériens et du coeur à 8, 28 et 56 h post-infection et les lésions macroscopiques dans les sacs aériens, le foie et le coeur furent également examinées. Les niveaux sériques de JZL184 furent quantifiés par chromatographie liquide couplée à la spectrométrie de masse en tandem (LC-MS/MS), qui indiqua que le médicament était distribué systémiquement. Le nombre d'oiseaux positifs pour aérosacculite après infection par APEC O78 était légèrement plus élevé dans le groupe traité avec JZL184 que dans le groupe témoin (P = 0,064). Plutôt que d'augmenter les mécanismes de défense de l'hôte et d'améliorer l'élimination de l'agent pathogène, ces résultats suggèrent que JZL184 pourrait avoir des effets immunosuppresseurs qui ont exacerbé l'infection par APEC O78 chez les poulets.(Traduit par Docteur Serge Messier).

A Novel Study Design Using Continuous Intravenous and Intraduodenal Infusions of Midazolam and Voriconazole for Mechanistic Quantitative Assessment of Hepatic and Intestinal CYP3A Inhibition.

The extent of a drug-drug interaction (DDI) mediated by cytochrome P450 (CYP) 3A inhibitors is highly variable during a dosing interval, as it depends on the temporal course of victim and perpetrator drug concentrations at intestinal and hepatic CYP3A expression sites. Capturing the time course of inhibition is therefore difficult using standard DDI studies assessing changes in area under the curve; thus, a novel design was developed. In a 4-period changeover pilot study, 6 healthy men received intraduodenal or intravenous infusions of the CYP3A substrate midazolam (MDZ) at a rate of 0.26 mg/h for 24 hours. This was combined with intraduodenal or intravenous infusion of the CYP3A inhibitor voriconazole (VRZ), administered at rates of 7.5 mg/h from 8 to 16 hours and of 15 mg/h from 16 to 24 hours, after starting midazolam administration. Plasma and urine concentrations of VRZ, MDZ, and its major metabolites were quantified by liquid chromatography-tandem mass spectrometry and analyzed by semiphysiological population pharmacokinetic nonlinear mixed-effects modeling. A model including mechanism-based inactivation of the metabolizing enzymes (maximum inactivation rate constant kinact , 2.83 h-1 ; dissociation rate constant KI , 9.33 µM) described the pharmacokinetics of VRZ well. By introducing competitive inhibition by VRZ on primary and secondary MDZ metabolism, concentration-time profiles, MDZ and its metabolites were captured appropriately. The model provides estimates of local concentrations of substrate and inhibitor at the major CYP3A expression sites and thus of the respective dynamic extent of inhibition. A combination of intravenous and intraduodenal infusions of inhibitors and substrates has the potential to provide a more accurate assessment of DDIs occurring in both gut wall and liver.

Ascending-Dose Study of Controlled-Release Ketamine Tablets in Healthy Volunteers: Pharmacokinetics, Pharmacodynamics, Safety, and Tolerability.

Parenteral ketamine has fast-onset antidepressant and antianxiety effects; however, it causes dissociation, hypertension, and tachycardia shortly after dosing. Ketamine's antidepressant effects may be due to active metabolites rather than to ketamine itself. We hypothesized that oral controlled-release ketamine tablets would improve safety and tolerability compared with injected ketamine by reducing peak ketamine exposures compared with dosing by injection. In this randomized, placebo-controlled ascending-dose study, ketamine doses of 60, 120, or 240 mg or matching placebo (single dose followed by every-12-hours dosing for 5 doses) were given to 24 healthy volunteers. Pharmacokinetics, pharmacodynamics (brain-derived neurotropic factor), adverse events, and vital signs were assessed up to 72 hours. Drug release occurred over ∼10 hours, with most drug substance present as norketamine (∼90%). Area under the concentration-time curve and peak concentration were dose proportional. Elimination half-life was prolonged (7-9 hours) compared with published data from immediate-release oral formulations. There were no changes in blood pressure or heart rate after any dose. Mild dissociation was reported after 240 mg but not lower doses; mean dissociation ratings in this group were minimal (1-2/76). There were no clinically significant changes in ECGs or safety laboratory tests at any time. Compared with injected ketamine, oral controlled-release ketamine tablets did not increase blood pressure or heart rate, and only at doses of 240 mg was dissociation of mild intensity reported. Reducing and delaying ketamine peak concentration by oral dosing with controlled-release ketamine tablets improve this drug's tolerability for patients with depression/anxiety.

Nanostructured lipid carriers-mediated brain delivery of carbamazepine for improved in vivo anticonvulsant and anxiolytic activity.

The limited brain delivery of carbamezapine (CBZ) presents a major hurdle in the successful epilepsy treatment. The potential of carbamezapine-loaded nanostructured lipid carriers (CBZ-NLCs) for improved brain delivery is investigated in the current study. CBZ-NLCs were prepared by using binary mixture of trilaurin and oleic acid as a lipid core stabilized with Poloxamer 188, Tween 80 and Span 80. CBZ-NLCs were evaluated for physicochemical properties, in vitro release, in vivo brain kinetics, anticonvulsant and anxiolytic activities. The optimized CBZ-NLCs demonstrated nanometric particle size (97.7 nm), surface charge of -22 mV and high drug incorporation (85%). CBZ-NLCs displayed biphasic release pattern with initial fast followed by sustained drug release. CBZ-NLCs significantly enhanced the AUC of CBZ (520.4 µg·h/mL) in brain compared with CBZ dispersion (244.9 µg·h/mL). In vivo anticonvulsant activity of CBZ-NLCs in PTZ-induced seizure model showed a significant increase in the onset time (143.0 sec) and reduction in duration (17.2 sec) of tonic-clonic seizures compared with CBZ dispersion (75.4 and 37.2 sec). The anxiolytic activity in light-dark box and elevated-plus maze models also demonstrated superiority of CBZ-NLCs to CBZ dispersion. From the results, CBZ-NLCs presents a promising strategy to improve brain delivery and therapeutic outcomes of CBZ in epilepsy.

Design, synthesis and evaluation of activity and pharmacokinetic profile of new derivatives of xanthone and piperazine in the central nervous system.

Searching for CNS active cyclic amines derivatives containing heterocyclic xanthone core we designed and synthesized a set of fourteen novel 2- or 4-methylxanthone substituted by alkyl- or aryl-piperazine moieties. The compounds were evaluated in vivo for their potential antidepressant-like activity (in the forced swim test) and anxiolytic-like activity (four-plate test) and their inhibitory effect against rat 5-HT2 receptor was checked. The pharmacokinetic analysis of active compounds done by a non-compartmental approach have shown a rapid absorption of all studied molecules from intraperitoneal cavity and good penetration the blood-brain barrier after i.p. administration with brain to plasma ratios varied from 2.8 to 31.6. Genotoxicity and biotransformation of active compounds were studied. Compound 19 interactions with major classes of GPCRs, uptake systems and ion channels were tested and results indicated that it binds to 5-HT2A, 5-HT2B receptors and sodium channels.

A Novel Self-Emulsifying Drug Delivery System (SEDDS) Based on VESIsorb® Formulation Technology Improving the Oral Bioavailability of Cannabidiol in Healthy Subjects.

Cannabidiol (CBD), a phytocannabinoid compound of Cannabis sativa, shows limited oral bioavailability due to its lipophilicity and extensive first-pass metabolism. CBD is also known for its high intra- and inter-subject absorption variability in humans. To overcome these limitations a novel self-emulsifying drug delivery system (SEDDS) based on VESIsorb® formulation technology incorporating CBD, as Hemp-Extract, was developed (SEDDS-CBD). The study objective was to evaluate the pharmacokinetic profile of SEDDS-CBD in a randomized, double-blind, cross-over design in 16 healthy volunteers under fasted conditions. As reference formulation, the same Hemp-Extract diluted with medium-chain triglycerides (MCT-CBD) was used. CBD dose was standardized to 25 mg. Pharmacokinetic parameters were analyzed from individual concentration-time curves. Single oral administration of SEDDS-CBD led to a 4.4-fold higher Cmax and a 2.85-/1.70-fold higher AUC0-8h/AUC0-24h compared to the reference formulation. Tmax was substantially shorter for SEDDS-CBD (1.0 h) compared to MCT-CBD (3.0 h). Subgroup analysis demonstrated a higher bioavailability in women compared to men. This difference was seen for MCT-CBD while SEDDS-CBD mitigated this gender effect. Overall, SEDDS-CBD showed a significant improvement for all determined pharmacokinetic parameters: increased CBD plasma values (Cmax), favorably enhanced bioavailability (AUC) and fast absorption (Tmax). No safety concerns were noted following either administration.

8-Hydroxylation and Glucuronidation of Mirtazapine in Japanese Psychiatric Patients: Significance of the Glucuronidation Pathway of 8-Hydroxy-Mirtazapine.

INTRODUCTION: To investigate the metabolism of mirtazapine (MIR) in Japanese psychiatric patients, we determined the plasma levels of MIR, N-desmethylmirtazapine (DMIR), 8-hydroxy-mirtazapine (8-OH-MIR), mirtazapine glucuronide (MIR-G), and 8-hydroxy-mirtazapine glucuronide (8-OH-MIR-G). METHODS: Seventy-nine Japanese psychiatric patients were treated with MIR for 1-8 weeks to achieve a steady-state concentration. Plasma levels of MIR, DMIR, and 8-OH-MIR were determined using high-performance liquid chromatography. Plasma concentrations of MIR-G and 8-OH-MIR-G were determined by total MIR and total 8-OH-MIR (i. e., concentrations after hydrolysis) minus unconjugated MIR and unconjugated 8-OH-MIR, respectively. Polymerase chain reaction was used to determine CYP2D6 genotypes. RESULTS: Plasma levels of 8-OH-MIR were lower than those of MIR and DMIR (median 1.42 nmol/L vs. 92.71 nmol/L and 44.96 nmol/L, respectively). The plasma levels (median) of MIR-G and 8-OH-MIR-G were 75.00 nmol/L and 111.60 nmol/L, giving MIR-G/MIR and 8-OH-MIR-G/8-OH-MIR ratios of 0.92 and 59.50, respectively. Multiple regression analysis revealed that smoking was correlated with the plasma MIR concentration (dose- and body weight-corrected, p=0.040) and that age (years) was significantly correlated with the plasma DMIR concentration (dose- and body weight-corrected, p=0.018). The steady-state plasma concentrations of MIR and its metabolites were unaffected by the number of CYP2D6*5 and CYP2D6*10 alleles. DISCUSSION: The plasma concentration of 8-OH-MIR was as low as 1.42 nmol/L, whereas 8-OH-MIR-G had an approximate 59.50 times higher concentration than 8-OH-MIR, suggesting a significant role for hydroxylation of MIR and its glucuronidation in the Japanese population.

Microdosed midazolam for the determination of cytochrome P450 3A activity: Development and clinical evaluation of a buccal film.

Cytochrome P450 3A (CYP3A) isozymes metabolize about 50% of all marketed drugs. Their activity can be modulated up to 400-fold, which has great impact on individual dose requirements for CYP3A substrates. The activity of CYP3A can be monitored using the CYP3A substrate midazolam. To avoid pharmacological midazolam effects during phenotyping, a microdosing approach is preferred. However, the preparation of microdosed dosage forms remains a challenge. Fast dissolving buccal films are therefore proposed to facilitate this task. It was the aim of the present study to clinically evaluate a novel buccal film containing microdoses of midazolam for assessment of CYP3A activity. In a randomized, open-label crossover design, the pharmacokinetics of midazolam and its active hydroxy-metabolite, 1'­OH­midazolam, was assessed in 12 healthy volunteers after administration of single microdoses of midazolam (30 µg) as buccal film or buccal solution. The buccal film did rapidly disintegrate, was well tolerated, and no adverse events occurred. The film and the solution showed very similar midazolam plasma concentration-time profiles but were not bioequivalent according to EMA and FDA guidelines. For Cmax, AUC0-12h, and AUC0-∞ the geometric mean ratios of film to solution, with their 90% confidence intervals in parentheses, were 1.15 (1.00-1.32), 1.16 (1.04-1.28), and 1.19 (1.08-1.31), respectively. As a proxy for CYP3A activity, molar metabolic ratios of midazolam and 1'­OH­midazolam were analyzed over time, which revealed good correlations already 1 h or 2 h after application of the film or the solution, respectively. The tested midazolam buccal film is a convenient dosage form that facilitates administration of a phenotyping probe considerably and may potentially be used in special patient populations such as pediatric patients. Clinical Trials.gov Identifier: NCT03204578.

1,3-Dioxane as a scaffold for potent and selective 5-HT1AR agonist with in-vivo anxiolytic, anti-depressant and anti-nociceptive activity.

A series of compounds generated by ring expansion/opening and molecular elongation/simplification of the 1,3-dioxolane scaffold were prepared and tested for binding affinity at 5-HT1AR and α1 adrenoceptors. The compounds with greater affinity were selected for further functional studies. N-((2,2-diphenyl-1,3-dioxan-5-yl)methyl)-2-(2-methoxyphenoxy)ethan-1-ammonium hydrogen oxalate (12) emerged as highly potent full agonist at the 5-HT1AR (pKi 5-HT1A = 8.8; pD2 = 9.22, %Emax = 92). The pharmacokinetic data in rats showed that the orally administered 12 has a high biodistribution in the brain compartment. Thus, 12 was further investigated in-vivo, showing an anxiolytic and antidepressant effect. Moreover, in the formalin test, 12 was able to decrease the late response to the noxious stimulus, indicating a potential use in the treatment of chronic pain.

Buspirone Hydrochloride Loaded In Situ Nanovesicular Gel as an Anxiolytic Nasal Drug Delivery System: In Vitro and Animal Studies.

Nasal nanovesicular gels of buspirone hydrochloride (BH) were prepared and characterized aiming for sustained delivery and enhancing bioavailability. Buspirone hydrochloride has low bioavailability of about 4% after oral administration due to first pass metabolism. Buspirone hydrochloride nanovesicles were formulated by thin film hydration method (TFH). The selected nanovesicular formulation was incorporated into two types of in situ gels (pH-induced and thermoreversible) using carbopol 974P and poloxamer 407 (P407), respectively, together with different mucoadhesive polymers. The in situ gels were examined for pH, gelling capability, viscosity, content uniformity, mucoadhesiveness, and in vitro drug release. The ex vivo permeation performance of the in situ gel formulations that showed the most sustained release was also assessed. The in vivo study was done by the determination of BH blood level in albino rabbits after nasal administration. Results revealed that nanovesicles prepared using Span 60 and cholesterol in a ratio of 80:20 showed the highest EE% (70.57 ± 1.00%). The ex vivo permeation data confirmed higher permeability figures for carbopol formulation in comparison to poloxamer formulations. The in vivo study data showed an increase of 3.26 times in BH bioavailability when formulated into the carbopol nanovesicular in situ gel relative to control (nasal drug solution).

Distribution of clomipramine, citalopram, midazolam, and metabolites in skeletal tissue after chronic dosing in rats.

In recent years, the use of skeletal tissue as an alternative matrix in forensic toxicology has received new interest. In cases where extreme decomposition has taken place, analysis of skeletal tissue is often the only option left. In this article, a fully validated method is presented and the distribution of clomipramine, citalopram, midazolam, and metabolites after chronically administration is examined within skeletal tissue. Rats were chronically dosed with respectively clomipramine, citalopram, or midazolam. Extracts were quantitatively analyzed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Clomipramine, citalopram, and metabolites, respectively desmethylclomipramine and desmethylcitalopram are shown to be detectable in all bone types sampled. Midazolam and its metabolite α-OH-midazolam could not be detected. The absence of midazolam in extracts gives an indication that drugs with pKa values under physiological pH are badly or not incorporated in bone tissue. Bone and post-mortem blood concentrations were compared. A range of different bone types was compared and showed that the concentration is strongly dependent on the bone type. In concordance with previous publications, the humerus shows the highest drug levels. Skeletal tissue concentrations found ranged from 1.1 to 587.8 ng/g. Comparison of the same bone type between the different rats showed high variances. However, the drugs-metabolite ratio proved to have lower variances (<20%). Moreover, the drugs-metabolite ratio in the sampled bones is in close concordance to the ratios seen in blood within a rat. From this, we can assume that the drugs-metabolite ratio in skeletal tissue may prove to be more useful than absolute found concentration.

Benzodiazepines in Pregnancy.

Benzodiazepine use and dependence are on the rise as well as the number of deaths attributable to the combination of opioids and benzodiazepines. Anxiety, the most frequent condition for which benzodiazepines are prescribed, occurs commonly, and is increasingly noted to coincide with pregnancy. Use of both benzodiazepine anxiolytics and anxiety in pregnancy is associated with preterm delivery and low birth weight. Short-term neonatal effects of hypotonia, depression, and withdrawal are described but long-term sequelae, if any, are poorly understood. Benzodiazepines are associated with physical dependence and withdrawal symptoms which can be serious. To avoid withdrawal, tapering off these medications is recommended. What is known about the pharmacology and pharmacokinetics, pregnancy implications, tapering schedules, and alternative strategies for anxiety are discussed.

Determination of the pharmacokinetics of a single oral dose of trazodone and its effect on the activity level of domestic pigeons (Columba livia).

OBJECTIVE: To determine the pharmacokinetics of a single oral dose of trazodone and its effect on the activity of domestic pigeons (Columba livia). ANIMALS: 6 healthy adult male domestic pigeons. PROCEDURES: During the first of 3 experiments, birds received orally administered trazodone at doses ranging from 3 to 30 mg/kg to determine the dose for subsequent experiments. During the second experiment, each bird received 1 dose of trazodone (30 mg/kg, PO). Blood was collected for determination of plasma trazodone concentration before and at predetermined times for 24 hours after drug administration. Pharmacokinetic parameters were calculated by noncompartmental analysis. During experiment 3, birds were instrumented with ultralightweight accelerometers and received orally administered trazodone (30 mg/kg) or an equal volume of water twice at a 48-hour interval. Activity of birds was monitored for 24 hours after administration of each treatment. RESULTS: No adverse effects were observed. Mean ± SD terminal half-life of trazodone was 5.65 ± 1.75 hours. Plasma trazodone concentrations remained > 0.130 µg/mL for approximately 20 hours. Trazodone did not affect the activity of birds during the first 2 and 15 hours after administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that oral administration of 1 dose (30 mg/kg) of trazodone to healthy pigeons was safe and resulted in plasma drug concentrations that were similar to those considered therapeutic in humans and dogs for up to 20 hours. Further research is necessary to characterize the pharmacokinetics for repeated doses as well as the clinical effects of trazodone in birds with behavior problems.