The severity of the ongoing opioid crisis, recently exacerbated by the COVID-19 pandemic, emphasizes the importance for individuals suffering from opioid use disorder (OUD) to have access to and receive efficacious, evidence-based treatments. Optimal treatment of OUD should aim at blocking the effects of illicit opioids while controlling opioid craving and withdrawal to facilitate abstinence from opioid use and promote recovery. The present work analyses the relationship between buprenorphine plasma exposure and clinical efficacy in participants with moderate to severe OUD using data from two clinical studies (39 and 504 participants).
View Article and Find Full Text PDFBuprenorphine extended-release (BUP-XR) formulation is a once-monthly subcutaneous injection for the treatment of opioid use disorder (OUD). Buprenorphine undergoes extensive cytochrome P450 (CYP) 3A4 metabolism, leading to potential drug-drug interactions (DDIs) as reported for sublingual buprenorphine. Sublingual buprenorphine is subject to first-pass extraction, as a significant proportion of the dose is swallowed.
View Article and Find Full Text PDFBackground: Two phase I studies assessed the pharmacokinetics of buprenorphine, its metabolite norbuprenorphine, and naloxone following administration of buprenorphine/naloxone sublingual tablets in Chinese participants.
Methods: In the first phase I, open-label, single ascending-dose (SAD) study, 82 opioid-naïve volunteers received a single buprenorphine/naloxone dose ranging from 2 mg/0.5 mg to 24 mg/6 mg while under naltrexone block.
Extensive 12-lead electrocardiogram monitoring and drug concentrations were obtained during development of BUP-XR, a monthly subcutaneous injection for the treatment of opioid use disorder (OUD). Matched QT and plasma drug concentrations (11,925) from 1,114 subjects were pooled from 5 studies in OUD. A concentration-QT model was developed, which accounted for confounding factors (e.
View Article and Find Full Text PDFThe glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) exenatide and lixisenatide reduce cholecystokinin (CCK)-induced gallbladder emptying in healthy subjects. It is unknown if all GLP-1 RAs share this effect; therefore, the effect of the GLP-1 RA albiglutide on gallbladder function was assessed. In this randomized, double-blind, 2-way crossover study, a single dose of subcutaneous albiglutide 50 mg or placebo was administered to 17 healthy subjects, and CCK-induced gallbladder contractility was measured by ultrasonography.
View Article and Find Full Text PDFUnlabelled: Albiglutide is a glucagon-like peptide-1 analogue composed of tandem copies of modified human glucagon-like peptide-1 (7-36) coupled to recombinant human albumin that is approved in adults for the treatment of type 2 diabetes mellitus. After subcutaneous administration, albiglutide is likely primarily absorbed via the lymphatic circulation, with maximum concentrations being reached in 3 to 5 days; steady-state exposures are achieved following approximately 4 to 5 weeks of once-weekly administration. The elimination half-life of albiglutide is approximately 5 days.
View Article and Find Full Text PDFHuman radiolabel studies are traditionally conducted to provide a definitive understanding of the human absorption, distribution, metabolism and excretion (ADME) properties of a drug. However, advances in technology over the past decade have allowed alternative methods to be employed to obtain both clinical ADME and pharmacokinetic (PK) information. These include microdose and microtracer approaches using accelerator mass spectrometry, and the identification and quantification of metabolites in samples from classical human PK studies using technologies suitable for non-radiolabelled drug molecules, namely liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy.
View Article and Find Full Text PDFBackground: Chronic kidney disease is frequently present in patients with type 2 diabetes mellitus (T2DM). New therapeutic options in this patient subpopulation are needed.
Objectives: Assess the effect of renal impairment on the pharmacokinetics (PK), efficacy, and safety of albiglutide in single- and multiple-dose studies.
Introduction: Albiglutide, a selective once-weekly glucagon-like peptide-1 receptor agonist, is being developed for the treatment of type 2 diabetes mellitus. Albiglutide's effect on cardiac repolarization (QTc interval) was assessed in a randomized, double-blind, placebo-controlled, parallel-group study in healthy subjects with a nested crossover comparison for moxifloxacin.
Methods: Subjects were randomized to albiglutide (n = 85) or placebo (n = 89) and received injections of 30 mg albiglutide or placebo on Days 1 and 8 and 50 mg albiglutide or placebo on Days 15, 22, 29, and 36.
Given the tremendous growth of bioactivity databases, the use of computational tools to predict protein targets of small molecules has been gaining importance in recent years. Applications span a wide range, from the 'designed polypharmacology' of compounds to mode-of-action analysis. In this review, we firstly survey databases that can be used for ligand-based target prediction and which have grown tremendously in size in the past.
View Article and Find Full Text PDFPurpose: To develop a semi-mechanistic population pharmacokinetic model based on gastric emptying function for acetaminophen plasma concentration in critically ill patients tolerant and intolerant to enteral nutrition before and after prokinetic therapy.
Methods: Acetaminophen plasma concentrations were available from a study with 10 tolerant and 20 intolerant patients before and after prokinetic therapy with either erythromycin or metoclopramide. Population pharmacokinetic modelling was carried out in a nonlinear mixed effects analysis software, NONMEM.
Drug development is expensive and prone to failure. It is potentially much less risky and expensive to reuse a drug developed for one condition for treating a second disease, than it is to develop an entirely new compound. Systematic approaches to drug repositioning are needed to increase throughput and find candidates more reliably.
View Article and Find Full Text PDFAlvimopan is a novel, oral, peripherally acting mu-opioid receptor (PAM-OR) antagonist that blocks the effects of opioids on the gastrointestinal tract, without blocking opioid-induced analgesic effects. It is metabolized by gut microflora to an active amide-hydrolysis metabolite, which is equipotent to alvimopan. The objective of this study was to characterize the pharmacokinetics of alvimopan and metabolite before, during, and after administration of a short course of antibiotics in healthy adult participants.
View Article and Find Full Text PDFEcological network analysis is used to evaluate the impact of pesticide use on ecological systems in the context of agricultural farmland environments. The aim is to provide support for the design of effective and minimally damaging pest control strategies. The ecological network analysis can identify species that are important to the integrity of the ecological network.
View Article and Find Full Text PDFIn normal vision, visual scenes are predictable, as they are both spatially and temporally redundant. Evidence suggests that the visual system may use the spatio-temporal regularities of the external world, available in the retinal signal, to extract information from the visual environment and better reconstruct current and future stimuli. We studied this by recording neuronal responses of primary visual cortex (area V1) in anaesthetized and paralysed macaques during the presentation of dynamic sequences of bars, in which spatio-temporal regularities and local information were independently manipulated.
View Article and Find Full Text PDFStructure entails function, and thus a structural description of the brain will help to understand its function and may provide insights into many properties of brain systems, from their robustness and recovery from damage to their dynamics and even their evolution. Advances in the analysis of complex networks provide useful new approaches to understanding structural and functional properties of brain networks. Structural properties of networks recently described allow their characterization as small-world, random (exponential) and scale-free.
View Article and Find Full Text PDFThe spatio-temporal properties of saccadic eye movements can be influenced by the cognitive demand and the characteristics of the observed scene. Probably due to its crucial role in social communication, it is argued that face perception may involve different cognitive processes compared with non-face object or scene perception. In this study, we investigated whether and how face and natural scene images can influence the patterns of visuomotor activity.
View Article and Find Full Text PDFCentre-surround interaction in the primary visual cortex (area V1) has been studied extensively using artificial, abstract stimulus patterns, such as bars, gratings and simple texture patterns. In this experiment, we extend the study of centre-surround interaction by using natural scene images. We systematically varied the contrast of natural image surrounds presented outside the classical receptive field (CRF), and recorded neuronal response to a natural image patch presented within the CRF in area V1 of awake, fixating macaques.
View Article and Find Full Text PDFIt is generally agreed that information flow through the cortex is constrained by a hierarchical architecture. Lack of precise data on areal connectivity leads to indeterminacy of existing models. The authors introduce two quantitative parameters (SLN and FLN) that hold the promise of resolving such indeterminacy.
View Article and Find Full Text PDFSpatial and temporal regularities commonly exist in natural visual scenes. The knowledge of the probability structure of these regularities is likely to be informative for an efficient visual system. Here we explored how manipulating the spatio-temporal prior probability of stimuli affects human orientation perception.
View Article and Find Full Text PDFAim: To investigate the efficacy of low doses of naltrexone in relapse prevention for heroin dependence.
Design: Double blind, randomised comparison of three groups-Group 1 taking 50mg per day, Group 2: 0.5mg per day, and Group 3: 0.
Measuring functional magnetic resonance imaging (fMRI) responses to parametric stimulus variations in imaging experiments can elucidate how sensory information is represented in the brain. However, a potential limitation of this approach is that fMRI responses reflect only a regional average of neuronal activity. For this reason stimulus-induced changes in fMRI signal may not always reflect how sensory information is encoded by neuronal population activity.
View Article and Find Full Text PDFTo test the hypothesis that correlated neuronal activity serves as the neuronal code for visual feature binding, we applied information theory techniques to multiunit activity recorded from pairs of V1 recording sites in anaesthetised cats while presenting either single or separate bar stimuli. We quantified the roles of firing rates of individual channels and of cross-correlations between recording sites in encoding of visual information. Between 89 and 96% of the information was carried by firing rates; correlations contributed 4-11% extra information.
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