Nowadays, the ever-increasing costs of research and development in the pharmaceutical industry have created a big demand for predicting the performances of drug candidates. Of those, the desire to establish an in vitro-in vivo correlation (IVIVC) to better predict the oral drug exposure for different drug products is a growing need. Once a robust IVIVC is established, the performance of different drug products can be predicted and selected for testing in clinical trials with greater confidence.
View Article and Find Full Text PDFStroke is among the leading causes of death in the United States, and with our aging population, it will remain a pertinent obstacle in the acute setting. While the field of neuroradiology has advanced tremendously over the years, particularly in improving what we can visualize and quantify, the phrase "time is brain" yet dominates acute stroke management. Optimizing diagnostic protocols for suspected stroke requires a careful balance of data acquisition and speed, as well as taking into account available resources.
View Article and Find Full Text PDFPLoS One
December 2020
Objective: The gastrointestinal environment in which drug products need to disintegrate before the drug can dissolve and be absorbed has not been studied in detail due to limitations, especially invasiveness of existing techniques. Minimal in vivo data is available on undisturbed gastrointestinal motility to improve relevance of predictive dissolution models and in silico tools such as physiologically-based pharmacokinetic models. Recent advances in magnetic resonance imaging methods could provide novel data and insights that can be used as a reference to validate and, if necessary, optimize these models.
View Article and Find Full Text PDFThis study presents an effective approach to tackle the challenge of long-term monitoring of contaminated groundwater sites where remediation leaves residual contamination in the subsurface. Traditional long-term monitoring of contaminated groundwater sites focuses on measuring contaminant concentrations and is applicable to sites where contaminant mass is removed or degraded to a level below the regulatory standard. The traditional approach is less effective at sites where risk from metals or radionuclides continues to exist in the subsurface after remedial goals are achieved.
View Article and Find Full Text PDFIn the present work, we explored if Coca-Cola had a beneficial impact on the systemic outcome of the weakly basic drug loratadine (Wal-itin, immediate-release formulation, 10 mg, generic drug product). To map the contribution of underlying physiological variables that may positively impact the intestinal absorption of loratadine, a multi-compartmental and dynamic dissolution device was built, namely the Gastrointestinal Simulator (GIS). The luminal behavior of one immediate-release (IR) tablet of 10 mg of loratadine was tested under four different fasted state test conditions in the GIS: (i) with 250 mL of water and applying a predetermined gastric half-life (t) of 15 min; (ii) with 250 mL of water and applying a t of 30 min; (iii) with 250 mL of Coca-Cola and a t of 15 min; (iv) with 250 mL of Coca-Cola and a t of 30 min.
View Article and Find Full Text PDFAmorphous solid dispersions (ASDs) are commonly used to enhance the oral absorption of drugs with solubility or dissolution rate limitations. Although the ASD formulation is typically constrained by physical stability and in vivo performance considerations, ASD particles can be engineered using the spray-drying process to influence mechanical and flow properties critical to tableting. Using the ASD formulation of 20% w/w felodipine dispersed in polyvinyl pyrrolidone vinyl acetate, spray-drying atomization and drying conditions were tuned to achieve 4 different powders with varying particle properties.
View Article and Find Full Text PDFBackground/aims: High-resolution methods have advanced esophageal and anorectal manometry interpretation but are incompletely established for intestinal manometry. We characterized normal fasting duodeno-jejunal manometry parameters not measurable by standard techniques using clustered closely-spaced recordings.
Methods: Ten fasting recordings were performed in 8 healthy controls using catheters with 3-4 gastrointestinal manometry clusters with 1-2 cm channel spacing.
Exploring the intraluminal behavior of an oral drug product in the human gastrointestinal (GI) tract remains challenging. Many in vivo techniques are available to investigate the impact of GI physiology on oral drug behavior in fasting state conditions. However, little is known about the intraluminal behavior of a drug in postprandial conditions.
View Article and Find Full Text PDFThe bicarbonate buffer capacity is usually considered in a phase-homogeneous system, at equilibrium, with no CO transfer between the liquid buffer phase and another phase. However, typically, an in vitro bicarbonate buffer-based system is a phase-heterogeneous system, as it entails continuously sparging (bubbling) the dissolution medium with CO in a gas mixture, at constant ratio, to maintain a constant partial pressure of CO and CO molarity at a prescribed value, with CO diffusing freely between the gas and the aqueous phases. The human gastrointestinal tract is also a phase-heterogeneous system, with CO diffusing across the mucosal membrane into the mesenteric arterial blood, which serves as a sink for CO from the intestinal lumen.
View Article and Find Full Text PDFOver the past decade, formulation predictive dissolution (fPD) testing has gained increasing attention. Another mindset is pushed forward where scientists in our field are more confident to explore the in vivo behavior of an oral drug product by performing predictive in vitro dissolution studies. Similarly, there is an increasing interest in the application of modern computational fluid dynamics (CFD) frameworks and high-performance computing platforms to study the local processes underlying absorption within the gastrointestinal (GI) tract.
View Article and Find Full Text PDFThe goal of this study was to create a mass transport model (MTM) model for gastric emptying and upper gastrointestinal (GI) appearance that can capture the in vivo concentration-time profiles of the nonabsorbable drug phenol red in solution in the stomach and upper small intestine by direct luminal measurement while simultaneously recording the contractile activity (motility) via manometry. We advanced from a one-compartmental design of the stomach to a much more appropriate, multi-compartmental 'mixing tank' gastric model that reflects drug distribution along the different regions of the stomach as a consequence of randomly dosing relative to the different contractile phases of the migrating motor complex (MMC). To capture the intraluminal phenol red concentrations in the different segments of the GI tract both in fasted and fed state conditions, it was essential to include a bypass flow compartment ('magenstrasse') to facilitate the transport of the phenol red solution directly to the duodenum (fasted state) or antrum (fed state).
View Article and Find Full Text PDFBr J Clin Pharmacol
October 2018
Aims: Unavailability and lack of appropriate, effective and safe formulations are common problems in paediatric therapeutics. Key factors such as swallowing abilities, organoleptic preferences and dosage requirements determine the need for optimization of formulations. The provisional Biopharmaceutics Classification System (BCS) can be used in paediatric formulation design as a risk analysis and optimization tool.
View Article and Find Full Text PDFIn vivo drug dissolution in the gastrointestinal (GI) tract is largely unmeasured. The purpose of this clinical study was to evaluate the in vivo drug dissolution and systemic absorption of the BCS class IIa drug ibuprofen under fed and fasted conditions by direct sampling of stomach and small intestinal luminal content. Expanding current knowledge of drug dissolution in vivo will help to establish physiologically relevant in vitro models predictive of drug dissolution.
View Article and Find Full Text PDFThe rate and extent of drug dissolution and absorption from solid oral dosage forms is highly dependent on the volume of liquid in the gastrointestinal tract (GIT). However, little is known about the time course of GIT liquid volumes after drinking a glass of water (8 oz), particularly in the colon, which is a targeted site for both locally and systemically acting drug products. Previous magnetic resonance imaging (MRI) studies offered novel insights on GIT liquid distribution in fasted humans in the stomach and small intestine, and showed that freely mobile liquid in the intestine collects in fairly distinct regions or "pockets".
View Article and Find Full Text PDFThe overall objective of OrBiTo, a project within Innovative Medicines Initiative (IMI), is to streamline and optimize the development of orally administered drug products through the creation and efficient application of biopharmaceutics tools. This toolkit will include both experimental and computational models developed on improved understanding of the highly dynamic gastrointestinal (GI) physiology relevant to the GI absorption of drug products in both fasted and fed states. A part of the annual OrBiTo meeting in 2015 was dedicated to the presentation of the most recent progress in the development of the regulatory use of PBPK in silico modeling, in vivo predictive dissolution (IPD) tests, and their application to biowaivers.
View Article and Find Full Text PDFThe validation of laboratory paradigms that reliably induce a stress response [including hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS) activation], is critical for understanding how children's stress-response systems support emotional and cognitive function. Early childhood research to date is markedly limited, given the difficulty in establishing paradigms that reliably induce a cortisol response. Furthermore, research to date has not included a control condition or examined concurrent ANS reactivity.
View Article and Find Full Text PDFJ Pharm Sci
January 2017
Magnesium stearate is the salt of a complex mixture of fatty acids, with the majority being stearate and palmitate. It has multiple crystalline forms and, potentially, an amorphous form. Magnesium stearate is used in the pharmaceutical manufacturing industry as a powder lubricant, and typically is added at low levels (∼1%) during the manufacturing process and blended for a relatively short time (∼5 min).
View Article and Find Full Text PDFThe purpose of this study was to assess the feasibility of a multicompartmental in vitro dissolution apparatus, gastrointestinal simulator (GIS), in assessing the drug dissolution of 2 commercially available oral dosage forms for itraconazole (ICZ). The GIS consists of 3 chambers, mimicking the upper gastrointestinal tract. In vitro dissolution of ICZ capsule or oral solution was evaluated in United States Pharmacopeia apparatus II and GIS.
View Article and Find Full Text PDFHawaiian forest birds serve as an ideal group to explore the extent of climate change impacts on at-risk species. Avian malaria constrains many remaining Hawaiian forest bird species to high elevations where temperatures are too cool for malaria's life cycle and its principal mosquito vector. The impact of climate change on Hawaiian forest birds has been a recent focus of Hawaiian conservation biology, and has centered on the links between climate and avian malaria.
View Article and Find Full Text PDFUSP apparatus I and II are gold standard methodologies for determining the in vitro dissolution profiles of test drugs. However, it is difficult to use in vitro dissolution results to predict in vivo dissolution, particularly the pH-dependent solubility of weak acid and base drugs, because the USP apparatus contains one vessel with a fixed pH for the test drug, limiting insight into in vivo drug dissolution of weak acid and weak base drugs. This discrepancy underscores the need to develop new in vitro dissolution methodology that better predicts in vivo response to assure the therapeutic efficacy and safety of oral drug products.
View Article and Find Full Text PDFThe rate and extent of drug dissolution and absorption from solid oral dosage forms is highly dependent upon the volumes and distribution of gastric and small intestinal water. However, little is known about the time courses and distribution of water volumes in vivo in an undisturbed gut. Previous imaging studies offered a snapshot of water distribution in fasted humans and showed that water in the small intestine is distributed in small pockets.
View Article and Find Full Text PDFOccupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation.
View Article and Find Full Text PDFThe Biopharmaceutics Classification System (BCS) has become widely accepted today in the academic, industrial, and regulatory world. While the initial application of the BCS was to regulatory science bioequivalence (BE) issues and related implications, it has come to be utilized widely by the pharmaceutical industry in drug discovery and development as well. This brief manuscript will relate the story of the BCS development.
View Article and Find Full Text PDFThis review further clarifies the concept of pharmaceutical quality by design (QbD) and describes its objectives. QbD elements include the following: (1) a quality target product profile (QTPP) that identifies the critical quality attributes (CQAs) of the drug product; (2) product design and understanding including identification of critical material attributes (CMAs); (3) process design and understanding including identification of critical process parameters (CPPs), linking CMAs and CPPs to CQAs; (4) a control strategy that includes specifications for the drug substance(s), excipient(s), and drug product as well as controls for each step of the manufacturing process; and (5) process capability and continual improvement. QbD tools and studies include prior knowledge, risk assessment, mechanistic models, design of experiments (DoE) and data analysis, and process analytical technology (PAT).
View Article and Find Full Text PDFOccupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation.
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