Search results for "permeability"
showing 10 items of 596 documents
Water transmission properties of a sandy-loam soil estimated with Beerkan runs differing by the infiltration time criterion
2021
Abstract The Beerkan method consists of a ponded infiltration experiment from a single ring inserted a small depth into the soil. Fixed, small volumes of water are repeatedly poured into the ring to maintain a quasi-zero head on the soil surface. According to the standard Beerkan infiltration run, a new water volume is poured on the infiltration surface when the previously applied volume has completely infiltrated and the soil surface is entirely exposed to air (ta criterion). However, water could also be applied when the soil exposition to air begins (to criterion) or half the soil surface is exposed to air (tm criterion). The effect of the infiltration time criterion on determination of t…
Essential versus accessory aspects of cell death: recommendations of the NCCD 2015
2015
Cells exposed to extreme physicochemical or mechanical stimuli die in an uncontrollable manner, as a result of their immediate structural breakdown. Such an unavoidable variant of cellular demise is generally referred to as ?accidental cell death' (ACD). In most settings, however, cell death is initiated by a genetically encoded apparatus, correlating with the fact that its course can be altered by pharmacologic or genetic interventions. "Regulated cell death" (RCD) can occur as part of physiologic programs or can be activated once adaptive responses to perturbations of the extracellular or intracellular microenvironment fail. The biochemical phenomena that accompany RCD may be harnessed to…
Controlled iontophoretic release of glucocorticoids through epithelial cell monolayers
1998
In the present study the iontophoretic transdermal delivery of three different glucocorticoids through a confluent monolayer of MDCK cells, mimicking biological barriers, was studied. For this experiment an in vitro model with platinum electrodes for iontophoresis and MDCK cells was developed. With this model investigations concerning the biocompatibility of the cells depending on different current densities and the iontophoretic permeation of the three glucocorticoids through the cell monolayer were carried out. The permeation behavior of this living biological barrier should be very similar to the non-living barrier, human stratum corneum. Different current densities (12.74-38.22 microA/c…
Anaerobic treatment of urban wastewater in membrane bioreactors: evaluation of seasonal temperature variations
2014
The objective of this study was to evaluate the effect of seasonal temperature variations on the anaerobic treatment of urban wastewater in membrane bioreactors (MBRs). To this aim, sludge production, energy recovery potential, chemical oxygen demand (COD) removal and membrane permeability were evaluated in a submerged anaerobic MBR fitted with industrial-scale membrane units. The plant was operated for 172 days, between summer and winter seasons. Sludge production increased and energy recovery potential decreased when temperature decreased. COD removal and membrane permeability remained nearby stable throughout the whole experimental period.
Global testing of a consensus solubility assessment to enhance robustness of the WHO biopharmaceutical classification system
2020
The WHO Biopharmaceutical Classification System (BCS) is a practical tool to identify active pharmaceutical ingredients (APIs) that scientifically qualify for a waiver of in vivo bioequivalence studies. The focus of this study was to engage a global network of laboratories to experimentally quantify the pH-dependent solubility of the highest therapeutic dose of 16 APIs using a harmonized protocol. Intra-laboratory variability was ≤5 %, and no apparent association of inter-laboratory variability with API solubility was discovered. Final classification “low solubility” vs “high solubility” was consistent among laboratories. In comparison to the literature-based provisional 2006 WHO BCS classi…
Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Bisoprolol Fumarate
2014
Abstract Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate-release (IR) solid oral dosage forms containing bisoprolol as the sole active pharmaceutical ingredient (API) are reviewed. Bisoprolol is classified as a Class I API according to the current Biopharmaceutics Classification System (BCS). In addition to the BCS class, its therapeutic index, pharmacokinetic properties, data related to the possibility of excipient interactions, and reported BE/bioavailability problems are taken into consideration. Qualitative compositions of IR tablet dosage forms of bisoprolol with a marketing authorization (MA) in ICH (Inter…
Activation of cGMP-dependent Protein Kinase Iβ Inhibits Interleukin 2 Release and Proliferation of T Cell Receptor-stimulated Human Peripheral T Cells
2000
Several major functions of type I cGMP-dependent protein kinase (cGK I) have been established in smooth muscle cells, platelets, endothelial cells, and cardiac myocytes. Here we demonstrate that cGK Ibeta is endogenously expressed in freshly purified human peripheral blood T lymphocytes and inhibits their proliferation and interleukin 2 release. Incubation of human T cells with the NO donor, sodium nitroprusside, or the membrane-permeant cGMP analogs PET-cGMP and 8-pCPT-cGMP, activated cGK I and produced (i) a distinct pattern of phosphorylation of vasodilator-stimulated phosphoprotein, (ii) stimulation of the mitogen-activated protein kinases ERK1/2 and p38 kinase, and, upon anti-CD3 stimu…
Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Moxifloxacin Hydrochloride.
2020
Abstract In this monograph, literature data is reviewed to evaluate the feasibility of waiving in vivo bioequivalence testing and instead applying the Biopharmaceutics Classification System (BCS) based methods to the approval of immediate-release solid oral dosage forms containing moxifloxacin hydrochloride as the sole active pharmaceutical ingredient. To facilitate the feasibility decision, solubility and permeability and dissolution characteristics in the context of the BCS, therapeutic index, therapeutic use, pharmacokinetic parameters, bioequivalence/bioavailability issues, drug-excipient interactions and other relevant data were taken into consideration. Moxifloxacin is a BCS class I d…
Evaluating equilibrium and non-equilibrium transport of bromide and isoproturon in disturbed and undisturbed soil columns.
2007
19 pages; International audience; In this study, displacement experiments of isoproturon were conducted in disturbed and undisturbed columns of a silty clay loam soil under similar rainfall intensities. Solute transport occurred under saturated conditions in the undisturbed soil and under unsaturated conditions in the sieved soil because of a greater bulk density of the compacted undisturbed soil compared to the sieved soil. The objective of this work was to determine transport characteristics of isoproturon relative to bromide tracer. Triplicate column experiments were performed with sieved (structure partially destroyed to simulate conventional tillage) and undisturbed (structure preserve…
Pore scale modelling of calcite cement dissolution in a reservoir sandstone matrix
2019
E3S Web of Conferences 98, 05010 (1-5) (2019). doi:10.1051/e3sconf/20199805010