Search results for "Valence"
showing 10 items of 2732 documents
Influence of Ad Congruence and Social Cues on the Probability of Choosing a Restaurant
2020
Abstract. Information processing of digital content includes conscious and un-conscious processes, memory, attitudes, and emotions and moods. Build up into the Heuristic‐Systematic Model, that states that persuasion can occur through a systematic or heuristic way, this research explores the effect of social media (SM) ratings and the ad content embedded in the SM website. Online ratings (part of the user-generated content (UGC) in SM platforms) are often heuristics cues. Subtle forms of congruence, such as the matching category between a restaurant advertiser and the third-party ad, as well as UGC, could have an impact on con-sumers’ attitudes towards the former. However, research on …
Biowaiver Monographs for Immediate-Release Solid Oral Dosage Forms: Folic Acid.
2018
This work presents a review of literature and experimental data relevant to the possibility of waiving pharmacokinetic bioequivalence studies in human volunteers for approval of immediate-release solid oral pharmaceutical forms containing folic acid as the single active pharmaceutical ingredient. For dosage forms containing 5 mg folic acid, the highest dose strength on the World Health Organization Essential Medicines List, the dose/solubility ratio calculated from solubility studies was higher than 250 mL, corresponding to a classification as "not highly soluble." Small, physiological doses of folic acid (≤320 μg) seem to be absorbed completely via active transport, but permeability data f…
In silicoprediction of drug dissolution and absorption with variation in intestinal pH for BCS class II weak acid drugs: ibuprofen and ketoprofen
2012
The FDA Biopharmaceutical Classification System guidance allows waivers for in vivo bioavailability and bioequivalence studies for immediate-release solid oral dosage forms only for BCS class I. Extensions of the in vivo biowaiver for a number of drugs in BCS class III and BCS class II have been proposed, in particular, BCS class II weak acids. However, a discrepancy between the in vivo BE results and in vitro dissolution results for BCS class II acids was recently observed. The objectives of this study were to determine the oral absorption of BCS class II weak acids via simulation software and to determine if the in vitro dissolution test with various dissolution media could be sufficient …
Risk analysis in bioequivalence and biowaiver decisions
2013
This article evaluates the current biowaiver guidance documents published by the FDA, EU and WHO from a risk based perspective. The authors introduce the use of a Failure Mode and Effect Analysis (FMEA) risk calculation tool to show that current regulatory documents implicitly limit the risk for bioinequivalence after granting a biowaiver by reduction of the incidence, improving the detection and limiting the severity of any unforeseen bioinequivalent product. In addition, the authors use the risk calculation to expose yet unexplored options for future extension of comparative in vitro tools for biowaivers.
Multivariate equivalence tests for use in pharmaceutical development.
2014
Statistical equivalence analyses are well-established parts of many studies in the biomedical sciences. Also in pharmaceutical development and manufacturing equivalence testing methods are required in order to statistically establish similarities between machines, process components, or complete processes. This article presents a choice of multivariate equivalence testing procedures for normally distributed data as generalizations of existing univariate methods. In all derived methods, variability is interpreted as nuisance parameter. The use of the proposed methods in pharmaceutical development is demonstrated with a comparative analysis of dissolution profiles.
Bioequivalence of oral products and the biopharmaceutics classification system: science, regulation, and public policy.
2011
The demonstration of bioequivalence (BE) is an essential requirement for ensuring that patients receive a product that performs as indicated by the label. The BE standard for a particular product is set by its innovator, and this standard must subsequently be matched by generic drug products. The Biopharmaceutics Classification System (BCS) sets a scientific basis for an improved BE standard for immediate-release solid oral dosage forms. In this paper, we discuss BE and the BCS, as well as the issues that are currently relevant to BE as a pharmaceutical product standard.
Relationships betweenin vitrodrug dissolution andin vivoresponse
2012
In recent years there has been an effort to relate manufacturing variables to the performance of the dosage form from a clinical point of view (in terms of safety and efficacy). Consequently any control strategy or the establishment of meaningful specifications should take into consideration the clinical impact on the patient. Since plasma levels are considered to be one of the most useful surrogates for clinical safety (in that bioequivalent plasma levels are considered therapeutically equivalent) and dissolution is the best surrogate for bioavailability, it is a natural consequence that dissolution be used to establish the design space in which all the formulations would have similar safe…
Drude-type conductivity of charged sphere colloidal crystals: Density and temperature dependence
2005
We report on extensive measurements in the low-frequency limit of the ac conductivity of colloidal fluids and crystals formed from charged colloidal spheres suspended in de-ionized water. Temperature was varied in a range of 5 degrees CTheta35 degrees C and the particle number density n between 0.2 and 25 microm(-3) for the larger, respectively, 2.75 and 210 microm(-3) for the smaller of two investigated species. At fixed Theta the conductivity increased linearly with increasing n without any significant change at the fluid-solid phase boundary. At fixed n it increased with increasing Theta and the increase was more pronounced for larger n. Lacking a rigorous electrohydrodynamic treatment f…
Cation Environment of BaCeO3−Based Protonic Conductors II: New Computational Models
2011
Quantum chemical calculations have been carried out to simulate Y-doped BaCeO(3) derivatives. Hartree-Fock energy functional was used to study octahedral site environments embedded in a Pmcn orthorhombic framework, showing local arrangement characterized by Ce-O-Ce, Ce-O-Y, and Y-O-Y (Z-O-Ξ) configurations and including or not hydrogen close to the moieties encompassing those configurations. The latter are, in fact, representative of - and, in our modeling approach, were treated as - local arrangements that could be found in Y:BaCeO(3)-doped materials. The geometrical optimizations performed on the structural models and a detailed orbital analysis of these systems allowed us to confirm and …
Optical phonons in theNaTiSi2O6oxide withS=12spin chains
2005
. The infrared-active phonon frequencies are obtained by Kramers-Kronig analy-sis of the reflectivity data. The assignment of the observed modes is done using lattice dynamical calculationsbased on the valence shell model. A phase transition at about 210 K is manifested through a dramatic changeof the mode frequency and broadening, and the appearance of new phonon modes. Analyzing the phononfrequency and damping vs temperature we have found that the phase transition leaves a fingerprint in thephonon dynamics of NaTiSi