Search results for "testi"
showing 10 items of 4607 documents
Hierarchical Mass Transfer Analysis of Drug Particle Dissolution, Highlighting the Hydrodynamics, pH, Particle Size, and Buffer Effects for the Disso…
2020
Dissolution is a crucial process for the oral delivery of drug products. Before being absorbed through epithelial cell membranes to reach the systemic circulation, drugs must first dissolve in the human gastrointestinal (GI) tract. In vivo and in vitro dissolutions are complex because of their dependency upon the drug physicochemical properties, drug product, and GI physiological properties. However, an understanding of this process is critical for the development of robust drug products. To enhance our understanding of in vivo and in vitro dissolutions, a hierarchical mass transfer (HMT) model was developed that considers the drug properties, GI fluid properties, and fluid hydrodynamics. T…
Activity–Bioavailability balance in Oral Drug Development for a Selected Group of 6‐Fluoroquinolones
2002
Abstract A nomogram is proposed to select the best candidate in drug development studies with quinolones and is intended to substitute other possible models. The nomogram is referred to as an activity–bioavailability balance (ABB) because it includes the following two criteria: ABB= 1 / gm MIC ( drug candidate ) 1 /gm MIC ( ciprofloxacin ) · F calc \( drug candidate \) F calc ( ciproflaxacin ) . The in vitro activity of a group of 4′ N ‐alkyl‐ciprofloxacin derivatives was determined together with that of ciprofloxacin, initially against some reference strains and subsequently against 159 clinical isolates of eight selected species. The inverse of the geometric mean of the lowest concentrati…
Does the addition of caseinophosphopeptides or milk improve zinc in vitro bioavailability in fruit beverages?
2009
Abstract The influence of caseinophosphopeptides (CPPs) added to fruit beverage versus milk based fruit beverage upon zinc retention, transport, and uptake, as well as the influence of Fe supplementation, were studied using a combined simulated gastrointestinal digestion/Caco-2 cell system. Zinc retention, transport, and uptake of milk based fruit beverage was 4- to 5-fold greater than that of fruit beverages with or without CPPs – no statistically significant differences being observed in relation to the presence or absence of CPPs. Possibly, a slow release of CPPs throughout the digestive tract, as can be expected to take place during the digestion of casein, has a more beneficial effect …
Beeinflussung der Darmmotorik durch Xylit
1963
Mit Hilfe der Tuschetransportmethode wurde an Mausen die Darmwirksamkeit von Xylit gepruft. Durch perorale Xylitgaben in Mengen von 0,5–1,0 g/kg Korpergewicht wurde die Darmtatigkeit deutlich angeregt. Kleinere Xylit-Dosen hatten demgegenuber keinen Einflus auf die Darmperistaltik. Die Anregung der Darmmotorik durch hohe Xylitgaben wird als osmotischer Effekt gedeutet.
Ab initio study of rotational isomerism and electronic structure of isomeric bipyrroles
1985
Abstract Ab initio calculations using STO-3G and 4-31G basis sets have been performed on the internal rotation barriers and conformational stabilities for 2,3′- and 3,3′-bipyrrole. The twofold rotation potential predicted for both isomers at minimal basis level becomes a more involved fourfold potential when the split-valence basis set is employed, because it takes into account more properly the nonbonded interannular interactions. A transoid-gauche minimum is predicted to have the minimal absolute conformational energy in both isomers. The electronic structure of the highest occupied MOs of 2,2′-, 2,3′- and 3,3′-bipyrrole are analyzed in terms of the single pyrrole MO pattern and a similar…
Structure, magnetizability, and nuclear magnetic shielding tensors of bis-heteropentalenes. IV. Dihydrophospholophosphole isomers
2005
The geometry of the heteropentalenes formed by two phosphole units has been determined at the DFT level. The magnetic susceptibility and the nuclear magnetic shielding at the nuclei of these systems have also been calculated using gauge-including atomic orbitals and a large Gaussian basis set to achieve near Hartree-Fock estimates. A comparative study of the various isomers, of their flattened analogs, and of the parent phosphole molecule, shows that the [3,4-c] isomer is the most aromatic system in the set considered, assuming diatropicity and degree of planarity as indicators, even if it is the less stable in terms of total molecular energy. Plots of magnetic field-induced current densiti…
3-Formyl-2-furanboronic acid: X-ray and DFT studies
2004
The molecule of the title compound, C5H5BO4, is almost planar with the boronic acid group inclined to the furan ring by 3.7 (1)°. DFT (density functional theory) calculations at the B3LYP/6-311+G** level of theory (with no imaginary frequencies) were used to approximate the influence of hydrogen bonding on the molecular geometry and have confirmed the planarity of the molecule. No significant differences in geometrical parameters in the solid state and in the gas phase are associated with the presence of the O—H⋯O intermolecular hydrogen-bonding network. The crystal packing is characterized by O—H⋯O hydrogen-bonded dimers, which are additionally linked by O—H⋯O, as well as C—H⋯O interactio…
Zur Frage der Resorption von Polyphosphaten
1965
Zur Klarung der Frage nach der Resorption von Polyphosphaten wurden Losungen von32P-markiertem Diphosphat, Triphosphat und einem Natriumpolyphosphat mit 64% P2O5 Ratten mit der Schlundsonde appliziert. Nach einer Verweildauer von 1, 2, 4, 8 und 16 Std dieser Polyphosphate im Magen-Darmtrakt wurden die Ratten dekapitiert und das erhaltene Frischblut radiometrisch und papierchromatographisch untersucht. Im enteiweisten Vollblut konnten nur Monophosphat und AMP nachgewiesen werden, d. h. es wird ausschlieslich anorganisches Monophosphat resorbiert, das durch enzymatische Aufspaltung der Polyphosphate gebildet wird. Dieses Monophosphat wird dann in die organische Bindung der AMP ubergefuhrt und…
Bioinspired self-assembly of tyrosinase-modified silicatein and fluorescent core-shell silica spheres.
2014
Inspired by the intermolecular cross-linking of mussel foot proteins and their adhesive properties, tyrosinase has been used to modify recombinant silicatein. DOPA/DOPAquinone-mediated cross-linking and interfacial interactions enhanced both self-assembly of silicatein building blocks and templating of core–shell silica spheres, resulting in fluorescent biomimetic silicatein–silica hybrid mesofibers.