Search results for "ZOL"
showing 10 items of 4792 documents
Simultaneous dissolution profiles of two drugs in pharmaceutical formulations by an FIA manifold
2002
Abstract This article deals with the simultaneous determination of dissolution profiles of two drugs with overlapped spectra, present in the same pharmaceutical formulation. The official procedure for the dissolution profile is adapted to the continuous-flow methodology; the dissolution vessel is connected to an FIA manifold, in which the sample aliquots from the dissolution vessel are treated in order to adjust to the suitable pH and dilution degree to be monitored. The resulting solution is injected into the carrier stream, an acetic acid–acetate buffer at pH 4.3 and forced to the flow-cell of the spectrophotometer. The simultaneous determination of both profiles is based on the first der…
Flow-cytometric enumeration of reticulocytes with the new fluorochrome 1′,3′-diethyl-4,2′-quinolylthiacyanine
1992
Several flow-cytometric methods for reticulocyte enumeration in whole blood have been developed, with different degrees of practical use. Recently, a new fluorochrome, 1′,3′-diethyl-4,2′-quinolylthyacianine (DEQTC) was proposed in a brief report, as an alternative to thiazole orange for reticulocyte counting. We have evaluated the usefulness of this fluorescent stain by assessing the optimal conditions for the flow-cytometric analysis, and by comparing in double-blind assays the quantitative results of this technique with those obtained by manual counting with brilliant cresyl blue. Our results show that flow cytometry with DEQTC is highly correlated to the manual method (r=0.95–0.99), supp…
Effects of the Phosphodiesterase Inhibitor Enoximone on the Autonomic Innervation of the Isolated Heart
1989
Enoximone is a selective inhibitor of a low Km, cyclic AMP-specific type of phosphodiesterase (PDE III). In guinea pig and chicken atria, enoximone (0.1-100 mumol/L) caused a weak increase in the force of contraction. The heart rate was slightly enhanced or was unchanged (chicken). Enoximone (30 mumol/L) also failed to shift the concentration-response curves for the positive inotropic and chronotropic effects of norepinephrine in guinea pig atria. Under almost the same conditions, enoximone and the nonselective PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX) markedly potentiated the forskolin-induced mobilization of choline from phospholipids. The concentrations of IBMX (100 mumol/L) and o…
Fast enantiomeric separation of uniconazole and diniconazole by electrokinetic chromatography using an anionic cyclodextrin: application to the deter…
2000
The enantiomeric resolution of the fungicides uniconazole and diniconazole was performed using electrokinetic chromatography with cyclodextrins as pseudostationary phase (CD-EKC). A systematic evaluation of several chiral selectors was made. The anionic derivative carboxymethylated-gamma-cyclodextrin (CM-gamma-CD) was found to be the most appropriate for the enantioseparation of fungicides among all cyclodextrins tested. The influence of some experimental conditions such as nature and buffer pH, chiral selector concentration, and temperature on the enantiomeric separation of the compounds studied was also investigated. The use of a 50 mM phosphate buffer (pH 6.5) containing 5 mM CM-gamma-CD…
Amyloid fibrils formation and amorphous aggregation in Concanavalin A
2007
We here report an experimental study on the thermal aggregation process of concanavalin A, a protein belonging to the legume lectins family. The aggregation process and the involved conformational changes of the protein molecules were followed by means of fluorescence techniques, light scattering, circular dichroism, zeta potential measurements and atomic force microscopy. Our results show that the aggregation process of concanavalin A may evolve through two distinct pathways leading, respectively, to the formation of amyloids or amorphous aggregates. The relative extent of the two pathways is determined by pH, as amyloid aggregation is favored at high pH values ( approximately 9), while th…
Experimental and theoretical characterization of the strong effects on DNA stability caused by half-sandwich Ru(II) and Ir(III) bearing thiabendazole…
2020
Abstract: The synthesis and characterization of two half-sandwich complexes of Ru(II) and Ir(III) with thiabendazole as ancillary ligand and their DNA binding ability were investigated using experimental and computational methods. 1H NMR and acid–base studies have shown that aquo-complexes are the reactive species. Kinetic studies show that both complexes bind covalently to DNA through the metal site and non covalently through the ancillary ligand. Thermal stability studies, viscosity, circular dichroism measurements and quantum chemical calculations have shown that the covalent binding causes breaking of the H-bonding between base pairs, bringing about DNA denaturation and compaction. Addi…
Separation, isolation and stereochemical assignment of imazalil enantiomers and their quantitation in an in vitro toxicity test
2016
A simple method for the separation of the enantiomers of the fungicide imazalil was developed. Racemic imazalil was separated into its enantiomers with an enantiomeric purity of 99% using HPLC-UV with an enantioselective column (permethylated cyclodextrin) operated in reversed phase mode (water with 0.2% trimethylamine and 0.08% acetic acid and methanol). The absolute configuration of the separated enantiomers was assigned and unequivocally confirmed by optical rotation as well as by vibrational circular dichroism (VCD) and electronic circular dichroism (ECD) combined with ab-initio calculations. The same enantioselective column was also used to develop an HPLC-MS/MS method for the quantifi…
Bovine Serum Albumin protofibril-like aggregates formation: Solo but not simple mechanism
2011
We report an experimental study on the model protein Bovine Serum Albumin (BSA), with the aim of elucidating the mechanisms by which a fully folded globular protein undergoes different aggregation pathways leading to the formation of amyloid fibrils or amorphous aggregates. We observe thermally induced formation of fibrillar structures at pH far from the protein isoelectric point. The increase of electrostatic repulsion results in protein destabilization and in modifications of inter and intra-molecular interactions leading to the growth of fibril-like aggregates stabilized by inter-molecular-β sheets. The aggregation kinetics is studied by means of fluorescence techniques, light scattering…
Metabolomics of the effect of AMPK activation by AICAR on human umbilical vein endothelial cells
2011
AMP-activated protein kinase (AMPK) is a metabolic master switch expressed in a great number of cells and tissues. AMPK is thought to modulate the cellular response to different stresses that increase cellular AMP concentration. The adenosine analog, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) is an AMPK activator used in many studies to assess the effects of AMPK activation on cellular metabolism and function. However, the effect of AICAR on cell metabolism reaches many different pathways and metabolites, some of which do not seem to be fully related to AMPK activation. We have now for the first time used NMR metabolomics on human umbilical vein endothelial cells (HUVEC) fo…
Comparison of the activity of antifungal hexapeptides and the fungicides thiabendazole and imazalil against postharvest fungal pathogens
2003
8 pages, 2 figures, 3 tables.-- PMID: 14623382 [PubMed].-- Printed version published Dec 31, 2003.