Preparation and stability of indomethacin solutions

1982 ◽  
Vol 60 (7) ◽  
pp. 988-992 ◽  
Author(s):  
Stephen H. Curry ◽  
Edgar A. Brown ◽  
Hilken Kuck ◽  
Sidney Cassin
Keyword(s):  
High Pressure ◽  
Ductus Arteriosus ◽  
Alkaline Solutions ◽  
Related Research ◽  
Ph Values ◽  
Peg 400 ◽  
Biological Studies ◽  
Two Temperatures ◽  
Stable Solutions ◽  
Near Term

Indomethacin is used in closure of the ductus arteriosus in newborn humans as well as in related research in near-term sheep and goats. Conflicting data in these studies have led to a reexamination of indomethacin stability. Solutions at various pH values, at two temperatures, and in polyethylene glycol (PEG-400), were assessed by high-pressure liquid chromatography for indomethacin and its products. Solutions below pH 7.4 were stable. Decomposition was rapid in alkaline solutions. Solutions at pH 7.4 showed no changes up to 24 h. Solutions of sodium indomethacin, and of indomethacin in PEG were stable. Solutions in aqueous Na2CO3 were variably stable depending on the mode of mixing. A solution prepared directly in 0.1 M Na2CO3 (pH 10.7) lost 75% of its content in 80 min; a similar solution diluted immediately with two volumes of pH 7.4 buffer (final pH 9.9) showed less decomposition. A solution in Na2CO3 adjusted to pH 7.4 with HCl was stable (at least 24 h). Solutions prepared by suspending indomethacin in 0.9% NaCl and adding Na2CO3 slowly were stable for 80 min; rapid mixing led to decomposition. Solutions in plasma were stable at −20 °C (2 months). Lack of indomethacin activity in some biological studies may have resulted from injection of inactive solutions.

The aquation of cis-Chlorodi(methyl sulphoxide)bisethylenediaminecobalt(III), cis-Chlorodimethylformamidebisethylenediaminecobalt(III), and cis-Chlorodimethylacetamidebisethylenediaminecobalt(III) ions

1966 ◽  
Vol 19 (10) ◽  
pp. 1821 ◽  
Author(s):  
IR Lantzke ◽  
DW Watts
Keyword(s):  
Solvent Molecule ◽  
Chloride Ion ◽  
Side Reaction ◽  
Base Hydrolysis ◽  
Alkaline Solutions ◽  
Replacement Reaction ◽  
Ph Values ◽  
Trigonal Bipyramidal ◽  
Entropy Of Activation ◽  
Solvent Replacement

The aquation of each of three octahedral chloro(solvent)bisethylene- diaminecobalt(III) ions, involving the solvent ligands dimethyl sulphoxide (DMSO), dimethylformamide (DMF), and dimethylacetamide (DMA), has been examined in solutions of different pH. In solutions of pH less than 6, the predominant reaction is replacement of the solvent molecule by water in an SN1 process, involving a trigonal bipyramidal transition state and resulting in a mixture of the trans- and cis- chloroaquo complexes. The slow loss of chloride ion is an accompanying side reaction. In solutions of pH greater than 6 base hydrolysis becomes important, and in alkaline solutions the rate of solvent loss is too fast to measure by conventional techniques. The rate of liberation of chloride ion is also greatly increased with increasing pH. Values of the activation energy, and entropy of activation, are reported for the solvent replacement reaction at a pH of 1.90.

scholarly journals Effect of alkaline solutions on the tensile properties of glass-polyester pipes

2011 ◽  
pp. 185-195 ◽  
Author(s):  
Slavisa Putic ◽  
Marina Stamenovic ◽  
Jelena Petrovic ◽  
Marko Rakin ◽  
Bojan Medjo
Keyword(s):  
Tensile Properties ◽  
Construction Materials ◽  
Ammonium Hydroxide ◽  
Longitudinal Direction ◽  
Testing Procedure ◽  
Circumferential Direction ◽  
Process Equipment ◽  
Alkaline Solutions ◽  
Ph Values ◽  
Definite Structure

Construction materials, traditionally used in process equipment, are today successfully replaced by composite materials. Hence, many pipes are made of these materials. The subject of this study was the influence of liquids on the state of stresses and tensile strengths in the longitudinal and circumferential direction of glass-polyester pipes of a definite structure and known fabrication process. These analyses are of great importance for the use of glass-polyester pipes in the chemical industry. The tensile properties (the ultimate tensile strength and the modulus of elasticity) were tested and determined for specimens cut out of the pipes; flat specimens for the tensile properties in the longitudinal direction and ring specimens for the tensile properties in the circumferential direction. First, the tension test was performed on virgin samples (without the influence of any liquid), to obtain knowledge about the original tensile properties of the material composite studied. Subsequently, the specimens were soaked in alkaline solutions: sodium hydroxide (strong alkali) and ammonium hydroxide (weak alkali). These solutions were selected because of their considerable difference in pH values. The specimens and rings were left for 3, 10, 30 and 60 days in each liquid at room temperature. Then, the samples were tested on tension by the standard testing procedure. A comparison of the obtained results was made based on the pH values of the aggressive media in which the examined material had been soaked, as well as based on the original tensile properties and the number of days of treatment. Micromechanical analyses of sample breakage helped in the elucidation of the influence of the liquids on the structure of the composite pipe and enabled models and mechanisms that produced the change of strength to be proposed.

scholarly journals Corrosion Inhibition Efficiencies of Polymeric Materials on Alloy Steel in Dilute Hydrochloric Acid and Sodium Hydroxide Solutions at Ambient Temperature

2020 ◽  
Vol 7 (2) ◽  
pp. C27-C32
Author(s):  
I.E. Ekengwu ◽  
O.G. Utu ◽  
K.O. Anyanwu
Keyword(s):  
Corrosion Rate ◽  
Ambient Temperature ◽  
Alloy Steel ◽  
Corrosion Inhibition ◽  
High Density Polyethylene ◽  
Inhibition Efficiency ◽  
Polymeric Materials ◽  
High Density ◽  
Alkaline Solutions ◽  
Ph Values

A corrosion control test was conducted on alloy steel, using polymeric coatings (polyurethane, bitumen (medium airing), and high-density polyethylene) in dilute HCl solutions of pH values 4, 7, and 12, respectively for acid, neutral and alkaline solutions at ambient temperature. In the study, Eighty-four coupons of alloy steel were used. The coupons were mechanized, ground, polished, etched with natal, and weighed using a digital weighing balance (Beva 206B). The mass of each coupon was recorded according to the tag number on them. Twenty-one of the coupons were coated with polyurethane, 21 coated with medium curing bitumen (MC), and 21 coated with high-density polyethylene, while 21 were left uncoated. Seven polyurethane-coated samples, bitumen coating, and uncoated coupons were suspended in dilute HCl solutions of pH values 4, 7, and 12. Every week, one sample is taken from each of the solutions, the coatings and the corrosion products were removed, and the coupons were etched with natal. Then the coupons were reweighed, and their masses were recorded in accordance with their tag number. The weight loss per unit area of the coupons, corrosion rate, and percentage corrosion inhibition efficiencies of the coatings was calculated over seven weeks. The results obtained were tabulated and represented graphically. From the results obtained, it is seen that the corrosion inhibition efficiency of polyurethane coatings is higher compared with bitumen and polyethylene. It is also seen from the graphs that the corrosion rate of the coupons is higher in acid, a little bit lower in alkaline, and much lower in neutral solution. It is also observed that the corrosion rates fall with time as the inhibition efficiency also falls with time.

Barofractionation as an Innovative Method to Obtain Pectic Polysaccharides

2021 ◽  
Vol 899 ◽  
pp. 599-605
Author(s):  
Dara Slobodova ◽  
Raisa Gorshkova ◽  
Stanislav Pankov
Keyword(s):  
High Pressure ◽  
Physicochemical Parameters ◽  
New Method ◽  
High Yield ◽  
Dynamic Mode ◽  
High Quality ◽  
Pectic Polysaccharides ◽  
Ph Values ◽  
Pectin Polysaccharides ◽  
Innovative Method

An innovative method has been developed and an installation has been created for obtaining pectin polysaccharides in a dynamic mode under the influence of high pressure. The process of degradation of protopectin at various pH values pH of the hydrolyzing agent was studied using the example of sunflower baskets. It has been established that the use of the new method makes it possible to obtain high-quality target products with a high yield in gentle conditions. The possibility of combining the stages of hydrolysis-extraction and fractionation has been demonstrated, which makes it possible to control the process of obtaining pectic polysaccharides in the direction of obtaining substances with specified physicochemical parameters.

Use of ionic and zwitterionic (Tris/BisTris and HEPES) buffers in studies on hemoglobin function

1992 ◽  
Vol 72 (4) ◽  
pp. 1611-1615 ◽  
Author(s):  
R. E. Weber
Keyword(s):  
Binding Sites ◽  
Ionic Composition ◽  
Oxygen Affinity ◽  
Chloride Concentration ◽  
Anion Binding ◽  
Chloride Binding ◽  
Ph Values ◽  
Two Temperatures ◽  
Ethanesulfonic Acid ◽  
Chloride Concentrations

The functional characteristics of hemoglobin (Hb) depend on oxygenation-linked proton and anion binding and thus on solvent buffer groups and ionic composition. This study compares the oxygenation properties of human Hb in ionic [tris(hydroxymethyl)aminomethane (Tris) and BisTris] buffers with those in zwitterionic N-2-hydroxy-ethylpiperazine-N′-2-ethanesulfonic acid (HEPES) buffer under strictly controlled chloride concentrations at different pH values, two temperatures, and in the absence and presence of the erythrocytic cofactor, 2,3-diphosphoglycerate (DPG). In contrast to earlier studies (carried out at the same or different chloride concentrations) it shows only small buffer effects that are manifested at low chloride concentration and high pH. These observations suggest chloride binding to the Tris buffers, which reduces the interaction with specific chloride binding sites in the Hb. The findings indicate that HEPES allows for more accurate assessment of Hb-oxygen affinity and its anion and temperature sensitivities than ionic buffers and advocates standard use of HEPES in studies on Hb function. Precise oxygen affinities of Hb dissolved in both buffers are defined under standard conditions.

Development Status of Coal-Fired Gas Heaters for Brayton-Cycle Cogeneration Systems

1983 ◽  
Author(s):  
S. V. Gunn ◽  
J. R. McCarthy
Keyword(s):  
High Pressure ◽  
Heat Exchangers ◽  
Coal Combustion ◽  
Operating Experience ◽  
Department Of Energy ◽  
Test Facility ◽  
Brayton Cycle ◽  
Pulverized Coal Combustion ◽  
Development Status ◽  
Near Term

Under contract from the Department of Energy, Rocketdyne is developing the technology of coal-fired gas heaters for utilization in Brayton-cycle cogeneration systems. The program encompasses both atmospheric fluidized bed and pulverized coal combustion systems; and it is directed toward the development of gas heater systems capable of delivering high pressure air or helium at 1550 F, when employing metallic heat exchangers, and 1750 F, when employing ceramic heat exchangers. This paper reports on the development status of the program, with discussions of the completed “screening” corrosion/erosion tests of candidate heat exchanger materials, a description and summary of the operating experience with the 6- by 6-foot AFB test facility and a projection of the potential for relatively near term commercialization of such heater systems.

scholarly journals Boron removal from aqueous solutions by a polyethylenimine-epichlorohydrin resin

2018 ◽  
Vol 83 (2) ◽  
pp. 251-264 ◽  
Author(s):  
Sofia Sarri ◽  
Panagiotis Misaelides ◽  
Dimitrios Zamboulis ◽  
Jolanta Warchoł
Keyword(s):  
Aqueous Solutions ◽  
Boron Concentration ◽  
Kinetic Studies ◽  
Alkaline Solutions ◽  
Competitive Sorption ◽  
Boron Removal ◽  
Boron Uptake ◽  
Acidic Solutions ◽  
Ph Values ◽  
Batch Technique

The use of a polyethylenimine?epichlorohydrin resin for the boron removal from aqueous solutions (boron concentration: 100?5000 mg L-1) of non-adjusted and pre-adjusted pH (pHnat, pHinit 8.0, 9.0 and 10.0) aqueous solutions was investigated using a batch technique. The boron concentration in the solutions after sorption was determined photometrically. The results indicated that the pH-dependent boron uptake was related to the protonation/deprotonation of the surface functional groups of the resin and to the boron speciation in solutions of different pH values. The maximum boron sorption capacity observed in solutions of pH 9.0 was 55 mg g-1 exceeding the majority of other commercial or alternative sorbents. Five empirical adsorption equations (Freundlich, Langmuir, Redlich?Peterson, Langmuir?Freundlich and Toth) were applied to the modelling of the boron adsorption equilibrium. The modelling results identified the homogenous boron sorption from acidic and heterogeneous from alkaline solutions. At alkaline pH, the system non-ideality can originate either from the different binding mechanism or from the competitive sorption of different boron species. The homogenous type boron sorption from acidic solutions was further confirmed by kinetic studies

scholarly journals Effect of the Acidic and Alkaline Solutions on K2CrO4 and K2Cr2O7 by Ultraviolet and Visible Measurement

2019 ◽  
Vol 30 (1) ◽  
pp. 221
Author(s):  
Mohammad Radi Mohammad ◽  
Hasanain Saad Azeez
Keyword(s):  
Ph Value ◽  
Red Shift ◽  
Alkaline Solutions ◽  
Visible Spectroscopy ◽  
Solution Ph ◽  
Effect Of Ph ◽  
Ph Values ◽  
Uv Visible

In this work different amount of acidic (HCl) and alkaline (NaOH) solutions were added to stoke solutions of K2CrO4 and K2Cr2O7 to show the effect of pH values on their spectra. The results of UV-Visible spectroscopy shows that, the Changing of solution pH value when drops of HCl were added led to shift wavelength of K2CrO4 spectrum while no change has been occurred in K2Cr2O7 spectrum. However, Changing PH values solution by adding drops of NaOH led to change in wavelength red shift for K2Cr2O7 while no changes has been occurred in spectrum of K2CrO4.

Denture Cleansers, Soft Lining Materials and Water Temperature: What is the Effect?

2008 ◽  
Vol os15 (2) ◽  
pp. 53-58 ◽  
Author(s):  
Rajesh K Handa ◽  
Daryll C Jagger ◽  
Richard W Vowles
Keyword(s):  
Surface Roughness ◽  
Water Temperature ◽  
Contact Surface ◽  
Detrimental Effect ◽  
Three Dimensional ◽  
Acrylic Resin ◽  
Ph Values ◽  
Wide Range ◽  
Two Temperatures ◽  
Denture Cleansers

Aim To investigate the effect of water temperature, in association with four denture cleansers, on the colour and surface roughness of five soft lining materials. Method Two silicone soft lining materials (Molloplast B and Sofreliner) represented the heat-cured, laboratory-based and chairside materials that are available. The wide range of chairside, acrylic resin-based, temporary soft lining materials was represented by Coe-Soft, Viscogel and Eversoft. An alkaline hypochlorite (Dentural) and three effervescent peroxide solutions with a range of active pH values (Steradent Active Plus, pH 6; Steradent Extra Strength, pH 3; Superdrug Fresh, pH 11) were selected as the cleansers. The denture cleansers were used at two temperatures: 55 °C (manufacturers’ recommended temperature) and 80 °C. The colour of the specimens was evaluated using a colorimeter and the surface roughness was assessed using a three-dimensional, non-contact surface profilometer. This study reported on the effect of using both the higher temperatures and the recommended temperature on the colour and roughness of permanent and temporary soft lining materials. Results and Conclusion The results of the study showed that the temperature of the water used with denture cleansers might have a detrimental effect on the colour and surface roughness of some permanent and temporary soft lining materials.

Brain Type Natriuretic Peptide

2008 ◽  
Vol 27 (5) ◽  
pp. 343-346 ◽  
Author(s):  
Patricia Nash
Keyword(s):  
Heart Failure ◽  
Natriuretic Peptide ◽  
Transplant Rejection ◽  
Ductus Arteriosus ◽  
Left Ventricular ◽  
Preterm Neonates ◽  
Term Infants ◽  
End Diastolic Volume ◽  
Ventricular Diastolic Dysfunction ◽  
Near Term

BRAIN TYPE NATRIURETIC PEPTIDE, also called B-type natriuretic peptide (BNP), has emerged as a valuable diagnostic and prognostic marker in the assessment of heart failure in adults.1–7 Serum BNP levels have also been shown to differentiate pulmonary from cardiac causes of dyspnea and to be useful as a screening tool for ventricular hypertrophy, ventricular diastolic dysfunction, transplant rejection, and risk for sudden death in adult patients with congestive heart failure (CHF).3,7,8 In pediatric patients, BNP levels have been found to increase with a hemodynamically significant ventricular septal defect and to correlate with the volume of the shunt and the left ventricular end diastolic volume.7 Recently, BNP levels have been investigated for use in determining the hemodynamic significance of a patent ductus arteriosus (PDA) in preterm neonates.3,7,9–11 They have also been studied for use in the diagnosis and management of persistent pulmonary hypertension in term and near-term infants.6 This article reviews BNP terminology, structure, physiology, measurement, and potential utility in the NICU.

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