scholarly journals Iodometric determination of cystamine dihydrochloride in tablets using diperoxyadipic acid

2020 ◽  
Vol 8 (1) ◽  
pp. 19-27
Author(s):  
Mykola Blazheyevskiy ◽  
Valeriy Moroz
Keyword(s):  
Analytical Techniques ◽  
Second Order ◽  
Order Conditions ◽  
Buffer Solution ◽  
Buffer Solutions ◽  
Water Ph ◽  
Bulk Drug ◽  
Kinetics Of ◽  
Official Procedure

The kinetics of cystamine dihydrochloride oxidation by diperoxyadipic acid (DPAA) was studied in aqueous buffer solutions of pH 2.9, 6.9, 8.0, 8.5 and 9.2 under second-order conditions at the temperature 293 K. The second order rate constants, k (L mol−1 min−1) were calculated from kinetic values. A suitable mechanism scheme based on these observations was proposed. The possibility of application of DPAA as reagent for oxidimetric determination of cystamine dihydrochloride in tabtets was investigated. Cystamine dihydrochloride was determined by indirect titration with DPAA. The required amount of Cystamine dihydrochloride was dissolved in water, pH 8.0 buffer solution and DPAA solution was added. After 7 min, the solution was acidified. The excess DPAA was determined via iodometric titration. The advantages of the applied analytical techniques in the determination of cystamine dihydrochloride in tablets «Cystamine 0.2 g» was presented. The recovery of сystamine dihydrochloride was 99.32±1.45%. A paired t-test showed that all results obtained for bulk drug and in tablets «Cystamine 0.2 g», using the proposed procedure and the official procedure respectively, agreed at the 95% confidence level.

Determination of the Nucleophilicity of Tricarbonyliron Coordinated Cyclohepta-1,3,5-triene

1999 ◽  
Vol 64 (11) ◽  
pp. 1770-1779 ◽  
Author(s):  
Herbert Mayr ◽  
Karl-Heinz Müller
Keyword(s):  
Gibbs Energy ◽  
Ambient Temperature ◽  
Rate Constants ◽  
Second Order ◽  
Order Rate ◽  
Electrophilic Additions ◽  
Kinetics Of

The kinetics of the electrophilic additions of four diarylcarbenium ions (4a-4d) to tricarbonyl(η4-cyclohepta-1,3,5-triene)iron (1) have been studied photometrically. The second-order rate constants match the linear Gibbs energy relationship log k20 °C = s(E + N) and yield the nucleophilicity parameter N(1) = 3.69. It is concluded that electrophiles with E ≥ -9 will react with complex 1 at ambient temperature.

Spectrofluorimetric determination of uric acid based on its activation of catalytic oxidation of pyronine Y

2008 ◽  
Vol 62 (3) ◽  
Author(s):  
Suling Feng ◽  
Xueping Liu
Keyword(s):  
Uric Acid ◽  
Buffer Solution ◽  
Activation Effect ◽  
Buffer Solutions ◽  
Spectrofluorimetric Method ◽  
Spectrofluorimetric Determination ◽  
Uric Acid Determination ◽  
Catalyzed Oxidation ◽  
Acid Determination

AbstractA novel kinetic spectrofluorimetric method for the determination of uric acid based on the activation effect of uric acid on the Cu(II) ion catalyzed oxidation of pyronine Y by hydrogen peroxide was developed. The influence of different buffer solutions was tested and the Britton-Robinson buffer solution with pH 2.2 was found to be the optimum. The detection limit and the linear range for uric acid are 0.09 μg mL−1 and 0.3–3.0 μg mL−1, respectively. The RSD for eleven determinations of 1.6 μg mL−1 uric acid was 1.6 %. Satisfactory results were obtained when using this method of uric acid determination in human urine.

scholarly journals Kinetika Reaksi Hidrolisis Pati Biji Alpukat (Persea americana Mill) dengan Katalis HCl

2020 ◽  
Vol 4 (1) ◽  
pp. 120-131
Author(s):  
Sitti Rahmawati ◽  
Asnila Asnila ◽  
Suherman Suherman ◽  
Paulus Hengky Abram
Keyword(s):  
Reaction Order ◽  
Second Order ◽  
Hydrolysis Reaction ◽  
Starch Hydrolysis ◽  
First Order ◽  
Graph Method ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Avocado Seed

One of the plants that can be used as raw material for making sugar is plants that contain starch content such as avocado seeds. This study aims to determine the reaction order, the reaction rate constant from the hydrolysis of avocado seed starch using HCl. The method of this research is to determine the optimum concentration of HCl hydrolysis reaction from avocado seed starch using various concentrations of HCl (0.5 M; 1 M; 1.5 M; 2 M; 2.5 M) at the optimum temperature and stirring time (90oC for 70 minute). The hydrolysis process was followed by neutralization using 5 M NaOH solution and evaporated to obtain concentrated glucose, glucose was analyzed qualitatively and quantitatively by the Benedict method and the phenol sulfuric acid method. Based on the results of the maximum glucose levels obtained from the hydrolysis of variations in the concentration of HCl avocado seed starch, HCl 1.5 M. Furthermore, determine the kinetics of the starch hydrolysis reaction using time variations (30, 40, 50, 60 and 70) minutes at 90oC and concentrations The HCl 1.5 M. reaction order is determined by the intral method and the graph method. Determination of the first order graph method is done by plotting the value of ln [A] versus time, while the second order by plotting the value of 1 / [A] versus time. The first order with a 93% confidence level was obtained from the value of R2 = 0.9312, while the second order was 85% obtained from the value of R2 = 0.8581. Determination of the order of the integral method k value tends to remain in the first order formula with an average of k = 0.01962 minutes-1. Based on the two methods, it can be determined that the kinetics of the avocado seed starch hydrolysis reaction follows a first-order reaction.

Crystal pseudopolymorphism of secnidazole bulk drug, C7H11N3O3

1999 ◽  
Vol 14 (2) ◽  
pp. 136-141 ◽  
Author(s):  
Héctor Novoa de Armas ◽  
Rolando González Hernández ◽  
Anailien Boza Rivera ◽  
Ramón Pomés Hernández ◽  
Irminia Herrera Martínez
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Powder Diffraction ◽  
Structure Determination ◽  
Powdered Sample ◽  
Buffer Solution ◽  
Cell Dimensions ◽  
Bulk Drug ◽  
Unit Cell Dimensions

An indexed powder diffraction pattern and related crystallographic data are reported for secnidazole [C7H11N3O3, IUPAC name: 1-(2-hydroxypropyl)-2-methyl-5-nitroimidazole], which is not represented in the Powder Diffraction File. The unit cell dimensions were determined from diffractometer methods, using monochromatic CuKα1 radiation, and evaluated by indexing programs. The monoclinic cell found for 1-(2-hydroxypropyl)-2-methyl-5-nitroimidazole is: a=12.426(2) Å, b=12.173(2) Å, c=6.656(1) Å, β=100.19(1)°, Z=4, space group P21/c (No. 14), Dx=1.271 g/cm3. Crystallization of an anhydrous powdered sample of secnidazole in a buffer solution of Na2B4O7 and NaOH (pH 10.4) resulted in crystals that contained water of crystallization, as shown by single crystal structure determination. Secnidazole exhibits crystal pseudopolymorphism, because the experimental powder pattern of the anhydrous form and the calculated pattern from the structure determination of the hydrate form are similar. Observed powder diffraction data for this drug were interpreted with the aid of a calculated pattern based upon the crystal structure determined. The cell found by TREOR90P for anhydrous secnidazole is in good agreement with that of the hemihydrate form determined from single crystal diffraction: a=12.424(2) Å, b=12.187(2) Å, c=6.662(1) Å, β=100.9(1)°; Z=4.

Electroanalytical Determination of Some Sulfonamides on Overoxidized Polypyrrole Electrodes

2011 ◽  
Vol 64 (7) ◽  
pp. 965 ◽  
Author(s):  
Sabriye Percin Ozkorucuklu ◽  
Levent Ozcan ◽  
Yucel Sahin ◽  
Guleren Alsancak
Keyword(s):  
Correlation Coefficients ◽  
Differential Pulse ◽  
Pencil Graphite Electrode ◽  
Buffer Solution ◽  
Graphite Electrodes ◽  
Buffer Solutions ◽  
Pharmaceutical Tablet ◽  
Overoxidized Polypyrrole ◽  
Pulse Voltammetry

The electrochemical behaviours of five sulfonamides (sulfanilamide, sulfadiazine, sulfamerazine, sulfamonomethoxine, sulfamethoxazole) were investigated with overoxidized polypyrrole (OPPy) modified pencil graphite electrodes. The performance of the OPPy electrode was evaluated by differential pulse voltammetry in Britton–Robinson buffer solutions prepared in different ratio of acetonitrile-water binary mixture, between pH 1.5 and 7.0. The highest anodic signals of sulfonamides were obtained in Britton–Robinson buffer solution prepared in 50% (v/v) acetonitrile-water at pH 2.5 and 3.0. The OPPy electrodes exhibited good performance for sulfonamides with wide linear ranges (≈10–5–10–3 M), highly reproducible responses (RSD% ≤0.92) and correlation coefficients (≥0.9990). The calculated limits of detection were ~10–6 or 10–7 M at 3σ. In order to verify the reliability of the OPPy electrode as a sensor, it is used for determination of sulfamethoxazole in a pharmaceutical tablet. The recovery was found as 95.96% with the RSD% of 0.68. The overoxidized polypyrrole modified pencil graphite electrode showed a stable and reproducible response without any influence of interferent commonly existing in pharmaceutical containing sulfamethoxazole.

Chitosan-Pectin-Stearic Acid Film for Controlled-Release of Curcumin

2019 ◽  
Vol 948 ◽  
pp. 69-77
Author(s):  
Dwi Siswanta ◽  
Fithriya Hasanah ◽  
Heni Octaviani ◽  
Mudasir Mudasir
Keyword(s):  
Stearic Acid ◽  
Diffusion Mechanism ◽  
Acetic Acid Solution ◽  
Ethanol Solution ◽  
Release Mechanism ◽  
Buffer Solution ◽  
Buffer Solutions ◽  
Ft Ir ◽  
Isopropanol Solution ◽  
Kinetics Of

The release of curcumin from chitosan-pectin-stearic acid films was studied in the variation of the pH of the buffer solutions, the addition of ethanol in the buffer solution, the amount of loaded curcumin, the amount of stearic acids in the films. The chitosan-pectin films were prepared by addition of 1% acetic acid solution of chitosan into 1% aqueous pectin solution, followed by addition of isopropanol solution of stearic acid. The films were characterized using FT-IR spectrophotometer. The study of curcumin release was performed by soaking the film in buffer-ethanol solutions for 6hand measuring the released curcumin by UV-Vis spectrophotometer. The kinetics of releasing curcumin was analyzed using Korsmeyer-Peppas equations. The result showed that the releasing of curcumin was influenced by the amount of loaded curcumin, the amount of stearic acid in the film and buffer pH of the solution. The optimum releasing rate at buffer pH 7 in 40% ethanol solution was obtained when the amount of curcumin loaded and stearic acid were c.a. 55.5 and 136.4 mg/g film, respectively, which the curcumin release achieved 66.04%. Releasing kinetics of the curcumin followed a Korsmeyer-Peppas model with a rate constant (k) of 7.5270 and n of 0.378. The curcumin release mechanism was mainly based on the diffusion mechanism.

scholarly journals Determination of Kinetic Parameters in the Biosorption of Chromium (VI) in Aqueous Solution

2020 ◽  
Vol 16 (31) ◽  
pp. 129-143
Author(s):  
Candelaria Tejada-Tovar ◽  
Angel Villabona-Ortíz ◽  
Rodrigo Ortega-Toro
Keyword(s):  
New Technologies ◽  
Theoretical Models ◽  
Second Order ◽  
Maximum Adsorption Capacity ◽  
Adsorption Sites ◽  
Chromium Vi ◽  
Batch System ◽  
Pseudo Second Order ◽  
Kinetics Of

he contamination of aquatic bodies by heavy metals is a growing environmental problem, making more critical the study and development of new technologies and materials that can be used for the removal of this type of pollutants. Thus, adsorption arises using residual materials as a sustainable alternative for the solution to this problem. In the present study, the use of plantain peels in the adsorption of Cr (VI) in a batch system is proposed, establishing the kinetics of the process at different temperature conditions, particle size and amount of adsorbent. The fit of the data was done using the theoretical models of pseudo-first-order, pseudo-second-order and Elovich. From the data, it is established that the pseudo-second-order and Elovich models show a better adjustment, so that the adsorption in the material occurs on two adsorption sites and that such process is related to chemical adsorption. The maximum adsorption capacity of Cr (VI) was found at a condition of 0.0306 g, 0.6775 mm and 55°C at a time of 420 min establishing the efficient use of plantain peels for the removal of the ion metallic in the studio.

Determination of Radiochemical Purity and Pharmacokinetic Parameters of 99mTc-Sulphur Colloid and 99mTc-Tin Colloid

1981 ◽  
Vol 20 (06) ◽  
pp. 279-282 ◽  
Author(s):  
D. Konstantinovska ◽  
K. Milivojević ◽  
J. Bzenić ◽  
V. Jovanović
Keyword(s):  
Radiochemical Purity ◽  
Slow Component ◽  
Pharmacokinetic Parameters ◽  
Optimum Size ◽  
Buffer Solution ◽  
Chromatography Method ◽  
Fast Phase ◽  
Biodistribution Studies ◽  
Biological Half Time

Labelling yield and radiochemical purity, higher than 95%, of 99mTc-colloid preparations were determined by using the paper chromatography method. Less than 3% of labelled citric acid, added to the preparation as a buffer solution, has been found in 99mTc-sulphur colloid. High radiochemical purity and optimum size of colloid particles has also been proved by biodistribution studies on experimental animals. The analysis performed has shown that more than 50% of 99mTc-colloid preparations excreted by urine is 99mTcO–, the remaining past 50% being protein bound 99mTc. Biological half-time of excretion of the fast phase is the same for both preparations, i.e. 10 min, while for the slow component it is 120 min in 99mTc-S-colloid and 160 min in 99mTc-Sn colloid.

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