direct titration
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2019 ◽  
Vol 4 (2) ◽  
pp. 151-157
Author(s):  
Lana Mohammed Ali ◽  
Mariwan Abdulla Hama Salih ◽  
Omed Ismael Hayder

Drug analysis is an important method for determination of active components of any therapeutic drugs. HPLC, Spectrometry, Direct titration and Back-titration are common effective techniques in drug analysis. They were used in this study in a comparative way for the determination of the correct amount of acetyl salicylic acid in aspirin formulations. The aim of this study is to analysis of aspirin and compares both Direct titration and Back-titration techniques to the standard HPLC technique in order to find alternative, the easy and cheaper procedure to assess the quality of active components of medications aspirin in particular in Sulaimani city. Additionally, Spectrophotometric technique were also used and compared with the standard HPLC method. The samples were collected from different local drug stores in which distribute medications to pharmacies and they were from different companies. The analyses were performed after preparing a solution from each of the samples with a standard solutions for titration procedures. Both direct and back-titration techniques were used to find the concentration of active components in aspirin samples then compared with the data from standard HPLC as a reference value. The study showed that those companies which provide medications to this region were used a standard amount of acetyl salicylic acid in aspirin tablets. The result from Spectrophotometric method showed more accurate than both direct and indirect titration when compared to the reference value from standard HPLC technique due to the high rate of accuracy and precision of this method. However, the result also showed some inconsistent data in terms of the back titration compared to direct titration due to the inaccuracy in back titration. This study concluded with the necessity for quality control to use all these techniques for monitoring all medications which interring this region.


2019 ◽  
Vol 16 (3) ◽  
pp. 405-412 ◽  
Author(s):  
Ahmed A.O. Abeed ◽  
Talaat I. El-Emary ◽  
Mohamed S.K. Youssef

<p>Aim and Objective: This work presents the synthetic capability and the exploitation of 1,3-diphenyl- 1H-pyrazole-4-carboxladehyde 1 and 5-diphenyl pyrazolyl-2-pyrazoline analogue 8 to serve as excellent precursors for the synthesis of substituted indol-2,3-dione, trizolo[3,4-a]benzazoles, thiazolo[2,3- a]benzimidazole-3-one, substituted 2-pyrazoline and pyrazole-substituted-pyrazolines using various reagents. </P><P> Materials and Methods: Using chemicals from Aldrich, Fluka, or Merck, and pure solvents, we apply the synthetic procedures for the synthesis of novel heterocycles. The melting points of these compounds were determined using APP. Digital ST 15 melting point apparatus. SP3-100 spectrophotometer recorded FT-IR spectra (KBr) (cm-1). NMR spectra (&#948;, ppm) were recorded on 400 MHz AVANCE-III High-Performance FT-NMR Spectrometer BRUCKER (Switzerland) and some 1H NMR spectra were recorded on Varian EM-360L NMR Spectrophotometer (90 MHz) (USA) in CDCl3 or DMSO-d6 as a solvent. Elemental analyses were carried out at a Vario EL C, H, N, and S Analyzer. Bromine was determined using direct titration method after carius combustion. </P><P> Results: The structures of the compounds were confirmed by IR, 1H NMR, 13C NMR, and elemental analyses. </P><P> Conclusion: 1,3-Diphenyl-1H-pyrazole-4-carboxladehyde 1 and 2-pyrazoline derivative 9 confirmed their importance in the synthetic organic chemistry. Depending on the formyl group of aldehyde 1 and active methylene of pyrazoline 8, we synthesized new series of heterocycles; indol-2,3-dione, trizolo[3,4-a]benzazole, thiazolo[2,3-a]benzimidazole-3-one and pyrazolyl-pyrazoline derivatives expecting their pharmacological applications. The targeted compounds were substantiated from its spectral data.</p>


2019 ◽  
Author(s):  
Maria F. Camões ◽  
Gary D. Christian ◽  
David Brynn Hibbert
Keyword(s):  

2018 ◽  
Vol 273 ◽  
pp. 122-127
Author(s):  
Wen Ni Tan ◽  
Che Rose Laili ◽  
Suhaimi Hamdan

In this work, liquid crystal emulsion with aloe vera (AV) was formulated and characterised its physical properties. A direct titration method was used to determine the composition of liquid crystal emulsion in a system consisting of water/mixed Tween 80: Span 85/hexane. AV gel was added to produce AV liquid crystal emulsion (AVLCE), which was then subjected to various characterisation such as microscopic analysis, stability test, rheological test and particle size analysis. Results showed that the application of AVCLE employed better performances in terms of stability, particle size and moisturizing. This study suggest that the formulated AVLCE may be suitable to be used as topical application on wounded skin.


2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Zhenhua Yin ◽  
Yong Zhang ◽  
Juanjuan Zhang ◽  
Wenyi Kang

This study aimed to establish a HPLC method for simultaneous determination of the changing of quercitrin, 3-hydroxyphloridzin, and phloridzin in physical process of M. halliana tea. Meanwhile, the nutritional compositions were determined, using anthrone-sulfuric acid colorimetry and direct titration determination of total sugar and reducing sugar, respectively, in order to provide theoretical basis for quality control and tea production. The results showed that the regression equations for quercitrin, 3-hydroxyphloridzin, and phloridzin were linear in the range of 0.0972–12.15 μg (r=0.999 8), 0.0932~11.65 μg (r=0.999 1), and 0.9~112.5 μg (r=0.999 6), respectively. The average recoveries ranged from 98.19% to 99.35%. The contents of crude protein and the crude fat were measured by spectrophotometric detection and soxhlet extraction detection, respectively. The contents of total sugar, reducing sugar, the fat, and protein were 6.8 g/100 g, 8.5 mg/100 g, 2.399 g/100 g, and 4.362 g/100 g, respectively, in M. halliana tea.


2016 ◽  
Vol 103 ◽  
pp. 44-53 ◽  
Author(s):  
Jakub Ederer ◽  
Pavel Janoš ◽  
Petra Ecorchard ◽  
Václav Štengl ◽  
Zuzana Bělčická ◽  
...  

2016 ◽  
Vol 5 (4) ◽  
pp. 261
Author(s):  
Michael M. Bratychak ◽  
Volodymyr B. Vostres ◽  
Marc J.M. Abadie

<p>New bifunctional oligomers bearing peroxy groups have been synthesized by telomerization in one step reaction. For obtaining oligoperoxides (PO) by telomerization method, epoxide compounds will react with substances containing labile hydrogen atom. Using the principle of stochiometric imbalance between diepoxy compounds and substances with mobile hydrogen atoms and employing a functional peroxide as telogen, the synthesis of PO was studied. 2,2–Di[4–(2,3–epoxy–1-propoxy)phenyl]–propane (diglycidyl ether of diphenylol propane - DGEDPP), 1,2–Di (2,3–epoxy–1-propoxy) ethane (diglycidyl ether of ethylene glycol - DGEEG) and 1,2–Epoxy–3–tert–butylperoxypropane (EP) have been synthesized by methods reported in the literature. Chemical structures have been confirmed by NMR and FTIR, number-average molecular weights M<sub>n</sub> of PO<sub>s</sub> by cryoscopy, active oxygen content [O]<sub>act</sub>. for PO<sub>s</sub> was determined by iodometry and epoxy number (<em>e.n</em>.) for PO<sub>s</sub> was measured via direct titration of PO samples. A 50% solution of potassium or sodium isopropylates in 2-propanol is used to catalyze the telomerisation. Different parameters such as ratio of components, temperature, reaction time have been optimized in vu to get well defined peroxy oligomers. The presence of peroxy groups in synthesized POs allows us to employ these compounds as curing agents for polymers containing unsaturated double bonds and may be used to improve performance of unsaturated polyester GFR systems.</p>


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