scholarly journals Spectrophotometric investigation of famotidine-Pd(II) complex and its analytical application in drug analysis

2004 ◽  
Vol 69 (6) ◽  
pp. 485-492 ◽  
Author(s):  
Zagorka Koricanac ◽  
Tatijana Jovanovic ◽  
Jelena Petkovic ◽  
Dragica Minic-Popovic
Keyword(s):  
Ionic Strength ◽  
Stability Constant ◽  
Drug Analysis ◽  
Dosage Forms ◽  
Conditional Stability ◽  
Buffer Solution ◽  
Conditional Stability Constant ◽  
Spectrophotometric Methods ◽  
Optimum Ph ◽  
Ph Range

By using different spectrophotometric methods, it was found that famotidine and palladium(II) ions form a complex, Pd(II): famotidine = 1:1, which has an absorptionmaximum at 345 nm. The formation of the complex between famotidine and palladium(II) chloride in Britton?Robinson buffer solution in the pH range 2.23?8.50 was studied. The conditional stability constant of the complex at the optimum pH 2.62 and ionic strength 0.5M was found to be log K?= 3.742 ??0.025. The Beer?s law was verified over the famotidine concentration range from 5x10-5?6x10-4 M. The proposed method was found to be suitable for accurate and sensitive analysis of famotidine both as the substance (RSD = 1.02?1.80 %) and its dosage forms (RSD = 1.75?1.83 %).

scholarly journals The solubility of Ca(OH)2 in extremely concentrated NaOH solutions at 25°C

2012 ◽  
Vol 10 (2) ◽  
pp. 332-337 ◽  
Author(s):  
Attila Pallagi ◽  
Ágost Tasi ◽  
Attila Gácsi ◽  
Miklós Csáti ◽  
István Pálinkó ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Stability Constant ◽  
Solubility Product ◽  
Hydroxo Complex ◽  
Solubility Data ◽  
Alkaline Solutions ◽  
Conditional Stability ◽  
Experimental Protocol ◽  
Conditional Stability Constant

AbstractThe solubility of Ca(OH)2 in aqueous NaOH solutions up to 12.50 M at 25°C has been determined. The solubility data obtained for NaOH concentrations lower than 3 M was compared with those published in the literature. The solubility of Ca(OH)2 steadily decreases with the increasing NaOH concentration. The solubility data obtained at a constant ionic strength (I = 1 M Na(Cl,OH)) enabled the determination of the conditional solubility product of Ca(OH)2(s) (lgLCa(OH)2 = − 4.10 ± 0.02). Formation of the hydroxo complex CaOH+(aq) was invoked to describe the variation of [Ca2+]T with [OH−]T. Its conditional stability constant was found to be lgKCaOH+ = 0.97 ± 0.02. The experimental protocol employed was proven to be suitable for accurate solubility determinations in rapidly equilibrating systems comprising of highly concentrated, alkaline solutions and containing analytes in the ppm range.

scholarly journals The Effect of pH and Concentration of KNO3 Solution to the Performance of Nd3+ Ion Selective Electrode Using HPMBP Ionophore

2018 ◽  
Vol 3 (3) ◽  
pp. 193
Author(s):  
Husain Sosidi ◽  
Buchari Buchari ◽  
Indra Noviandri
Keyword(s):  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Buffer Solution ◽  
Potential Measurement ◽  
Ph Variation ◽  
Measurement Results ◽  
Optimum Ph ◽  
Electrode Method ◽  
Potentiometric Analysis ◽  
Ph Range

<p>The phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP) synthesized and characterized as ionophore in potentiometric analysis of ion selective electrode method (ISE) with polytetrafluoroethylene (PTFE) as the supporting phase. The pH and concentration of the ionic strength adjuster (ISA) were varied to know at the optimum pH and concentration of the ion-selective electrode (ESI) KNO<sub>3</sub>, thus potential Nd<sup>3+</sup> gives the best performance. Before use the PTFE membrane was immersed in a chloroform-HPMBP solution of 1.5-2.0% w/v for 24 h. The pH variation of the buffer solution was adjusted to the pH range of 2-10 using HCl and NaOH solutions, whereas the concentration of KNO<sub>3</sub> varies from 10<sup>-1</sup> to 10<sup>-3</sup> M. The concentration range of Nd<sup>3+</sup> is between 10<sup>-2</sup> and 10<sup>-7</sup> M. The electrode potential measurement results (E<sub>Nd</sub>) obtained the best performance value at pH 4 with KNO<sub>3</sub> concentration of 10<sup>-2</sup> M, sensitivity (S) 18.39 ± 1.2 mV/decade and response time less than 23 s.</p>

scholarly journals Spectrophotometric Estimation of Cefuroxime and Ceftazidime in Bulk and in Dosage Forms

2001 ◽  
Vol 69 (2) ◽  
pp. 143-150 ◽  
Author(s):  
A. Amin ◽  
H. Khalli ◽  
H. Saleh
Keyword(s):  
Molar Absorptivity ◽  
Dosage Forms ◽  
Acetate Buffer Solution ◽  
Sodium Fluorescein ◽  
Buffer Solution ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Relative Standard ◽  
Optimum Concentration Range

Three simple, accurate and sensitive spectrophotometric methods (A, B and C) for the determination of cefuroxime and ceftazidime in bulk samples and in dosage forms are described. They are based on the reaction with nitrous acid forming a nitroso derivatives which can be measured at λmax 350 and 355 nm for cefuroxime (I) and ceftazidime (II), respectively (method A) or by oxidation of drug I or II with an excess of freshly prepared hypobromite and the residual hypobromite was treated with sodium fluorescein at the optimum experimental conditions and measured at λmax at 517 nm (method B). Method C is based on the formation of tris (0-phenanthroline) iron(II) complex (ferroin) upon the oxidation of the studied drug I or II with an iron (III)-o-phenanthroline mixture in acetate buffer solution of pH 3.6 and measuring at λmax 509 nm. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 0.2 – 6.0, 0.2 – 3.2 and 0.1 – 5.6 μg ml−1 for methods A, B and C, respectively. The apparent molar absorptivity, Sandell sensitivity, detection and quantitation limits were calculated. For more accurate results, Ringbom optimum concentration range was 0.2 – 5.6 μg ml−1. The validity of the proposed methods was tested by analysing dosage forms containing the studied drugs I and II. The relative standard deviations were ≤ 1.25% with recoveries 98.6 – 101.4% .

scholarly journals Spectrophotometric Determination of Pipazethate Hydrochloride in Pure Form and in Pharmaceutical Formulations

2007 ◽  
Vol 90 (3) ◽  
pp. 686-692 ◽  
Author(s):  
Ragaa El-Shiekh ◽  
Alaa S Amin ◽  
Faten Zahran ◽  
Ayman A Gouda
Keyword(s):  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Pure Form ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Accurate Analysis ◽  
Spectrophotometric Methods ◽  
Relative Standard ◽  
Optimum Ph

Abstract Three simple, sensitive, and reproducible spectrophotometric methods (AC) for the determination of pipazethate hydrochloride (PiCl) in pure form and in pharmaceutical formulations are described. The first and second methods, A and B, are based on the oxidation of the drug by Fe3+ in the presence of o-phenanthroline (o-phen) or bipyridyl (bipy). The formation of tris-complex upon reactions with Fe3+-o-phen and/or Fe3+-bipy mixture in an acetate buffer solution of the optimum pH values was demonstrated at 510 and 522 nm, respectively, with o-phen and bipy. The third method, C, is based on the reduction of Fe(III) by PiCl in acid medium and subsequent interaction of Fe(II) with ferricyanide to form Prussian blue, which exhibits an absorption maximum at 750 nm. The concentration ranges are from 0.5 to 8, 2 to 16, and 3 to 15 g/mL for Methods AC, respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, and detection and quantitation limits were calculated. The developed methods were successfully applied to the determination of PiCl in bulk and pharmaceutical formulations without any interference from common excipients. The relative standard deviations were 0.83% with recoveries of 98.9101.15%.

Investigation of a new “N2S2O2” chelating agent with high Po(iv) affinity

2017 ◽  
Vol 53 (48) ◽  
pp. 6492-6495 ◽  
Author(s):  
Ali Younes ◽  
Gilles Montavon ◽  
Sébastien G. Gouin ◽  
Emy André-Joyaux ◽  
Roxane Peumery ◽  
...  
Keyword(s):  
Stability Constant ◽  
Chelating Agent ◽  
Water Soluble ◽  
Complexing Agent ◽  
Conditional Stability ◽  
Conditional Stability Constant

A water-soluble complexing agent for 210-polonium decorporation was designed and synthesised with a high conditional stability constant.

scholarly journals Swellable Copolymers of N-isopropylacrylamide and Alkyl Acrylic Acids for Optical pH Sensing

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1408
Author(s):  
Barry K. Lavine ◽  
Sandhya R. Pampati ◽  
Kaushalya S. Dahal ◽  
Mariya Kim ◽  
U. D. Nuwan T. Perera ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Dispersion Polymerization ◽  
High Ionic Strength ◽  
Ph Sensing ◽  
Buffer Solution ◽  
Hydrogel Membrane ◽  
Enthalpy And Entropy ◽  
Ph Range ◽  
Acrylic Acids ◽  
Pva Hydrogel

Swellable polymers that respond to pH (including a portion of the physiological pH range) have been prepared from N-isopropylacrylamide (NIPA) copolymerized with acrylic acid, methacrylic acid, ethacrylic acid or propacrylic acid by dispersion polymerization. When the swellable polymer particles are dispersed in a polyvinyl alcohol (PVA) hydrogel membrane, large changes occur in the turbidity of the membrane (which is measured using an absorbance spectrometer) as the pH of the buffer solution in contact with the hydrogel membrane is varied. The swelling of the NIPA copolymer is nonionic, as the ionic strength of the buffer solution in contact with the PVA membrane was increased from 0.1 to 1.0 M without a decrease in the swelling. For many of these NIPA copolymers, swelling was also reversible in both low- and high ionic strength pH-buffered media and at ambient and physiological temperatures. The composition of the formulation used to prepare these copolymers of NIPA can be correlated to the enthalpy and entropy of the pH-induced swelling.

scholarly journals A spectrophotometric investigation of the complex between titanyl oxalate and 3-hydroxyflavone in water ethanolic mixtures

2000 ◽  
Vol 65 (9) ◽  
pp. 631-638 ◽  
Author(s):  
Mara Aleksic ◽  
Slavica Blagojevic ◽  
Dusan Malesev ◽  
Zorica Radovic
Keyword(s):  
Stability Constant ◽  
Room Temperature ◽  
Aqueous Ethanol ◽  
Ethanol Solution ◽  
Aqueous Ethanol Solution ◽  
Spectrophotometric Methods ◽  
Oxalate Anion ◽  
Ph Range ◽  
Titanyl Oxalate

It has been established, by the application of suitable spectrophotometric methods and pH-metric measurements, that titanyl oxalate anion and 3-hydroxyflavone (3HF) form a [TiO(C2O4)2(C15H9O3)2]4-complex. The investigation of the composition and the concentration stability constant of the complex were carried out in a 50 % aqueous ethanol solution at room temperature (20?C), in the pH range from 1.9 to 9.0. The concentration stability constant of the complex, log b2, ranged from 16.65 at pH 5.0 to 13.96 at pH 7.0. The conditions for the spectrophotometric determination of 3HF by means of the complex formation were investigated in the concnetration range from 2.5?10-5 to 3.0?10-4 mol dm-3 3HF.

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