CONDUCTOMETRIC TITRATION METHOD FOR DETERMINATION OF ETILEFRINE HYDROCHLORIDE, FENTOTEROL HYDROBROMIDE AND PIPAZETHATE HYDROCHLORIDE USING SILVER NITRATE

 ABSTRACT Objective: The objective of this work is to develop a simple, precise, rapid, and low-cost conductometric method for determination of etilefrine hydrochloride, fenoterol hydrobromide and pipazethate hydrochloride in pure form and in pharmaceutical formulations using silver nitrate.Method: The method is based on the precipitation of chloride or bromide ions coming from the cited drugs with silver ions yielding silver chloride or silver bromide and the conductance of the solution is measured as a function of the volume of titrant. The studied drugs were evaluated in double distilled water in the range of 1-10 mg, various experimental conditions were established.Results :     Results obtained showed good recoveries with relative standard deviation of 0.684, 0.817 and 0.864 for etilefrine hydrochloride, fenoterol hydrobromide and pipazethate hydrochloride, respectively. The proposed procedures were applied successfully to the analysis of these drugs in their pharmaceutical formulations,results were successfully comparable to the official or reference methods.Conclusion: Simple and rapid procedure described in this work can be an alternative to the more complex and expensive methods for assay of the cited drugs. Keywards:  Conductometric titration,   etilefrine , fenoterol , pipazethate .Â

Application of 4-chloro-7-nitrobenzofurazan for the analysis of propafenone and diltiazem hydrochlorides using kinetic spectrophotometric and spectrofluorimetric methods

Several simple, sensitive, accurate and inexpensive spectrophotometric and spectrofluorimetric methods were developed for the determination of propafenone HCl and diltiazem HCl using 4-chloro-7-nitrobenzofurazan (NBD-Cl) accompanied with kinetic study, either in pure form or in pharmaceutical preparations. In this work, the cited drugs react with (NBD-Cl) in presence of borate buffer of pH = 7.6 at a fixed time of 30 minutes on thermostated water bath at (75-80 °C). The absorbance was measured using spectrophotometric technique at 489 and 481 nm for propafenone HCl and diltiazem HCl, respectively, or by using spectrofluorimetric technique after dilution at the specific wavelength of excitation and emission.The calibration curves were linear in the range of 4-44, 16-96 µg/mL when using spectrophotometric method, and 0.4-3.6, 1.6-8.8 µg/mL when spectrofluorimetric method was applied for propafenone HCl and diltiazem HCl, respectively. The limit of quantitation and the limit of detection were also calculated. The methods were applied successfully to commercial dosage form and can be further applied for their determination on a large scale in quality control laboratories. The obtained results statistically agreed with those obtained by reference methods. The determination of the studied drugs by the fixed concentration and rate constant methods is feasible with the calibration equations obtained, but the fixed time method proves to be more applicable

Conductometric determination of sibutramine HCl, sumatriptan succinate and lomefloxacine HCl and the solubility products of their ion associates with molybdophosphoric acid

Conductometric determination of sibutramine HCl, sumatriptan succinate and lomefloxacine HCl with molybdophosphoric acid as a precipitating reagent was investigated. Various experimental conditions were evaluated and results obtained showed good recoveries, (mean recovery values of 100.51, 99.68, 99.41 and relative standard deviation of 0.332, 0.404, 0.509 for sibutramine HCl, sumatriptan succinate and lomefloxacine HCl, respectively). Numerical derivatization (first and second derivative) of the data was also applied, showing more accurate results compared to classical ones. The described procedures allowed the determination of equilibrium constants those indicated high degree of completeness of the precipitation reaction. Other parameters related to ion pair complex such as solubility and solubility product were also calculated. The described procedures allowed the determination of the studied drugs in the range of 5-15 mg. The precipitate obtained by ion pairing of lomefloxacine HCl with molybdophosphoric acid was spectroscopically characterized using IR. The method was further applied successively to pharmaceutical formulations, the proposed method offering a high degree of accuracy and precision when compared to reference methods

Development of green differential pulse voltammetric strategy for the determination of alfuzosin hydrochloride at pencil graphite and modified carbon paste electrodes

A sensitive and inexpensive differential pulse voltammetric technique was applied to investigate the electrochemical behavior of alfuzosin hydrochloride at two different working electrodes: silica gel modified carbon paste and pencil graphite electrodes (PGE). The voltammetric conditions were optimized using cyclic voltammetry, showing an irreversible anodic peak in Britton-Robinson buffered medium (pH 6) at 0.86–0.90 V. The electrochemical responses were linearly correlated with alfuzosin concentrations (R2> 0.999) in the ranges of 0.6–20 and 0.3–20 μM, exhibiting higher electrocatalytic activity at PGE with a low detection limit/ detectability of 0.099 μM. In addition, this study was a successful attempt for the drug determination in tablets and spiked urine samples with green profile evaluation, employing the National Environmental Methods Index, analytical Eco-Scale score, and Green Analytical Procedure Index

GREEN VALIDATED METHOD FOR DETERMINATION OF TIMONIUM METHYL SULPHATE USING RP-HPLC TECHNIQUE WITH STABILITY-INDICATING STUDIES

Abstract    Objective:  The objective of this method was to develop a  simple, sensitive, rapid reversed phase high-performance liquid chromatography (RP-HPLC) and applied for determination of Tiemonium methyl sulphate (TIM) in bulk , pharmaceutical formulations with stability indicating studies.   Methods: The stability-indicating capability of this method had been established by subjected TIM  to several stress conditions of acidic, basic, oxidative, freezing, heating ,photolytic and catalytic degradation Results: good separation between the target analyte and its degradation products without any interference referring to specificity and selectivity of this method had been reported. Reversed-phase C18 Kinetex® column( 100 x 4.6 mm I.D., 2.6μm ) , isocratic mobile phase composed of an aqueous solution adjusted to pH 2.3 by 0.1% orthophosphoric acid–acetonitrile (80:20, v/v) at 0.8 ml/min flow rate were used. The assay showed good linearity over the concentration range of 1-25 μg/ml  with correlation of coefficient >0.999 and with a detection limit of 0.249 μg/ml and a quantitation limit of 0.755 μg/ml  .Results of the analysis were validated statistically by recovery studies.Conclusion: validated stability-indicating RP-HPLC has been developed for estimation of TIM in its pure and commercial forms in addition to good separation from its degradation products within reasonable time   Key words: Tiemonium methyl sulphate, RP-HPLC, stability-indicating.Â

Green Spectrophotometric Estimation of Minor Concentrations of Methyldopa and Terbutaline Sulphate in Pure Forms and Tablets Using Polyvinylpyrrolidone-Capped Silver Nanoparticles

Sensitive and simple colorimetric method was developed for determination of methyldopa and terbutaline sulphate in pure and pharmaceutical dosage forms. The method was based on reduction of silver ions by the cited drugs in basic medium at 90 ℃ to silver nanoparticles in the presence of stabilizing agent as polyvinylpyrrolidone. The formed silver nanoparticles were distinguished by UV-Vis absorption spectroscopy indicating the characteristic surface plasmon resonance which can be also observed as intense yellow color solution. The plasmon absorbance of the silver nanoparticles was measured at 410 nm for quantitative estimation of methyldopa and terbutaline sulphate over the range of 80-480 and 40-600 ng/mL respectively. Limit of detection was obtained as 26, 13 ng/mL for methyldopa and terbutaline sulphate respectively. The eco-friendly developed method could be successfully applied to the pharmaceutical formulations with studying the interference of different excipients

DETERMINATION OF ETILEFRINE HYDROCHLORIDE, FENOTEROL HYDROBROMIDE, SALBUTAMOL SULPHATE AND ESTRADIOL VALERATE USING SURFACE PLASMON RESONANCE BAND OF SILVER NANOPARTICLES

Objective: The aim of this work was to evaluate a simple, sensitive, effective and validated procedure for the determination of etilefrine hydrochloride, fenoterol hydrobromide, salbutamol sulphate and estradiol valerate.Methods: In this study the method based on the ability of the cited drugs to reduce Ag+ions to silver nanoparticles (Ag-NPs) in the presence of polyvinyl pyrrolidone (PVP) as a stabilizing agent producing very intense surface plasmon resonance peak of Ag-NPs (λmax = 417-425 nm). The plasmon absorbance of the Ag-NPs allows the quantitative spectrophotometric detection of the cited drugs.Results: The calibration curves were linear with concentrations range of 0.4-0.8, 0.1-0.9, 0.8-2 and 1.6-9.6 µg/ml for the cited drugs. Apparent molar absorptivity, detection and quantitative limits were calculated.Applications of the proposed methods to representative pharmaceutical formulations are successfully presented; also the proposed method was applied for the determination of estradiol valerate in human urine samples.Conclusion: The extracellular synthesis of nanoparticles was fast and eco-friendly; moreover, the method doesn't require various elaborate treatments and tedious extraction procedures.Â

Spectrophotometric Determination of Etilefrine HCl, Salbutamol Sulphate and Tiemonium Methyl Sulphate Using Surface Plasmon Resonance Band of Gold Nanoparticles

A simple and sensitive method was developed for spectrophotometric determination of etilefrine hydrochloride, salbutamol sulphate and tiemonium methyl sulphate in pure form and in their pharmaceutical formulations. The method was based on reduction of gold solution to gold nanoparticles by the studied drugs in presence of sodium dodecyl sulphate as stabilising agent. Gold nanoparticles (Au NPs) showed a new absorption band at 530 nm that was used for quantitative determination of the cited drugs. Different variables were examined and optimised in the experiment as gold solution concentration, type of buffer, suitable pH, stabilising agent, order of addition, time and temperature of the reaction. Under optimum conditions, the calibration curves were linear with concentration ranges of 3.0-20.0, 5.0-18.0 and 2.0-26.0 μg/mL for etilefrine Hydrochloride, salbutamol sulphate and tiemonium methyl sulphate respectively. The method was applied successfully to determine the studied drugs in pure form and in their pharmaceutical dosage forms, exhibiting good reproducibility and accuracy

Aggregation of Gold Nanoparticles for Spectrophotometric Determination of Bisoprolol Hemifumarate, Buspirone HCl and Doxazosin Mesylate

A simple, rapid and sensitive spectrophotometric method was developed for determination of bisoprolol hemifumarate, buspirone HCl and doxazosin mesylate in pure form and in pharmaceutical formulations. The method was based on aggregation of synthesized gold nanoparticles (Au NPs). Gold nanoparticles showed an absorption band at 520 nm. Upon interaction with the cited drugs, the band at 520 nm disappeared with formation of a new red shifted band at 616, 656 and 670 nm for doxazosin mesylate, bisoprolol hemifumarate and buspirone HCl, respectively. Different experimental factors were optimized for higher sensitivity. The calibration curves were linear with concentrations of 3-14, 0.1-1.2 and 0.2-1.0 μg/mL for bisoprolol hemifumarate, buspirone HCl and doxazosin mesylate, respectively. The method was applied successfully to determine the studied drugs in minor concentrations in pure form and in their pharmaceutical dosage forms

High - throughput spectrofluorimetric approach for one-step, sensitive, and green assays of alfuzosin hydrochloride using a 96-well microplate reader: Application to tablet formulations and human urine

In the current study, a novel fluorescence-based microplate methodology was introduced for the one-step determination of alfuzosin hydrochloride, with an assessment of the eco-friendliness of the two developed methods. The development of rapid analytical methods with high sensitivity, selectivity, and low cost is a growing trend. In this context, we propose two simple and rapid spectrofluorimetric methods for the quantitative analysis of alfuzosin in the form of active pharmaceutical ingredient, tablets, and urine samples. The first method relies on a direct assay of the native fluorescence of alfuzosin in water, whereas the second method exploits the quenching effect of alfuzosin on calcein dye for its assay at emission wavelengths of 390 and 520 nm, respectively. The obtained results showed high sensitivity with good linearity (> 0.999) over the concentration ranges of 0.75–12.5 and 10–1200 ng/mL, respectively. The eco-friendly features of the proposed methods were proven by greenness evaluation studies employing the National Environmental Methods Index, analytical Eco-scale score, and Green Analytical Procedure Index as three assessment tools. It was concluded that both methods are efficient analytical tools from a green perspective and are promptly applicable for the alfuzosin assay, while the first method demonstrated 10-fold higher sensitivity. In addition, ever-increasing miniaturization as handling large numbers of micro-volume samples simultaneously and reagents in the proposed methods have enabled them to be safer alternatives for rapid routine analysis in quality control units