Hend Yamani - Academia.edu (original) (raw)

Papers by Hend Yamani

Research paper thumbnail of Comparative Study of Calix-6-arene, 2-Hydroxy Propyl Beta Cyclodextrin and 18-Crown-6 as Ionophores in Potentiometric Ion-Selective Electrodes for Determination of Trigonelline in Trigonella foenum-graecum Seeds Extract and Plasma

Journal of Applied Pharmaceutical Science, 2014

The present work evaluates the influence of Calix-6-arene, 2-hydroxy propyl β-cyclodextrin and 18... more The present work evaluates the influence of Calix-6-arene, 2-hydroxy propyl β-cyclodextrin and 18-crown-6 as ionophores on the fabrication of trigonelline selective electrodes 1, 2 and 3, respectively. The three proposed sensors showed Nernstian slopes of 59, 60 and 55.75 mV/concentration decades over pH range 4-9 for sensors 1, 2 and 3, respectively. Both sensors 1 and 2 covered the concentration range 10-3-10-5 M, while sensor 3 showed linear response over the range 10-2-10-4 M. The proposed sensors offer the advantages of fast response and moderate stability time. The selectivity coefficients of the developed sensors indicated excellent selectivity for trigonelline. The proposed electrodes were successfully applied for direct determination of trigonelline in pure form, Trigonella foenum-graecum seeds extract and plasma without prior separation or pretreatment steps. The proposed sensors can be used in quality control labs and in clinical trails for routine analysis of trigonelline in Trigonella foenum-graecum seeds extract and plasma.

Research paper thumbnail of Simultaneous spectrophotometric determination of indacaterol and glycopyrronium in a newly approved pharmaceutical formulation using different signal processing techniques of ratio spectra

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2016

Three spectrophotometric methods have been developed and validated for determination of indacater... more Three spectrophotometric methods have been developed and validated for determination of indacaterol (IND) and glycopyrronium (GLY) in their binary mixtures and novel pharmaceutical dosage form. The proposed methods are considered to be the first methods to determine the investigated drugs simultaneously. The developed methods are based on different signal processing techniques of ratio spectra namely; Numerical Differentiation (ND), Savitsky-Golay (SG) and Fourier Transform (FT). The developed methods showed linearity over concentration range 1-30 and 10-35 (μg/mL) for IND and GLY, respectively. The accuracy calculated as percentage recoveries were in the range of 99.00%-100.49% with low value of RSD% (<1.5%) demonstrating an excellent accuracy of the proposed methods. The developed methods were proved to be specific, sensitive and precise for quality control of the investigated drugs in their pharmaceutical dosage form without the need for any separation process.

Research paper thumbnail of Development of microwave-assisted extraction followed by headspace solid-phase microextraction and gas chromatography–mass spectrometry for quantification of camphor and borneol in Flos Chrysanthemi Indici

Analytica Chimica Acta, 2006

For potent biological activity natural phenols are considered as compounds with perspective of be... more For potent biological activity natural phenols are considered as compounds with perspective of being isolated in their pure form from natural sources. For analytical purposes, as well as for potential industrial application, it is important to apply extraction procedure that allows efficient and time-consuming extraction of polyphenols. In this study a microwave-assisted extraction procedure has been optimized in respect to the recovery of rosemary polyphenols. The optimization was performed in respect to total polyphenols, flavonoids, total anthocyanins, monomeric and condensed anthocyanins. The efficiency of different solvents was investigated for different classes of polyphenols, as well as the influence of the magnetron power and the extraction time. The efficiency of the extraction using optimized extraction protocol for total phenolics was compared with that achieved by Soxhlet and ultrasound-assisted extraction. The present work proposes an optimal microwave-assisted extraction program for the determination of total polyphenolics, flavonoids, total anthocyanins, monomeric and condensed anthocyanins from rosemary.

Research paper thumbnail of Comparative study of calix-6-arene and 2-hydroxy propyl â-cyclodextrin as ionophores in potentiometric ion-selective electrodes for determination of gallic acid in Acacia arabica bark extract

Analytical chemistry, an Indian journal, 2014

The present work evaluates the influence of Calix-6-arene and 2-hydroxy propyl â-cyclodextrin as ... more The present work evaluates the influence of Calix-6-arene and 2-hydroxy propyl â-cyclodextrin as ionophores on the fabrication of gallic acid selective electrodes 1 and 2, respectively. The proposed sensors showedNernstian slopes of 57.70 and 55.30 mV/concentration decades over concentration range 10-3 – 10-5 M for sensors 1 and 2, respectively. Fast response and moderate stability time were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for gallic acid. The proposed electrodes were successfully applied for direct determination of gallic acid in pure form and Acacia arabica bark extract without prior separation or pretreatment steps. Thus, they can be used in quality control labs for routine analysis of gallic acid in Acacia arabica bark extract.

Research paper thumbnail of TiO2 nanoparticles and ionic liquid platform for selective electrochemical determination of indacaterol in pharmaceutical formulations and human fluids: application to content uniformity

Journal of the Iranian Chemical Society

The present work described the first voltammetric sensor for the estimation of indacaterol (IND) ... more The present work described the first voltammetric sensor for the estimation of indacaterol (IND) in the presence of its co-formulated drug glycopyrronium bromide. Indacaterol (IND) is used to treat chronic obstructive pulmonary disease, which is a major cause of morbidity and mortality worldwide so the quick analysis of minor concentrations of this drug is very important. Titanium(IV) oxide nanoparticles (TiO2-NPs) and the ionic liquid (IL) n-hexyl-3-methylimidazolium hexafluorophosphate were used for the new formulated carbon paste electrode. Other factors, such as the pH of the solution, the TiO2-NP concentration and the scan rate, were also optimized using cyclic voltammetry. Scanning electron microscopy, chronoamperometry and electrochemical impedance spectroscopy were utilized for determination of the character of the electrochemical sensor. Moreover, the electrochemical redox mechanism of IND at the proposed sensor was studied. Under the optimum conditions, the proposed TiO2-NP–IL–MCPE showed good linearity over a concentration range of 2.00 nM–200.00 mM using square wave voltammetry. The LOD was found to be 500 pM, indicating excellent sensitivity. Satisfactory recoveries of IND from pharmaceutical formulations, content uniformity tests and human plasma and urine were achieved, clearly revealing that the new sensor can be used in the clinical analysis of IND and in quality control laboratories.

Research paper thumbnail of Microwave-assisted extraction of the gallic acid biomarker from Acacia arabica bark followed by HPLC analysis

Archives of Pharmaceutical Sciences Ain Shams University

An efficient and fast microwave-assisted extraction (MAE) technique was developed for extracting ... more An efficient and fast microwave-assisted extraction (MAE) technique was developed for extracting gallic acid as an indicative biomarker for the quality control of Acacia arabica bark. The MAE technique was optimized and compared with other conventional extraction techniques. The optimal conditions of MAE were 20% methanol as solvent, solid/liquid ratio 1:40 (g/mL), irradiation power 20% and two extraction cycles, 5 min each. The proposed extraction technique produced a maximum yield of 10.59 (mg/g) gallic acid in 10 min, which was 1.03 and 1.15 times more efficient than 6 h of heat reflux and 24 h of maceration extraction, respectively. This high yield, along with saving of time, energy, and solvent would position MAE as a valuable and cost-effective technology suitable for today's highly competitive industries, with growing demand for increased productivity, improved efficiency, and reduced cycle time. Moreover, a new high-performance liquid chromatography method was developed and validated for the determination of gallic acid in Acacia arabica bark extract. The method was found to be rapid, sensitive, accurate, precise, and robust. The method showed good linearity over concentration range 1-100 (µg/mL) with LOD 16.08 (ng/mL) and LOQ 48.73 (ng/mL). The average recovery obtained using standard addition technique was 100.36% with a low value of RSD% (1.19%) indicating the accuracy of the proposed method for determination of gallic acid in Acacia arabica bark extract.

Research paper thumbnail of Stable glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-walled carbon nanotubes, polyaniline nanoparticles and polyaniline microparticles as ion-to-electron transducers: A comparative study

Sensors and Actuators B: Chemical

Abstract Glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-wa... more Abstract Glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-walled carbon nanotubes (MWCNTs), polyaniline nanoparticles (PANI NPs) and microparticles (PANI MPs) as ion-to-electron transducers were fabricated and compared to transducer free blank sensor. Their inclusion in solid contact (SC) sensors offer shorter response time, lower potential drift and longer life time. From a comparative point of view, inclusion of MWCNTs offer longer lifetime (50 days) to the SC sensor compared to PANI based SC sensors. While, the inclusion of PANI showed shorter response times. Hence, PANI-based sensors showed better stability on short term, while MWCNTs offered long term stability. PANI NPs gave faster response than MPs. This may be attributed to the higher surface/volume ratio in NPs which enlarges the contact area with the polymeric membrane, increasing the transduction at the interface. Moreover, PANI NPs showed lower potential drift and relatively longer life time than MPs. Nano-sized particles result in smooth surfaces with a good surface coverage (protection) of the underlying SC. The proposed sensors were successfully applied to content uniformity testing of GLY in a newly approved pharmaceutical dosage form with high accuracy.

Research paper thumbnail of Comparative Study of Calix-6-arene, 2-Hydroxy Propyl Beta Cyclodextrin and 18-Crown-6 as Ionophores in Potentiometric Ion-Selective Electrodes for Determination of Trigonelline in Trigonella foenum-graecum Seeds Extract and Plasma

Journal of Applied Pharmaceutical Science, 2014

The present work evaluates the influence of Calix-6-arene, 2-hydroxy propyl β-cyclodextrin and 18... more The present work evaluates the influence of Calix-6-arene, 2-hydroxy propyl β-cyclodextrin and 18-crown-6 as ionophores on the fabrication of trigonelline selective electrodes 1, 2 and 3, respectively. The three proposed sensors showed Nernstian slopes of 59, 60 and 55.75 mV/concentration decades over pH range 4-9 for sensors 1, 2 and 3, respectively. Both sensors 1 and 2 covered the concentration range 10-3-10-5 M, while sensor 3 showed linear response over the range 10-2-10-4 M. The proposed sensors offer the advantages of fast response and moderate stability time. The selectivity coefficients of the developed sensors indicated excellent selectivity for trigonelline. The proposed electrodes were successfully applied for direct determination of trigonelline in pure form, Trigonella foenum-graecum seeds extract and plasma without prior separation or pretreatment steps. The proposed sensors can be used in quality control labs and in clinical trails for routine analysis of trigonelline in Trigonella foenum-graecum seeds extract and plasma.

Research paper thumbnail of Simultaneous spectrophotometric determination of indacaterol and glycopyrronium in a newly approved pharmaceutical formulation using different signal processing techniques of ratio spectra

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2016

Three spectrophotometric methods have been developed and validated for determination of indacater... more Three spectrophotometric methods have been developed and validated for determination of indacaterol (IND) and glycopyrronium (GLY) in their binary mixtures and novel pharmaceutical dosage form. The proposed methods are considered to be the first methods to determine the investigated drugs simultaneously. The developed methods are based on different signal processing techniques of ratio spectra namely; Numerical Differentiation (ND), Savitsky-Golay (SG) and Fourier Transform (FT). The developed methods showed linearity over concentration range 1-30 and 10-35 (μg/mL) for IND and GLY, respectively. The accuracy calculated as percentage recoveries were in the range of 99.00%-100.49% with low value of RSD% (<1.5%) demonstrating an excellent accuracy of the proposed methods. The developed methods were proved to be specific, sensitive and precise for quality control of the investigated drugs in their pharmaceutical dosage form without the need for any separation process.

Research paper thumbnail of Development of microwave-assisted extraction followed by headspace solid-phase microextraction and gas chromatography–mass spectrometry for quantification of camphor and borneol in Flos Chrysanthemi Indici

Analytica Chimica Acta, 2006

For potent biological activity natural phenols are considered as compounds with perspective of be... more For potent biological activity natural phenols are considered as compounds with perspective of being isolated in their pure form from natural sources. For analytical purposes, as well as for potential industrial application, it is important to apply extraction procedure that allows efficient and time-consuming extraction of polyphenols. In this study a microwave-assisted extraction procedure has been optimized in respect to the recovery of rosemary polyphenols. The optimization was performed in respect to total polyphenols, flavonoids, total anthocyanins, monomeric and condensed anthocyanins. The efficiency of different solvents was investigated for different classes of polyphenols, as well as the influence of the magnetron power and the extraction time. The efficiency of the extraction using optimized extraction protocol for total phenolics was compared with that achieved by Soxhlet and ultrasound-assisted extraction. The present work proposes an optimal microwave-assisted extraction program for the determination of total polyphenolics, flavonoids, total anthocyanins, monomeric and condensed anthocyanins from rosemary.

Research paper thumbnail of Comparative study of calix-6-arene and 2-hydroxy propyl â-cyclodextrin as ionophores in potentiometric ion-selective electrodes for determination of gallic acid in Acacia arabica bark extract

Analytical chemistry, an Indian journal, 2014

The present work evaluates the influence of Calix-6-arene and 2-hydroxy propyl â-cyclodextrin as ... more The present work evaluates the influence of Calix-6-arene and 2-hydroxy propyl â-cyclodextrin as ionophores on the fabrication of gallic acid selective electrodes 1 and 2, respectively. The proposed sensors showedNernstian slopes of 57.70 and 55.30 mV/concentration decades over concentration range 10-3 – 10-5 M for sensors 1 and 2, respectively. Fast response and moderate stability time were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for gallic acid. The proposed electrodes were successfully applied for direct determination of gallic acid in pure form and Acacia arabica bark extract without prior separation or pretreatment steps. Thus, they can be used in quality control labs for routine analysis of gallic acid in Acacia arabica bark extract.

Research paper thumbnail of TiO2 nanoparticles and ionic liquid platform for selective electrochemical determination of indacaterol in pharmaceutical formulations and human fluids: application to content uniformity

Journal of the Iranian Chemical Society

The present work described the first voltammetric sensor for the estimation of indacaterol (IND) ... more The present work described the first voltammetric sensor for the estimation of indacaterol (IND) in the presence of its co-formulated drug glycopyrronium bromide. Indacaterol (IND) is used to treat chronic obstructive pulmonary disease, which is a major cause of morbidity and mortality worldwide so the quick analysis of minor concentrations of this drug is very important. Titanium(IV) oxide nanoparticles (TiO2-NPs) and the ionic liquid (IL) n-hexyl-3-methylimidazolium hexafluorophosphate were used for the new formulated carbon paste electrode. Other factors, such as the pH of the solution, the TiO2-NP concentration and the scan rate, were also optimized using cyclic voltammetry. Scanning electron microscopy, chronoamperometry and electrochemical impedance spectroscopy were utilized for determination of the character of the electrochemical sensor. Moreover, the electrochemical redox mechanism of IND at the proposed sensor was studied. Under the optimum conditions, the proposed TiO2-NP–IL–MCPE showed good linearity over a concentration range of 2.00 nM–200.00 mM using square wave voltammetry. The LOD was found to be 500 pM, indicating excellent sensitivity. Satisfactory recoveries of IND from pharmaceutical formulations, content uniformity tests and human plasma and urine were achieved, clearly revealing that the new sensor can be used in the clinical analysis of IND and in quality control laboratories.

Research paper thumbnail of Microwave-assisted extraction of the gallic acid biomarker from Acacia arabica bark followed by HPLC analysis

Archives of Pharmaceutical Sciences Ain Shams University

An efficient and fast microwave-assisted extraction (MAE) technique was developed for extracting ... more An efficient and fast microwave-assisted extraction (MAE) technique was developed for extracting gallic acid as an indicative biomarker for the quality control of Acacia arabica bark. The MAE technique was optimized and compared with other conventional extraction techniques. The optimal conditions of MAE were 20% methanol as solvent, solid/liquid ratio 1:40 (g/mL), irradiation power 20% and two extraction cycles, 5 min each. The proposed extraction technique produced a maximum yield of 10.59 (mg/g) gallic acid in 10 min, which was 1.03 and 1.15 times more efficient than 6 h of heat reflux and 24 h of maceration extraction, respectively. This high yield, along with saving of time, energy, and solvent would position MAE as a valuable and cost-effective technology suitable for today's highly competitive industries, with growing demand for increased productivity, improved efficiency, and reduced cycle time. Moreover, a new high-performance liquid chromatography method was developed and validated for the determination of gallic acid in Acacia arabica bark extract. The method was found to be rapid, sensitive, accurate, precise, and robust. The method showed good linearity over concentration range 1-100 (µg/mL) with LOD 16.08 (ng/mL) and LOQ 48.73 (ng/mL). The average recovery obtained using standard addition technique was 100.36% with a low value of RSD% (1.19%) indicating the accuracy of the proposed method for determination of gallic acid in Acacia arabica bark extract.

Research paper thumbnail of Stable glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-walled carbon nanotubes, polyaniline nanoparticles and polyaniline microparticles as ion-to-electron transducers: A comparative study

Sensors and Actuators B: Chemical

Abstract Glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-wa... more Abstract Glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-walled carbon nanotubes (MWCNTs), polyaniline nanoparticles (PANI NPs) and microparticles (PANI MPs) as ion-to-electron transducers were fabricated and compared to transducer free blank sensor. Their inclusion in solid contact (SC) sensors offer shorter response time, lower potential drift and longer life time. From a comparative point of view, inclusion of MWCNTs offer longer lifetime (50 days) to the SC sensor compared to PANI based SC sensors. While, the inclusion of PANI showed shorter response times. Hence, PANI-based sensors showed better stability on short term, while MWCNTs offered long term stability. PANI NPs gave faster response than MPs. This may be attributed to the higher surface/volume ratio in NPs which enlarges the contact area with the polymeric membrane, increasing the transduction at the interface. Moreover, PANI NPs showed lower potential drift and relatively longer life time than MPs. Nano-sized particles result in smooth surfaces with a good surface coverage (protection) of the underlying SC. The proposed sensors were successfully applied to content uniformity testing of GLY in a newly approved pharmaceutical dosage form with high accuracy.