Sphinx journal of Pharmaceutical and Medical Sciences, Apr 1, 2022
The history of this planet is full of Pandemics, that have repeatedly influenced the path of medi... more The history of this planet is full of Pandemics, that have repeatedly influenced the path of medical care and effectively inspired a big deal of vaccination science as well as introducing new codes of hygiene measures, social responsibility and even economic responses and charts. The Covid-19 pandemic was, in this regard, no exception. Despite that an end of the pandemic is not anticipated in near vision, yet a number of lessons from the poor quality of crisis management whether globally or locally, are already there. The WHO imposed a number of indices to predict and help decision makers to control the disease. None of these proved to be enough as a single criteria for community based decisions, or interventional measures implementation. In this article we are going to discuss lessons from Covid-19 crisis from the authors" point of view. Taking into consideration the progression of pandemic in many countries and the related measures taken.
An one-pot hydrothermal method was developed for synthesis of carbon quantum dots co-doped with c... more An one-pot hydrothermal method was developed for synthesis of carbon quantum dots co-doped with copper and nitrogen (Cu, N@CQDs). The synthesized Cu, N@CQDs has unique advantages such as high fluorescence quantum yield (39.1%) and high catalytic activity. Oxidative coupling of amoxicillin (AMX) with 4-aminoantipyrine (4-NH2-APE) in the presence of H2O2 as an oxidant to produce pink quinoneimine chromogen was carried out with the aid of Cu, N@CQDs as a peroxidase-like catalyst. This system was used for the colorimetric and fluorometric assays of AMX with reliable results. Colorimetric method is based on the measurement of a pink-colored product at λmax = 505 nm while the fluorometric assay is based on the quenching of the fluorescence emission of Cu, N@CQDs at 440 nm after excitation at 370 nm. For the colorimetric method, the absorption intensity linearly increased over the concentration range 4.3–110.0 µM with LOD (S/N = 3) of 1.3 µM. For the fluorometric method, the emission intensity of Cu, N@CQDs linearly decreased upon addition of AMX in the concentration range 0.2–120.0 µM with a limit of detection (LOD, S/N = 3) of 0.06 µM. The proposed system was applied to the determination of AMX in different real samples such as pharmaceutical capsules, human serum, milk, and conduit water samples with recoveries in the range 95.8–104.1% and relative standard deviation (RSD %) less than 4.1%.
The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with flu... more The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with fluorescence detection for estimation of donepezil (DZ) in rabbit plasma using silodosin as the internal standard (IS). The prepared samples were quantified on reversed phase column Luna C<sub>18(2) </sub>(150 × 4.6 mm i.d., 5 µm particle size) operated at room temperature using the mobile phase consisting of methanol: 0.1% acetic acid (50 : 50, v/v) at a flow rate of 1 ml min<sup>−1</sup>. The method was fully validated according to bioanalytical validation guidelines of FDA in terms of system suitability, selectivity, sensitivity, precision and stability. It was found that the increase in peak areas followed the increase of DZ concentration in the range of 2.56–200.00 ng ml<sup>−1</sup> with LOD of 0.85 ng ml<sup>−1</sup>. The method was successfully applied for the determination of DZ in rabbit plasma using manual shaking dispersive liquid...
The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with flu... more The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with fluorescence detection for estimation of donepezil (DZ) in rabbit plasma using silodosin as the internal standard (IS). The prepared samples were quantified on reversed-column Luna C<sub>18(2) </sub>(150 mm × 4.6 mm i.d, 5 µm particle size) operated at room temperature using the mobile phase consisting of methanol: 0.1% acetic acid (50 : 50, v/v) at a flow rate of 1 ml min<sup>−1</sup>. The method was fully validated according to bioanalytical validation guidelines of FDA in terms of system suitability, selectivity, sensitivity, precision and stability. It was found that the increase in peak areas followed the increase of DZ concentration in the range of 2.56–200.00 ng ml<sup>−1</sup> with LOD of 0.85 ng ml<sup>−1</sup>. The method was successfully applied for the determination of DZ in rabbit plasma using manual shaking dispersive liquid–liqu...
Sphinx Journal of Pharmaceutical and Medical Sciences, 2021
The Angiotensin-converting enzyme inhibitors and antagonists are widely used in the management of... more The Angiotensin-converting enzyme inhibitors and antagonists are widely used in the management of essential hypertension, stable chronic heart failure, myocardial infarction and diabetic nephropathy, so that specific and sensitive methods are needed for the qualitative and quantitative determinations of these drugs in pharmaceutical dosage forms and in biological material. In the last few years, there was no review published covering all different analytical methods used for the determination of these drugs. The aim of this work is to review the most important recent methods for their analysis in pure forms, in different pharmaceutical dosage forms and in biological fluids due to the great importance of this class of drugs. This review includes two parts: the first part presents the methods applied for the analysis of pharmaceuticals. The second part is devoted to the methods elaborated for the assays in biological material (blood, plasma and urine).
International Journal of Biological Macromolecules, 2019
A novel green magnetic molecularly imprinted solid phase extraction (MMI-SPE) for separation of m... more A novel green magnetic molecularly imprinted solid phase extraction (MMI-SPE) for separation of memantine (MEM) from complicated matrices was proposed. The nanomaterial was synthesized via crosslinking of chitosan (CHIT) with [3-(2, 3-epoxypropoxy)-propyl] trimethoxysilane (EPPTMS) in presence of MEM as a template. The nanocomposites, in all steps, were characterized by SEM, FTIR and PXRD techniques. The adsorbed drug was removed from magnetic molecular imprinted polymer (MMIP) cavity by ethanol: acetic acid (8:2, v/v) and then, coupled with sodium 1, 2-naphthoquinone-4-sulphonate (NQS) in iodine/alkaline medium to yield highly fluorescent product, after reduction with potassium borohydride (KBH 4). Variables affecting extraction of MEM from imprinted sites and its fluorometric analysis were studied. The linearity was achieved over concentration range of 1.84-95.0 ng mL −1 with LOD of 0.6 ng mL −1. The method was successfully applied for determination of MEM in its pharmaceutical tablets and human serum with recoveries of 100.8 ± 3.0, 97.6 ± 2.9, respectively.
A highly sensitive and cost-effective HPTLC method was developed for the determination of rivasti... more A highly sensitive and cost-effective HPTLC method was developed for the determination of rivastigmine hydrogen tartarate (RIV) in bulk and capsules. Moreover, magnetic solid phase extraction procedure (MSPE) was performed for analysis of RIV in human plasma to preconcentrate RIV and decrease interference from plasma constituents. The magnetic nanoparticles (MNPs) were prepared by co-precipitation process and characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), powdered X-ray diffraction (PXRD) and dynamic light scattering (DLS). These prepared MNPs have shown high extraction efficiency and all parameters affecting the adsorption of RIV on the MNPs were fully investigated. The method was validated according to FDA bio-analytical guidelines and was found to be linear over the range of 30.2-648 ng/spot. The LLOQ and LOD were 26.2 and 8.6 ng/spot, respectively.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2019
This paper describes the decoration of pencil graphite electrode (PGE) with a thin film of soloch... more This paper describes the decoration of pencil graphite electrode (PGE) with a thin film of solochrome black T (SBT) and Ndoped carbon nanodots (N-CNDs)/ cobalt nanoparticles (CoNPs) to amplify signal of the measurement. This nanocomposite was chosen to enhance surface activity and electron transfer toward donepezil HCl (DZ HCl) oxidation. The physical properties of nanocomposite were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), electron impedance spectroscopy (ESI) and energy dispersive X-ray (EDX) spectroscopy. Cyclic voltammetry was utilized to quantify DZ HCl at the modified PGE in Britton-Robinson buffer (pH = 6.5). Under optimized experimental conditions, peak current increased with the increase in the concentration of DZ HCl and was linear between the range of 1.5 nM-400 μM with a relatively low detection limit of 0.0005 μM. Due to high sensitivity, simplicity and costeffectiveness of the designated sensor; it was used as a simple method for detecting DZ HCl in rabbit plasma and during its pharmacokinetic study.
The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with flu... more The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with fluorescence detection for estimation of donepezil (DZ) in rabbit plasma using silodosin as the internal standard (IS). The prepared samples were quantified on reversed phase column Luna C 18(2) (150 × 4.6 mm i.d., 5 µm particle size) operated at room temperature using the mobile phase consisting of methanol: 0.1% acetic acid (50 : 50, v/v) at a flow rate of 1 ml min −1 . The method was fully validated according to bioanalytical validation guidelines of FDA in terms of system suitability, selectivity, sensitivity, precision and stability. It was found that the increase in peak areas followed the increase of DZ concentration in the range of 2.56–200.00 ng ml −1 with LOD of 0.85 ng ml −1 . The method was successfully applied for the determination of DZ in rabbit plasma using manual shaking dispersive liquid–liquid microextraction.
Asian Journal of Biomedical and Pharmaceutical Sciences, Dec 26, 2014
Simple, cost effective and reproducible spectrophotometric methods are proposed for the determina... more Simple, cost effective and reproducible spectrophotometric methods are proposed for the determination of enalapril maleate, lisinopril dihydrate, moexipril hydrochloride and ramipril hydrochloride in pure and tablet doage forms. The methods are based on oxidation of these drugs by either potassium dichromate or potassium permanganate in sulphuric acid medium then measuring of the developed colored reaction products or the decrease in the intensity of color at λmax 610, 520 nm for the potassium dichromate (method A) and potassium permanganate (method B) respectively. Different variables affecting the reaction conditions were carefully studied and optimized. Under optimal experimental conditions the linear range is 20-900 µg.ml -1 (method A) and 2-500 µg.ml -1 (method B). The proposed methods were successfully applied to the analysis of the investigated drugs in pure and tablet dosage form. Results were comparable with those obtained by reported spectrophotometric methods.
Sphinx journal of Pharmaceutical and Medical Sciences, Apr 1, 2022
The history of this planet is full of Pandemics, that have repeatedly influenced the path of medi... more The history of this planet is full of Pandemics, that have repeatedly influenced the path of medical care and effectively inspired a big deal of vaccination science as well as introducing new codes of hygiene measures, social responsibility and even economic responses and charts. The Covid-19 pandemic was, in this regard, no exception. Despite that an end of the pandemic is not anticipated in near vision, yet a number of lessons from the poor quality of crisis management whether globally or locally, are already there. The WHO imposed a number of indices to predict and help decision makers to control the disease. None of these proved to be enough as a single criteria for community based decisions, or interventional measures implementation. In this article we are going to discuss lessons from Covid-19 crisis from the authors" point of view. Taking into consideration the progression of pandemic in many countries and the related measures taken.
An one-pot hydrothermal method was developed for synthesis of carbon quantum dots co-doped with c... more An one-pot hydrothermal method was developed for synthesis of carbon quantum dots co-doped with copper and nitrogen (Cu, N@CQDs). The synthesized Cu, N@CQDs has unique advantages such as high fluorescence quantum yield (39.1%) and high catalytic activity. Oxidative coupling of amoxicillin (AMX) with 4-aminoantipyrine (4-NH2-APE) in the presence of H2O2 as an oxidant to produce pink quinoneimine chromogen was carried out with the aid of Cu, N@CQDs as a peroxidase-like catalyst. This system was used for the colorimetric and fluorometric assays of AMX with reliable results. Colorimetric method is based on the measurement of a pink-colored product at λmax = 505 nm while the fluorometric assay is based on the quenching of the fluorescence emission of Cu, N@CQDs at 440 nm after excitation at 370 nm. For the colorimetric method, the absorption intensity linearly increased over the concentration range 4.3–110.0 µM with LOD (S/N = 3) of 1.3 µM. For the fluorometric method, the emission intensity of Cu, N@CQDs linearly decreased upon addition of AMX in the concentration range 0.2–120.0 µM with a limit of detection (LOD, S/N = 3) of 0.06 µM. The proposed system was applied to the determination of AMX in different real samples such as pharmaceutical capsules, human serum, milk, and conduit water samples with recoveries in the range 95.8–104.1% and relative standard deviation (RSD %) less than 4.1%.
The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with flu... more The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with fluorescence detection for estimation of donepezil (DZ) in rabbit plasma using silodosin as the internal standard (IS). The prepared samples were quantified on reversed phase column Luna C<sub>18(2) </sub>(150 × 4.6 mm i.d., 5 µm particle size) operated at room temperature using the mobile phase consisting of methanol: 0.1% acetic acid (50 : 50, v/v) at a flow rate of 1 ml min<sup>−1</sup>. The method was fully validated according to bioanalytical validation guidelines of FDA in terms of system suitability, selectivity, sensitivity, precision and stability. It was found that the increase in peak areas followed the increase of DZ concentration in the range of 2.56–200.00 ng ml<sup>−1</sup> with LOD of 0.85 ng ml<sup>−1</sup>. The method was successfully applied for the determination of DZ in rabbit plasma using manual shaking dispersive liquid...
The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with flu... more The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with fluorescence detection for estimation of donepezil (DZ) in rabbit plasma using silodosin as the internal standard (IS). The prepared samples were quantified on reversed-column Luna C<sub>18(2) </sub>(150 mm × 4.6 mm i.d, 5 µm particle size) operated at room temperature using the mobile phase consisting of methanol: 0.1% acetic acid (50 : 50, v/v) at a flow rate of 1 ml min<sup>−1</sup>. The method was fully validated according to bioanalytical validation guidelines of FDA in terms of system suitability, selectivity, sensitivity, precision and stability. It was found that the increase in peak areas followed the increase of DZ concentration in the range of 2.56–200.00 ng ml<sup>−1</sup> with LOD of 0.85 ng ml<sup>−1</sup>. The method was successfully applied for the determination of DZ in rabbit plasma using manual shaking dispersive liquid–liqu...
Sphinx Journal of Pharmaceutical and Medical Sciences, 2021
The Angiotensin-converting enzyme inhibitors and antagonists are widely used in the management of... more The Angiotensin-converting enzyme inhibitors and antagonists are widely used in the management of essential hypertension, stable chronic heart failure, myocardial infarction and diabetic nephropathy, so that specific and sensitive methods are needed for the qualitative and quantitative determinations of these drugs in pharmaceutical dosage forms and in biological material. In the last few years, there was no review published covering all different analytical methods used for the determination of these drugs. The aim of this work is to review the most important recent methods for their analysis in pure forms, in different pharmaceutical dosage forms and in biological fluids due to the great importance of this class of drugs. This review includes two parts: the first part presents the methods applied for the analysis of pharmaceuticals. The second part is devoted to the methods elaborated for the assays in biological material (blood, plasma and urine).
International Journal of Biological Macromolecules, 2019
A novel green magnetic molecularly imprinted solid phase extraction (MMI-SPE) for separation of m... more A novel green magnetic molecularly imprinted solid phase extraction (MMI-SPE) for separation of memantine (MEM) from complicated matrices was proposed. The nanomaterial was synthesized via crosslinking of chitosan (CHIT) with [3-(2, 3-epoxypropoxy)-propyl] trimethoxysilane (EPPTMS) in presence of MEM as a template. The nanocomposites, in all steps, were characterized by SEM, FTIR and PXRD techniques. The adsorbed drug was removed from magnetic molecular imprinted polymer (MMIP) cavity by ethanol: acetic acid (8:2, v/v) and then, coupled with sodium 1, 2-naphthoquinone-4-sulphonate (NQS) in iodine/alkaline medium to yield highly fluorescent product, after reduction with potassium borohydride (KBH 4). Variables affecting extraction of MEM from imprinted sites and its fluorometric analysis were studied. The linearity was achieved over concentration range of 1.84-95.0 ng mL −1 with LOD of 0.6 ng mL −1. The method was successfully applied for determination of MEM in its pharmaceutical tablets and human serum with recoveries of 100.8 ± 3.0, 97.6 ± 2.9, respectively.
A highly sensitive and cost-effective HPTLC method was developed for the determination of rivasti... more A highly sensitive and cost-effective HPTLC method was developed for the determination of rivastigmine hydrogen tartarate (RIV) in bulk and capsules. Moreover, magnetic solid phase extraction procedure (MSPE) was performed for analysis of RIV in human plasma to preconcentrate RIV and decrease interference from plasma constituents. The magnetic nanoparticles (MNPs) were prepared by co-precipitation process and characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), powdered X-ray diffraction (PXRD) and dynamic light scattering (DLS). These prepared MNPs have shown high extraction efficiency and all parameters affecting the adsorption of RIV on the MNPs were fully investigated. The method was validated according to FDA bio-analytical guidelines and was found to be linear over the range of 30.2-648 ng/spot. The LLOQ and LOD were 26.2 and 8.6 ng/spot, respectively.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2019
This paper describes the decoration of pencil graphite electrode (PGE) with a thin film of soloch... more This paper describes the decoration of pencil graphite electrode (PGE) with a thin film of solochrome black T (SBT) and Ndoped carbon nanodots (N-CNDs)/ cobalt nanoparticles (CoNPs) to amplify signal of the measurement. This nanocomposite was chosen to enhance surface activity and electron transfer toward donepezil HCl (DZ HCl) oxidation. The physical properties of nanocomposite were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), electron impedance spectroscopy (ESI) and energy dispersive X-ray (EDX) spectroscopy. Cyclic voltammetry was utilized to quantify DZ HCl at the modified PGE in Britton-Robinson buffer (pH = 6.5). Under optimized experimental conditions, peak current increased with the increase in the concentration of DZ HCl and was linear between the range of 1.5 nM-400 μM with a relatively low detection limit of 0.0005 μM. Due to high sensitivity, simplicity and costeffectiveness of the designated sensor; it was used as a simple method for detecting DZ HCl in rabbit plasma and during its pharmacokinetic study.
The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with flu... more The aim of this paper is to develop sensitive, accurate, reproducible and robust RP-HPLC with fluorescence detection for estimation of donepezil (DZ) in rabbit plasma using silodosin as the internal standard (IS). The prepared samples were quantified on reversed phase column Luna C 18(2) (150 × 4.6 mm i.d., 5 µm particle size) operated at room temperature using the mobile phase consisting of methanol: 0.1% acetic acid (50 : 50, v/v) at a flow rate of 1 ml min −1 . The method was fully validated according to bioanalytical validation guidelines of FDA in terms of system suitability, selectivity, sensitivity, precision and stability. It was found that the increase in peak areas followed the increase of DZ concentration in the range of 2.56–200.00 ng ml −1 with LOD of 0.85 ng ml −1 . The method was successfully applied for the determination of DZ in rabbit plasma using manual shaking dispersive liquid–liquid microextraction.
Asian Journal of Biomedical and Pharmaceutical Sciences, Dec 26, 2014
Simple, cost effective and reproducible spectrophotometric methods are proposed for the determina... more Simple, cost effective and reproducible spectrophotometric methods are proposed for the determination of enalapril maleate, lisinopril dihydrate, moexipril hydrochloride and ramipril hydrochloride in pure and tablet doage forms. The methods are based on oxidation of these drugs by either potassium dichromate or potassium permanganate in sulphuric acid medium then measuring of the developed colored reaction products or the decrease in the intensity of color at λmax 610, 520 nm for the potassium dichromate (method A) and potassium permanganate (method B) respectively. Different variables affecting the reaction conditions were carefully studied and optimized. Under optimal experimental conditions the linear range is 20-900 µg.ml -1 (method A) and 2-500 µg.ml -1 (method B). The proposed methods were successfully applied to the analysis of the investigated drugs in pure and tablet dosage form. Results were comparable with those obtained by reported spectrophotometric methods.
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