Browsing by Author "Medhat, Passant M"

Now showing 1 - 5 of 5

Cobalt oxide nanoparticles modified coated graphite potentiometric sensor for quantification of sulfacetamide sodium in its pharmaceutical dosage form and spiked rabbit aqueous humor samples with greenness assessment
(Elsevier Inc, 2023-09) Fares, Nermine V; Medhat, Passant M; Ayad, Miriam F; El Maraghy, Christine M
This study presents the fabrication of an innovative coated graphite electrode modified with cobalt oxide nanoparticles, for potentiometric determination of Sulfacetamide sodium. The functionalized nano-electrode was compared to a classical one; to study the advantages of addition of nanoparticles which was found to improve the performance characteristics of the electrode including improved sensitivity and selectivity, as well as, extended operational lifespan. The functionalized nano-electrode was more sensitive than the classical one with linearity range (1 × 10− 7 –1 × 10− 2 M) and a limit of detection down to 2.24 × 10− 8 M. This small modification increased the electrode’s potential stability by preventing the formation of a water layer on the surface of the solid contact electrode. The electrochemical performance of the proposed sensors was evaluated according to the IUPAC recommendation data and was found to be within the acceptable ranges. These developed potentiometric platforms were applied to quantitatively analyze Sulfacetamide sodium in its pure solutions, pharmaceutical dosage form and spiked rabbit aqueous humor with satisfactory recovery percentages without pre-extraction procedure nor interference of the co-formulated drug; Prednisolone acetate and excipients. The proposed method was statistically compared with the reported method in literature and no statistically significant dif- ference was found. The proposed method was evaluated for its environmental sustainability utilizing the Green Analytical Procedure index (GAPI) as a greenness assessment tool.
Implementation of green‑assessed nanotechnology and quality by design approach for development of optical sensor for determination of tobramycin in ophthalmic formulations and spiked human plasma
(BioMed Central Ltd, 2024-07) El‑Maraghy, Christine M; Medhat, Passant M; Hathout, Rania M; Ayad, Miriam F; Fares, Nermine V
A fast eco-friendly colorimetric method was developed for the determination of Tobramycin in drug substance, ophthalmic formulations, and spiked human plasma using silver nanoparticles optical sensor. Even though tobramycin is non-UV–visible absorbing, the developed method is based on measuring the absorbance quenching of silver nanoparticles resulting from the interaction with tobramycin. Different factors affecting the absorbance intensity were studied as; silver nanoparticle concentration, pH, buffer type, and reaction time using quality by design approach. Validation of the proposed method was performed according to ICH guidelines and was found to be accurate, precise, and sensitive. The linearity range of tobramycin was 0.35–4.0 μg/mL. The optical sensor was successfully applied for the determination of Tobramycin in ophthalmic formulations and spiked human plasma without pre-treatment. Additionally, the binding between Tobramycin and PVP- capped silver nanoparticles was studied using molecular docking software. The method was assessed and compared to colorimetric reported methods for the green character using Green Analytical Procedure Index (GAPI) and Analytical GREEnness calculator (AGREE) tools and found to be greener.
Implementation of quality by design approach for optimization of the green voltammetric analysis of a brain doping agent (Piracetam) using a novel molecular imprinted polymeric sensor
(Elsevier Inc, 2024-08) Medhat, Passant M; Fouad, Manal Mohamed; Mahmoud, Amr M; Ghoniem, Nermine S; Monir, Hany H
It is encouraging to note that in recent years there has been a growth of high-quality articles detailing molecular imprinted sensors for the detection of biomolecules, illicit narcotics, and explosives, paving the way for the technology's usage in forensic and medical diagnostics. Thus in this work, a molecularly imprinted polymeric sensor was fabricated, for the first time, for the sensitive and selective determination of a brain doping agent; Piracetam, using a pencil-graphite electrode. This sensor was created by the simple anodic electro-polymerization of o-phenylenediamine (o-PD) with Piracetam as the template. Then the sensor was activated by removing the template using a suitable solvent mixture. Because of Piracetam's lack of electro-activity, [Fe (CN)6]3−/4− has been used as an electrochemical probe that produces analytically relevant voltammetric signals by competing for the binding sites. Based on UV-spectrophotometric measurements, Job's approach confirmed the expected stoichiometric ratio between Piracetam and the chosen monomer. X-ray photoelectron spectroscopy and cyclic voltammetry techniques were used for the characterization of the fabricated sensors. Different factors affecting the electro-polymerization conditions as; the effect of scan rate, number of cycles, pH of electro-polymerization, and the incubation time for rebinding were studied and optimized using fractional factorial design, in which the predicted model fits well to the experimental data as proved by ANOVA results. The developed voltammetric platform was applied for the in-line quantification of Piracetam in its pure solutions, pharmaceutical dosage form, and spiked human plasma with high accuracy and selectivity without the interference of the co-formulated drug; Citicoline sodium and excipients. The proposed molecular imprinted sensor was very sensitive with a linearity range (1.00 × 10−13 − 1.00 × 10−12 M), with LOD down to 4.38 × 10−15 M. This method was statistically compared with the reported method, and no statistically significant difference was found. The proposed method was assessed for greenness quantitatively and qualitatively using the Green Analytical Procedure Index (GAPI) and Analytical GREEnness metric (AGREE) as new greenness assessment tools.
Influence of Nitrogen-Doped Carbon Dot and Silver Nanoparticle Modified Carbon Paste Electrodes on the Potentiometric Determination of Tobramycin Sulfate: A Comparative Study
(MDPI, 03/07/2021) Fares, Nermine V; Medhat, Passant M; El Maraghy, Christine M; Okeil, Sherif; Ayad, Miriam F
Abstract: Two inexpensive and simple methods for synthesis of carbon nanodots were applied and compared to each other, namely a hydrothermal and microwave-assisted method. The synthesized carbon nanodots were characterized using transmission electron microscopy (TEM), ultravioletvisible (UV-Vis), photoluminescence (PL), Fourier transform-infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The synthesized microwave carbon nanodots had smaller particle size and were thus chosen for better electrochemical performance. Therefore, they were used for our modification process. The proposed electrodes performance characteristics were evaluated according to the IUPAC guidelines, showing linear response in the concentration range 1006–1002 , 10 7–1002 , and 1008–1002 M of tobramycin with a Nernstian slope of 52.60, 58.34, and 57.32 mV/decade for the bare, silver nanoparticle and carbon nanodots modified carbon paste electrodes, respectively. This developed potentiometric method was used for quantification of tobramycin in its co-formulated dosage form and spiked human plasma with good recovery percentages and without interference of the co-formulated drug loteprednol etabonate and excipients
Influence of Nitrogen-Doped Carbon Dot and Silver Nanoparticle Modified Carbon Paste Electrodes on the Potentiometric Determination of Tobramycin Sulfate: A Comparative Study
(MDPI, 03/07/2021) Fares, Nermine V; Medhat, Passant M; El Maraghy, Christine M; Okeil, Sherif; Ayad, Miriam F
Two inexpensive and simple methods for synthesis of carbon nanodots were applied and compared to each other, namely a hydrothermal and microwave-assisted method. The synthesized carbon nanodots were characterized using transmission electron microscopy (TEM), ultravioletvisible (UV-Vis), photoluminescence (PL), Fourier transform-infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The synthesized microwave carbon nanodots had smaller particle size and were thus chosen for better electrochemical performance. Therefore, they were used for our modification process. The proposed electrodes performance characteristics were evaluated according to the IUPAC guidelines, showing linear response in the concentration range 1006–1002 , 1007–10 2 , and 1008–1002 M of tobramycin with a Nernstian slope of 52.60, 58.34, and 57.32 mV/decade for the bare, silver nanoparticle and carbon nanodots modified carbon paste electrodes, respectively. This developed potentiometric method was used for quantification of tobramycin in its co-formulated dosage form and spiked human plasma with good recovery percentages and without interference of the co-formulated drug loteprednol etabonate and excipients.