Hassan SA, Ibrahim N, Elzanfaly ES, El Gendy AE. Simultaneous Determination of Amlodipine and Olmesartan Using HPLC with Fluorescence Detection. Pharmaceutical Chemistry Journal. 2021;55(2):206-12. Abstract

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Hassan SA, Abdelaal SH, El Azab NF, El-Kosasy AM. Micellar-enhanced synchronous spectrofluorimetric determination of anticancer trans-Resveratrol: a sustainable quality control tool for dietary supplements integrating circular analytical chemistry in the post-reform FDA era. Microchemical Journal. 2025;219:115911. AbstractWebsite

The growing dietary supplement (DS) market continues to face concerns regarding product quality and regulatory oversight. In response, the U.S. Food and Drug Administration (FDA) has launched a sweeping reorganization to consolidate and modernize its food-related divisions under the Human Foods Program. As part of this effort, the Office of Dietary Supplement Program has been integrated into a newly established Office of Food Chemical Safety, Dietary Supplements, and Innovation, underscoring the urgent need for improved analytical capabilities and sustainable quality control frameworks. In this context, we developed and validated a sustainable and green micellar-enhanced synchronous spectrofluorimetric method for the determination of trans-Resveratrol (RES), a bioactive polyphenol widely used in DS formulations. The method employs micellar enhancement using Triton X-100 (TX-100) to amplify the native fluorescence of RES without requiring chemical derivatization or photodegradation, offering a greener alternative to conventional chromatographic techniques. The method showed excellent sensitivity with a detection limit of 1.78 ng/mL and linearity over 10–170 ng/mL. Sustainability was systematically assessed through multi-dimensional tools confirming the method's minimal environmental impact. A novel sustainability framework was introduced in this work via alignment with Circular Analytical Chemistry (CAC) goals, marking the first application of this emerging concept in analytical method evaluation. These results reinforce the method's suitability for deployment in modern quality control laboratories aligned with the FDA's regulatory modernization goals. This study not only introduces RES as a model compound for micellar-enhanced fluorimetry but also demonstrates the potential of spectrofluorimetry as a sustainable, regulatory-aligned platform for the evolving landscape of DS quality assessment.

Wahba IA, El-Mosallamy SS, Fayed AS, Hassan SA. Beyond greenness and whiteness, a sustainability assessment framework integrating circularity for pharmaceutical quality control: Application to chemometric impurity profiling of paracetamol. Sustainable Chemistry and Pharmacy. 2026;51:102410. AbstractWebsite

The transition from Green to sustainable chemistry demands a paradigm shift in how analytical methodologies are evaluated, moving beyond isolated performance metrics toward holistic life-cycle assessment. In this study, we introduce a novel Sustainability Assessment Framework (Greenness, Applicability, Sustainability) to rigorously benchmark analytical strategies. As a proof-of-concept, the framework was applied to a complex pharmaceutical challenge: the impurity profiling of paracetamol (PAR) along with three official impurities: para-aminophenol (PAP), para-nitrophenol (PNP), and para-chloroacetanilide (PCA), and two co-formulated drugs ibuprofen (IBU) and chlorzoxazone (CHZ). Two chemometric models, partial least squares (PLS) and artificial neural networks (ANN), were utilized to achieve this purpose. Furthermore, both models were subjected to a variable selection process using genetic algorithm (GA) to identify the most significant wavelengths. The genetic algorithm-optimized neural network (GA-ANN) demonstrated superior predictive accuracy for the six-component mixture. The core innovation of this work lies in the comparative application of the Sustainability Assessment Framework, benchmarking the proposed chemometric method against a reference HPLC method using eight state-of-the-art metrics. Greenness was evaluated via Analytical Eco-Scale, GAPI, and AGREE; Applicability via BAGI, RGB12 algorithm, and EPPI; and Sustainability via the Carbon Footprint, NQS Index, and %Circularity. This study establishes the Framework as a robust prototype for modern quality control, validating chemometrics not merely as an alternative technique, but as a superior sustainable evolution aligned with the principles of the circular economy.

El-Fattah MA, Sharaf YA, El-Sayed HM, Hassan SA. A sensitive, aqueous-based spectrofluorimetric approach for the determination of favipiravir in presence of its acid-induced degradation product. BMC Chemistry. 2026;20:56. AbstractWebsite

The COVID-19 pandemic has emphasized the critical need for novel therapeutic approaches. Favipiravir (FAV), an antiviral drug primarily used for influenza, has shown promising potential in treating COVID-19 and other RNA viral infections. A precise, reliable, and rapid fluorimetric method was established for the quantification of FAV in pharmaceutical formulations, even in the presence of its acid-induced degradation product. The acid-induced degradation product (ADP) of FAV was prepared through forced degradation, followed by characterization using IR and MS. The method leveraged the intrinsic fluorescence characteristics of FAV, exhibiting a linear response within the concentration range of 5–80 ng/mL at 416.5 nm using the first-order derivative processing. Key methodological parameters were optimized to enhance sensitivity, achieving detection and quantification limits of 1.6 ng/mL and 4.8 ng/mL, respectively. All calibration and fluorimetric measurement steps were performed in distilled water without the use of organic solvents or buffers, making the analytical determination phase entirely aqueous and environmentally benign. This method was effectively applied to FAV in both pure drug and pharmaceutical dosage forms. Compared with previously reported fluorimetric methods, it offers the unique combination of aqueous-based operation, stability-indicating capability, and superior analytical performance. Additionally, its environmental sustainability was evaluated using GAPI, AGREE, and RGB12 metrics, which confirmed its green and eco-friendly attributes.

Hassan SA, Abdelaal SH, El Azab NF, El-Kosasy AM. A new era in dietary supplement regulation: sustainable chemometric approach for quality control of four dietary ingredients in slimming preparations. Journal of Food Composition and Analysis. 2025;148:108619. AbstractWebsite

By the end of 2024, the largest reorganization in the modern history of the U.S. FDA took effect. This overhaul included the establishment of the Office of Food Chemical Safety, Dietary Supplements, and Innovation (OFCSDSI), underscoring the growing need for stringent oversight of the dietary supplement (DS) industry. Phenethylamines stimulants are on regulatory monitoring lists, yet they remain available in the DS market. With this reshaping of the regulatory framework of DS, there is an increasing demand for specific and sensitive analytical methods to monitor and control such dietary ingredients. This study introduces chemometrics as a pivotal tool in the enhanced regulatory oversight of DS. Advanced spectrophotometric techniques, coupled with chemometric models, were employed for the simultaneous quantitation of 2-Phenethylamine, caffeine, p-Hordenine, and p-Synephrine in complex slimming supplement formulations. Three multivariate models—Partial Least Squares-1 (PLS-1), Genetic Algorithm-Partial Least Squares (GA-PLS), and Genetic Algorithm-Artificial Neural Networks (GA-ANN)—were evaluated. Notably, the GA-based models (GA-ANN) outperformed PLS-1 in resolving spectral overlap without preliminary separation steps, even in the presence of formulation additives. These findings demonstrate the potential of chemometrics as viable eco-friendly alternative for chromatography in routine quality control of DS under the FDA’s new regulatory paradigm.

ElDin NB, Abd El-Rahman MK, Zaazaa HE, Moustafa AA, Hassan SA. An eco-friendly potentiometric sensor for in-line monitoring of methacholine chloride hydrolysis: A ‘Green-Dip’ approach. Journal of Electroanalytical Chemistry. 2025;996:119371. AbstractWebsite

Methacholine chloride (MCh), a hydrolyzable cholinergic agonist, is widely employed in bronchoprovocation tests for asthma diagnosis. However, the instability of MCh in aqueous solutions poses a major concern during the methacholine challenge test. To address this issue, the innovative ‘Green-Dip’ approach was developed for in-line potentiometric monitoring of MCh hydrolysis in inhalation solutions prepared for the challenge test. A portable, eco-friendly, and disposable screen-printed electrode (SPE) was designed and optimized to quantify MCh and monitor its hydrolytic degradation under varying pH conditions, enabling the determination of key kinetic parameters. The SPE was enhanced for improved selectivity, detection limit, and resistance to potential drift by incorporating calix[4]arene (CX4) as an ionophore within the ion-sensing membrane (ISM) and multiwalled carbon nanotubes (MWCNTs) as a transducing layer between the ISM and the electrode surface. The proposed sensor exhibited Nernstian behavior for MCh over a concentration range of 3.05 × 10−7 M to 1.00 × 10−2 M, with a detection limit of 8.91 × 10−8 M and a slope of 57.20 ± 0.33 mV/decade. It demonstrated excellent performance characteristics, including minimal potential drift (1.10 mV/h), a rapid response time (4 ± 1 s), and an extended operational lifetime of approximately 50 days. As part of the ‘Green-Dip’ approach and to enhance environmental sustainability, 2-methyltetrahydrofuran (MeTHF) was utilized as an eco-friendly alternative to tetrahydrofuran (THF) for dissolving the components of the ion-sensing membrane (ISM). The proposed sensor facilitated real-time monitoring of MCh hydrolysis, enabling the evaluation of pH and temperature effects, as well as the calculation of reaction rate constants, half-life, and activation energy. This cost-effective, eco-friendly in-line tool provides a reliable solution for assessing the stability of MCh solutions in methacholine challenge tests, addressing both analytical precision and environmental concerns.

Sharaf YA, Abd El-Fattah MH, Mahmoud AM, El-Sayed HM, Hassan SA. Novel carbon paste sensor modified with MWCNT and Ca-doped ZnO nanocomposite for therapeutic monitoring of Favipiravir in COVID-19 patients. Microchemical Journal. 2025;208:112364. Abstract

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Abdelaal SH, El Azab NF, Hassan SA, El-Kosasy AM. Monitoring of the prohibited 2-phenethylamine in dietary supplements using a t-Butyl calix[8]arene/Ag/CuO composite-based potentiometric sensor. Microchemical Journal. 2024;201:110695. AbstractWebsite

2-phenethylamine (PEA) is a prohibited trace amine, that possesses amphetamine-like effect and toxicity. However, it is still present in many weight loss dietary supplements on which the quantities of PEA are not always listed. Therefore, monitoring of this toxic compound in these hypothetically safe products is essential. Herein, PEA was assayed using ion-selective potentiometric membrane sensors. A novel combination of silver doped copper oxide (Ag/CuO) nanoparticles with 4-tert-butylcalix[8]arene (BCX8) was investigated as a new ion-to-electron transducer layer used with solid contact glassy carbon electrodes. To study the effect of this novel combination, three sensors were proposed based on the incorporation of plain sodium tetraphenylborate (TPB) ion exchanger (sensor 1), TPB with BCX8 only (sensor 2) and TPB with Ag/CuO nanoparticles and BCX8 (sensor 3). The doped metal oxide nanoparticles were prepared using a simple wet co-precipitation synthesis procedure and were characterized for particle shape and size, elemental composition, and optical band gap energy. Near Nernstian responses were achieved with slope values of 52.28 ± 0.45, 54.64 ± 0.98 and 55.34 ± 0.35 mV/concentration decade and LOD of 9.88 × 10−5, 7.18 × 10−5, and 9.77 × 10−6 M for sensors 1, 2 and 3; respectively. Sensor 3 showed linearity range 1 × 10−5 to 1 × 10−2 M and response time of 10 s. The Ag/CuO nanoparticles incorporated within BCX8 network provided improved electron transfer kinetics, and was found to provide the best sensitivity, widest linearity range and the most stable and fastest response among the compared sensors. The proposed sensors showed excellent percent recoveries when applied for the analysis of PEA in its multi-ingredient formulation and showed no statistical difference with the reported method.

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