Hassan SA, Nashat NW, Elghobashy MR, Abbas SS, Moustafa AA. Stability-indicating RP-HPLC and CE methods for simultaneous determination of bisoprolol and perindopril in pharmaceutical formulation: a comparative study. Journal of Chromatographic Science. 2020;58(8):747-58. Abstract
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Hassan SA, ElDin NB, Zaazaa HE, Moustafa AA, Mahmoud AM. Point-of-care diagnostics for drugs of abuse in biological fluids: application of a microfabricated disposable copper potentiometric sensor. Microchimica Acta. 2020;187(9):491. Abstract
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Basha MA, Abd El-Rahman MK, Bebawy LI, Moustafa AA, Hassan SA. A comparative Study of two analytical techniques for the simultaneous determination of Amprolium HCl and Ethopabate from combined dosage form and in presence of their alkaline degradation. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2020;243:118756. Abstract
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Ibrahim N, Elzanfaly ES, El Gendy AE, Hassan SA. Development, optimization, and validation of a green spectrofluorimetric method for the determination of moxifloxacin using an experimental design approach. Research Journal of Pharmacy and Technology. 2021;14(4):1880-6. Abstract
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Abdel-Gawad SA, Arab HH, Hassan SA. Signal processing techniques for the spectrophotometric quantitation of binary mixture of dapagliflozin and saxagliptin: A comparative study. Tropical Journal of Pharmaceutical Research. 2021;20(7):1489-96. Abstract
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El Azab NF, Abdelaal SH, Hassan SA, El-Kosasy AM. Dietary supplement mislabelling: case study on selected slimming products by developing a green isocratic HPLC method for their quality control. Scientific Reports. 2022;12(1):22305. AbstractWebsite

Nowadays, a huge population consumes Dietary supplements for losing weight. Products are often claimed as botanical blends, yet they aren't necessarily safe. Misleading labels are also very common. Thus, validated analytical methods for a wide range of slimming compounds are highly needed. Herein, we present a simple HPLC/PDA method for the quantitation of seven popular slimming ingredients. Studied compounds were Caffeine, Raspberry Ketone, trans-Resveratrol, p-Synephrine, p-Octopamine, p-Hordenine and 2-phenethylamine. After optimization, separation was carried out on a C18 column and mobile phase was a mixture of Acetonitrile:Water containing 0.1% phosphoric acid (50:50, %v/v). The last compound was eluted at 9.76 min. Separation was efficient showing baseline- separated symmetric peaks, without using any gradient programs, organic mobile phase modifiers or modified stationary phases. Method validation was done following ICH guidelines. Calibration curves were linear over wide concentration ranges and calculated LOD values were in the range 0.02–0.09 µg/mL. Method greenness was assessed using Analytical Eco-scale, GAPI and AGREE metric tools. Further, four random sample products purchased from online supplement stores were assayed. Results proved some mislabeling actions. To support our findings, standard addition was carried out and average % recoveries were 96.67 – 101.44% with standard deviation ≤ 2.83 between measurements.

Sharaf YA, Abd El-Fattah MH, El-Sayed HM, Hassan SA. A solvent-free HPLC method for the simultaneous determination of Favipiravir and its hydrolytic degradation product. Scientific Reports. 2023;13(1):18512. AbstractWebsite

During COVID-19 pandemic, Favipiravir (FPV) showed a great efficacy against COVID-19 virus, it produced noticeable improvements in recovery of the patients. The aim of this study was to develop a new, green and simple method for the simultaneous determination of FPV and its acid-induced degradation product (ADP) in its pure and pharmaceutical dosage forms. This method will be key for the inevitable development of FPV solution and inhaler formulations. A green micellar RP-HPLC method was developed using an RP-VDSPHERE PUR 100 column (5 µm, 250 × 4.6 mm) and an isocratic mixed micellar mobile phase composed of 0.02 M Brij-35, 0.1 M SDS and 0.01 M potassium dihydrogen orthophosphate anhydrous and adjusted to pH 3.0 with 1.0 mL min−1 flow rate. The detection was performed at 280 nm with a run time of less than six min. Under the optimized chromatographic conditions, linear relationship has been established between peak area and concentration of FPV and its ADP in the range of 5–100 and 10–100 µg mL−1 with elution time of 3.8 and 5.7 min, respectively. The developed method was validated according to the ICH guidelines and applied successfully for determination of FPV in its pharmaceutical dosage form.

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