Ramadan, N. K., H. A. Merey, S. S. Diab, and A. A. Moustafa, "In-Line Green Potentiometric Monitoring of Dissolution Behavior of Losartan Potassium Versus Pharmacopeial Methods: A Comparative Study", Analytical Chemistry Letters, vol. 12, issue 1, pp. 13-28, 2022.
Merey, H. A., N. K. Ramadan, S. S. Diab, and A. A. Moustafa, "Green spectrophotometric methods for the determination of a binary mixture of lidocaine hydrochloride and cetylpyridinium chloride in the presence of dimethylaniline.", Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, vol. 242, pp. 118743, 2020. Abstract

Three green, simple, precise, accurate and sensitive spectrophotometric methods were developed for the determination of a binary mixture of lidocaine hydrochloride (LDC) and cetylpyridinium chloride (CPC) in the presence of dimethylaniline (DMA). In the three methods, the interference of DMA spectrum is eliminated using the ratio subtraction method. Method (A) depended on determining LDC and CPC by measuring the first derivative of the ratio spectra (DD) at 271.0 and 268.4 nm, respectively. Method (B) was the ratio difference (RD), based on dividing the absorption spectrum of the binary mixture by a standard spectrum of CPC or LDC, then measuring the amplitude difference of the ratio spectra (∆P) between 231.2 and 240.0 nm for LDC and between 242.8 and 258.0 nm for CPC. Method (C) based on the application of dual wavelength coupled with the isoabsorptive point method. This was achieved by measuring the absorbance difference (∆A) between 243.0 and 268.6 nm for the determination of LDC, followed by application of isoabsorptive point method comprised of measurement the total content of the mixture of LDC and CPC at their isoabsorptive point at 240.0 nm. The content of CPC was obtained by subtraction. The specificity of the developed methods was investigated by analyzing laboratory prepared mixtures containing different ratios of LDC and CPC in presence of DMA. The proposed methods displayed useful analytical characteristics for the determination of LDC and CPC in bulk powder and their combined dosage form. The obtained results were statistically compared with those obtained by the official methods, showing no significant difference with respect to accuracy and precision.

Merey, H. A., N. K. Ramadan, S. S. Diab, and A. A. Moustafa, "Chromatographic methods for the simultaneous determination of binary mixture of Saxagliptin HCl and Metformin HCl", Bulletin of Faculty of Pharmacy, Cairo University, vol. 55, pp. 311-317, 2017.
Merey, H. A., N. K. Ramadan, S. S. Diab, and A. A. Moustafa, "Validated Spectrophotometric Methods for Simultaneous Determination of Lercanidipine HCl and Enalapril MALEATE in their Binary Mixture", Der Pharma Chemica, vol. 9, issue 16, pp. 33-41, 2017.
Merey, H. A., N. K. Ramadan, S. S. Diab, and A. A. Moustafa, "Development and validation of UPLC methods for simultaneous determination of selected antihypertensive drugs in their dosage forms", 17th International Conference on Medical and Health Science (ICMHS), Paris, France, 7th November, 2015.
Merey, H. A., N. K. Ramadan, S. S. Diab, and A. A. Moustafa, "Spectrophotometric methods for simultaneous determination of ternary mixture of amlodipine besylate, olmesartan medoxomil and hydrochlorothiazide", Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 125, issue 5, pp. 138–146, 2014. AbstractWebsite

Four, accurate, precise, and sensitive spectrophotometric methods are developed for the simultaneous determination of a ternary mixture containing amlodipine besylate (AM), olmesartan medoxomil (OL) and hydrochlorothiazide (HZ), where AM is determined at its λmax 364.6 nm (0D), while (OL) and (HZ) are determined by different methods. Method (A) depends on determining OL and HZ by measuring the second derivative of the ratio spectra (2DD) at 254.4 and 338.6 nm, respectively. Method (B) is first derivative of the double divisor ratio spectra (D-1DD) at 260.4 and 273.0 nm for OL and HZ, respectively. Method (C) based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method then measuring OL and HZ at their isoabsorptive point at 260.0 nm, while HZ is measured using the amplitude of first derivative at 335.2 nm. Method (D) is mean centering of the ratio spectra (MCR) at 252.0 nm and 220.0 nm for OL and HZ, respectively. The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs and their combined dosage form. The obtained results are statistically compared with those obtained by the official or reported methods, showing no significant difference with respect to accuracy and precision at p = 0.05.

Tourism