Browsing by Author "Fouad M."

Now showing 1 - 4 of 4

A combination of isocratic and gradient elution modes in HPLC with the aid of time-overlapping process for rapid determination of methyldopa in human urine
(Taylor and Francis Inc., 2015) Emara S.; Masujima T.; Zarad W.; Kamal M.; Fouad M.; El-Bagary R.; Department of Pharmaceutical Chemistry; Faculty of Pharmacy; Misr International University; Km 28 Ismailia Road; Ismailia; Cairo; 41522; Egypt; P.I. Lab. Single Cell MS; RIKEN Quantitative Biology Center; Suita; Osaka; Japan; Department of Pharmaceutical Analytical Chemistry; Faculty of Pharmacy; Modern Sciences and Arts University; Cairo; Egypt; Department of Pharmaceutical Chemistry; Faculty of Pharmacy; Cairo University; Cairo; Egypt
A new rapid time-overlapping high-performance liquid chromatography method using coupled-column double-injection technique with fluorescence detection has been developed and validated to determine methyldopa (MTD) in human urine. The method was based on injecting a new sample onto the second column before finalizing the cleanup and the re-equilibration of the first column for the former sample. A combination of isocratic and gradient elution was employed according to a pre-set program. At the beginning, isocratic step of acetate buffer solution (0.1 M, pH 2.4) was set until 7 min. Subsequently, a gradient elution step using acetate buffer (0.1 M, pH 2.4) as mobile phase A and acetonitrile as mobile phase B was employed. After the end of each gradient step, the column was re-equilibrated with 4 mL of the starting isocratic elution system before the next analysis. The overall cycle time was 7 min per each sample. The calibration curve was linear over the concentration range of 0.1-40 ?g/mL MTD. The overall mean recoveries were in the range of 98.29-101.39%. The applicability of the method was successfully evaluated by monitoring the incremental urinary excretion of MTD in human urine over 12 hr after a single oral administration of 250 mg. � 2015 Taylor & Francis Group, LLC.
An eco-friendly direct injection HPLC method for methyldopa determination in serum by mixed-mode chromatography using a single protein-coated column
(Oxford University Press, 2015) Emara S.; Masujima T.; Zarad W.; Kamal M.; Fouad M.; El-Bagary R.; Pharmaceutical Chemistry Department; Faculty of Pharmacy; Misr International University; Km 28 Ismailia Road; Cairo; Egypt; P.I. Lab. Single Cell MS; RIKEN Quantitative Biology Center; 6-2-3; Furuedai; Suita; Osaka 565-0874; Japan; Pharmaceutical Analytical Chemistry Department; Faculty of Pharmacy; Modern Sciences and Arts University; 26 July Mehwar Road Intersection With Wahat Road; 6 October City; Egypt; Pharmaceutical Chemistry Department; Faculty of Pharmacy; Cairo University; Kasr El Aini St.; Cairo; 11562; Egypt
A simple, rapid and environment-friendly direct injection HPLC method for the determination of methyldopa (MTD) in human serum has been developed and validated. The method was based on cleanup and separation of MTD from serum by mixed-mode liquid chromatography using a single protein-coated TSK gel ODS-80 TM analytical column (50 x 4.0 mm i.d., 5 ?m). The protein-coated column exhibited excellent resolution, selectivity and functioned in two chromatographic modes: size-exclusion chromatography [i.e., solid-phase extraction (SPE) for serum proteins] and reversed-phase chromatography for the final separation of MTD. SPE and HPLC separation were carried out simultaneously with a green mobile phase consisting of acetate buffer (0.1 M, pH 2.4) at a flow rate of 1 mL/min and at room temperature (23 � 1�C). The eluent was monitored at emission and excitation wavelengths of 320 and 270 nm, respectively. A calibration curve was linear over the range of 0.1-30 ?g/mL with a detection limit of 0.027 ?g/mL. This online SPE method was successfully applied to real samples obtained from patients receiving MTD therapy. � The Author 2015. Published by Oxford University Press. All rights reserved.
Field-amplified sample stacking cyclodextrin modified capillary electrophoresis for quantitative determination of diastereomeric saponins
(Springer Netherlands, 2014) Emara S.; Masujima T.; Zarad W.; Mohamed K.; Kamal M.; Fouad M.; EL-Bagary R.; Faculty of Pharmacy; Pharmaceutical Chemistry Department; Misr International University; Km 28 Ismailia Road; Cairo; Egypt; P.I. Laboratory Single Cell MS; RIKEN Quantitative Biology Center; 6-2-3; Furuedai; Suita; Osaka; 565-0874; Japan; Faculty of Pharmacy; Pharmacognosy Department; Assiut University; Assiut; 71526; Egypt; Faculty of Pharmacy; Pharmaceutical Analytical Chemistry Department; Modern Sciences and Arts University; 26 July Mehwar Road Intersection with Wahat Road; 6 October City; Egypt; Faculty of Pharmacy; Pharmaceutical Chemistry Department; Cairo University; Kasr El Aini St.; Cairo; 11562; Egypt
Successful simultaneous diastereomeric separation and sensitive determination of two pairs of triterpenoidal saponins have been achieved by capillary electrophoresis (CE) using ?-cyclodextrin (?-CD) as a stereoselective agent to cooperate with borate complexation. A usual technique for isolation and group separation of saponins was developed as an appropriate purification step prior to the determination of individual saponins by CE. Soyasaponin I (S1), azukisaponin V (S2), bersimoside I (S3) and bersimoside II (S4) could be well separated within 14 min in a fused-silica capillary (60 cm long to the detector with an additional 10 cm to the cathode; 75 ?m i.d.). The background electrolyte was borate buffer (80 mM, pH 10), containing 24 mM ?-CD. The separation voltage was 14 kV with a detection wavelength of 195 nm. The sample was electrokinetically injected using a voltage of 16 kV for 12 s. Methanol (70%) was used as the diluent for field-amplified sample stacking after hydrodynamic injection of short water plug (5 cm, 4 s). The method was partially validated for linearity, repeatability, reproducibility, limits of detection and limits of quantification. The correlation coefficients of the calibration curves were all >0.998, and the recoveries were from 98.23 to 96.21%. The Author [2013]. Published by Oxford University Press. All rights reserved.
Simultaneous Determination of Five Coccidiostats in Veterinary Powders, Feed Premixes, and Baby Food by Micellar Electrokinetic Chromatography: Application to Chicken Tissues and Liver
(Springer New York LLC, 2018) Belal F.; El-Razeq S.A.; Fouad M.; Zayed S.; Fouad F.; Department of Pharmaceutical Analytical Chemistry; Faculty of Pharmacy; University of Mansoura; Mansoura; Egypt; Department of Analytical Chemistry; Faculty of Pharmacy; Al-Azhar University; Cairo; Egypt; Department of Analytical Chemistry; Faculty of Pharmacy; Al-Azhar University; October University for Modern Sciences and Arts; Cairo; Egypt; Unit of Drug Analysis; Faculty of Pharmacy; University of Mansoura; Mansoura; Egypt
A new, simple, and reliable micellar electrokinetic chromatographic method was developed and validated for the simultaneous determination of amprolium, ethopabate, diaveridine, sulphadimidine, and sulphaquinoxaline. The separation was achieved using 50�mM tris buffer (pH 8.5) with 50�mM SDS and 15% acetonitrile (v/v) at 28�kV and the components were detected at 200�nm. Different factors affecting the electrophoretic mobility of the five investigated drugs were studied and optimized. Method validation showed that calibration plots were linear within the range from 0.5 to 100�?g/mL with a correlation coefficient > 0.998. Intraday and interday precision and accuracy evaluated by relative standard deviation were lower than 2%. The limits of detection were in the ranges of 0.02 to 0.07�?g/mL. The new method with simple sample pretreatment based on aqueous methanol extraction has been successfully applied for analysis of these drugs in powder preparations, feed premixes, baby food, chicken tissues, and liver samples with the recoveries of 97�101%. The present method is suitable and favorable for the analysis of the five coccidiostats drugs on account of its cost effectiveness, simplicity, rapidity, and sensitivity. � 2018, Springer Science+Business Media, LLC, part of Springer Nature.