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  • Author or Editor: E. Ahmed x
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Authors: R. Itawi, S. Al-Jobori, M. Jalil, S. Farhan, A. Mheemeed, Kh. Saaeed and E. Ahmed

Abstract  

Eleven food colouring substances are analyzed for their elemental content by the method of instrumental neutron activation analysis, and the concentrations of fourteen elements present in these samples are presented.

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Authors: R. Itawi, S. Al-Jobori, M. Jalil, S. Farhan, A. Mheemeed, Kh. Saaeed and E. Ahmed

Abstract  

Thirteen textile dyes have been analyzed by the method of insturmental neutron activation analysis for their components of major and trace elements, and the concentration of thirteen elements in these samples are presented.

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Authors: Dustin M. Clifford, Ahmed A. El-Gendy, Amos J. Lu, Dmitry Pestov and Everett E. Carpenter

Abstract

Cobalt nanoparticles were synthesized using continuous-flow (CF) chemistry in a stainless steel microreactor for the first time at high output based on the ethanol hydrazine alkaline system (EHAS) producing a yield as high as 1 g per hour [1, 2]. Continuous-flow (CF) synthetic chemistry provides uninterrupted product formation allowing for advantages including decreased preparation time, improved product quality, and greater efficiency. This successful synthetic framework in continuous-flow of magnetic Co nanoparticles indicates feasibility for scaled-up production. The average particle size by transmission electron microscopy (TEM) of the as-synthesized cobalt was 30±10 nm, average crystallite size by Scherrer analysis (fcc phase) was 15±2 nm, and the estimated magnetic core size was 6±1 nm. Elemental surface analysis (X-ray photoelectron spectroscopy [XPS]) indicates a thin CoO surface layer. As-synthesized cobalt nanoparticles possessed a saturation magnetization (M s) of 125±1 emu/g and coercivity (H c) of 120±5 Oe. The actual M s is expected to be greater since the as-synthesized cobalt mass was not weight-corrected (nonmagnetic mass: reaction by-products, solvent, etc.). Our novel high-output, continuous-flow production (>1 g/hr) of highly magnetic cobalt nanoparticles opens an avenue toward industrial-scale production of several other single element magnetic nanomaterials.

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A new spectrodensitometric method was developed for the simultaneous determination of a quaternary mixture of antihyperlipidemics containing niacin, atorvastatin, and bezafibrate with either ezetimibe or simvastatin. Densitometric analysis was carried out using high-performance thin-layer chromatographic (HPTLC) silica gel 60G F254 plates as the stationary phase. The plates were developed with benzene—ACN—n-butanol (7:2:1, v/v) + 1.50%, v/v, glacial HOAC in absorbance mode at 242 nm. The retention factors of niacin, atorvastatin, bezafibrate, ezetimibe, and simvastatin were 0.17, 0.38, 0.51, 0.65, and 0.66, respectively. The method was validated according to the United States Pharmacopeia and National Formulary (USP 31—NF 26) and the International Conference on Harmonization (ICH) guidelines. Linearity ranges of all studied drugs were found to be in the range of 15–650 ng band−1 with correlation coefficient values of 0.9975 or more. Limits of detection and quantitation were 5–50 and 15–150 ng band−1, respectively. Upon applying polynomial regression to the same concentration ranges of standard solutions of all investigated drugs as well as spiked bezafibrate samples to rabbit plasma, correlation coefficient values had greatly improved. The proposed method was successfully applied for the simultaneous determination of the studied antihyperlipidemic drugs in plasma and in their pharmaceutical formulations. The developed method was utilized to study the pharmacokinetic behavior of bezafibrate and its drug—drug interaction with atorvastatin in rabbit males. This study has proven the increased myotoxicity risk upon coadministration of atorvastatin with bezafibrate.

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Abstract

Chloroquine phosphate (CQ) the antimalarial drug and suggested to treat the pandemic disease coronavirus (COVID-19) is often adulterated with some of the non-steroidal anti-inflammatory drugs (NSAIDs) such as paracetamol, aspirin (ASP), or both. The purpose of this study is to detect such counterfeited drugs, using a reversed phase high pressure liquid chromatography (RP-HPLC) method with fluorescence detection. Analysis was divided into three phases. In the first phase, a Plackett-Burman design (PBD) was used to screen five independent factors, namely, buffer pH, buffer concentration (mM), acetonitrile content (%), flow rate (mL/min) and triethylamine (TEA) content in the buffer preparation (%). The selected dependent variables were (resolution, symmetry of peaks and run time). The objective of the second phase was to optimize the method performance using Box-Behnken design (BBD) and desirability function for multiple response optimization to obtain the best chromatographic performance with the shortest run time. Optimal chromatographic separation was achieved on a YMC-pack pro C18 ODS-A column (15 cm × 4.6 mm, 5 µm) at room temperature The optimum mobile phase consisted of acetonitrile and 5 mM sodium dihydrogen phosphate buffer containing 0.5% triethyamine (30:70, v/v) with the pH adjusted to 3.5 using an orthophosphoric acid solution. The flow rate was maintained at 1 mL/min, and the detection was performed with a fluorescence detector fixed at 380 nm (λemission) after excitation at 335 nm (λexcitation). The third phase was method validation according to ICH guidelines, providing to be specific, precise, accurate, and robust. The method is linear over a range of 0.4–8 µg/mL for chloroquine and ASP, while for paracetamol it is linear over 16–48 µg/mL. The developed RP-HPLC method was used for quantitation of the three drugs in chloroquine dosage form samples. The method shows a great tendency in the classification between the genuine chloroquine and the adulterated ones in pharmaceutical preparations and breast milk.

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Context

Bacoside A, a triterpenoid saponin, is a major constituent isolated from Bacopa monnieri (L.) Wettst. (Scrophulariaceae), used as a memory enhancer. Bacoside A and B are active ingredients in Bacopa herb and have antioxidant and hepatoprotective activities

Objective

A new rapid, simple, and economical high-performance thin-layer chromatographic (HPTLC) method was developed and validated for densitometric quantitative analysis of bacoside A in powdered leaves from different geographical regions of India.

Materials and methods

An amount of 10 mg mL−1 methanol extract of powdered leaves from different geographic regions was used for sample application on precoated silica gel 60 F254 aluminum sheets. Standard bacoside A (1 mg mL−1) was used for calibration curve. HPTLC separation was performed on percolated silica gel aluminum plate 60 F254 (20 cm × 10 cm with 0.2 mm thickness) as a stationary phase using ethyl acetate–methanol–water (4:1:1) as the mobile phase. Quantification was achieved by densitometric analysis at 598 nm over the concentration range of 500–4000 ng band−1.

Result

Compact and well-resolved bands for bacoside A from powdered leaves of different geographic regions were found at retardation factor (R f) 0.53 ± 0.02. The linear regression analysis data for calibration curve showed good linear relationship with regression coefficient r 2 = 0.9996 and r 2 = 0.99810 with respect to peak area and peak height. The method was validated for precision, recovery, and robustness as per the International Conference on Harmonization (ICH) guidelines. Variation in quantitative analysis of bacoside A in powdered leaves sample from different geographic regions was found by HPTLC method.

Discussion and conclusion

The highest and lowest content of bacoside A in powdered leaves sample from Jammu and Kerala regions, respectively. The variety of B. monnieri in Jammu is superior to other regions of India. The proposed developed HPTLC method can be applied for the quantitative determination of bacoside A in powdered leaves of plant and its formulation.

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