Publications by authors named "Abd El-Galil E Amr"

93 Publications

Paper-Based Potentiometric Sensors for Nicotine Determination in Smokers' Sweat.

ACS Omega 2021 May 22;6(17):11340-11347. Epub 2021 Apr 22.

Chemistry Department, Faculty of Science, King Khalid University, Abha 61413, Saudi Arabia.

Herein, we describe for the first time, the design and fabrication of a novel nicotine paper-based sensor, in which a miniaturized paper reference electrode is integrated for potentiometric measurements. The paper-based sensors were designed using printed wax barriers to define the electrochemical cell and the sample zones. The electrodes were based on the use of the ion association complexes of the nicotinium cation (Nic) with either tetraphenylborate (TPB) or 5-nitrobarbiturate (NB) counter anions as sensing materials for nicotine recognition. A poly (3,4 ethylenedioxythiophene)/poly-(styrene sulfonate) (PEDOT/PSS) conducting polymer was used as an ion-to-electron transducer. The performance characteristics of the proposed sensors were evaluated and it revealed a rapid and stable response with a Nernstian slope of 55.2 ± 0.3 and 51.2 ± 0.6 mV/decade over the linear range of 1.0 × 10 to 1.0 × 10 M and detection limits of 6.0 and 8.0 μM for [Nic/TPB] and [Nic/NB], respectively. The sensors revealed a constant response over the pH range 3.5-6.5. The designed sensors provided a portable, inexpensive, and disposable way of measuring trace levels of nicotine coming from different cigarettes and in the collected human sweat of heavy smokers. All results were compared favorably with those obtained by the standard gas chromatographic method.
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http://dx.doi.org/10.1021/acsomega.1c00301DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8153920PMC
May 2021

All-Solid-State Potentiometric Ion-Sensors Based on Tailored Imprinted Polymers for Pholcodine Determination.

Polymers (Basel) 2021 Apr 7;13(8). Epub 2021 Apr 7.

Department of Chemistry, Faculty of Science, Ain Shams University, Cairo 11566, Egypt.

In recent times, the application of the use of ion-selective electrodes has expanded in the field of pharmaceutical analyses due to their distinction from other sensors in their high selectivity and low cost of measurement, in addition to their high measurement sensitivity. Cost-effective, reliable, and robust all-solid-state potentiometric selective electrodes were designed, characterized, and successfully used for pholcodine determination. The design of the sensor device was based on the use of a screen-printed electrode modified with multiwalled carbon nanotubes (MWCNTs) as a solid-contact transducer. Tailored pholcodine (PHO) molecularly imprinted polymers (MIPs) were prepared, characterized, and used as sensory receptors in the presented potentiometric sensing devices. The sensors exhibited a sensitivity of 31.6 ± 0.5 mV/decade ( = 5, = 0.9980) over the linear range of 5.5 × 10 M with a detection limit of 2.5 × 10 M. Real serum samples in addition to pharmaceutical formulations containing PHO were analyzed, and the results were compared with those obtained by the conventional standard liquid chromatographic approach. The presented analytical device showed an outstanding efficiency for fast, direct, and low-cost assessment of pholcodine levels in different matrices.
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http://dx.doi.org/10.3390/polym13081192DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8067864PMC
April 2021

Design, synthesis and molecular docking of new pyrazole-thiazolidinones as potent anti-inflammatory and analgesic agents with TNF-α inhibitory activity.

Bioorg Chem 2021 Jun 17;111:104827. Epub 2021 Mar 17.

Pharmaceutical Medicinal Chemistry Department, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo, Egypt.

A new set of derivatives bearing pyrazole-methylenehydrazono-thiazolidinone scaffold 4-23 was designed, synthesized and confirmed by different spectroscopic means and elemental analyses. In-vivo anti-inflammatory and ulcerogenic evaluation was performed for all the newly synthesized derivatives using indomethacin, celecoxib and diclofenac as standard drugs. The compounds 5, 10, 15, 17, 21, 22 appeared to be the most promising candidates producing rapid onset and long duration of anti-inflammatory activity as well as promising GIT safety profile. Furthermore, analgesic evaluation revealed that the compounds 5, 10, 15 and 22 produced potent and long acting analgesia accompanied with significant inhibition of the inflammatory cytokine TNF-α level in comparison with the standard drugs. Molecular docking study of the latter derivatives was also carried out to rationalize their binding affinities and their modes of interactions with the active site of TNF-α.
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http://dx.doi.org/10.1016/j.bioorg.2021.104827DOI Listing
June 2021

Antiproliferative Activity of Some Newly Synthesized Substituted Pyridine Candidates Using 4-(Aaryl)-6-(naphthalen-1-yl)-2-oxo-1,2-dihydropyridine-3-carbonitrile as Synthon.

ACS Omega 2021 Mar 2;6(10):7147-7156. Epub 2021 Mar 2.

Pharmaceutical Chemistry Department, Drug Exploration and Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Herein, we used nicotinonitrile derivatives , as scaffolds to build novel and active antineoplastic agents. The reaction of nicotinonitrile derivatives , with POCl/PCl and/or hydrazine hydrate afforded 2-chloropyridones , and 2-hydrazinyl nicotinonitrile derivatives ,, respectively, as building blocks for various heterocyclic compounds. The structures of all of the synthesized heterocycles were elucidated from their spectral and elemental analyses. The cytotoxic activities of the prepared derivatives were evaluated against different cancer cell lines. Results revealed potential cytotoxic effects of the synthesized compounds against evaluated cell lines, where NCIH 460 and RKOP 27 cell lines were the most affected by the prepared compounds. Derivative was the most effective against all tested cell lines in terms of the obtained IC values (25 ± 2.6, 16 ± 2, 127 ± 25, 422 ± 26, and 255 ± 2 nM against NCIH 460, RKOP 27, HeLa, U937, and SKMEL 28 cells, respectively).
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http://dx.doi.org/10.1021/acsomega.1c00202DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7970580PMC
March 2021

Synthesis and Characterization of Macrocyclic Chiral Tröger's Base Phenhomazine Candidates as Anticancer Agent.

Front Chem 2020 28;8:633065. Epub 2021 Jan 28.

Bioproducts Research Chair, Zoology Department, Faculty of Science, King Saud University, Riyadh, Saudi Arabia.

1,4,7,10-Tetraoxa[10](2,8)trögerophane was synthesized from its corresponding precursors. Heating of with p-nitrophenoxide afforded bis(p-nitrophenyl)ether , which was treated with hydrazine hydrate to give bis(p-aminophenyl)ether . Treatment of with paraformaldehyde and triflouroacetic anhydride gave trögerophane . Reaction of with trifluroacetic anhydride afforded phenhomazine derivative , which was treated with potassium carbonate to afford tetrahydrophenhomazine . Finally, reaction of with phenacylchloride, bromoacetic acid, or ethyl bromoacetate in the presence of triethyl amine under reflux, afforded the corresponding macrocyclic compounds and , respectively. The synthesized trögerophane,precursors and its newly synthesized phenhomazines derivatives were screened for anticancer activity. Results revealed that 1,4,7,10-tetraoxa[10](2,8)trögerophane had a promising selectivity towards colon cancer cell line with an IC of 92.7 µg/ml.
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http://dx.doi.org/10.3389/fchem.2020.633065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7976657PMC
January 2021

An all-solid-state potentiometric sensor modified with multi-walled carbon nanotubes (MWCNTs) for silicate assessment and water-quality testing.

Anal Methods 2021 03 10;13(12):1495-1501. Epub 2021 Mar 10.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

A simple and cost-effective approach is proposed for silicate ion determination. The approach is based on designing an all-solid-state potentiometric sensor. The plasticized polyvinyl chloride (PVC) membrane sensor is based on the ion-association complex [Ni(bphen)][SiO] as a sensory recognition material. The sensor is modified with multi-walled carbon nanotubes (MWCNTs) as an ion-to-electron transducer material. The performance characteristics of the new silicate-selective electrode were evaluated using a potentiometric water-layer test, potentiometric measurements, impedance spectroscopy, and current-reversal chronopotentiometry. The developed electrodes exhibited a low detection limit (0.11 μg mL) over a wide linear range (4.0 × 10 to 1.0 × 10 M) and near-Nernstian sensitivity (slope = -28.1 ± 1.4 mV per decade). They presented a very short response time (<5 s) over the pH range 6-12 and provided acceptable reliability, ease of design and miniaturization, and high potential stability, in addition to good accuracy and precision. The sensors exhibited enhanced selectivity for silicate over many common interfering anions, such as SO, NO, CHCOO, CO, Cl, S, and PO. These results could qualify the developed sensor to be used in a successful way for the trace determination of silicate ions in different matrices. The developed method was successfully applied to the potentiometric detection of silicate in different pre-packaged bottled drinking water samples.
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http://dx.doi.org/10.1039/d1ay00061fDOI Listing
March 2021

Synthesis and Characterization of New Dihydronaphthalene Candidates as Potent Cytotoxic Agents against MCF-7 Human Cancer Cells.

Biomed Res Int 2020 23;2020:8649745. Epub 2020 Dec 23.

Zoology Department, Faculty of Science, King Saud University, Riyadh 11451, Saudi Arabia.

In the present work, a new series of dihydronaphthalene derivatives were synthesized starting with 6-methoxy-1-tetralone , and the corresponding hydrazine derivative . Reaction of compound with aryl isothiocyanates produced thiosemicarbazides , which were reacted with ethyl chloroacetate to give thiazolidinone derivatives . Pyrano thiazolecarbonitrile derivatives - were prepared by heating a mixture of compounds or , aryl aldehydes, and malononitrile utilizing distilled water in the presence of catalytic amount of potassium hydrogen phthalate. Also, treatment of with DMF-DMA under solvent-free conditions gave enaminone derivative , which condensed with ethyl acetoacetate or acetylacetone or malononitrile or cyanothioacetamide to give compounds -, respectively. Finally, reaction of the enaminone with 2-aminoimidazol or 2-aminothiazol in the presence of glacial acetic acid produced derivatives and , respectively. Cytotoxic evaluation of eleven compounds, against MCF-7 (human breast adenocarcinoma) cell lines, was estimated. Results revealed that five of the examined compounds , , , , and showed potent cytotoxic activities recording, IC values; 0.93 ± 0.02, 1.76 ± 0.04, 2.36 ± 0.06, 2.83 ± 0.07, and 3.73 ± 0.09 M, respectively, which were more potent than the reference used (Saturosporin, IC6.08 ± 0.15 M). The new products were also examined towards normal epithelial breast cells (MCF10A). All of them showed very good safety profile with different degrees and were safer than the reference drug used. Compound was the most effective against MCF-7 cells and was less toxic than Saturosporin by about 18.45-folds towards MCF01A normal cells. All the new compounds were fully characterized by the different spectral and analytical tools. Herein, detailed syntheses, spectroscopic, and biological data are reported.
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http://dx.doi.org/10.1155/2020/8649745DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7787731PMC
December 2020

Solid-State Membrane Sensors Based on Man-Tailored Biomimetic Receptors for Selective Recognition of Isoproturon and Diuron Herbicides.

Membranes (Basel) 2020 Oct 12;10(10). Epub 2020 Oct 12.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Solid-contact ion-selective electrodes (SC-ISEs) have shown great potential for routine and portable ion detection. The introduction of nanomaterials as ion-to-electron transducers and the adoption of different performance-enhancement strategies have significantly promoted the development of SC-ISEs. Herein, new solid-contact ion-selective electrodes, along with the implementation of multiwalled carbon nanotubes (MWCNTs) as ion-to-electron transducers and potassium tetrakis (p-chlorophenyl) borate (KTpClB) as lipophilic ionic additives, were presented for the detection of isoproturon (IPU) and diuron (DU) herbicides. Molecularly imprinted polymers (MIPs), with special molecule recognition properties for isoproturon (IPU) and diuron (DU), were prepared, characterized, and introduced as sensory recognition materials in the presented electrodes. Sensors revealed a near-Nernstian response for both isoproturon (IPU) and diuron (DU) with slopes of 53.1 1.2 ( = 0.997) and 57.2 0.3 ( = 0.998) over the linear ranges of 2.2 × 10-1.0 × 10 M and 3.2 × 10-1.0 × 10 M with detection limits of 8.3 × 10 and 1.4 × 10 M, respectively. The response time of the presented sensors was found to be <5 s and the lifetime was at least eight weeks. The sensors exhibited good selectivity towards isoproturon (IPU) and diuron (DU) in comparison with some other herbicides, alkali, alkaline earth, and heavy metal ions. The presented sensors were successfully applied for the direct determination of isoproturon (IPU) and diuron (DU) in real water samples.
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http://dx.doi.org/10.3390/membranes10100279DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7599700PMC
October 2020

Validated Reversed-Phase Liquid Chromatographic Method with Gradient Elution for Simultaneous Determination of the Antiviral Agents: Sofosbuvir, Ledipasvir, Daclatasvir, and Simeprevir in Their Dosage Forms.

Molecules 2020 Oct 10;25(20). Epub 2020 Oct 10.

Pharmaceutical Chemistry Department, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia.

A simple, rapid, sensitive, and precise reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of four direct-acting antivirals, sofosbuvir (SF), ledipasvir (LD), declatasvir (DC), and simeprevir (SM), in their respective pharmaceutical formulations. Effective chromatographic separation was achieved on an Agilent Eclipse plus C8 column (250 mm × 4.6 mm, 5 µm) at 40 °C with gradient elution using a mobile phase composed of acetonitrile:phosphate buffer (pH 6.5). The quantification of SF and DC was based on peak area measurements at 260 nm, while the quantification of LD and SM was achieved at 330 nm. The linearity was acceptable from 1.0 to 20.0 μg/mL for the studied drugs, with correlation coefficients >0.999. The analytical performance of the newly proposed HPLC procedure was thoroughly validated according to ICH guidelines in terms of linearity, precision (RSD%, 0.39-1.57), accuracy (98.05-101.90%), specificity, limit of detection (LOD) (0.022-0.039 μg/mL), limit of quantification (LOQ) (0.067-0.118 μg/mL), and robustness. The validated HPLC method was successfully used to analyze the abovementioned drugs in their pure and dosage forms without interference from common excipients present in commercial formulations.
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http://dx.doi.org/10.3390/molecules25204611DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7587186PMC
October 2020

Novel Validated Analytical Method Based on Potentiometric Transduction for the Determination of Citicoline Psychostimulant/Nootropic Agent.

Molecules 2020 Jul 31;25(15). Epub 2020 Jul 31.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Herein, a novel validated potentiometric method is presented for the first time for citicoline determination. The method is based on measuring the potential using new constructed citicoline electrodes. The electrodes are based on the use of citicolinium/phosphomolybdate [Cit][PM] (sensor I) and citicolinium/tetraphenylborate [Cit][TPB] (sensor II) ion association complexes. These sensory materials were dispersed in plasticized polyvinyl chloride (PVC) polymeric membranes. The sensors revealed a Nernstian response with the slopes 55.9 ± 1.8( = 0.9994) and 51.8 ± 0.9 ( = 0.9991) mV/decade over a linearity range of 6.3 × 10-1.0 × 10 and 1.0 × 10-1.0 × 10 M and detection limits of 3.16 × 10 and 7.1 × 10 M for sensors I and II, respectively. To ensure the existence of monovalent citicoline, all measurements were performed in 50 mM acetate buffer at pH 3.5. All presented electrodes showed good performance characteristics such as rapid response, good selectivity, high potential-stability and long life-span. Method verification and validation in terms of response linearity, quantification limit, accuracy, bias, trueness, robustness, within-day variability and between-days variability were evaluated. The method was introduced for citicoline determination in different pharmaceutical formulations and compared with the standard high performance liquid chromatography (HPLC) method.
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http://dx.doi.org/10.3390/molecules25153512DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7435782PMC
July 2020

Novel heterocyclic hybrids of pyrazole targeting dihydrofolate reductase: design, biological evaluation and studies.

J Enzyme Inhib Med Chem 2020 Dec;35(1):1491-1502

Zoology Department, Bioproducts Research Chair, Faculty of Science, King Saud University, Riyadh, Saudi Arabia.

A novel series of pyrazole analogues including hydrazones, pyrazolo[4,3-]-pyridazines, pyrazolo[3,4-][1,2,4]triazine and pyrazolo[3,4-][1,2,3]triazoles was designed, synthesised and screened for their antimicrobial and DHFR inhibition activity. Compounds bearing benzenesulphonamide moiety incorporated with 3-methyl-5-oxo-1-pyrazol-4(5)-ylidene) hydrazine or 6-amino-7-cyano-3-methyl-5-pyrazolo[4,3-]pyridazine revealed excellent and broad spectrum antimicrobial activity comparable to ciprofloxacin and amphotericin B as positive antibiotic and antifungal controls, respectively. Furthermore, these derivatives proved to be the most active DHFR inhibitors with IC values 0.11 ± 1.05 and 0.09 ± 0.91 µM, in comparison with methotrexate (IC = 0.14 ± 1.25 µM). The studies were done to calculate the drug-likeness and toxicity risk parameters of the newly synthesised derivatives. Additionally, the high potency of the pyrazole derivatives bearing sulphonamide against DHFR was confirmed with molecular docking and might be used as an optimum lead for further modification.
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http://dx.doi.org/10.1080/14756366.2020.1791842DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7470138PMC
December 2020

Liquid Contact-Selective Potentiometric Sensor Based on Imprinted Polymeric Beads Towards 17β-Estradiol Determination.

Polymers (Basel) 2020 Jul 7;12(7). Epub 2020 Jul 7.

Bioproducts Research Chair, Zoology Department, Faculty of Science, King Saud University, Riyadh 11362, Saudi Arabia.

Novel potentiometric devices "ion-selective electrodes (ISEs)" were designed and characterized for the detection of 17β-estradiol (EST) hormone. The selective membranes were based on the use of man-tailored biomimics (i.e., molecularly imprinted polymers (MIPs)) as recognition ionophores. The synthesized MIPs include a functional monomer (methacrylic acid (MAA)) and a cross-linker (ethylene glycol dimethacrylic acid (EGDMA)) in their preparation. Changes in the membrane potential induced by the dissociated 17β-estradiol were investigated in 50 mM CO/HCO buffer solution at pH 10.5. The ion-selective electrodes (ISEs) exhibited fast response and good sensitivity towards 17β-estradiol with a limit of detection 1.5 µM over a linear range starts from 2.5 µM with an anionic response of 61.2 ± 1.2 mV/decade. The selectivity pattern of the proposed ISEs was also evaluated and revealed an enhanced selectivity towards EST over several phenolic compounds. Advantages revealed by the presented sensor (i.e., wide range of assay, enhanced accuracy and precision, low limit of detection, good selectivity, long-term potential stability, rapid response and long life-span and absence of any sample pretreatment steps) suggest its use in routine quality control/quality assurance tests. They were successfully applied to estradiol determination in biological fluids and in different pharmaceutical preparations collected from the local market.
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http://dx.doi.org/10.3390/polym12071506DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7407799PMC
July 2020

A New Validated Potentiometric Method for Sulfite Assay in Beverages Using Cobalt(II) Phthalocyanine as a Sensory Recognition Element.

Molecules 2020 Jul 6;25(13). Epub 2020 Jul 6.

Zoology Department, Faculty of Science, King Saud University, Riyadh 11451, Saudi Arabia.

A simple potentiometric sensor is described for accurate, precise, and rapid determination of sulfite additives in beverages. The sensor is based on the use of cobalt phthalocyanine as a recognition material, dispersed in a plasticized poly(vinyl chloride) matrix membrane. -Nitrophenyl octyl ether (-NPOE) as a membrane solvent and tri-dodecylmethyl- ammonium chloride (TDMAC) as ion discriminators are used as membrane additives. Under the optimized conditions, sulfite ion is accurately and precisely measured under batch and flow injection modes of analysis. The sensor exhibits fast and linear response for 1.0 × 10-1.0 × 10 M (800-0.08 µg/mL) and 1.0 × 10-5.0 × 10 M (8000-4 µg/mL) sulfite with Nernstian slopes of -27.4 ± 0.3 and -23.7 ± 0.6 mV/concentration decade under static and hydrodynamic modes of operation, respectively. Results in good agreement with the standard iodometric method are obtained.Validation of the assay method is examined in details including precision, accuracy, bias, trueness, repeatability, reproducibility, and uncertainty and good performance characteristics of the method are obtained. The sensor response is stable over the pH range of 5 to 7 without any significant interference from most common anions. The advantages offered by the proposed sensor (i.e., wide range of assay, high accuracy and precision, low detection limit, reasonable selectivity, long term response stability, fast response, and long life span and absence of any sample pretreatment steps) suggest its use in the quality control/quality assurance routine tests in beverages industries, toxicological laboratories and by inspection authorities.
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http://dx.doi.org/10.3390/molecules25133076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7412148PMC
July 2020

Solid-Contact Potentiometric Sensors Based on Stimulus-Responsive Imprinted Polymers for Reversible Detection of Neutral Dopamine.

Polymers (Basel) 2020 Jun 23;12(6). Epub 2020 Jun 23.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Herein, we present for the first time a novel potentiometric sensor based on the stimulus-responsive molecularly imprinted polymer (MIP) as a selective receptor for neutral dopamine determination. This smart receptor can change its capabilities to recognize according to external environmental stimuli. Therefore, MIP-binding sites can be regenerated in the polymeric membrane by stimulating with stimulus after each measurement. Based on this effect, reversible detection of the analyte via potentiometric transduction can be achieved. MIPs based on 4-vinylphenylboronic acid as the functional monomer were prepared as the selective receptor. This monomer can successfully bind to dopamine via covalent binding and forming a five- or six-membered cyclic ester in a weakly alkaline aqueous solution. In acidic medium, the produced ester dissociates and regenerates new binding sites in the polymeric membrane. The proposed smart sensor exhibited fast response and good sensitivity towards dopamine with a limit of detection 0.15 µM over the linear range 0.2-10 µM. The selectivity pattern of the proposed ISEs was also evaluated and revealed an enhanced selectivity towards dopamine over several phenolic compounds. Constant-current chronopotentiometry is used for evaluating the short-term potential stability of the proposed ISEs. The obtained results confirm that the stimulus-responsive MIPs provide an attractive way towards reversible MIP-based electrochemical sensors designation.
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http://dx.doi.org/10.3390/polym12061406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7362186PMC
June 2020

Synthesis, Antimicrobial Activity and Molecular Docking of Novel Thiourea Derivatives Tagged with Thiadiazole, Imidazole and Triazine Moieties as Potential DNA Gyrase and Topoisomerase IV Inhibitors.

Molecules 2020 Jun 15;25(12). Epub 2020 Jun 15.

Department of Chemistry, Faculty of Women, Ain Shams University, Heliopolis, Cairo 11457, Egypt.

To develop new antimicrobial agents, a series of novel thiourea derivatives incorporated with different moieties was designed and synthesized and their biological activities were evaluated. Compounds , and exhibited excellent antimicrobial activity against all Gram-positive and Gram-negative bacteria, and the fungal with minimum inhibitory concentration (MIC) values ranged from 0.95 ± 0.22 to 3.25 ± 1.00 μg/mL. Furthermore, cytotoxicity studies against MCF-7 cells revealed that compounds and were the most potent with IC values of 10.17 ± 0.65 and 11.59 ± 0.59 μM, respectively. On the other hand, the tested compounds were less toxic against normal kidney epithelial cell lines (Vero cells). The in vitro enzyme inhibition assay of displayed excellent inhibitory activity against DNA B gyrase and moderate one against Topoisomerase IV (IC = 0.33 ± 1.25 and 19.72 ± 1.00 µM, respectively) in comparison with novobiocin (IC values 0.28 ± 1.45 and 10.65 ± 1.02 µM, respectively). Finally, the molecular docking was done to position compound into the DNA B and Topoisomerase IV active pockets to explore the probable binding conformation. In summary, compound may serve as a potential dual DNA B and Topoisomerase IV inhibitor.
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http://dx.doi.org/10.3390/molecules25122766DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356696PMC
June 2020

Validation of a Novel Potentiometric Method Based on a Polymeric PVC Membrane Sensor Integrated with Tailored Receptors for the Antileukemia Drug Cytarabine.

Polymers (Basel) 2020 Jun 14;12(6). Epub 2020 Jun 14.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

A simple, rapid and easy method is proposed for the detection of a cytostatic therapeutic drug, cytarabine, in real samples. The method is based on potentiometric transduction using prepared and characterized new ion-selective electrodes for cytarabine. The electrodes were integrated with novel man-tailored imprinted polymers and used as a sensory element for recognition. The electrodes revealed a remarkable potentiometric response for cytarabine over the linearity range 1.0 × 10-1.0 × 10 M at pH 2.8-4 with a detection limit of 5.5 × 10 M. The potentiometric response was near-Nernstian, with average slopes of 52.3 ± 1.2 mV/decade. The effect of lipophilic salts and plasticizer types on the potentiometric response was also examined. The electrodes exhibited an enhanced selectivity towards cytarabine over various foreign common ions. Validation and verification of the presented assay method are demonstrated by evaluating the method ruggedness and calculating the detection limit, range of linearity, accuracy (trueness), precision, repeatability (within-day) and reproducibility (between-days). The proposed ion-selective electrodes revealed good performance characteristics and possible application of these electrodes for cytarabine monitoring in different matrices. The electrodes are successfully applied to cytarabine determination in spiked biological fluid samples and in pharmaceutical formulations.
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http://dx.doi.org/10.3390/polym12061343DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7361695PMC
June 2020

CuFeO/Polyaniline (PANI) Nanocomposite for the Hazard Mercuric Ion Removal: Synthesis, Characterization, and Adsorption Properties Study.

Molecules 2020 Jun 12;25(12). Epub 2020 Jun 12.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Copper ferrite nano-particles (CuFeO) were synthesized, characterized, modified with polyaniline to form CuFeO/PANI nano-composite. They were used as new adsorbents for the removal of the hazardous mercuric ions from aqueous solutions. High resolution transmission electron microscope (HR-TEM), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) and Brunauer-Emmett-Teller (BET) were used for the characterization of the synthesized CuFeO nano-particles (NPs) in presence and absence of PANI nano-composite. The synthesized CuFeONPs were of spherical shape with an average size of 10.8 nm. XRD analysis displayed crystal peaks for CuFeONPs and amorphous peaks CuFeO/PANI nano-composite due to the existence of polyaniline layer. Contact time, adsorbent dose, solution pH, adsorption kinetics, adsorption isotherm and recyclability were studied. The method at the optimum conditions exhibited high performance with high mercury removal percentage of up to 99% with a maximum adsorption capacity 12.5 and 157.1 mg/g for CuFeO and CuFeO/PANI, respectively. The adsorption processes were fitted to Langmuir isotherms. The adsorption behavior of [email protected] composite towards Hg ions is attributed to the soft acid-soft base strong interaction between PANI and Hg(II) ions. High stability and enhanced re-usability are offered using [email protected] composite due to its enhanced removal efficiency. No significant removal decrease was noticed after five adsorption-desorption cycles. In addition, it possesses an easy removal from aqueous solutions by external magnetic field after adsorption experiments. These indicated the enhancement of polyaniline to the surface of CuFeO toward the adsorption of mercury from aqueous solutions.
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http://dx.doi.org/10.3390/molecules25122721DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356621PMC
June 2020

Porous Activated Carbon from Lignocellulosic Agricultural Waste for the Removal of Acetampirid Pesticide from Aqueous Solutions.

Molecules 2020 May 17;25(10). Epub 2020 May 17.

Chemistry Department, Faculty of Science, Ain Shams University, Abbasia, Cairo 11566, Egypt.

A facile eco-friendly approach for acetampirid pesticide removal is presented. The method is based on the use of micro- and mesoporous activated carbon (TPAC) as a natural adsorbent. TPAC was synthesized via chemical treatment of tangerine peels with phosphoric acid. The prepared activated carbon was characterized before and after the adsorption process using Fourier- transform infrared (FTIR), X-ray diffraction (XRD), particle size and surface area. The effects of various parameters on the adsorption of acetampirid including adsorbent dose (0.02-0.2 g), pH 2-8, initial adsorbate concentration (10-100 mg/L), contact time (10-300 min) and temperature (25-50 °C) were studied. Batch adsorption features were evaluated using Langmuir and Freundlich isotherms. The adsorption process followed the Langmuir isotherm model with a maximum adsorption capacity of 35.7 mg/g and an equilibration time within 240 min. The adsorption kinetics of acetamiprid was fitted to the pseudo-second-order kinetics model. From the thermodynamics perspective, the adsorption was found to be exothermic and spontaneous in nature. TPAC was successfully regenerated and reused for three consecutive cycles. The results of the presented study show that TPAC may be used as an effective eco-friendly, low cost and highly efficient adsorbent for the removal of acetamiprid pesticides from aqueous solutions.
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http://dx.doi.org/10.3390/molecules25102339DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7287952PMC
May 2020

Imprinted Polymeric Beads-Based Screen-Printed Potentiometric Platforms Modified with Multi-Walled Carbon Nanotubes (MWCNTs) for Selective Recognition of Fluoxetine.

Nanomaterials (Basel) 2020 Mar 21;10(3). Epub 2020 Mar 21.

Chemistry Department, Faculty of Science, Mansoura University, Mansoura 35516, Egypt.

Herein, we present a new validated potentiometric method for fluoxetine (FLX) drug monitoring. The method is based on the integration of molecular imprinting polymer (MIP) beads as sensory elements with modified screen-printed solid contact ion-selective electrodes (ISEs). A multi-walled carbon nanotube (MWCNT) was used as a nanomaterial for the ion-to-electron transduction process. The prepared MIP beads depend on the use of acrylamide (AAm) and ethylene glycol dimethacrylic acid (EGDMA) as a functional monomer and cross-linker, respectively. The sensor revealed a stable response with a Nernstian slope of 58.9 ± 0.2 mV/decade and a detection limit of 2.1 × 10 mol/L in 10 mmol/L acetate buffer of pH 4.5. The presented miniaturized sensors revealed good selectivity towards FLX over many organic and inorganic cations, as well as some additives encountered in the pharmaceutical preparations. Repeatability, reproducibility and stability have been studied to evaluate the analytical features of the presented sensors. These sensors were successfully applied for FLX assessment in different pharmaceutical formulations collected from the Egyptian local market. The obtained results agreed well with the acceptable recovery percentage and were better than those obtained by other previously reported routine methods.
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http://dx.doi.org/10.3390/nano10030572DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7153386PMC
March 2020

Synthesis and Characterization of CuFeO Nanoparticles Modified with Polythiophene: Applications to Mercuric Ions Removal.

Nanomaterials (Basel) 2020 Mar 23;10(3). Epub 2020 Mar 23.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

In this research, CuFeO nanoparticles were synthesized by co-precipitation methods and modified by coating with thiophene for removal of Hg(II) ions from aqueous solution. CuFeO nanoparticles, with and without thiophene, were characterized by x-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), energy dispersive x-ray (EDX), high-resolution transmission electron microscopy (HRTEM) and Brunauer-Emmett-Teller (BET). Contact time, adsorbent dose, solution pH, adsorption kinetics, adsorption isotherm and recyclability were studied. The maximum adsorption capacity towards Hg ions was 7.53 and 208.77 mg/g for CuFeO and [email protected] composite, respectively. Modification of CuFeO nanoparticles with thiophene revealed an enhanced adsorption towards Hg removal more than CuFeO nanoparticles. The promising adsorption performance of Hg ions by [email protected] composite generates from soft acid-soft base strong interaction between sulfur group of thiophene and Hg(II) ions. Furthermore, [email protected] composite has both high stability and reusability due to its removal efficiency, has no significant decrease after five adsorption-desorption cycles and can be easily removed from aqueous solution by external magnetic field after adsorption experiments took place. Therefore, [email protected] composite is applicable for removal Hg(II) ions from aqueous solution and may be suitable for removal other heavy metals.
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http://dx.doi.org/10.3390/nano10030586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7153709PMC
March 2020

Cost-Effective Potentiometric Platforms Modified with Multi-Walled Carbon Nanotubes (MWCNTs) and Based on Imprinted Receptors for Fluvoxamine Assessment.

Polymers (Basel) 2020 Mar 17;12(3). Epub 2020 Mar 17.

Chemistry Department, Faculty of Science, Mansoura University, 35516 Mansoura, Egypt.

A simple, efficient and reliable analytical method was developed and used for the determination of the fluvoxamine drug (FLV) in pharmaceutical preparations and biological fluids. The method is based on the cost-effective screen-printed platform for the potential transduction of the drug. Host-tailored molecular imprinting polymer (MIP) was integrated with the potentiometric platform as a recognition receptor, in which FLV, acrylamide (AAm), ethylene glycol dimethacrylate (EGDMA) and acetonitrile were used as a template, functional monomer, cross-linker, and solvent, respectively. MIP particles were dispersed in plasticized poly (vinyl chloride) (PVC) and the membrane was drop-casted on carbon screen-printed electrode. The MIP, in addition to non-imprinted polymers (NIP), was characterized and the binding experiment revealed high affinity and adsorption capacity of MIP towards FLV. The proposed sensor displayed near-Nernstian cationic slope of 55.0 ± 0.8 mV/decade ( = 0.999) with a low detection limit of 4.8 × 10 mol/L over a wide pH range (3.0-8.5). The electrochemical features of the proposed sensors including electrochemical impedance spectroscopy (EIS) and chronopotentiometry measurements (CP) in the presence of multi-walled carbon nanotubes (MWCNTs) as a solid contact transducer were also investigated. The applications of the proposed sensor for the determination of FLV in different dosage forms with recovery values (98.8%-101.9%) and (97.4%-101.1%), respectively compared with the reference HPLC method with acceptedFandt-student tests values at the 95% confidence level.
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http://dx.doi.org/10.3390/polym12030673DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7183319PMC
March 2020

Anticancer Activities of Newly Synthesized Chiral Macrocyclic Heptapeptide Candidates.

Molecules 2020 Mar 10;25(5). Epub 2020 Mar 10.

Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, PO Box 2457, Riyadh 11451, Saudi Arabia.

As important cancer therapeutic agents, macrocyclic peptides have recently drawn great attention, mainly because they are synthetically accessible and have lower toxicity towards normal cells. In the present work, we synthesized newly macrocyclic pyridoheptapeptide derivatives. The synthesized derivatives were characterized using standard chemical and spectroscopic analytical techniques, and their anticancer activities against human breast and hepatocellular cancer cells were investigated. Results showed that compounds 1a and 1b were the most effective against hepatocellular (HepG2) and breast (MCF-7) cancer cell lines, respectively.
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http://dx.doi.org/10.3390/molecules25051253DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7179445PMC
March 2020

Chiral Pyridine-3,5-bis- (L-phenylalaninyl-L-leucinyl) Schiff Base Peptides as Potential Anticancer Agents: Design, Synthesis, and Molecular Docking Studies Targeting Lactate Dehydrogenase-A.

Molecules 2020 Feb 29;25(5). Epub 2020 Feb 29.

Zoology Department, Bioproducts Research Chair, Faculty of Science, King Saud University, Riyadh 11451, Saudi Arabia.

A series of branched tetrapeptide Schiff bases - were designed and synthesized from corresponding tetrapeptide hydrazide as a starting material.In vitroevaluation of the synthesized compounds - against breast MCF-7 carcinoma cells identified their excellent anticancer potency, with IC ranging from 8.12 ± 0.14 to 17.55 ± 0.27 μM in comparison with the references, cisplatin and milaplatin (IC= 13.34 ± 0.11and 18.43 ± 0.13 μM, respectively). Furthermore, all derivatives demonstrated promising activity upon evaluation of theirin vitroandin vivosuppression of p53 ubiquitination and inhibition assessment for LDHA kinase. Finally, molecular docking studies were performed to predict the possible binding features of the potent derivatives within the ATP pocket of LDHA in an attempt to get a lead for developing a more potent LDHA inhibitor with anti-proliferative potency.
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http://dx.doi.org/10.3390/molecules25051096DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7179198PMC
February 2020

Modified Screen-Printed Potentiometric Sensors based on Man-Tailored Biomimetics for Diquat Herbicide Determination.

Int J Environ Res Public Health 2020 02 11;17(4). Epub 2020 Feb 11.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Screen-printed platforms integrated with molecularly imprinted polymers (MIP) were fabricated and characterized as potentiometric sensors for diquat (DQ). The synthesized MIP beads were studied as sensory carriers in plasticized poly(vinyl chloride) membranes. The sensors were constructed by using poly(3,4-ethylenedioxythiophene) (PEDOT) as solid-contact material to diminish charge-transfer resistance and water layer potential. Conventional ion-selective electrodes (ISEs) with internal filling solution were used for comparison. The designed electrodes showed near Nernstian slopes of 28.2 ± 0.7 (r² = 0.999) over the concentration range of 1.0 × 10-1.0 × 10 M with the limit of detection 0.026 µg/mL over the pH range 4.2-9.0. The electrode exhibited good selectivity for diquat cations over a large number of organic and inorganic cations. The sensor was successfully introduced for direct measurement of diquat content in commercial pesticide preparations and different spiked potato samples. The results showed that the proposed electrode has a fast and stable response, good reproducibility, and applicability for direct assessment of diquat content. The proposed potentiometric method is simple and accurate in comparison with the reported HPLC methods. Besides, it is applicable to turbid and colored sample solutions.
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http://dx.doi.org/10.3390/ijerph17041138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7068347PMC
February 2020

Modified Potentiometric Screen-Printed Electrodes Based on Imprinting Character for Sodium Deoxycholate Determination.

Biomolecules 2020 02 6;10(2). Epub 2020 Feb 6.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Potentiometric sensors have a great influence on the determination of most various compounds in their matrices. Therefore, efficient and new sensors were introduced to measure sodium Deoxycholate (NaDC) as a bile acid salt. These sensors are based on NaDC imprinted polymer (MIP) as sensory element. The MIP beads were synthesized using thermal polymerization pathway, in which acrylamide (AAm), ethylene glycol dimethacrylate (EGDMA), NaDC, and benzoyl peroxide (BPO) were used as the functional monomer, cross-linker, template, and initiator, respectively. The proposed sensors were fabricated using a coated screen-printed platform and the sensing membrane was modified by single-walled carbon nanotubes (SWCNTs) as an ion-to-electron transducer. The sensors exhibited high sensitivity that reached 4.7 × 10 M of near-Nernestian slope (-60.1 ± 0.9 mV/decade, = 0.999 (= 5)). In addition, the sensors revealed high selectivity, long lifetime, high potential stability, and conductivity that ensure reproducible and accurate results over a long time. MIP characterization was performed using Fourier Transform-Infrared (FT-IR) and a scanning electron microscope (SEM). Regarding the interaction of NaDC with serum albumin (SA), albumin is determined in human serum samples as human serum albumin (HSA), which was collected from different volunteers of different ages and gender.
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http://dx.doi.org/10.3390/biom10020251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072443PMC
February 2020

A SnO/CeO Nano-Composite Catalyst for Alizarin Dye Removal from Aqueous Solutions.

Nanomaterials (Basel) 2020 Feb 1;10(2). Epub 2020 Feb 1.

Bioproducts Research Department, Zoology Department, Faculty of Science, King Saud University, Riyadh, Saudi Arabia.

A new SnO/CeO nano-composite catalyst was synthesized, characterized and used for the removal of alizarin dyes from aqueous solutions. The composite material was prepared using a precipitation method. X-ray powder diffractometry (XRD), high resolution transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller methodology (BET) and Fourier Transform Infrared Spectrometry (ATR-FTIR) were utilized for the characterization of the prepared composite. The prepared nano-composite revealed high affinity for the adsorption and decomposition of alizarin dyes. The adsorption capacity under different experimental conditions (adsorbate concentration, contact time, adsorbent dose and pH) was examined. Under optimized experimental conditions, the removal of alizarin yellow, alizarin red and alizarin-3-methylimino-diacetic acid dyes from aqueous solutions was about 96.4%,87.8% and 97.3%, respectively. The adsorption isotherms agreed with the models of Langmuir, Freundlich and Temkin isotherms.
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http://dx.doi.org/10.3390/nano10020254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7075236PMC
February 2020

Paper Strip and Ceramic Potentiometric Platforms Modified with Nano-Sized Polyaniline (PANi) for Static and Hydrodynamic Monitoring of Chromium in Industrial Samples.

Molecules 2020 Jan 31;25(3). Epub 2020 Jan 31.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Screen-printed membrane sensors based on the use of paper and ceramic substrates are fabricated, characterized, and used for rapid batch and continuous monitoring of Cr in the form of CrO in some industrial products and wastewater samples. Strips of paper and ceramic platforms (15 × 5 mm) were covered with conductive carbon paint and then modified with polyaniline (PANI) film, to act as an ion-to-electron transducer, followed by a drop casting of plasticized poly (vinyl chloride) (PVC) Rhodamine-B chromate membrane as a recognition sensing material. In a 5.0 mmol L Trizma buffer solution of pH ~8, the fabricated paper and ceramic based membrane sensors exhibited a near Nernstian response for Cr ion with slopes of -29.7 ± 0.5 and -28.6 ± 0.3 mV decade, limit of detection 2.5 × 10 and 2.4 × 10 mol L (1.3-0.12 µg mL), and linear concentration range 7.5 × 10-5.0 × 10 and 7.5 × 10-1.0 × 10 mol L (390-0.5 µg mL), respectively. Both sensors exhibited fast and stable potentiometric response, excellent reproducibility, and good selectivity with respect to a number of common foreign inorganic species. Impedance spectroscopy and chronopotentiometry data revealed a small resistance and a larger double layer capacitance due to the presence of the intermediate polyaniline (PAN) conductive layer. Furthermore, the formation of a water layer between the ion selective membrane (ISM) and the underlying conductor polymer and between the conducting polymer and the carbon conducting surface was greatly reduced. The developed disposable solid-contact potentiometric sensors offer the advantages of simple design, long term potential stability, flexibility, miniaturization ability, short conditioning time, and cost effectiveness that enable mass production. The sensors were successfully used for static and hydrodynamic measurements of total chromium in some leather tanning wastewater and nickel-chrome alloy samples. The results compare favorably with data obtained by atomic absorption spectrometry.
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http://dx.doi.org/10.3390/molecules25030629DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7037674PMC
January 2020

Novel Solid-State Potentiometric Sensors Using Polyaniline (PANI) as A Solid-Contact Transducer for Flucarbazone Herbicide Assessment.

Polymers (Basel) 2019 Nov 1;11(11). Epub 2019 Nov 1.

Pharmaceutical Chemistry Department, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Novel potentiometric solid-contact ion-selective electrodes (SC/ISEs) based on molecularly imprinted polymers (MIPs) as sensory carriers (MIP/PANI/ISE) were prepared and characterized as potentiometric sensors for flucarbazone herbicide anion. However, aliquat S 336 was also studied as a charged carrier in the fabrication of Aliquat/PANI/ISEs for flucarbazone monitoring. The polyaniline (PANI) film was inserted between the ion-sensing membrane (ISM) and the electronic conductor glassy carbon substrate (GC). The sensors showed a noticeable response towards flucarbazone anions with slopes of -45.5 ± 1.3 (r = 0.9998) and -56.3 ± 1.5 (r = 0.9977) mV/decade over the range of 10-10, 10-10 M and detection limits of 5.8 × 10 and 8.5 × 10 M for MIP/PANI/ISE and Aliguat/PANI/ISE, respectively. The selectivity and long-term potential stability of all presented ISEs were investigated. The short-term potential and electrode capacitances were studied and evaluated using chronopotentiometry and electrochemical impedance spectrometry (EIS). The proposed ISEs were introduced for the direct measurement of flucarbazone herbicide in different soil samples sprayed with flucarbazone herbicide. The results agree well with the results obtained using the standard liquid chromatographic method (HPLC).
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http://dx.doi.org/10.3390/polym11111796DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6918223PMC
November 2019

Synthesis, Antiproliferative, and Antioxidant Evaluation of 2-Pentylquinazolin-4(3)-one(thione) Derivatives with DFT Study.

Molecules 2019 Oct 21;24(20). Epub 2019 Oct 21.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

The current study was chiefly designed to examine the antiproliferative and antioxidant activities of some novel quinazolinone(thione) derivatives -. The present work focused on two main points; firstly, comparing between quinazolinone and quinazolinthione derivatives. Whereas, antiproliferative (against two cell lines namely, HepG2 and MCF-7) and antioxidant (by two methods; ABTS and DPPH) activities of the investigated compounds, the best quinazolinthione derivatives were and which exhibited excellent potencies comparable to quinazolinone derivatives and , respectively. Secondly, we compared the activity of four series of Schiff bases which included the quinazolinone moiety (-). In addition, the antiproliferative and antioxidant activities of the compounds with various aryl aldehyde hydrazone derivatives (-) analogs were studied. The compounds exhibited potency that increased with increasing electron donating group in -position (OH > OMe > Cl) due to extended conjugated systems. Noteworthy, most of antiproliferative and antioxidant activities results for the tested compounds are consistent with the DFT calculations.
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http://dx.doi.org/10.3390/molecules24203787DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6832655PMC
October 2019

Potentiometric PVC-Membrane-Based Sensor for Dimethylamine Assessment Using A Molecularly Imprinted Polymer as A Sensory Recognition Element.

Polymers (Basel) 2019 Oct 16;11(10). Epub 2019 Oct 16.

Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

A new simple potentiometric sensor is developed and presented for sensitive and selective monitoring of dimethylamine (DMA). The sensor incorporates a molecularly imprinted polymer, with a pre-defined specific cavity suitable to accommodate DMA. The molecularly imprinted polymer (MIP) particles were dispersed in an aplasticized poly(vinyl chloride) matrix. The MIP is synthesized by using a template molecule (DMA), a functional monomer (acrylamide, AM), cross-linker (ethylene glycol dimethacrylate, EGDMA) and initiating reagent (benzoylperoxide, BPO). Using Trizma buffer solution (5 mmol L, pH 7.1), the sensor exhibits a rapid, stable and linear response for 1.0 × 10 to 1.0 × 10 mol L DMA with a calibration slope of 51.3 ± 0.3 mV decade, and a detection limit of 4.6 × 10 mol L (0.37 µg mL). The electrode exhibited a short response time (10 s) and stable potential readings (± 0.5 mV) for more than 2 months. Potentiometric selectivity measurements of the sensor reveal negligible interferences from most common aliphatic and aromatic amines. High concentration levels (100-fold excess) of many inorganic cations do not interfere. The sensor is successfully used for quantification of low levels of DMA down to 0.5 µg mL. Verification of the presented method was carried out after measuring the detection limit, working linearity range, ruggedness of the method, accuracy, precision, repeatability and reproducibility. Under flow-through conditions, the proposed sensor in its tubular form is prepared and introduced in a two-channel flow injection setup for hydrodynamic determination of DMA. The sampling rate is 50-55 samples h. The sensor is used to determine DMA in different soil samples with an accuracy range of 97.0-102.8%.
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http://dx.doi.org/10.3390/polym11101695DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6836042PMC
October 2019
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