NOPR Collection:

New Co(II) and Cu(II) complexes derived from an imidazolium ionic liquid-based Schiff base: synthesis, physico chemical characterization and exploration of antibacterial activities

2020-03-20T09:07:41Z

Title: New Co(II) and Cu(II) complexes derived from an imidazolium ionic liquid-based Schiff base: synthesis, physico chemical characterization and exploration of antibacterial activities Authors: Saha, Sanjoy Abstract: Two new Co(II) and Cu(II) complexes from an imidazolium ionic liquid based Schiff base 1-{2-(2-hydroxy-5-nitrobenzylideneamino)ethyl}-3-ethylimidazolium tetrafluoroborate have been synthesized and characterized by different analytical and spectroscopic techniques such as elemental analysis (CHN analysis), UV-Visible, ¹H-NMR, FTIR, Mass-spectra, Powder X-ray diffraction analysis, magnetic susceptibility measurements and molar conductance data. From these analytical results, tetra coordinated 1:2 metal-ligand stoichiometry is suggested for the both complexes. The molar conductance data of the complexes reveal their electrolytic nature (1:2). The synthesized complexes along with the ligand have been screened for in vitro antibacterial applications against gram negative and gram positive bacteria to assess their inhibition potentials. The complexes are proved to be very effective against the tested organisms. Page(s): 311-316

Synthesis and characterization of 2-aminoethylphosphonic acid-functionalized graphene quantum dots: biological activity, antioxidant activity and cell viability

2020-03-20T09:05:13Z

Title: Synthesis and characterization of 2-aminoethylphosphonic acid-functionalized graphene quantum dots: biological activity, antioxidant activity and cell viability Authors: Yapar, Gönül; Şenel, Behiye; Demir, Neslihan; Yıldız, Mustafa Abstract: A facile, environmentally friendly one-step reaction for the preparation of luminescent N-doped graphene quantum dots (GQDs) involving a hydrothermal reaction between citric acid and 2-aminoethylphosphonic acid has been designed. Graphene quantum dots have been characterized by UV-visible absorption, FTIR spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and dynamic light scattering (DLS) techniques. Furthermore, the biological activity of the GQDs has been studied. UV-visible spectroscopy studies of the interactions between the GQDs and calf thymus DNA (CT-DNA) showed that the compound interacts with CT-DNA via intercalative binding. DNA cleavage study showed that the GQDs cleaved DNA oxidatively. In addition, antioxidant activity of N-doped GQDs was measured using the DPPH method. As the concentration of the compound increased, the antioxidant activity also has increased. According to cell viability analyses results, the N-doped GQDs showed cell viability (70%) when the concentration reaches 228 μg/mL for A549, 200 μg/mL for MDA-MB-231 and 140 μg/mL for NIH-3T3 cell lines with 24 h incubation. Page(s): 317-323

Potentiometric determination of oxybutynin hydrochloride in pharmaceutical formulations at modified carbon paste electrodes

2020-03-20T08:59:03Z

Title: Potentiometric determination of oxybutynin hydrochloride in pharmaceutical formulations at modified carbon paste electrodes Authors: Mostafa, Maysa R; Mohamed, Gehad G; Mohamed, Marwa E; Frag, Eman Y Z Abstract: New potentiometric sensitive and selective modified carbon paste (MCPE) electrodes based on ion pair formation between phosphotungestic acid (PTA), sodium tetraphenyl borate (NaTPB), phosphomolybdic acid (PMA) or ammonium reineckate (RN) and oxybutynin hydrochloride (Ox.HCl) has been developed. The proposed electrodes have Nernstian slope values of 58.50±0.71, 58.71±1.20, 54.80±1.30 and 59.20±0.70 mV decade⁻¹ for electrodes modified with 20, 10, 5 and 10 mg of Ox-TPB (electrode I), Ox-RN (electrode II), Ox-PMA (electrode III) and Ox-PTA (electrode IV) ion pairs, respectively. It is found that the dynamic drug concentration range at 25 °C is 1.0×10⁻⁵–1.0×10⁻² mol L⁻¹. The response of MCPEs is pH independent in the range 2.0–6.0 with a fast response time of 10 s for electrode I and 12 s for electrodes II-IV. These electrodes have good Nernstian response in the temperature range 10–60 °C with slope (isothermal coefficient) equal 0.791×10⁻³, 0.769×10⁻³, 0.629×10⁻³and 1.277×10⁻³ V/°C for electrodes I, II , III and IV respectively. These small values indicate the high thermal stability of the electrodes. The MCPEs have shown a relatively long life time of 36 days. A pure and pharmaceutical formulation of Ox.HCl has quantified using calibration and standard addition methods and the obtained results agreed with that of the official HPLC method. Validation parameters have been optimized according to ICH recommendations. Limits of detection and quantification are calculated under the optimized conditions. For the analytical applications, pharmaceutical dose form has performed. Various interferents have been used to investigate the interference in the analytical application and found that the proposed method would be well adopted for real sample analysis. Page(s): 324-332

Sorption of Cd(II) and Pb(II) ions by nanolimestone from underground water samples from Tehama region of Saudi Arabia

2020-03-20T08:55:43Z

Title: Sorption of Cd(II) and Pb(II) ions by nanolimestone from underground water samples from Tehama region of Saudi Arabia Authors: Ragab, Ahmed H; Ahmed, Inas A; Bader, Dina D Abstract: Powdered nano limestone (NLS) has been investigated as an in-expensive adsorbent for removal of heavy toxic metals such as cadmium and lead from aqueous solutions. Batch experiments has been carried out, the favorable pH for maximum metals adsorption is found to be 6.8 for both. The surface area has increased in case of NLS up to 6.2 m²/g. The adsorption capacity calculated by Langmuir equation is found to be 75.1 mg/g for Cd (II) and 68.4 for Pb (II) ions at pH 6.8. The adsorption capacity has increased with temperature and the kinetics followed a First-order rate equation for both. The enthalpy change (ΔH⁰) is 25.4 J mol⁻¹ for Cd (II) and 20.8 J mol⁻¹ for Pb (II), while entropy change (ΔS⁰) is 41.6 J K⁻¹mol⁻¹ for Cd (II) and 38.7 J K⁻¹mol⁻¹ Pb (II), which indicate that adsorption process is endothermic and spontaneous in nature. About 25 collected samples of groundwater has been tested and found to be contaminated with cadmium and lead elements with different rates, with using NLS as adsorbent able to remove both metals from the samples. All of the results suggested that the NLS is excellent nano-adsorbents for cadmium and lead contaminated water samples. Page(s): 333-340