An assessment of the impact of green tea extract on palbociclib pharmacokinetics using a validated UHPLC–QTOF–MS method

Green tea extracts (GTE) has been reported to be a kinase inhibitor and modulator for various drug metabolizing enzymes. It may give synergetic antioncogenic effect, but with a possibility of pharmacokinetic interactions with various co‐administered anticancer agents like palbociclib (PAL), a selective inhibitor of CDK‐4/6 primarily metabolized by CYP3A enzyme. To explore the impact of GTE on PAL pharmacokinetics in Sprague–Dawley rats, a rapid and sensitive UHPLC–QTOF–MS method was established. Chromatographic separation was carried out on an Acquity UPLC BEH C₁₈ (100 × 2.1 mm, 1.7 μm) column using a gradient mobile phase system consisting of 0.1% formic acid and acetonitrile. Sample preparation was based on a simple protein precipitation method. Estimation of target ions [M + H]⁺ at m/z 448.2455 for PAL and m/z 441.2044 for ibrutinib (IS) was performed in selective ion mode ESI–HRMS. Good sensitivity (1.0 ng/mL) and linearity over a wide concentration range of 1–2000 ng/mL was exhibited by the method. The results indicated that the administration of GTE resulted in decreased oral bioavailability of PAL in both short‐ and long‐term conditions. However, when both conditions were compared, the variation was less for the peak concentration and area under the concentration–time curve level of PAL.     

Gold(0) catalyzed dehydrogenation of N-heterocycles

Gold nanoclusters are good catalyst precursors for the catalytic dehydrogenation of indolines, tetrahydroquinazolines, and related N-heterocycles. The catalytically active species is presumably Au(0) nanoparticles.     

A facile regioselective 1,3-dipolar cycloaddition protocol for the synthesis of new class of quinolinyl dispiro heterocycles

The 1,3-dipolar cycloaddition reaction of azomethine ylides generated in situ from isatin and secondary amino acids with quinolinyl dipolarophiles in refluxing methanol afforded new class of quinolinyl dispiro heterocycles with multi hetero core units. The regio and stereochemistry of the product was unambiguously assigned by ¹H, ¹³C, 2D NMR techniques and single crystal X-ray analysis. The structures of the compounds are stabilized through the presence of intermolecular hydrogen bonding and intramolecular non-covalent interactions.     

Enhanced stability of low temperature processed perovskite solar cells via augmented polaronic intensity of hole transporting layer

The commercial mass production of perovskite solar cells requires full compatibility with roll‐to‐roll processing with enhanced device stability. In line with this, the present work addresses following issues simultaneously from multiple fronts: (i) low temperature processed (140 °C) ZnO is used as electron transport layer (ETL) for fabricating the mixed organic cation based perovskite solar cells, (ii) the expensive hole transporting layer (HTL) spiro‐OMeTAD is replaced with F4TCNQ doped P3HT and (iii) the fabrication method does not incorporate the dopant TBP which is known to induce degradation processes in perovskite layer. All the devices under study were fabricated in ambient conditions. The F4TCNQ doped P3HT (HTL) based devices exhibits 14 times higher device stability compared to the conventional Li‐TFSI/TBP doped P3HT devices. The underlying mechanism behind the enhanced device lifetime in F4TCNQ doped P3HT (HTL) based devices was investigated via in‐depth electronic, ionic and polaronic characterization. The enhanced polaronic property in F4TCNQ doped P3HT HTL device ascertains its superior hole extraction and electron blocking capability; and consequently higher stability retained even after a month of ageing.

     

Synthesis, optical, electrochemical, and thermal studies on triazole-based dendrimers with diphenylamine as surface group

Fréchet-type dendrimers with hole-transporting diphenylamine as surface group and electron-transporting triazole moiety as building block have been synthesized by convergent synthetic strategy through ‘click chemistry’ methodology. First generation dendrimer exhibits longer relaxation time, higher quantum yield in the fluorescence spectrum, and better thermal stability than the zero and second generation dendrimers. CV studies showed irreversible reduction potential and the formation of radical cation due to diphenylamine moiety.     

Synthesis of heteroannulated cyclopent[b]indoles: Exploration of in vitro cytotoxicity and molecular docking studies

A series of novel cyclopent[b]indole analogues that hold isoxazolo-, pyrido-templates were designed and synthesized in good yields. The in vitro cytotoxicity was concerned for all the newly synthesized compounds by MTT assay against HeLa (cervix adeno carcinoma) and MCF-7 (breast cancer). These synthesized compounds were further compared with the standard drug ellipticine, 5-fluorouracil, cisplatin, and methotrexate. The synthesized heteroannulated cyclopent[b]indole compounds were found to show better cytotoxic activity against HeLa and MCF-7 with primary structure activity relationship studies. To identify with the nature of interactions of these molecules, we performed molecular docking studies using the protein kinase CK2 inhibitors. The docking results afforded some valuable information for the future design of more potent inhibitors.     

Stabilization of sensing performance for mixed-potential-type zirconia-based hydrocarbon sensor

The recently reported sensing characteristics of the mixed-potential-type yttria-stabilized zirconia (YSZ)-based hydrocarbon (HC) sensor attached with ZnCr₂O₄-sensing electrode (SE) were found to be changed after the 10-day operation at 550 °C under the wet condition (5 vol.% water vapor). To improve the stability of the present sensor, the several modifications of the SE material by adding YSZ powder were examined. As a result, the sensor using the laminated (ZnCr₂O₄/YSZ)-SE gave the stable electromotive force (emf) response against 100 ppm C₃H₆ at 550 °C for about one month examined. Based on the scanning electron microscopy (SEM) observation and the AC complex-impedance measurements, it was concluded that the stable behavior of the sensor using the laminated (ZnCr₂O₄/YSZ)-SE was provided by the stabilization of the interface between ZnCr₂O₄ grains and YSZ particles. The fabricated sensor exhibited the linear dependence of sensitivity on the logarithm of either C₃H₆ concentration (in the range of 20-800 ppm) or mixtures of various hydrocarbons (HCs) (in the range of 90-2600 ppmC). In addition, the emf response was not altered by the change of O₂ (2-20 vol.%), H₂O (0-10.8 vol.%) and CO₂ (0-20 vol.%) concentrations, and no interference of other gases (CO, NO, NO₂, H₂, and CH₄) was observed.     

Photochemical decoration of silver nanoparticles on ZnO nanowires as a three‐dimensional substrate for surface‐enhanced Raman scattering measurement

To increase the sensitivity in surface‐enhanced Raman scattering (SERS) measurement, a three‐dimensional (3D) SERS substrate was prepared by the decoration of silver nanoparticles (AgNPs) on the side walls of ZnO nanowires. The prepared 3D SERS substrates provide the advantages of highly loaded density of AgNPs, with a large specific surface area to interact with analytes, and the ease for the analytes to access the surfaces of AgNPs. To prepare the substrates, ZnO nanowires were first grown on a glass plate by wet chemical method. By treating SnCl₂ on the surfaces of ZnO nanowires, Ag seeds could be formed on the side wall of the ZnO nanowires, which were further grown to a suitable size for SERS measurements via photochemical reduction. To optimize and understand the influences of the parameters used in preparation of the substrates, the reaction conditions were systematically adjusted and examined. Results indicated that AgNPs could be successfully decorated on the side wall of the ZnO nanowires only by the assistances of SnCl₂. The size and density of AgNPs were affected by both the concentration of silver nitrate and the irradiation time. With optimized condition, the prepared 3D substrates provided an enhancement factor approaching 7 orders of magnitude compared with conventional Raman intensity. Copyright © 2014 John Wiley & Sons, Ltd.