Synthesis,characterization, thermal stability and antibacterial activity of coumarin based methacrylate copolymers

Monomer of 7-methacryloyloxy-4-methylcoumarin(MAOMC) was synthesized and characterized by FTIR, 1H-NMR and 13C-NMR spectroscopy. Copolymers of MAOMC with butoxyethylmethacrylate(BOEMA) at different feed compositions were prepared by free radical solution polymerization at(70 ± 1) °C in ethylmethylketone(EMK) using benzyl peroxide(BPO) as an initiator. The copolymers were characterized by FTIR and 1H-NMR spectroscopy. Thermogravimetric analysis(TGA) and differential scanning calorimetry(DSC) of the copolymers showed moderate thermal stability and higher Tg values. Gel permeation chromatography(GPC) was used to find out the molecular weights of the different copolymers. Antibacterial activities of the copolymers were also investigated against the selected pathogenic bacteria's. The antibacterial activity of the copolymer increases as the MAOMC content increases in the copolymer. This shows that coumarin moiety plays a very important role in the antibacterial activity.     

Development and validation of a HPLC method for quantification of rivastigmine in rat urine and identification of a novel metabolite in urine by LC‐MS/MS

A sensitive, specific and accurate HPLC method for the quantification of rivastigmine (RSM) in rat urine was developed and validated. The method involves the simple liquid–liquid extraction of RSM and pyridostigmine as an internal standard (IS) from rat urine with tertiary methyl butyl ether. The chromatographic separation of RSM and IS was achieved with 20 mm ammonium acetate buffer (pH 6.5) and acetonitrile (65:35, v/v) delivered at flow‐rate of 1 mL/min on a Kromasil KR‐100. The method was in linear range from 50 to 5000 ng/mL. The validation was done as per FDA guidelines and the results met the acceptance criteria. The method was successfully applied for the quantification of RSM in rat urine. Besides method validation, we have identified two metabolites of RSM in urine. Both the metabolites were characterized by HPLC‐PDA and LC‐MS/MS and it was found that one metabolite is novel. Copyright © 2010 John Wiley & Sons, Ltd.     

Ellagic Acid Normalizes Mitochondrial Outer Membrane Permeabilization and Attenuates Inflammation-Mediated Cell Proliferation in Experimental Liver Cancer

Despite great advances in our understanding of the molecular causes of liver cancer, significant gaps still remain in our knowledge of the disease pathogenesis and development of effective strategies for early diagnosis and treatment. The present study was conducted to evaluate the chemopreventive activity of ellagic acid (EA) against experimental liver cancer in rats. This is the first report that implies a possible role of EA in controlling liver cancer through activation of mitochondrial outer membrane permeability via activating proteins such as Bax, bcl-2, cyt-C, and caspase-9, which play important roles in apoptosis. Downregulation of NF-κB, cyclin D1, cyclin E1, matrix metalloproteinases (MMP)-2, MMP-9, and proliferating cell nuclear antigen (PCNA) were noted in EA-treated experimental rats and controlled inflammation mediated liver cancer when compared to the diethylnitrosamine (DEN)-induced group. Transmission electron microscopy (TEM) analysis of the livers of experimental rats demonstrated that EA treatment renovated its internal architecture. Overall, these results demonstrate the value of molecular approaches in identifying the potential role of EA as an effective chemopreventive agent.     

High-Performance Thin-Layer Chromatographic Determination of Etoricoxib in the Bulk Drug and in Pharmaceutical Dosage Form

JPC – Journal of Planar Chromatography – Modern TLC - A sensitive, accurate, precise, and stability-indicating high-performance thin-layer chromatographic method has been established...     

Explicit Evaluation Formula for Ramanujan’s Singular Moduli and Ramanujan–Selberg Continued Fractions

Mathematical Notes - At scattered places of his notebooks, Ramanujan recorded over 30 values of singular moduli $$\alpha_n$$ . All those results were proved by Berndt et. al by using...     

Wide Band Gap Transparent Polymer-Inorganic Composite Thin Films by Dip-Coating Method: Preparation and Characterizations

Wide band gap transparent polymer-inorganic (PVA-ZnO) composite thin films were prepared by the dip-coating method. Functional groups and metal oxide vibrations were found from Fourier transform-infrared spectroscopy. The elements Zn and O were confirmed from energy dispersive X-ray spectroscopy. The X-ray diffraction patterns revealed that the sharp diffraction peaks correspond to the hexagonal wurtzite structure of ZnO in the PVA matrix. Scanning electron microscopy images showed that the ZnO nanoparticles are randomly distributed throughout the entire film surface. The optical study reveals that the transmittance was more than 85% with very low absorption and wide band gap energy (4.03 to 3.95 eV). The obtained results indicate that the high transmittance, very low absorption, and wide band gap energy of the prepared dip-coated composite thin films make them suitable for use in transparent optoelectronic device applications in the near future.