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The aim of the work was to develop environmental friendly coir pith-based composites with a good balance of mechanical properties. Multilayered coir pith/ nylon fabric/epoxy hybrid composites were fabricated by the hand lay-up technique followed by compression molding. A set of composites of same composition having chemically treated coir pith was also prepared. Mechanical properties of composites such as tensile strength, impact strength, flexural strength, hardness, and abrasion resistance were evaluated. The hybridization with nylon fabric and the chemical treatment of coir pith enhances the mechanical properties of composites. Chemical resistance and void content of the composites were also determined and reported. A comparative evaluation is done between composites having chemically treated coir pith and untreated coir pith. Coir pith was subjected to different treatments such as sodium hydroxide treatment followed by sulfuric acid, dicumyl peroxide, sodium hypochlorite, acrylic acid, and acetic acid. POLYM. COMPOS., 37:649-657, 2016.

Cellulose microfibers were obtained from Hibiscus sabadariffa by steam explosion technique. Structural and surface analysis of the microfibers showed a reduction in diameter and changes in surface morphology from that of raw fibers. The chemical composition of fibers showed increase in a-cellulose content and decrease in lignin and hemicelluloses for the microfibers. These factors were further confirmed by XRD, SEM, and FTIR results. The CMF were introduced to EVA at different loading by melt extrusion. The composites were analyzed for their thermal stability and phase transition using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA analysis of the composites showed increased onset temperatures for composites compared with pure EVA indicating the superior thermal stability of the composites with fiber loading. DSC analysis shows increase in melting enthalpy and percentage crystallinity with fiber loading increases. Kinetic parameter for the degradation of the composites was obtained using Broido, Coats-Redfern, and Horowitz-Metzger methods. POLYM. COMPOS., 34:616-625, 2013. ª 2013 Society of Plastics Engineers

A new sensitive and stability indicating reverse phase high-performance liquid chromatography method has been developed for the quantitative determination of potential impurities of Ledipasvir, active pharmaceutical ingredient. Efficient chromatographic separation was achieved on waters × select column contains C18 stationary phase in gradient mode, quantitation at wavelength of 325 nm and mobile phase A is 50 mM ammonium formate pH 3.5 and mobile phase B is acetonitrile with flow rate 1.2 mL. The method was validated according to International Council for Hormonisation guideline, linearity studies has shown correlation coefficient value greater than 0.999 for Ledipasvir and all known impurities. Limit of detection and Limit of quantification were determined to be 0.01% and 0.03%, respectively, for all the impurities. The consistent recoveries were obtained for all impurities (95-105%). Various stress conditions were applied to study the degradation behavior of the drug substance. LC-MS was used to analyse the degraded samples and possible structural identifications were assigned based upon known reactivity of the drug. The method was found to be specific, selective and robust to the degradation products. Major degradation of the drug substance was found to occur under photolytic stress conditions resulting a novel impurity (impurity F). The formed degradant was identified and characterized by FT-IR, 1HNMR and LC-MS/MS. The stress samples quantified against qualified working standard and the mass balance found above 98%.