pH-sensitive polyvinylpyrrolidone-acrylic acid hydrogels: Impact of material parameters on swelling and drug release

In this study, we fabricated pH-sensitive polyvinylpyrrolidone/acrylic acid (PVP/AA) hydrogels by a free-radical polymerisation method with variation in the content of monomer, polymer and cross-linking agent. Swelling was performed in USP phosphate buffer solutions of pH 1.2, 5.5, 6.5 and 7.5 with constant ionic strength. Network structure was evaluated by different parameters and FTIR confirmed the formation of cross-linked hydrogels. X-ray crystallography showed molecular dispersion of tramadol HCl. A drug release study was carried out in phosphate buffer solutions of pH 1.2, 5.5 and 7.5 for selected samples. It was observed that swelling and drug release from hydrogels can be modified by changing composition and degree of cross-linking of the hydrogels under investigation. Swelling coefficient was high at higher pH values except for the one containing high PVP content. Drug release increased by increasing the pH of the medium and AA contents in hydrogels while increasing the concentration of cross-linking agent had the opposite effect. Analysis of the drug release mechanism revealed non-Fickian transport of tramadol from the hydrogels

Preparation and Study of Physical Properties of Starch-CMC Biodegradable Composite Film Containing Montmorillonite Nanoparticles

Novel citric acid modified starch-carboxy methyl cellulose (CMC) -montmorillonite (MMT) bionanocomposite films were prepared by casting method and the effect of MMT on the structural and physical properties of the starch-CMC biocomposites was studied. X-ray diffraction test showed thatstrong polar interactions between the hydroxyl groups present in the starch and CMC chains and in the silicate layers led to intercalation of biopolymer chains into MMT layers galleries. The water vapor permeability decreased from 2.44 to 1.13×10-7 g/mhPa as the MMT percentage increased from0 to 7%. At the level of 7% MMT, the composite films showed the highest ultimate tensile strength (27.55 MPa) and lowest strain-to-break (18.25%). The DSC tests showed that, the temperature position of the melting peak increased from 221.5°C to 243.0°C as MMT content increased from 1 to 7%, but the glass transition decreased and gradually disappeared

Studies on Electroactivity, Conductivity and Solubility of 2-Anilinoethanol Homopolymer and its Aniline Copolymers Using Oxidation andElectrochemical Methods

Copolymerization of aniline and 2-anilinoethanol was carried out by electrochemical and chemical polymerization. Homo and copolymer thin films were synthesized electrochemically, under cyclic voltammetric conditions in aqueous solutions of sulfuric acid as electrolyte at room temperature. The films were deposited on the surface of working electrode [Glassy Carbon ()GC)(] versus Ag/AgCl electrode in solution containing 0.1 M mixture of monomers and 1M H2SO4 as electrolyte by applying sequential linear potential scan rate of 25 mV/s between -0.1 to 0.9 V. The cyclic voltammograms CVs)( of obtained copolymer illustrate the formation of copolymer. The homo- and copolymers of aniline ()ANI)( and 2-anilinoethanol 2-ANE)( with different feed ratios of monomers were prepared in 1M H2SO4 in presence of ammonium persulfate [()NH4)(2S2O8] as an oxidant. FTIR spectroscopy and conductivity measurement using four-probe technique were applied for the characterization of the products. The solubility of copolymers was tested in various organic solvents