FABRICATION OF TEMPERATURE AND pH SENSITIVE BIOPOLYMER/CLAY BIOCOMPOSITE AS DRUG CARRIER FOR RANITIDINE – HCl

The scientific studies on drug delivery systems that transport drugs to the targeted tissues, at a certain rate and desired time intervals, have gained popularity. The main goal of the drug delivery and release systems is to maintain the drug level in the blood plasma by balancing the amount of active ingredient. In this study, pH and temperature sensitive drug carriers were prepared using chitosan as a biopolymer and clay as a natural material. The characterization of the prepared materials was performed for structural analysis by FT-IR and for morphological analysis by SEM instruments. The swelling properties of the prepared materials were investigated. In this work, Ranitidine-HCl was used as a model drug. The prepared drug carriers were first loaded with Ranitidine-HCl and release properties of the materials were investigated at two different temperatures (25oC, 37oC) and various pH medium. The data obtained from the experiments indicated that the maximum release of Ranitidine–HCl from the prepared sample was observed at pH=7,6 buffer solution at both temperatures by comparing buffer solutions. It has been shown that the materials prepared in this study are suitable carriers for the Ranitidine-HCl drug active ingredient

The synthesis of silica-coated magnetic nanoparticles and using as adsorbent

In this work, the silica-coated magnetic field-sensitive iron nanoparticles (Si-gamma Fe2O3) were successfully prepared by sol-gel method and used as the adsorbent in the adsorption of methylene blue. The adsorption capacity was evaluated. Batch adsorption experiments were performed as a function of contact time, initial dye concentration (5-20 mg/L), solution pH (4.0-9.6) and temperature (298-328 K). The structure and the morphology of this material were characterized by the Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The adsorption kinetic studies were achieved using pseudo-first order, and pseudo-second order kinetic models. The adsorption kinetic of methylene blue on Si-gamma Fe2O3 is consistent with the pseudo-second order kinetic model. Thermodynamic parameters such as Gibbs free energy (Delta GA degrees), enthalpy (Delta HA degrees) and entropy (Delta SA degrees) changes were evaluated and the results indicated that adsorption process was endothermic and spontaneous. The equilibrium isotherms for the adsorption of methylene blue on the adsorbent were described by the Freundlich and Langmuir isotherm models

Viscometric Analysis of Miscibility and Interactions for Binary, Ternary Polycarbonate/Brominated Polystyrene plus Chloroform Systems at Different Temperatures

Viscosities of ternary systems consist of polycarbonate (PC)/brominated polystyrene (PBrS) in chloroform and their corresponding binary systems were measured at different temperatures (20, 25, and 30 degrees C). All the measurements were carried out at the concentration ranges of 0.1-0.6gdL(-1). The mass ratio of PC to PBrS was selected as 75:25, 50:50, and 25:75 in the ternary solutions. Two empirical expressions of Huggins and Kraemer equations with three-parameters were used for reproducing of the experimental viscosity data. The fitting parameters were obtained for the corresponding temperatures. The miscibility criteria on the basis of the sign of [](m) based on the difference between experimental and ideal values of [](m), was calculated by applying the Garcia etal., theoretical equation. The effect of temperature on the viscosity data was also studied. The results from this method were correlated with the miscibility data obtained for the same system by differential scanning calorimeter (DSC) findings

Preparation and characterization of polymers based on PDMS and PEG-DMA as potential scaffold for cell growth

This work describes a soft lithographic method for the generation of patterned both biopolymer and silver with each covered on microscope glass. Because of their biocompatible nature and permeability to gases the biopolymers are convenient for cell culture studies. The microscope glass was covered by polyethylene glycol dimethyl acrylate (PEG-DMA), as biopolymer and patterned by the UV light passing through the printed photomask for the preparation of the PDMS stamps. PDMS stamps were originally fabricated in this work for pattern transfer. Ag and polymer covered on the microscope glass were patterned by using these PDMS stamps. The patterned Ag, PDMS mold and PEG-DMA biopolymer were used as scaffolds and cell growth experiments have been performed on these materials. The degree of cell viability was measured by seeding them with L929 mouse fibroblasts and the number of the cells was measured by neutral red uptake assay. An increase in the number of cells on the material surfaces was observed. The pattern and the cell growth properties were followed by optic microscope. The results obtained from the cell growth was subjected to student's t-test. (C) 2017 Elsevier B.V. All rights reserved

Corrosion Protection of Aluminum Alloy AA7020 in NaCl Solution by Hybrid Sol-Gel Coatings

In this study, two different hybrid sols as tetraethyl orthosilicate/(3-Glycidyloxypropyl) trimethoxysilane (TEOS/GPTMS) and tetrapropyl orthotitanate/(3-Glycidyloxypropyl) trimethoxysilane (TPOT/GPTMS) were prepared and Aluminum AA7020 alloy was coated with these sols by the dip-coating method. Corrosion behavior of coated samples in 3.5% NaCl solution was investigated using potentiodynamic polarization (Tp) and electrochemical impedance spectroscopy (EIS) methods. The same electrochemical test and analysis procedures were applied to an uncoated AA7020 sample in order to the investigate corrosion protective perfomance of TEOS/GPTMS and TPOT/GPTMS coatings in 3.5% NaCl solution. Morphological analyses of the coated and uncoated AA7020 samples were made before and after corrosion test measurements via Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectrometry (EDS). The results obtained from EIS and Tp measurements for the coated and uncoated specimens were reviewed for the corrosion protection activities of the sol-gels coating. TEOS/GPTMS and TPOT/GPTMS sol-gel coatings were found to have high protection effect for the corrosion of AA7020 alloy in a 3.5% NaCl medium

Efficient light emitting diodes from ternary blends of PPV-based copolymers

Light emitting diodes (LEDs) were prepared using ternary blends of block copolymers emitting in the blue (I and II) and green (III) regime. These blends were studied in terms of their absorbance, photoluminescence (PL), and electroluminescence (EL) spectra. The PL spectra in dilute solution and in the solid state were compared. Förster energy transfer from I and II to III was studied in the solid state. The EL device made using a ternary blend with the ratio (1 : 1 : 1) showed the highest EL quantum efficiency. Differential scanning calorimetry (DSC) measurements have been made to investigate the phase separation in these copolymer blends

Chitosan/alginate crosslinked hydrogels: Preparation, characterization and application for cell growth purposes

Chitosan hydrogels may be formed by various mechanisms. In this study, we aimed to form hybrid polymer networks of chitosan with alginate using a crosslinker which enabled the covalent binding of the two macromolecules. The structural and thermal characterization of these hydrogels was performed by using Fourier transform infrared (FTIR) and differential scanning calorimeter (DSC). The morphological analysis of the crosslinked material was investigated by scanning electron microscopy (SEM) and a scanning probe microscope with atomic force microscope (AFM) attachment. The swelling properties of these gels were analyzed in water and in phosphate buffered saline (PBS) solution. The presence of alginate in a chitosan/alginate hydrogel was shown to support the hydrogel stability. Compared to chitosan/alginate (1/2) hydrogel prepared with 1 wt% DCC, the swelling of chitosan/alginate (1/2) hydrogels prepared with 3 wt% DCC was limited. To measure the degree of cell proliferation, the hydrogels were seeded with L929 mouse fibroblasts and cell numbers measured by neutral red uptake assay. The cell attachment was also followed by (SEM) photography. It was observed that chitosan/alginate (1/2) hydrogels with 1 wt% (DCC) provides a better environment for cell attachment and proliferation. This study presents functional hydrogel formation by crosslinked chitosan and alginate, a novel biomaterial which also supports cell growth. (C) 2013 Published by Elsevier B.V

Alginate/Polyoxyethylene and Alginate/Gelatin Hydrogels: Preparation, Characterization, and Application in Tissue Engineering

Hydrogels are attractive biomaterials for three-dimensional cell culture and tissue engineering applications. The preparation of hydrogels using alginate and gelatin provides cross-linked hydrophilic polymers that can swell but do not dissolve in water. In this work, we first reinforced pure alginate by using polyoxyethylene as a supporting material. In an alginate/PEO sample that contains 20 % polyoxyethylene, we obtained a stable hydrogel for cell culture experiments. We also prepared a stable alginate/gelatin hydrogel by cross-linking a periodate-oxidized alginate with another functional component such as gelatin. The hydrogels were found to have a high fluid uptake. In this work, preparation, characterization, swelling, and surface properties of these scaffold materials were described. Lyophilized scaffolds obtained from hydrogels were used for cell viability experiments, and the results were presented in detail