جستجوی مقالات مرتبط با کلیدواژه « polyvinyl alcohol » در نشریات گروه « شیمی »

In the current study, fabrication and characterization of a biodegradable skin patch with controlled release of sodium diclofenac was reported. Gelatin and polyvinyl alcohol were considered the main part of the patch, and nanochitosan was selected as an agent for improving physical and mechanical properties and controlling the drug release.  Furthermore, diclofenac sodium was loaded into the polymer as a pain relief agent. The total weight percent of the polymer was selected as 5%. Different samples with weight ratios of gelatin to polyvinyl alcohol of 0.1, 0.25, 0.5, 1, 1.5, 3, and 4.5 were fabricated. The sample's appearance characteristics with a ratio of 3 were the best; therefore, this sample was considered for further characterization. Then different percentages of nanochitosan were added to the polymer substrate. The tensile strength test results showed that the highest strength is obtained in the presence of 1% by weight of nanochitosan. Afterward, different amounts of drugs were added to the gelatin/polyvinyl alcohol/nanochitosan sample. The samples' different properties were examined using the tensile test, drug release test, scanning electron microscopy, swelling test, degradation test, and thermal degradation test. The results showed that good interaction between the components and the uniform distribution of nanoparticles within the samples was achieved. Measurement of drug release rate in samples over 8 hours showed that the release rate was faster at the beginning of the test; furthermore, the drug's maximum loading was 95%. This study's findings can be a preliminary step to prove the potential of gelatin/polyvinyl alcohol/nanochitosan/diclofenac sodium compound as a pain relief skin patch.

Alcohol dehydration is accomplished by various processes, especially pervaporation with increased attention and applications. Many hydrophilic polymeric membranes have been prepared and used for alcohol dehydration. Polyvinyl alcohol (PVA) is one of the most important polymeric membranes in this regard. In this study, modification of the prepared polyvinyl alcohol membranes by blending method them with Agarose (Aga) in order to achieve higher separation performance is studied. PVA/Aga blended membranes are prepared and used for separation of ethanol/water solution using pervaporation process. The structure of the membranes was investigated using SEM and contact angle tests. In the carried out experiments, pervaporation operating temperature and pressure are kept fixed at 30 °C and - 830 mbar abs, respectively, and effects of the feed composition and the blending ratio on the membrane separation parameters are studied. The results showed that membranes have enhanced separation performance for water/ethanol mixtures. The highest selectivity as infinity and flux of 0.243 kg/m2h was obtained for the 50 wt. % Aga membrane and the feed mixture of 30 wt. %. The 60 wt. % Aga membrane selectivity and flux for dehydration of the feed mixture containing 70 wt. % ethanol are obtained as infinity and 0.838kg/m2h, respectively.

Solubility is one of the important parameters to find out desired concentration of drug in systemic circulation for intended pharmacological properties. More than 40% NCEs (new chemical entities) developed in pharmaceutical industry are practically insoluble in water. Any drug to be absorbed must be present in the form of solution at the site of absorption. Hence solubility has turned to a major challenge for formulation scientist.
In this research polyvinyl alcohol (PVA) fibers loaded with Trimethoprim (TMP) was fabricated by electrospinning and investigated as potential oral fast-dissolving films. Scanning electron microscopy (SEM) images showed that the fibers take the form of uniform cylinders with smooth surfaces and diameter less than 600 nm, and contain the drugs in the amorphous form. Drug–polymer intermolecular interactions were evidenced by infrared spectroscopy (FT-IR) and differential thermal analysis (DTA). Disintegration and drug released times, when they added to artificial saliva, were 30 s and 90 s respectively and during this time more than 90 % of drug was released. In-vitro bacterial inhibition test was also carried out to determine the relative activity of the released antibiotic. The data reported herein clearly demonstrate that these fast-dissolving films could be suitable candidates for administration of TMP, especially for children, aged people and patients with swallowing difficulties.

In this research, coaxial electrospinning method was used for preparing the core-shell fibers of polycaprolactone PCL and polyvinyl alcohol PVA, and silver nanoparticles were added through the reduction of silver nitrate in core solution before processing. The presence of silver nanoparticles was proved by observing the absorption peak in UV-visible spectroscopy test in the range of 420-430 nm. Antibacterial properties were investigated according to ATCC100 standard by usage of E.coli and S.aureus bacteria on single layer fibers mat of PCL, PVA, PCL containing silver and PVA containing silver, as well as core-shell fibers mat of PVA-Ag/PCL and PCL-Ag/PVA. The results showed that core-shell fibers have strong antibacterial properties like single layer fibers containing silver. Also, adding silver nanoparticles caused a slight enhancement in contact angle or hydrophobicity of the fibers. The water vapor transmission rate test exhibited that WVTR value decreased with the addition of silver and fabricating core-shell fibers while in comparison with commercial wound dressing, this value is more close to human WVTR value.