Amount Of Polyvinyl Alcohol Research Articles

Curcumin Intra-oral Controlled Release Films for Oral Candidiasis: A Comparative Study with Fluconazole, Elucidation of Release Mechanism

Objective: This research work aimed to develop bucco-adhesive patches, which release curcumin in the oral cavity for an extended duration thereby assisting in the cure of oral thrush (candidiasis). Fluconazole containing patches were also developed in order to compare the effectiveness of curcumin patches against Candida albicans. Method: After suitable preformulation studies, five formulations of curcumin were prepared using Eudragit S100 and polyvinyl alcohol (PVA) in varying ratios. Three batches of fluconazole formulations were prepared without PVA. Patches were evaluated for their physical properties and chemical integrity. Newer techniques were developed to determine their bioadhesion and tensile strength. Sterile formulations of P3 and F2 were prepared and compared for the antifungal activity against C. albicans, by zone of inhibition method. Results: All formulations exhibited satisfactory tensile strength ranging from 0.282 to 0.411 Kg/m2 with good folding endurance. Formulations containing higher amount of PVP exhibited better bioadhesive strength. P3 formulation containing curcumin and F2 formulation of fluconazole were found to sustain the drug release upto 5 hours. An increasing amount of PVA retarded the drug release. In antifungal studies, the zone of inhibition for P3 patches was 19mm, and for F2 patches, it was 13mm, indicating a better in vitro antifungal activity for curcumin against fluconazole. SEM analysis of P3 formulations revealed continuous, non-porous but non homogenous structure of the polymer film. Conclusion: The effectiveness of curcumin buccal patches in superior to fluconazole patches was well demonstrated. Mathematical modelling of drug release data indicated a first order anomalous transport causing the drug release. Kinetic modelling with zero, first order, Higuchi and Korsmeyer- peppas are explained in this article. Keywords: Buccal, curcumin, candidiasis, antifungal, tensile strength, drug release, korsmeyer-peppas.

Controllable preparation of three-dimensional porous WO3 with enhanced visible light photocatalytic activity via a freeze-drying method

Three dimensional porous WO3 was fabricated by a novel freeze-drying method using a polyvinyl alcohol (PVA)/phosphotungstic acid (H3PW12O40) aqueous solution as the precursor followed by calcination. Results revealed that WO3 interconnected porous structures have channels of 3–10 µm and wall thicknesses of about 0.68 µm. Interestingly, the morphology and porous structure of WO3 samples can be well controlled by the amount of PVA and calcination temperature. To further demonstrate their potential application in photocatalysis, their photocatalytic activities for the photodegradation of Rhodamine B under visible light irradiation were investigated. It was found that the highest photocatalytic activity was obtained by using the WO3 porous sample which prepared by fixing the addition amount of PVA at 7.5% (relative to solvent) and the calcination temperature at 800 °C. The enhanced photocatalytic performance of WO3 can be attributed to the combined effects of increased surface area, the interconnected macroporous as well as the enhanced crystal quality.

Preparation and evaluation of naringin-loaded polycaprolactone microspheres based oral suspension using Box-Behnken design

The objective of the current investigation was to study the outcome of the concentration of polycaprolactone (PCL), the concentration of polyvinyl alcohol (PVA) and the concentration of hydroxypropyl methylcellulose (HPMC) on the average particle size of microspheres and the drug entrapment efficiency of naringin-loaded polycaprolactone microspheres based oral suspension. Naringin-loaded polycaprolactone microspheres based oral suspension were prepared by solvent evaporation method. Further, in this work optimization of the formulation was done using a three factors, three levels Box-Behnken design (BBD). Drug-loaded microsphere suspension was prepared by employing solvent evaporation technique. Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) analysis was carried out to determine any incompatibility between the naringin and other components used in the formulations. Polymer alone (PVA concentration) or interaction effects of polymers (PCL-HPMC, PCL-PVA, HPMC-PVA, and PCL in higher order) have a substantial influence on particle size of microspheres. Amount of PVA and HPMC have a significant effect on entrapment efficiency of microspheres. The optimal conditions of PCL concertation were 7.7% w/v; HPMC concentration was 3.2% w/v and PVA concentration was 0.081% w/v. The optimized suspension showed particle size of 24μm with drug entrapment efficiency 96%. As a result, due to uniform distribution of microspheres, drug entrapment efficiency was achieved in optimized suspension.

Improved vaginal retention and enhanced antifungal activity of miconazole microsponges gel: Formulation development and in vivo therapeutic efficacy in rats

Traditional azole antifungal formulations suffer from poor retention in the vaginal cavity, irritation and burning of the vaginal area. In the present work, we aim at the development of a novel miconazole (MCZ) microsponges gel as an attractive dosage form for vaginal candidiasis. The proposed formula has the potential to minimize the local side effects of the drug due to the controlled release characteristic, which increases patient compliance. Moreover, the mucosal retention effect of the microsponges in addition to the bioadhesion property of Carbopol gel prolongs the retention of the dosage form in the vagina and consequently improves the therapeutic efficiency. MCZ microsponges were prepared applying Quasi emulsion method using Eudragit RS100. The effect of formulation factors, namely, drug:polymer ratio (1:1, 2:1 and 4:1), the amount of poly vinyl alcohol (PVA) (25, 50 and 75mg) and the volume of organic solvent (2.5, 5, 10mL) on the characteristics of MCZ microsponges has been investigated. The microsponges were optimized regarding the production yield (68.8±6.4%), particle size (78.2±2.1μm), entrapment efficiency (92.9±1.9%) and release rate (Q150 51.8±2.5%). The selected formula was further evaluated for its, flowability, porosity and surface morphology. MCZ microsponges were incorporated into Carbopol gel, then the viscosity and bioadhesion were examined. The in vitro antifungal activity of MCZ microsponges gel was comparable to the market product. In vivo, MCZ microsponges vaginal gel was more effective than the market product (p<0.05) in eradicating Candida infection in rats, which was supported by the histopathological findings.

Effects of Polyvinyl Alcohol Modification on Microstructure, Thermal Properties and Impermeability of Microencapsulated n -Dodecanol as Phase Change Material

In this study, a series of different mass of polyvinyl alcohol (PVA) modified microcapsules were synthesized through in-situ polymerization, where the bio-based n-dodecanol was selected as phase change material cores. The surface morphology, microstructure, thermal properties as well as impermeability were systematically characterized with field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and differential scanning calorimeter (DSC), respectively. The formation mechanism of microencapsulation and phase change behavior were investigated as well. And these effects of PVA on morphology, microstructure, thermal properties, particles size and distribution of microencapsulated n-dodecanol were also discussed. With the increase of PVA employed, the morphology of microcapsules changed apparently, and both the distribution and particles size of microcapsules decreased. The impermeability test results showed that impermeability of microencapsulated n-dodecanol enhanced after PVA modification, and the influence of PVA amount on impermeability enhancement of microcapsules was studied in this paper.

Enhancement of solubility and dissolution of ibuprofen microparticle prepared by ultrasonic spray drying

Ibuprofen (IBU) is one of the most commonly used nonsteroidal anti-inflammatory drugs with high permeability and low solubility. The aims of this research is to improve the solubility and dissolution of the IBU by reducing particle size using ultrasonic spray drying method and utilizing watersoluble polymer (polyvinyl alcohol (PVA)) and surfactant (sodium lauryl sulphate (SLS)) for particles formulation. The results showed that increasing amount of PVA, smaller particle size of as-prepared IBU-PVA-SLS was obtained, 6.3-fold smaller than untreated IBU. The in vitro drug release study for simulated gastric fluid without enzymes (0.1 N HCl or Buffer pH 1.2) shows the dissolution of prepared IBU-PVA-SLS significantly increase 2.4-fold higher than untreated IBU for dissolution time of 30 minutes. While the solubility of the IBU-PVA-SLS was increased 4.7-fold compare to untreated IBU. In general, IBU possessing relatively high dissolution in intestinal fluid. In contrast, the finding of recent investigation on dissolution of IBU-PVA-SLS is significantly increase in gastric fluid, either due to smaller particles size or PVA-SLS. Thus, despite the PVA and SLS determine the particles formation during polymerization yielding smaller particle size, they also responsible for effective drug delivery system. It was concluded that PVA and SLS in ultrasonic spray drying technique for IBU preparation successfully reduces the particle size and effectively enhances the solubility and dissolution rate of poorly water-soluble IBU in 0.1 N HCl.

Synthesis and characterization of reinforced hybrid porous beads: Application to the adsorption of malachite green in aqueous solution

This study focuses on the preparation by an extrusion-dripping method of sodium alginate (SA)/aluminum-pillared montmorillonite (Al-PILMt)/polyvinyl alcohol (PVA)/calcium carbonate (CaCO3) beads using different percentages of Al-PILMt, PVA and CaCO3. Mechanical and physical characteristics of these reinforced hybrid porous beads (RHPB) were connected to the thermodynamic and kinetic adsorption properties of malachite green (MG).Mechanical properties were investigated using uniaxial compression of single wet bead. The corresponding calculated Young’s moduli were found to correlate with the PVA amount which was used in the formulation of the beads. However, these modulus values increased by approximately 70% compared to SA beads taken as references. Beads samples based on PVA and Al-PILMt prove to be more elastic with a better mechanical stability. In contrast, the addition of calcium carbonate in the mixtures leads porous beads PB with a low stiffness less than the RHB. The efficiency of RHPB was evaluated towards the elimination of MG from aqueous solutions. The dye removal, about 8% with SA beads, increased significantly with RHPB (27%) and HPB without PVA (46%). Pseudo first order kinetics with rapid initial adsorption rate and Freundlich equation are respectively used for the description of kinetic and isotherm equilibrium results. Obtained results by the principal component analysis (PCA) method showed the influence of the two main structural variations (i.e. porosity and stiffness) on their adsorption properties.

Poly (vinyl alcohol)/poly (acrylamide‐ co ‐diallyldimethyl ammonium chloride) semi‐IPN hydrogels for ciprofloxacin hydrochloride drug delivery

Herein, the authors developed a new and potential semi-interpenetrating polymer network (semi-IPN) hydrogels of poly vinyl alcohol (PVA), acryl amide and diallyldimethyl ammonium chloride employing chemical cross-linker N, N'-methylene bisacrylamide (NNMBA) and ammonium persulphate as an initiator by radical polymerisation. To analyse the copolymer formation between two monomers and IPN cross-linking reaction, the resulting hydrogel was characterised by Fourier transform infrared spectroscopy and the surface morphology was analysed using scanning electron microscopy. Differential scanning calorimetry and X-ray diffraction studies were also carried out for investigating drug loading and distribution and swelling experiments were carried out for the uptake of water. In vitro release of ciprofloxacin hydrochloride from hydrogel was performed at intestinal conditions. The amount of PVA, NNMBA and total monomer concentration was found to strongly control the drug release behaviour from the hydrogels.

Hexavalent chromium removal by using synthesis of polyaniline and polyvinyl alcohol.

Over the past few years, heavy metals have been proved to be one of the most important contaminants in industrial wastewater. Chromium is one of these heavy metals, which is being utilized in several industries such as textile, finishing and leather industries. Since hexavalent chromium is highly toxic to human health, removal of it from the wastewater is essential for human safety. One of the techniques for removing chromium (VI) is the use of different adsorbents such as polyaniline. In this study, composites of polyaniline (PANi) were synthesized with various amounts of polyvinyl alcohol (PVA). The results showed that PANi/PVA removed around 76% of chromium at a pH of 6.5; the PVA has altered the morphology of the composites and increased the removal efficiency. Additionally, synthesis of 20 mg/L of PVA by PANi composite showed the best removal efficiency, and the optimal stirring time was calculated as 30 minutes. Moreover, the chromium removal efficiency was increased by decreasing the pH, initial chromium concentration and increasing stirring time.

Development of a colorimetric sensor for nickel ion based on transparent electrospun composite nanofibers of polycaprolactam-dimethylglyoxime/polyvinyl alcohol

A new type of optical sensor based on electrospun composite polycaprolactam (N6)-dimethylglyoxime (DMG) nanofibers collected on a glass slide was fabricated. The nanofibrous mat was then impregnated with a polyvinyl alcohol (PVA) solution to make it transparent. The colorimetric sensor, N6-DMG@glass, was coupled with absorbance spectrophotometry for analytical determination of nickel ions (Ni2+) as red Ni(DMG)2 complex. The main factors affecting performance of the sensor including DMG dosage, electrospinning time, polymer solution flow rate, electrospinning voltage, and PVA amount were investigated. Under the optimal conditions, limit of detection, limit of quantification, linear dynamic range, and determination coefficient (R 2) were 2, 5, 5–100 µg mL−1 and 0.9989, respectively. The relative standard deviation (%, n = 3) at the concentration level of 50 µg mL−1 was 3.1 %. The technique was applied successfully to the determination of Ni2+ in electroplating nickel pool, tap water, and laboratory wastewater.

Ferromagnetism in LaMnO3 Nanoparticles Prepared by Sol–Gel Method Combined with Polyvinyl Alcohol

This work presents the synthesis of rhombohedral LaMnO3 nanoparticles (NPs) by using a sol–gel method with the assistance of polyvinyl alcohol (PVA), followed with annealing at 700°C for 2 h in air. By changing the PVA amount from 0 ml to 15 ml, we have synthesized LaMnO3 NPs so that their ferromagnetic–paramagnetic phase-transition temperature (T C) can be tuned in the range between 228 K and 305 K. At 15 K, saturation magnetization (M s) and coercivity (H c) values are tunable in the ranges of 32–52 emu/g and 200–258 Oe, respectively, if varying PVA amount from 0 ml to 15 ml. X-ray photoelectron analyses revealed a large amount of La deficiency and oxygen excess in the NPs, particularly for the NPs synthesized with the presence of PVA at a suitable amount (≤10 ml). This leads to a coexistence of Mn3+ and Mn4+ ions, and changes the geometrical structure of nanocrystalline LaMnO3 NPs, as confirmed by x-ray absorption data. We believe that the variation of PVA changed the concentration ratio of Mn3+/Mn4+, enriching a magnetic-phase diagram of LaMnO3 nanoparticles.

Preparation of anticoagulant polyvinylidene fluoride hollow fiber hemodialysis membranes.

In this study, polyvinylidene fluoride (PVDF) hollow fiber membranes (HFMs) were modified by coating with polyvinyl alcohol (PVA) and chitosan. The influences of PVA and chitosan amount on PVDF membrane mechanical and separation performance were investigated. The results showed that the modified PVDF membranes had better mechanical and separation performance when the amount of PVA and chitosan was 20 mg/m2. At the same time, the biocompatibility of PVDF membranes was also investigated. Compared with virgin PVDF membranes, the modified PVDF membranes showed better anticoagulation, hydrophilicity, less bovine serum albumin (BSA) adsorption, and lower hemolytic ratio. The anticoagulation behavior of modified PVDF membranes coating with PVA had been obviously improved. Prothrombin time (PT) and activated partial thromboplastin time (APTT) of the modified PVDF membrane are 44.8 s and 72.5 s while the PT and APTT of virgin PVDF membrane are 15.6 s and 37.3 s. The advancing water contact angle (WCA) and BSA adsorption of the modified PVDF membrane coating with PVA are 24° and 23 mg/m2 while virgin PVDF membrane is 52° and 49 mg/m2. However, further biocompatibility evaluation is needed to obtain a more comprehensive conclusion.

Mechanical strength and damage tolerance of highly porous alumina ceramics produced from sintered particle stabilized foams

Highly porous alumina particle stabilized foams were prepared by combining the concepts of particle stabilized foams and gelcasting, using sulfonate surfactants and poly vinyl alcohol (PVA) as the gelcasting polymer. The ceramic samples sintered at 1500°C for 2h had porosities from 65% to 93%, with pore sizes in two categories: “big pore” around 300 μm and “small pore”, around 100–150μm, depending on the type and amount of surfactant added. The mechanical behaviour of the foams (axial and diametral compression) depended on the overall porosity and pore size. On average, tensile and compressive strengths around 5 and 16MPa respectively were measured for samples with bigger pore sizes and larger porosities. Samples with smaller pore sizes and lower porosities produced average values of 12 and 57MPa for tensile and compressive strengths, respectively. The elastic modulus reached a maximum around 3GPa for “small pore” size samples. The effect of increasing amount of PVA in the samples had a strong effect on the green mechanical strength, but it did not significantly affect the mechanical response of the sintered alumina foams. Large and complex shape sintered components produced using this route showed a remarkable damage tolerance, due to crack tip blunting.

Design and Evaluation of Buccal Patch Containing Combination of Hydrochlorothiazide and Lisinopril

Purpose: The objective of the present study was to formulate and evaluate buccal patches containing combination of lisinopril (LP) and hydrochlorothiazide (HCZ). Approach: Films were fabricated by solvent casting method, using combination of mucoadhesive polymers such as hydroxypropylmethyl cellulose (HPMC), hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA) and polyvinyl pyrolidone (PVP) and ethyl cellulose (EC) as backing layer. The patches were evaluated for physicochemical characteristics such as weight, thickness, surface pH, folding endurance, bioadhesive strength, swelling index, drug content, tensile strength, elongation at break, mucoadhesion time, in vitro and ex vivo drug permeation. Results: The IR spectra showed no interaction between drug and polymer. Physicochemical characteristics of all the samples were found to be satisfactory. Swelling of the films increased with increasing content of HPMC or HPC and PVP. Bioadhesive force, tensile strength, percentage elongation and mucoadhesion time increased with higher proportions of HPMC, HPC and PVA. In vitro drug release studies demonstrated slower release of both drugs in formulations with higher amount of HPMC, HPC and PVA. The in vitro drug release data of most formulations best fitted first order model, except for the formulations FA3 and FC. Ex vivo drug permeation studies of formulations through porcine buccal mucosa showed similar results as in vitro. Conclusion: Buccal delivery of this combination can resolve the drawbacks like incomplete absorption in the gut thereby possible improvement in bioavailability, apart from controlled release of the drugs.

Effect of the preparation method of supported Au nanoparticles in the liquid phase oxidation of glycerol

Catalytically-active gold nanoparticles that are stable in aqueous solution have been prepared by sodium borohydride reduction of the respective metal salts in the presence of the stabilising polymer PVA (polyvinylalcohol). By controlling the ratio of the polymer to the metal, nanoparticles with different particle size and size distribution were synthesised. By varying the concentration of the gold and PVA/Au wt/wt ratio, well-defined nanoparticles with mean diameters from 3 to 5nm could be fabricated. In general increasing the concentration of Au precursor, bigger particles size were obtained. Furthermore decreasing the amount of PVA, bigger particles were obtained, with the exception of the catalysts synthesized in presence of a large amount of PVA (PVA/Au=2) wt/wt. Probably, in presence of an excess of protective agent, the immobilization of the Au nanoparticles onto the support is more difficult, leading to partial aggregation and coalescence of Au. In addition, the studies on the effect of heat pre-treatment revealed a higher resistance to aggregation of Au nanoparticles supported on titania than on activated carbon. A selected series of the synthesised supported materials were studied in the liquid phase oxidation of glycerol with the purpose of correlating catalytic activity and selectivity with particle size and metal choice. We demonstrated that by both particles size and amount of protective agent strongly influence the activity and selectivity.

Novel neomycin sulfate-loaded hydrogel dressing with enhanced physical dressing properties and wound-curing effect

To develop a novel neomycin sulfate-loaded hydrogel dressing (HD), numerous neomycin sulfate-loaded HDs were prepared with various amounts of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) and sodium alginate (SA) using freeze-thawing technique, and their physical dressing properties, drug release, in vivo wound curing and histopathology in diabetic-induced rats were assessed. SA had a positive effect on a swelling capacity, but a negative effect on the physical dressing properties and drug release of HD. However, PVP did the opposite. In particular, the neomycin sulfate-loaded HD composed of drug, PVA, PVP and SA at the weight ratio of 1/10/0.8/0.8 had excellent swelling and bioadhesive capacity, good elasticity and fast drug release. Moreover, this HD gave more improved wound curing effect compared to the commercial product, ensured the disappearance of granulation tissue and recovered the wound tissue to normal. Therefore, this novel neomycin sulfate-loaded HD could be an effective pharmaceutical product for the treatment of wounds.

Florescent silica PVA hybrids via sol–gel processing

A cost-effective, one-pot synthesis approach is reported to fabricate Rhodamine 6G (R6G) silica hybrid xerogels. Polyvinyl alcohol (PVA) is used as a non-ionic surfactant to homogeneously trap the dye in silica matrix. Presence of R6G in silica matrix is confirmed through Fourier Transform Infrared (FTIR) spectroscopy and Thermo Gravimetric Analysis (TGA) studies. Hybrids containing larger amount of PVA are found to exhibit better thermal stability than the hybrids with lesser PVA content. Optical properties of the hybrids are analyzed via UV–visible spectroscopy, and it is discovered that hybrids containing larger amounts of PVA do not form aggregates. Uniform distribution of fluorophores in silica matrix helps to minimize formation of J-aggregates in the hybrids, therefore making them ideal candidates for use in dye lasers. The resultant hybrids can be ascribed as stable multicomponent systems that exhibit excellent monodispersity and brightness.

경량 기포콘크리트의 성능향상에 대한 섬유혼입의 영향

The objective of this study is to develop mixture proportioning approach of crack controlled lightweight foamed concrete without using high-pressure steam curing processes, as an alternative to autoclaved lightweight concrete blocks (class 0.6 specified in KS). To control thermal cracks owing to hydration heat of cementitious materials, 30% ground granulated blast-furnace slag (GGBS) was used as a partial replacement of ordinary portland cement (OPC). Furthermore, polyvinyl alcohol (PVA) and polyamid (PA) fibers were added to improve the crack resistance of foamed concrete. The use of 30% GGBS reduced the peak value of hydration production rate measured from isothermal tests by 28% and the peak temperature of foamed concrete measured from semi-adiabatic hydration tests by 9%. Considering the compressive strength development, internal void structure, and flexural strength of the lightweight foamed concrete, the optimum addition amount of PVA or PA fibers could be recommended to be , although PA fiber slightly preferred to PVA fiber in enhancing the flexural strength of foamed concrete.

Synthesis of Ultra-High Molecular Weight Polyacrylonitrile (UHMWPAN) by Aqueous Suspension Polymerization

Acrylonitrile (AN) and itaconic acid (IA) were used to synthesize UHMWPAN by aqueous suspension method with 2,2’-azobisisobutyronitrile (AIBN) as the initiator and polyvinylalcohol (PVA) as the disperser at different temperatures (55°C~75°C) for different timings (1.0h~3.0h). The usage amounts of AN, IA, AIBN and PVA were also technical polymerization parameters used to obtain the optimal polymerization process. We found that the conversion and the viscosity average molecular weight both achieved the optimum levels when the conditions were as follows: the total monomer concentration (21wt%), the monomer ratio (AN: IA=98:2), the usage amount of the initiator (AIBN, 0.01wt%), the usage amount of the disperser (PVA, 0.1wt%), the polymerization temperature (70°C) and the polymerization time (2h).

Preparation and Properties of Slag Wool Board using Modified Polyvinyl Alcohol as Binder

Slag wool boards were produced by using slag wool as the main raw material and adding modified polyvinyl alcohol (PVA) as the binder. The microstructure, thermal conductivity, compression strength, hydrophobicity, and other properties of the slag wool board were analyzed by using scanning electron microscopy, thermal conductivity tester, electronic universal testing machine, and other equipments. Also, the influence of different types and amount of binder on the properties of the slag wool board was studied. The results show that the addition of silica sol can improve the high temperature resistance of the slag wool board, and the addition of borax can improve the hydrophobic rate and compression strength of the slag wool board. Also, the concentration of PVA has obvious influence on the usage of silica sol and borax. In this study, we found that the optimal ratio of the binder should be 3 wt% addition of PVA, 20 wt% addition of silica sol, and 0.2 wt% of borax (relative to the amount of PVA), under the condition of satisfying the performance index of slag wool board and the convenience to spray the adhesive.