PVP Matrix Research Articles

Development and Evaluation of Polymer-bound Glibenclamide Oral Thin Film

Glibenclamide (GLB) is a second-generation sulfonylurea oral hypoglycemic agent used in the treatment of non-insulin dependent diabetes mellitus. The use of this drug is limited due to its poor dissolution and pharmacokinetic profile. In order to nullify these drawbacks, GLB oral thin films were prepared and evaluated to study the influence of preparatory conditions on the physicochemical properties by using Scanning Electron Microscopy (SEM), Fourier Transform Infra-red Spectroscopy (FTIR) and Differential Scanning Calorimetric (DSC). The surface pH of the GLB thin film was found to be in the range of 6.50 ± 0.10 and it is non-irritant to mucosal lining of the oral cavity. The results of the SEM analysis showed uniform surface morphology with homogenous distribution of GLB pure drug in PVP matrix. The in vitro drug release profile at pH 5.0 and 7.5 revealed sustained release patterns for a period of 8 h. The GLB oral thin film showed an enhanced in vivo insulin release profiles as compared to pure GLB drug. Thus, the results of the present study revealed that, the prepared GLB oral thin film can be used as alternative strategy to deliver glibenclamide for diabetes mellitus as it showed a significant role in increasing in vitro dissolution and in vivo insulin release profiles.

Synergetic catalytic effect of Cu2-xSe nanoparticles and reduced graphene oxide coembedded in electrospun nanofibers for the reduction of a typical refractory organic compound.

A new heterogeneous catalytic composite composed of nonstoichiometric Cu2-xSe nanoparticles (NPs) with high copper deficiency and graphene oxide (GO) is prepared by coembedding in electrospun nanofibers of a poly(vinylpyrrolidone) (PVP) support, wherein GO in the nanofibers is converted into reduced GO (rGO) via heat treatment. The as-prepared composite Cu2-xSe/rGO/PVP nanofibers have demonstrated superior catalytic activity toward the reduction of a refractory organic compound by taking 4-nitrophenol (4-NP) as an example. In the presence of NaBH4, the Cu2-xSe/rGO/PVP nanofibers display a synergetic effect between Cu2-xSe and rGO in PVP nanofibers compared to their independent components or corresponding nanofibers. Furthermore, the Cu2-xSe/rGO/PVP nanofibers exhibit a favorable water-stable property via heat treatment to solidify the hydrophilic PVP matrix, which makes the composite display good reusability, stability in aqueous solution, and separability from a water medium. This work not only presents a direct, convenient, and effective approach to doping semiconductor nanomaterials into polymer nanofibers but also provides fundamental routes for further investigations about the synergetic effect between different materials based on the platform of electrospun nanofibers.

Synthesis, characterization and Monte Carlo simulation of CoFe2O4/Polyvinylpyrrolidone nanocomposites: The coercivity investigation

To study the influence of polymer matrix on the effective magnetic anisotropy constant and coercivity of magnetic nanoparticles, we have synthesized the Cobalt ferrite/Polyvinylpyrrolidone (PVP) nanocomposites by co-precipitation method in four different processes. In addition the Monte Carlo simulation and law of approach to the saturation magnetization have been applied to achieve the anisotropy constants. The obtained experimental and theoretical results showed a decrease in anisotropy constant relative to the bulk cobalt ferrite. We have showed that the PVP matrix can interact with metal cations and made them approximately immobilized to participate in spinel structure. Hence different anisotropy constants or coercivity were obtained for synthesized nanocomposites. In addition, PVP matrix can attach to the surface of magnetic particles and make them approximately non-interacting. The synthesized samples have been characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Magnetic measurements were made at room temperature using a vibrating sample magnetometer (VSM).

Novel ternary poly(vinyl pyrrolidone)/poly(amide-imide)/ZnO nanocomposite: Synthesis, characterization, thermal and optical performance

Abstract The present work describes the synthesis and properties of polymer composites based on poly(vinyl pyrrolidone) (PVP) as polymer shell and poly(amide-imide)(PAI)/ZnO nanocomposite (ZNC) as efficient filler. At first, the alanine amino acid containing dicarboxylic acid was grafted on the surface of ZnO NPs. Then, modified ZnO (12 wt%) was incorporated into the PAI matrix under ultrasonic irradiations. The obtained hybrid ZNC showed high thermal stability and the size of the NPs in the TEM image of ZNC was about 31 nm. Secondly, PVP NCs with different ZNC loadings such as 2, 4 and 6 wt% were prepared via ultrasonication. Transmission electron microscopy (TEM) observations showed that the ZnO NPs were uniformly and highly dispersed in the PVP matrix. The UV–vis results exposed that the high UV-shielding efficiency of the obtained composites. Thermal analysis represented that the onset decomposition temperatures of the obtained PVPNCs had remarkable increasing in compared to the neat PVP due to the presence of both ZnO NPs and PAI.

Novel poly(N-vinyl-2-pyrrolidone) nanocomposites containing poly(amide–imide)/aluminum oxide nanostructure hybrid as a filler

In this work, the physicochemical properties of poly( N-vinyl-2-pyrrolidone) (PVP) reinforced with the poly(amide–imide)/alumina nanocomposite (PAN) under sonochemical treatment were studied. In the process of manufacturing PAN, the surface of alumina nanoparticles was grafted with 15 wt% of the bioactive dicarboxylic acid based on amino acid, and an amount of 10 wt% of this modified nanoparticle was loaded into the poly(amide–imide) using some powerful ultrasound irradiation. Subsequently, in order to prepare the PVP-PAN, various contents (2, 4, and 6 wt%) of the PANs were incorporated into the PVP matrix. The structure morphology and the physical properties of the obtained PVP/PANs were analyzed by Fourier transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, field-emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The data obtained from the thermal analysis of PVP/PANs indicated their noteworthy thermal stability, thereby implying the complete miscibility between PVP and the PAN hybrid.

Synthesis and Characterization of Poly(vinyl pyrrolidone)/Reduced Graphene Oxide Nanocomposite

Poly(vinyl pyrrolidone) (PVP)/reduced graphene oxide (RGO) nanocomposites were synthesized by reducing graphene oxide in the polymer matrix at different temperatures. The effects of the GO content on the properties of the nanocomposites were investigated by Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The degree of dispersion of GO in the PVP matrix was examined by field-emission scanning electron microscopy. The results showed that both GO and RGO were well dispersed in the PVP matrix. Under low filler content, the improvement of onset decomposition temperatures of PVP nanocomposites was not obviously observed, but the amounts of residual char of the PVP nanocomposites were clearly increased. In addition, the decomposition temperature peak values of the PVP nanocomposites were increased, while the peak was broadened.

Synthesis of Highly Mono-dispersed AgNPs within PVP Matrix via Gamma Irradiation

GAMMA-RADIATION synthesized silver/poly(vinyl pyrro-lidone) (Ag/PVP) nanocomposite films were prepared using PVP as a stabilizer. The prepared films were characterized by Ultra Violet/ Visible (UV/vis) spectroscopy, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) and Fourier Transform Infera Red (FTIR). The UV/vis analysis showed the appearance of surface plasmon resonance peaks at 403-406 nm confirming the formation of silver nanoparticles (AgNPs). The TEM images confirmed the formation of a highly mono-disperse and narrow size distributed AgNPs and the particle size was increased by increasing Ag

Effect of chemically modified date palm leaf fiber on mechanical, thermal and rheological properties of polyvinylpyrrolidone

Polyvinylpyrrolidone/date palm leaf fiber (PVP/DPL) biocomposites were prepared by melt mixing fabrication technique with different weight percentage of fibers. DPL fibers were chemically modified by acrylic acid in order to have better dispersion and compatibility with PVP matrix. The interaction of DPL fibers with PVP matrix was studied by Fourier transforms infrared spectroscopy (FTIR). Field emission scanning electron microscope (FESEM) was used for the study the morphology of chemically modified DPL fibers and PVP/DPL biocomposites. Mechanical properties were improved with fiber loading due to strong interfacial adhesion between PVP and DPL fibers. The storage modulus, loss modulus and tan delta values of PVA/DPL biocomposites were measured by DMTA. The rheological properties were investigated to study the shearing storage and loss modulii along with complex viscosity of biocomposites. The thermal and conducting properties of biocomposites were measured and compared with that of virgin PVP.

Preparation of poly(N-vinylpyrrolidone)-stabilized ZnO colloid nanoparticles.

We propose a method for the synthesis of a colloidal ZnO solution with poly(N-vinylpyrrolidone) (PVP) as stabilizer. Stable colloidal solutions with good luminescence properties are obtained by using PVP as stabilizer in the synthesis of ZnO nanoparticles by a sol–gel method assisted by ultrasound. Nanoparticles with sizes of 30–40 nm in a PVP matrix are produced as a solid product. The colloidal ZnO/PVP/methanol solution, apart from the most intense PL band at 356 nm coming from the PVP, exhibits a strong PL band at 376 nm (3.30 eV) which corresponds to the emission of the free exciton recombination in ZnO nanoparticles.

Electrical switching and conduction mechanisms of nonvolatile write-once-read-many-times memory devices with ZnO nanoparticles embedded in polyvinylpyrrolidone

We reported on the influence of zinc oxide nanoparticles (ZnO NPs) on the electrical bistable behavior of nonvolatile write-once-read-many-times (WORM) memory devices based on an indium-tin oxide/polyvinylpyrrolidone (PVP):ZnO NPs/aluminum (ITO/PVP:ZnO/Al) structure. The maximum ON/OFF current ratio of the nonvolatile WORM memory devices was approximately 3×103 and the devices remained in the ON state even after the applied voltage was turned off. In addition, reliability studies for response time and once write/continuous read operations of the optimal ZnO NPs concentration are presented. The response times of both rise-time and fall-time were about 3 and 6μs respectively. The conduction mechanisms of all voltage regions of the device were analyzed by theoretical models and electron trapping in the ZnO NPs of the electron tunneling among a PVP matrix was discussed.

Electrospinning composite fibers doped with rhenium complex: Preparation, characterization and photophysical feature comparison

In the present paper, a diamine ligand possessing an electron-pulling group 2-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole (denoted as PPYO) and its corresponding Re(I) complex Re(CO)3(PPYO)Br were synthesized and carefully characterized. The geometric structure of Re(CO)3(PPYO)Br was analyzed by its single crystal XRD. Theoretical calculation on the crystal suggested that the first few electronic excitations owned a mixed character of metal-to-ligand-charge-transfer (MLCT) and ligand-to-ligand-charge-transfer (LLCT). By doping Re(CO)3(PPYO)Br into a polymer host of poly(vinylpyrrolidone) with electrospinning technique, composite fibers were yielded. The photophysical feature comparison between bulk samples and composite fibers was performed, which suggested that both face-to-face π–π attraction in crystal and the immobilization in PVP matrix could repress the MLCT excited state geometric relaxation, leading to improved emissive parameters including emission blue shift, longer excited state lifetime and better photostability.

Colour-tuneable double-layer polymeric films doped with lanthanide β-diketonate complexes.

Double-layer polymeric films doped with lanthanide β-diketonate complexes were obtained. To eliminate the ligand exchange during the film processing the layers are composed of poly(methyl-methacrylate) (PMMA) and poly(N-vinylpyrrolidone) (PVP) polymers, which have different solubilities in organic solvents. Under selective excitation the pure green emission of Tb3+ and red emission of Eu3+ is observed with maxima at 543–544 and 612–613nm, respectively. The emission colour tuneability may be achieved not only by tailoring the films composition but also by changing the excitation wavelength. Films can be easily fabricated by sequential casting from solution, using e.g. the doctor blade technique. Moreover, due to the thermal stability of β-diketonate complexes the double-layer films can be also obtained by hot-press moulding of PMMA. The photophysical properties of the obtained films are presented and discussed. The emission intensity of Tb3+ tetrakis-complex with hexafluoroacetylacetonate ligand is significantly enhanced in PVP matrix as compared to that in PMMA.

Synthesis and characterisation of end-functionalised poly(N-vinylpyrrolidone) additives by reversible addition–fragmentation transfer polymerisation

We describe herein the synthesis of a series of multi-end functionalized poly(N-vinyl pyrrolidone) (PVP) additives bearing two or three C8F17 fluoroalkyl (CF) groups, designed as additives to modify surface properties. The PVP additives were prepared by reversible addition–fragmentation transfer (RAFT) polymerization, with end functionality imparted via the use of CF functionalized chain transfer agents (CTAs). The resulting PVP additives, when used in modest quantities dispersed in thin films of an unmodified PVP matrix significantly reduce the surface energy, rendering their surfaces more hydrophobic and lipophobic. This is achieved by virtue of the low surface energy of the pendant C8F17 end groups which cause the additive to spontaneously surface segregate during the spin coating process. The resulting thin films have been characterized by static contact angle measurements using dodecane as the contact fluid, and the impact of additive molecular weight, matrix molecular weight, the number of CF groups and additive concentration upon surface properties is reported herein. Significant increases in contact angle were observed with increasing additive concentration, up to a critical aggregation concentration (CAC). Increasing the number of CF groups (from 2 to 3); reducing additive molecular weight or increasing the matrix molecular weight, resulted in increased contact angles and hence surface lipophobicity. Rutherford backscattering (RBS) analysis was performed on films containing varying concentrations of additive, in order to quantitatively measure the near-surface fluorine concentration of these films. The results of these experiments were in excellent agreement with those obtained by contact angle analysis, confirming the surface activity and low surface energy of the additives.

Formation of the modified ultrafine anatase TiO2 nanoparticles using the nanofiber as a microsized reactor

This paper reports a facile method for preparation of modified ultrafine anatase titanium dioxide (TiO2) nanoparticles using the hybrid nanofiber as a microsized reactor. The hybrid nanofibers comprised of poly(vinyl pyrolidone) (PVP) and amorphous TiO2 nanoparticles were prepared via the electrospinning method. When the hybrid nanofibers were treated with water vapor at a temperature of 80 °C or above, the nanofibers acted as microsized reactors in which the amorphous TiO2 nanoparticles grew and crystallized into ultrafine anatase TiO2 nanoparticles. The PVP matrix in this microsized reactor could be regarded as a substrate for the reaction and protected the over-growth of the TiO2 nanoparticles during the reaction. Morphological and structural characteristics of the hybrid nanofibers and TiO2 nanoparticles were studied with scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) method, Raman spectroscopy, X-ray diffraction (XRD) patterns, Fourier transform infrared (FTIR) spectroscopy and thermal gravimetric (TG) analysis. The anatase TiO2 nanoparticles were modified with PVP molecules during the crystallization process, and are expected to be easily mixed with other polymers to fabricate functional textiles.

Simple hydrothermal route to synthesise a nanocrystalline ZnO/PVP composite film and its optical property

A nanocrystalline ZnO/PVP (polyvinylpyrrolidone) composite film was directly prepared on Zn foil via hydrothermal etching method. The microstructure, morphology, photocatalysis and photoluminescence of the composite film were investigated. X-ray diffraction, scanning electron microscopy and transmission electron microscopy indicated that all the nanocrystalline ZnO nanoparticles were embedded in the PVP matrix randomly with a single crystalline hexagonal wurtzite structure. The photoluminescence spectrum of the ZnO/PVP composite film showed enhanced ultraviolet emission and no green emission, which was due to the improved crystal quality of ZnO nanocrystallines. Moreover, the obtained ZnO/PVP film exhibited good photocatalytic activity for decomposing methyl orange.

Size-Controlled Synthesis of CdS Quantum Dots in PVP Matrix

Size-controlled CdS quantum dots are successfully synthesized in PVP matrix through chemical route. The obtained particles are characterized with XRD, UV/VIS and HRTEM. Nearly spherical and well dispersed particles of size 3-20 nm are obtained. The size of the prepared quantum dots can be readily tuned depending on temperature, stirring rate and concentration in the reaction system. This particle size produces a quantum confinement observed from blue shifted absorption edge at 211nm in UV/VIS absorption spectroscopy. Keywords: Chemical route, concentration, quantum dots, size-controlled, synthesis, temperature, CdS, QDs, PVP Matrix

Electrospun Borneol‐PVP Nanocomposites

The present work investigates the validity of electrospun borneol‐polyvinylpyrrolidone (PVP) nanocomposites in enhancing drug dissolution rates and improving drug physical stability. Based on hydrogen bonding interactions and via an electrospinning process, borneol and PVP can form stable nanofiber‐based composites. FESEM observations demonstrate that composite nanofibers with uniform structure could be generated with a high content of borneol up to 33.3% (w/w). Borneol is well distributed in the PVP matrix molecularly to form the amorphous composites, as verified by DSC and XRD results. The composites can both enhance the dissolution profiles of borneol and increase its physical stability against sublimation for long‐time storage by immobilization of borneol molecules with PVP. The incorporation of borneol in the PVP matrix weakens the tensile properties of nanofibers, and the mechanism is discussed. Electrospun nanocomposites can be alternative candidates for developing novel nano‐drug delivery systems with high performance.

Influence of solvent evaporation rate and formulation factors on solid dispersion physical stability

New chemical entities (NCEs) often show poor water solubility necessitating solid dispersion formulation. The aim of the current study is to employ design of experiments in investigating the influence of one critical process factor (solvent evaporation rate) and two formulation factors (PVP:piroxicam ratio (PVP:PRX) and PVP molecular weight ( P MW)) on the physical stability of PRX solid dispersion prepared by the solvent evaporation method. The results showed the rank order of an increase in factors contributing to a decrease in the extent of PRX nucleation being evaporation rate > PVP:PRX > P MW. The same rank order was found for the decrease in the extent of PRX crystal growth in PVP matrices from day 0 up to day 12. However, after 12 days the rank became PVP:PRX > evaporation rate > P MW. The effects of an increase in evaporation rate and PVP:PRX ratio in stabilizing PRX were of the same order of magnitude, while the effect from P MW was much smaller. The findings were confirmed by XRPD. FT-IR showed that PRX recrystallization in the PVP matrix followed Ostwald’s step rule, and an increase in the three factors all led to increased hydrogen bonding interaction between PRX and PVP. The present study showed the applicability of the Quality by Design approach in solid dispersion research, and highlights the need for multifactorial analysis.

Fluorescence enhancement in Sm3+/TiO2 nanocrystallites doped PVP matrix

The hybrid matrix containing TiO2 nanocrystals and Sm3+ ions prepared by the non hydrolytic sol–gel method, displays the characteristic emission of Sm3+ ions at the excitation energy corresponding to the energy gap of the TiO2 nanocrystals. On the other hand, emission of Sm3+ was too weak to be observed for the sample containing Sm3+ ions alone. The structural and optical analyses of the samples were carried out using X-ray diffraction technique, transmission electron microscopy, Raman spectroscopy and emission spectroscopy. The TEM image of the sample shows that the TiO2 nanocrystals are well dispersed in the PVP matrix and the XRD confirms the anatase phase of the TiO2 nanocrystals. The enhancement of the Sm3+ emission is attributed to the energy transfer from the TiO2 nanocrystals to Sm3+ ions.

Gold nanoparticle/polymer nanofibrous composites by laser ablation and electrospinning

Poly(vinylpyrolidone) (PVP) nanofibers incorporating gold nanoparticles (Au-NPs) were produced in combination with laser ablation and electrospinning techniques. The Au-NPs were directly synthesized in PVP solution by laser ablation and then, the electrospinning of PVP/Au-NPs solution was carried out for obtaining nanofibrous composites. The presence of Au-NPs in the PVP nanofibers was confirmed by SEM, TEM and EDX analyses. The SEM imaging elucidated that the electrospun PVP/Au-NPs nanofibers were bead-free having average fiber diameter of 810 ± 480 nm. The TEM imaging indicated that the Au-NPs were in spherical shape having diameters in the range of 5 to 20 nm and the Au-NPs were more or less dispersed homogeneously in the PVP nanofiber matrix. The FTIR study suggested the presence of molecular interactions between PVP matrix and the Au-NPs in the nanofibrous composites. The UV–Vis measurement confirmed the enhancement of the optical properties of the PVP/Au-NPs nanofibers in the solid state due to the surface plasma resonance effect of Au-NPs.