Effect Of Polyvinylpyrrolidone Research Articles

Effect of PVP K30 and/or l-Arginine on Stability Constant of Etoricoxib–HPβCD Inclusion Complex: Preparation and Characterization of Etoricoxib–HPβCD Binary System

The effect of polyvinyl pyrrolidone (PVP) K30 and/or l-arginine on etoricoxib–HPβCD complex was investigated. The phase solubility profiles were classified as AL-type, both in absence or presence of auxiliary substances used. The apparent stability constant (Kc) of binary complex obtained at room temperature, 371.80 ± 2.61 M−1, was decreased with the addition of PVP and arginine indicating no benefit of addition of auxiliary substances to promote higher complexation efficiency. Therefore, solid etoricoxib–HPβCD binary systems were prepared and characterized by proton nuclear magnetic resonance spectroscopy (1HNMR), X-ray powder diffractometry, Fourier transformation-infrared spectroscopy, and dissolution studies. Among all binary systems, a lyophilized product showed superior performance in enhancing dissolution of etoricoxib.

Effect of PolyVinyl Pyrrolidone on Sperm Membrane Integrity and Chromatin Status

Effect of PolyVinyl Pyrrolidone on Sperm Membrane Integrity and Chromatin Status

Effect of polyvinylpyrrolidone on the formation of perovskite phase and rosette-like structure in sol-gel–derived PLZT films

Poly-vinylpyrrolidones (PVP) with different molecular weights were used to modify the sol-gel solutions for preparing Pb0.91La0.09(Zr0.65,Ti0.35)0.9775O3 (PLZT, 9/65/35) thin films. The crystallization behavior and microstructural development of the PLZT films with and without PVP addition were investigated. It was found that the addition of PVP significantly improved perovskite phase formation of the PLZT films, but the films exhibited rosette-like morphology. Further study on the PLZT films and the gel particles showed that a premature nucleation of PbO grains in the PVP modified sol-gel solution induced the Pb-rich domains in the films, which accelerated the growth of the grains and thus led to the rosette-like structure. In addition, the electrical and optical properties of the PLZT films with rosette-like structure were also studied and discussed.

Effect of polyvinylpyrrolidone on the structure and laser damage resistance of sol–gel silica anti-reflective films

The effect of polyvinylpyrrolidone (PVP) on the structure and laser-induced damage threshold (LIDT) of sol–gel silica anti-reflective films is investigated. The results of dynamic light scattering, transmission electron microscopy, and small angle X-ray scattering, show that the PVP molecules surrounded the silica sol particles through the strong hydrogen bonds between Si-OH groups and the PVP. As a result, the growth of silica particles was restricted and thus the interface layer between the silica particles and the solvent become thickened with PVP content. Furthermore, the PVP reduced the porosity of the film, so the anti-reflection properties of the film were weakened. A multi-fractal analysis showed that the appropriate addition of PVP, 1 weight percent (wt%), could improve the surface fractal structure of the film, but that higher PVP content resulted in reduced surface uniformity. The addition of PVP lead to improved LIDT.

Effect of polyvinylpyrrolidone on the ammonia-catalyzed sol–gel process of TEOS: Study by in situ 29Si NMR, scattering, and rheology

Ammonia-catalyzed sol–gel process of polyvinylpyrrolidone/tetraethoxysilane (PVP/TEOS) system in methanol was studied by in situ liquid 29Si nuclear magnetic resonance (NMR), dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and rheology. A scientific connection was established between the reaction composition and the microstructures of sol particles. It was found that the concentration of PVP played an important role in the hydrolysis kinetics of TEOS and the SiO 2 sol–gel process. The results of in situ 29Si NMR showed that PVP addition reduced both hydrolysis rate and condensation rate of TEOS, and the condensation rate decreased more seriously than the hydrolysis rate. The particle size distributions obtained from DLS and SAXS indicated that PVP held back the growth of SiO 2 clusters by hydrogen-bonding the silanol groups on particle surface with the electronegative inner amide of PVP side chain. Thus, gelation was retarded and the rheology of sol was largely modified by PVP. Rheology study showed typical Newtonian fluid behavior before gelation and shear thinning fluid behavior after gelation point, respectively. The changes in fractal dimensions of PVP/SiO 2 sols, obtained by SAXS, explained the different microstructures of SiO 2 sol particles in the presence of PVP. The changes of microstructure and macroscopic properties should be pre-determined by the very early stages of sol–gel process.

Epinephrine potentiates the analgesic and antidepressant effects of polyvinylpyrrolidone and cholecystokinin due to stimulation of afferents in the gastric mucosa

Treatment with epinephrine, polyvinylpyrrolidone, and cholecystokinin in the minimum effective doses produced maximum analgesic and antidepressant effects and caused bradycardia in rats. Administration of epinephrine in combination with polyvinylpyrrolidone or cholecystokinin in threshold doses (1/10-1/25 of the minimum effective dose) produced maximum analgesic and antidepressant effects, but did not cause bradycardia. The potentiating effect of epinephrine is related to stimulation of afferents in the gastric mucosa.

Effect of polyvinylpyrrolidone on bovine oocyte maturation in vitro and subsequent fertilization and embryonic development

The exact role of polyvinylpyrrolidone (PVP) in culture medium for oocyte maturation is still largely unknown. Bovine cumulus–oocyte complexes (COC) were cultured in in-vitro maturation (IVM) medium supplemented with 10% fetal bovine serum (FBS), 0.3% PVP (K-90) or 10% serum substitute supplement (SSS) respectively. The rates of oocyte maturation, fertilization and early embryonic development were evaluated. In addition, the status of DNA fragmentation in the oocytes was determined by comet assay, and the ratio of trophectoderm (TE) cells and inner cell mass (ICM) in blastocysts was determined by differential staining. Furthermore, the percentage of apoptotic cells in the blastocysts was examined by TUNEL assay. The results indicated that the effect of PVP in IVM medium was similar to FBS in terms of oocyte maturation and subsequent embryonic development. However, the addition of SSS in IVM medium retarded further embryonic development and resulted in more oocyte DNA fragmentation and a higher ratio of TE cells and ICM in the blastocysts. However, the number of apoptotic cells in blastocysts was similar among the three groups. These results suggest for the first time that the addition of PVP in oocyte maturation medium is not only a suitable substitute for serum but is also beneficial to in-vitro oocyte maturation.

Molecular Interaction among Probucol/PVP/SDS Multicomponent System Investigated by Solid-State NMR

Effects of polyvinylpyrrolidone (PVP) molecular weight on the solid-state intermolecular interactions among probucol/PVP/sodium dodecyl sulfate (SDS) ternary ground mixtures (GM) and the formation of nanoparticles were investigated by solid-state NMR spectroscopy. Ternary GMs of probucol were prepared with PVP (K12, K17, K30 or K90) and SDS at a weight ratio of 1:3:1 and were ground for 15, 30 and 60 min. Solid-state interactions were evaluated using powder X-ray diffraction (PXRD) and solid-state cross polarization/magic angle spinning (CP/MAS) (13)C NMR spectroscopy. A high resolution scanning electron microscopy (SEM) was employed to observe nanoparticles of probucol in the GM. The solid-state (13)C CP/MAS NMR results indicate that the low molecular weight PVP interacts with probucol and SDS more strongly than the high molecular weight PVP in the ternary GM. This finding was consistent with the result that smaller drug nanoparticles were obtained using low molecular weight of PVP. SEM images of probucol/PVP K12/SDS confirmed the presence of nanoparticles (15-25 nm) in the GM. Grinding-induced solid-state interactions among drug, PVP and SDS could be detected using solid state (13)C NMR. The interactions in both probucol-PVP and PVP-SDS should occur simultaneously to generate nanometer-sized particles of probucol.

Effects of polyvinylpyrrolidone and carbon nanotubes on magnetorheological properties of iron‐based magnetorheological fluids

AbstractMagnetorheological (MR) fluids based on glycol, iron powder, polyvinylpyrrolidone (PVP), and carbon nanotubes (CNTs) were prepared. Effects of polyvinylpyrrolidone and carbon nanotubes on sedimentation stability and magnetorheological properties were studied. It is found that the synergetic effects of PVP and CNTs improve the sedimentation stability significantly, and the addition of CNTs reduces the sedimentation velocity and increases the equilibrium sedimentation ratio of the magnetizable particles in MR fluids remarkably. The addition of PVP can reduce the sedimentation velocity of the magnetizable particles, but cannot increase the equilibrium sedimentation ratio and will not change the up trend of apparent viscosity with the increasing intensity of the external magnetic field. When the PVP content is lower, the increment of original apparent viscosity of the MR fluids at zero‐intensity of magnetic field is inconspicuous, and their values of apparent viscosity under magnetic field are similar. However, the apparent viscosity of the MR fluids increases tremendously when the contents of PVP increase to certain degree. The results show that the synergetic effects of PVP and CNTs not only improve the sedimentation stability of the MR fluid but also promote its magnetorheological effect. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1653–1657, 2006

Effect of Polyvinyl Pyrrolidone on Strength and Some Other Properties of Cement

The effect of polyvinyl pyrrolidone (PVP) addition in the ordinary cement and mortar mixes on the properties such as setting time, heat of hydration, compressive and tensile strength has been studied by adding 0.5 to 5.0% additive by weight of cement. Hardness has been determined using the Vickers indentation method and the fracture toughness of cementitious bond and flexural strengths have been determined using three point bending system. Corrosion resistance of resulting products has been tested against each of 0.1 N and 1.0 N of HCl and H2SO4 and seawater. FTIR and X-ray diffraction techniques have been employed to determine the phase compositions of the material. The polymeric phase is interspersed in cement and causes decrease in water absorption; also its interaction with hydrating cement phases results in the additional bond formation, leading to the increase in strength.

Effect of polyvinylpyrrolidone on complexation and dissolution rate of β- and hydroxypropyl-β-cyclodextrin complexes of celecoxib

Complexation of celecoxib with β-cyclodextrin and hydroxypropyl-β-cyclodextrin in the presence and absence of polyvinylpyrrolidone and the effect of polyvinylpyrrolidone on the solubilizing efficiency of cyclodextrins and on the dissolution rate of celecoxib from the cyclodextrin complexes were investigated. The phase solubility studies indicated the formation of celecoxib-β-cyclodextrin and celecoxib-hydroxypropyl-β-cyclodextrin inclusion complexes at a 1:1 M ratio in solution, both in the presence and absence of polyvinylpyrrolidone. The complexes formed were quite stable. The solubility and dissolution rate of celecoxib were markedly enhanced by complexation with β-cyclodextrin and hydroxypropyl-β-cyclodextrin. Celecoxib-hydroxypropyl-β-cyclodextrin (1:2) inclusion complex gave a 36.57-fold increase in the dissolution rate of celecoxib. Addition of polyvinylpyrrolidone resulted in higher complexation efficiency and markedly enhanced solubilizing efficiency of β-cyclodextrin and hydroxypropyl-β-cyclodextrin. Solid inclusion complexes of cyclodextrins with polyvinylpyrrolidone gave several times higher rates of dissolution than those of celecoxib and its complexes with cyclodextrins alone.

Effect of Polyvinylpyrrolidone and Sodium Lauroyl Isethionate on Kaolinite Suspension in an Aqueous Phase

Suspension of concentrated kaolinite (20 g/30 ml-medium) in the presence of polyvinylpyrrolidone (PVP) and sodium lauroyl isethionate (SLI) was allowed to evaluate its degree of dispersion based on their rheological studies. Flow curves at low shear rate, measured by means of cone-plate method, showed a non-Newtonian flow. Plastic viscosity and Bingham yield value were derived from the flow curves. Relative viscosity, effective volume fraction and void fraction of secondary particle were also obtained. Results of dispersity and fluidity of the suspension were explained. PVP acted as a flocculant at a concentration lower than 0.1% but as a dispersant at a higher concentration. The presence of SLI could decrease both the Bingham yield value and suspension viscosity. Cooperative and competitive effects of PVP and SLI were found. Results indicated that SLI enhanced the degree of dispersion of kaolinite when PVP was less than 0.1%. The suspension, however, showed a maximum flocculation (i.e., aggregation) at 4 mM SLI when the concentration of PVP was higher than 0.1%.

Effect of polyvinylpyrrolidone on the corrosion resistance of steel

The effect of polyvinylpyrrolidone (PVP) on the corrosion resistance of steel reinforced concrete was assessed by measuring the corrosion potential, linear polarization resistance and AC impedance during 60 days immersion in NaCl and NaCl + PVP solutions. Polarization resistance (R(sub p)) values of PVP added reinforced concrete were much higher than those without PVP. The relationship between corrosion potential and linear polarization resistance was analysed. Results from corrosion potential measurements were well comparable with the linear polarization resistance data. AC impedance spectra revealed that the resistance of PVP mixed electrodes was also quite higher than the other electrodes. The mechanical properties of concrete were measured. It was observed that the compressive strength of concrete had increased approximately 44% in the specimens containing PVP. (A) Reprinted with permission from Elsevier.

Photoanodic properties of sol–gel-derived iron oxide thin films with embedded gold nanoparticles: effects of polyvinylpyrrolidone in coating solutions

Fe 2O 3 thin films containing dispersed Au nanoparticles were prepared on nesa silica glass substrates, using Fe(NO) 3·9H 2O–HAuCl 4·4H 2O–CH 3COCH 2COCH 3–CH 3OC 2H 4OH solutions containing polyvinylpyrrolidone (PVP). The photoanodic properties were studied in a three-electrode cell with the film sample as the working electrode and an aqueous buffer solution of pH=7 as the supporting electrolyte. The Au particles increased photoanodic quantum efficiency at wavelengths <500–600 nm. Quantum efficiency was further increased by modifying the microstructure of the film electrodes through the addition of PVP. The maximum incident photon to current efficiency (IPCE) of about 20% was achieved in an Au-dispersed film prepared from a solution containing PVP. PVP in coating solutions provided the fired films with an increase in size of the grains and voids between them and in donor density, either of which could contribute to the increased IPCE.

Effect of binary and ternary polyvinylpyrrolidone and/or hydroxypropyl-β-cyclodextrin complexes on the photochemical and photosensitizing properties of Naproxen

The effect of the polyvinylpyrrolidone and/or hydroxypropyl-β-cyclodextrin on the photolability of aqueous solutions of the anti-inflammatory drug Naproxen was studied. Kinetic studies revealed that the presence of all of these additives reduced drug photodegradation. In all cases, the presence of the different additives elicited a change in the photomixture composition, being the alcoholic derivative the major photoproduct formed. Nevertheless, the change in the efficiency of the process and the amount of the photoproducts formed in the different systems were not related with the biodamage produced by the drug. In this sense, the presence of free Naproxen clearly sensitized the photoperoxidation of linoleic acid. The photosensitizing effect decreased as the PVP concentration increased. Different protection provides the binary (Naproxen:HP-β-CD) and ternary (Naproxen:HP-β-CD:PVP) complexes. The binary complex formation had not effect on the prevention of photooxidation of linoleic acid sensitized by the drug, whereas the ternary complex formation supresses the drug effect. The different behaviour observed with β-CD and HP-β-CD and the structural differences of both cyclodextrins seem to indicate that in the case of the HP-β-CD the linoleic binds with the CD and takes contact with the drug. These results confirm that in these systems the prevention of biodamage would be due to a decrease in the contact between the short-lived species generated during Naproxen photodegradation and biological structures, rather than due to the nature or amount of the photoproducts. In addition, the ability of the complex to interact with the biological structure depends on the structure of both interacting species.

Effect of polyvinylpyrrolidone on morphology and performance of hemodialysis membranes prepared from polyether sulfone

AbstractFlat‐sheet hemodialysis membranes were prepared by phase inversion technique using polyether sulfone (PES) dissolved in dimethylacetamide (DMAc) with and without the addition of polyvinylpyrrolidone (PVP). The effect of the composition of the casting solution on membrane morphology and performance were investigated. The performances of membranes were elucidated on the basis of removal of uremic toxins (urea, uric acid, and creatinine) from human blood serum. The membrane prepared from 12 wt % PES with 2.8 wt % PVP demonstrated better performance compared to the other compositions. The membrane performance is a consequence of membrane morphology. Membranes with channel‐like or long finger‐like structures provide superior removal efficiencies. If the morphology turns to a sponge structure, the effectiveness is diminished. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3804–3813, 2004

Evolution of Stress in Alkoxide-Derived Titania Gel Films under Heat-Treatment: Effects of Polyvinylpyrrolidone and Acetic Acid in Coating Solutions

Evolution of Stress in Alkoxide-Derived Titania Gel Films under Heat-Treatment: Effects of Polyvinylpyrrolidone and Acetic Acid in Coating Solutions

Investigation of endotoxin adsorption with polyether polymer alloy dialysis membranes

Endotoxin (ET) in the dialysate is known to be adsorbed by dialysis membranes made of polyether polymer alloy (PEPA) and polymethylmethacrylate (PMMA). In the present study, the effect of polyvinylpyrrolidone (PVP) localization of the PEPA dialysis membrane on the adsorption of ET was investigated. The compounding of PVP in the PEPA membrane was changed, and hydrophobic membrane in both blood side and dialysate side, and hydrophilic membrane in only the blood side were used. Adsorption was evaluated by filling the contaminated dialysate inside and outside the membrane after priming with physiological saline, and determining the ET concentration in the blood side and dialysate side of dialysis membrane during the 240 min period from the start of filling the contaminated dialysate. With the PEPA membranes investigated, ET was significantly adsorbed to the hydrophobic side and was not adsorbed to the blood side of hydrophilic type membrane. These results suggest that in addition to electrostatic action attributable to the compounding of hydrophilic agent PVP to the dialysis membrane, the distribution of PVP that was compounded and the potential of the membrane itself may cause differences in adsorption of ET.

Evolution of Stress in Alkoxide-Derived Titania Gel Films Under Heat-Treatment: Effects of Polyvinylpyrrolidone and Acetic Acid in Coating Solutions

Evolution of Stress in Alkoxide-Derived Titania Gel Films Under Heat-Treatment: Effects of Polyvinylpyrrolidone and Acetic Acid in Coating Solutions

Mechanistic studies of the effect of hydroxypropyl-β-cyclodextrin on in vitro transdermal permeation of corticosterone through hairless mouse skin

Literature reports reveal that the issue of whether cyclodextrins may act as skin permeation enhancers has not been resolved. Accordingly, in vitro skin transport studies were conducted to address this question. Corticosterone ( 3 H -CS and/or non-radiolabeled CS) was chosen as the model permeant for transport experiments with hairless mouse skin (HMS) and with a synthetic cellulose membrane of 500 molecular weight cut off (MWCO), the latter to help establish baseline behavior. Hydroxypropyl-β-cyclodextrin (HPβCD) was selected as the representative cyclodextrin. The CS/HPβCD complexation constant was determined both from solubility data (saturation conditions) in phosphate buffered saline (PBS), pH 7.4 and with data obtained from PBS/silicone polymer partitioning experiments, the latter experiments permitting the determination of the complexation constant at low CS concentrations. These results were used in the calculations of the free CS concentrations in the donor chamber of the transport experiments. The CS transport experiments were conducted at CS solubility saturation and under supersaturation (resulting from autoclaving at 121 °C) conditions as well at very low (tracer level) concentrations. The effect of polyvinylpyrrolidone as a solution additive was also evaluated. The following were the key outcomes of this study. Contrary to literature reports, there was no evidence that HPβCD is an enhancer for CS transport through HMS. The CS permeability coefficient values obtained with HMS in all of the experiments were found to be the same within experimental error when calculated on the basis of the free CS concentration as the driving force for permeation. The constancy of the permeability coefficient in the presence and absence of HPβCD is interpreted to mean that, in these experiments, HPβCD did not alter the barrier properties of HMS stratum corneum to any significant extent nor did it enhance CS transport in any other manner such as by a carrier mechanism involving the aqueous boundary layer or by a carrier mechanism within the stratum corneum.