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PubMed1992

Separation of proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of soluble, aqueous polymers: Ficoll and polyvinylpyrrolidone.

In previous studies we have demonstrated that water soluble polymers of dextran and methylcellulose, when incorporated into sodium dodecyl sulfate (SDS)-polyacrylamide gels, can be used to sharpen the protein bands. We have extended these studies to enhance the separations in the mid-molecular weight range. Enhanced separation of protein molecular weight markers between 30,000-67,000 was best achieved in SDS-gels containing 2.5% polyvinylpyrrolidone (average molecular weight 10,000).

Electrophoresis, Polyacrylamide Gel↗
PubMed1994

Improved separation of diastereomeric derivatives of enantiomers by a physical network of linear polyvinylpyrrolidone applied as pseudophase in capillary zone electrophoresis.

Diastereomeric analytes were separated using capillary zone electrophoresis with polyvinylpyrrolidone as polymeric additive to the buffer solution. As test substances derivatives of D- and L- alpha-amino and alpha-hydroxy acids formed by reaction with (+)-O,O'-diacetyl- and (+)-O,O'-dibenzoyl-L-tartaric anhydride, respectively, were used. The physical network formed by the linear polymer is supposed to act as a kind of pseudophase. It was found that the network affects the mobility of diastereomeric compounds to a different extent, enhancing the selectivity of the system. In nearly all cases of aromatic acids the diastereomer carrying the D-amino acid was more strongly retained than the L-isomer, as opposed to the situation with aliphatic acids.

Amino Acids↗
PubMed1998

Separation and microgram-scale isolation of sea urchin egg granules by electrophoresis in polyvinylpyrrolidone solution, using horizontal gel electrophoresis apparatus with fluorescence detector.

A homogenate of sea urchin (Lytechinus pictus) eggs rich in exocytotic membrane vesicles (granules) was subjected to analytical and preparative electrophoresis in the commercial automated horizontal gel electrophoresis apparatus (HPGE-1000, LabIntelligence, Belmont, CA) capable of intermittent scanning of the migration path, using buffered solutions of polyvinylpyrrolidone (PVP). The nonfluorescent granules were detected by "fluorescence reduction", i.e., a decrease of fluorescence intensity due to the absorbance and/or light scattering properties of the particle. Granules migrated at linear migration rates in buffers ranging from 0 to 2.5% PVP. Two bands were observed and optimally separated in 1.5% PVP solution. As shown by sodium dodecyl sulfate (SDS)-polypeptide patterns, the material recovered from the bands was qualitatively indistinguishable from the two major fractions A and C of granules previously separated by free-flow electrophoresis in the absence of polymer. Ferguson plot analysis failed to provide the sizes of the granules in view of the narrow PVP concentration range available for mobility measurement and the unavailability of chemically homogeneous size standards.

Animals↗
PubMed2003

Polyvinylpyrrolidone modified bioactive glass fibers as tissue constructs: in vitro mesenchymal stem cell response.

The sol-gel synthesis of a bioactive glass (BAG) sol with the incorporation of polyvinylpyrrolidone and the subsequent spraying of short, discontinuous fibers is reported. The incorporation of the polymer into the BAG sol allowed for increased control of the rheological properties and resulted in a more homogeneous fibrous material when sprayed through an air gun. Reaction kinetics and sol viscosity were monitored and analyzed during synthesis, and fibers were characterized using scanning electron microscopy and thermal analysis. Fibers were sintered at 900 degrees C and were examined for in vitro bioactivity in a simulated body fluid solution. The presence of hydroxyapatite crystals is confirmed by examination with scanning electron microscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Both the proliferation rate and cell density of rat mesenchymal stem cells cultured on BAG fiber constructs of varying porosities were shown to be dependent upon fiber spacing.

Animals↗
PubMed2006

Preparation and magnetic resonance imaging effect of polyvinylpyrrolidone-coated iron oxide nanoparticles.

Polyvinylpyrrolidone (PVP)-coated iron oxide nanoparticles were prepared by the thermal decomposition of Fe(CO)(5) (iron pentacarbonyl) in one step. X-ray diffraction (XRD), transmission electron microscopy (TEM), electrophoretic light scattering (ELS), infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) together with the variation of the molar ratio of PVP/Fe(CO)(5), solvent, and molecular weight of PVP, were used to characterize the PVP-coated iron oxide nanoparticles. Fifty to hundred nanometer-sized iron oxide nanoclusters with a spherical shape were formed in dimethylformamide (DMF), used as a solvent, and exhibited an enhanced stability in the aqueous media. Their magnetic properties were investigated by superconducting quantum interface device (SQUID). The in vitro cytotoxicity test revealed that the PVP-coated iron oxide nanoparticles exhibited excellent biocompatibility by MTT assay. Magnetic resonance imaging (MRI) effect was observed with the administration of PVP-coated iron oxide nanoparticles through the marginal vein of rabbit, resulting in improved detection of the liver lesions.

Coated Materials, Biocompatible↗
PubMed2003

Reaction of a peptide with polyvinylpyrrolidone in the solid state.

During stability studies at high temperature (70 degrees C) and low relative humidity ( approximately 0%), the recovery of an asparagine containing hexapeptide (VYPNGA) and its known deamidation products from solid polyvinylpyrrolidone (PVP) matrices was incomplete. To determine the causes of this mass loss, formulations were prepared by lyophilizing solutions containing PVP, glycerol, and the Asn-hexapeptide in pH 7.5 phosphate buffer, followed by storage at 70 degrees C and 0% relative humidity. Asn-hexapeptide loss was mono-exponential and reached a plateau at about 30% remaining. Total recovery of the peptide and its known deamidation products was approximately 30% of peptide load. Size exclusion chromatography with fluorescence detection indicated the formation of a PVP-peptide adduct that was stable in the presence of 6 M guanidine hydrochloride. Similar stability studies using N-acetyl phenylalanine, phenylalanine ethyl ester, and N-acetyl tyrosine ethyl ester demonstrated that the reaction involves the peptide N-terminus. The adduct was disrupted in the presence of carboxypeptidase-A, suggesting the formation of an amide bond between the peptide and PVP. (15)N solid-state nuclear magnetic resonance spectroscopy using (15)N-labeled valine as a model of the peptide N-terminus showed different populations of (15)N, suggesting that noncovalent peptide-polymer interactions precede amide bond formation.

Chromatography, High Pressure Liquid↗
PubMed2004

Ability of polyvinylpyrrolidone and polyacrylic acid to inhibit the crystallization of amorphous acetaminophen.

The inhibition of crystallization of amorphous acetaminophen (ACTA) by polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) was studied using amorphous solid dispersions prepared by melt quenching. Co-melting with PVP and PAA decreased the average molecular mobility, as indicated by increases in glass transition temperature and enthalpy relaxation time. The ACTA/PAA dispersion exhibited much slower crystallization than the ACTA/PVP dispersion with a similar glass transition temperature value, indicating that interaction between ACTA and polymers also contributed to the stabilizing effect of these polymers. The carboxyl group of PAA may interact with the hydroxyl group of ACTA more intensely than the carbonyl group of PVP does, resulting in the stronger stabilizing effect of PAA. Dielectric relaxation spectroscopy showed that the number of water molecules tightly binding to PVP per monomer unit was larger than that to PAA. Furthermore, a small amount of absorbed water decreased the stabilizing effect of PVP, but not that of PAA. These findings suggest that the stronger stabilizing effect of PAA is due to the stronger interaction with ACTA. The ability of PAA to decrease the molecular mobility of solid dispersion was also larger than that of PVP, as indicated by the longer enthalpy relaxation time.

Acetaminophen↗
PubMed2005

Study on the interactions between polyvinylpyrrolidone (PVP) and acetaminophen crystals: partial dissolution pattern change.

The objective of the study was to investigate the interactions between polyvinylpyrrolidone (PVP) and acetaminophen crystal especially on crystal surface. The effects of PVP on the etching pattern change of the acetaminophen (010) face, solubility enhancement as well as the intrinsic dissolution rate (IDR) of acetaminophen crystals have been studied. The etching patterns of the acetaminophen (010) face in the presence of PVP have stable ledges in the direction of a-axis, but deviate from c-axis, which shows that the dissolution on the (010) face has been affected by the adsorbed PVP especially in the direction of c-axis through van der Waals interactions rather than hydrogen bonding interactions. Even though PVP(K30) can enhance the solubility of acetaminophen in concentration higher than 1 mg/mL, the IDR of acetaminophen in diluted PVP solutions was lower than in water. Because the viscosity of those diluted PVP(K30) solutions were the same as water viscosity, the lowered IDR of acetaminophen cannot be explained simply by the viscosity effects of PVP solutions. Overall, the study suggests that the PVP molecules adsorbed on the surface of acetaminophen crystals play an important role in etching pattern change as well as the intrinsic dissolution rate change.

Acetaminophen↗
PubMed1978

Comparison of adsorbed films of a polyvinylpyrrolidone copolymer with spread monolayers.

The adsorption of a polyvinylpyrrolidone-polyvinyl acetate graft copolymer from solution was studied by surface pressure measurement. Adsorption from the dilute solutions was slow, limited, in part, by diffusion of polymer molecules to the surface. When absorbed monolayers were compressed on a surface balance, the resulting surface pressure values paralled those of a spread monolayer, strongly suggesting that the structures of adsorbed and spread monolayers are the same.

Adsorption↗
PubMed1979

Structure of polyvinylpyrrolidone-iodine (povidone-iodine).

Hydrogen triiodide adducts were prepared from N,N-dimethylacetamide, N-alkylpyrrolidone derivatives, and polyvinylpyrrolidone, and their structures were investigated by IR spectra and X-ray structure analyses and compared with the structure of povidone-iodine USP. The results suggest that the iodine in povidone-iodine USP is complexed by the polymer such that a proton is fixed via a short hydrogen bond between two carbonyl groups of two pyrrolidone rings and that a triiodide anion is bound ionically to this cation.

Chemical Phenomena↗
PubMed1987

Evidence for solid- and liquid-state interactions in a furosemide-polyvinylpyrrolidone solid dispersion.

The solid-state interactions between furosemide (FUR) and polyvinylpyrrolidone (PVP) in a solid dispersion system have been investigated by dispersive and Fourier Transform IR. Using spectral subtraction procedures, shifts to lower frequencies are seen in FUR-NH stretching vibrations in amorphous FUR-PVP systems in comparison with the crystalline FUR spectrum. The magnitude of shifts are similar to those seen when FUR is dissolved in the hydrogen-bonding solvent 1,4 dioxan (0.015-0.155 M, 20 degrees C). Spectral assignment indicates the FUR sulfonamide group binds to PVP in preference to the FUR secondary amine which is shown to possess an intramolecular hydrogen bond by analysis of published X-ray crystal data. With a molecular graphics computer program, the FUR crystal unit cell was compiled, and analyses of nonbonded intermolecular distances are useful in interpreting IR shift data in amorphous solid dispersions. A study of FUR-PVP interactions in solution, examined by proton NMR, reveals a downfield shift of the FUR sulfonamide proton resonance. This shift exhibits dilution and temperature (298-338 K) dependence consistent with an intermolecular hydrogen bond. The secondary amine proton resonance exhibits temperature but not dilution or solvent bonding potential dependence, characteristics of an intramolecular hydrogen bond. The proposed hydrogen bond FUR-PVP interaction may account for the formation and stabilization of the amorphous solid dispersion.

Furosemide↗
PubMed1993

The effect of polyvinylpyrrolidone and the cooling rate during corneal cryopreservation.

The effect upon endothelial cell survival of (a) PVP and (b) the cooling rate was investigated during the cryopreservation of rabbit corneas with 3 mol/liter dimethyl sulfoxide (Me2SO) dissolved in a hyperkalemic buffer vehicle solution that we designated CPTES; this solution was designed specifically to restrict deleterious ionic imbalances and cell swelling during hypothermic procedures. Polyvinylpyrrolidone (PVP) was used as the colloid and the corneas were cooled at 0.03, 0.1, 1, 25, or 125 degrees C/min, using the minimum amount of extracellular solution. Electron microscopy as well as staining with fluorescein diacetate and ethidium bromide (FDA/EB) was used to assess cellular integrity. To reduce osmotic stress, steps for the serial equilibration of the cryoprotectant additives (CPAs) were based upon calculations that predict endothelial volume during CPA exchange. A toxicity study showed that at 0 degrees C all the CPA equilibration protocols were well tolerated; for example, FDA/EB staining indicated that 97% intact cells were retained following direct transfer to 3 mol/liter Me2SO in CPTES to which 40% w/v PVP had been added as an osmotic buffer. However, less than 20% of cells were intact by FDA/EB staining with all corneas frozen at rates > 1 degree C/min regardless of which equilibration protocol was employed, nor were there any intact cells when 3 mol/liter Me2SO in CPTES was used alone at the lowest cooling rate. At intermediate cooling rates viability was improved: the highest mean survival of 81% was obtained using 3 mol/liter Me2SO in CPTES plus 40% PVP. Electron microscopy showed that detachment of the endothelial layer often occurred, but least damage was evident following exposure to 3 mol/liter Me2SO in CPTES plus 40% PVP and cooling at 1 degree C/min. No thawed cornea could maintain normal control of hydration immediately upon return to isotonic medium. The results show that, with these cryopreservation protocols, loss of cell integrity occurs at cooling rates greater than 1 degree C/min, whereas at lower rates higher survival of individual cells was achieved, but cellular adhesion to the basement membrane was impaired.

Animals↗
PubMed1995

The influence of polyvinylpyrrolidone on freezing of bovine IVF blastocysts following biopsy.

A study was conducted to develop a better freezing protocol for in vitro developed biopsied bovine blastocysts. Biopsied blastocysts were exposed to 1.8 M ethylene glycol (EG) + 0.05 M trehalose (T) and different concentration (5, 10, and 20%) of polyvinylpyrrolidone (PVP). Exposure to the solutions alone did not affect their in vitro development (Experiment 1). Experiments 2, 3, and 4 tested the viability of biopsied blastocysts cryopreserved in 1.8 M EG + different concentrations of T (0, 0.05, 0.1, and 0.3 M), 1.8 M EG + different concentrations of PVP (0, 5, 10, and 20%), and 1.8 M EG + 0.05 M T + different concentrations of PVP (0, 5, 10, and 20%), respectively. The proportion of biopsied blastocysts that reexpanded following cryopreservation in 1.8 M EG + 0.05 M T (38.5%) and 1.8 M EG + 0.1 M T (36.1%) was significantly (P < 0.05) higher than the proportion that reexpanded in 1.8 M EG + 0.3 M T (13.9%) (Experiment 2). The viability and the percentage of embryos that developed to > 250 microns in diameter in the 5, 10, and 20% PVP groups (77.8 and 50.0%, 78.1 and 43.8%, 76.9 and 65.4%, respectively) were significantly higher than those that developed cryopreserved without PVP (55.1 and 20.7%) (Experiment 3). Optimum development of in vitro culture of frozen-thawed biopsied blastocysts was obtained using 1.8 M EG + 0.05 M T and 20% PVP. Analysis of blastocysts > 250 microns in diameter showed that the number of ICM cells of biopsied blastocysts cryopreserved in 1.8 M EG + 0.05 M T with or without PVP was not different from the number of unfrozen biopsied blastocysts. These results indicate that PVP has some beneficial effect on freezing of biopsied bovine blastocysts.

Animals↗
PubMed1996

Normal calves obtained after direct transfer of vitrified bovine embryos using ethylene glycol, trehalose, and polyvinylpyrrolidone.

In the present study, IVF bovine embryos were vitrified using as the cryoprotectants, ethylene glycol plus trehalose plus the polymer, polyvinylpyrrolidone (PVP). In Experiment I, toxicity of the vitrification solution (VS) containing 20% PVP was tested in relation to temperature and exposure time. One hundred percent embryo development was observed with treatment at 5 degrees C for 5 min, whereas only 55.5% embryos were developed when the treatment was carried out at 20 degrees C for 5 min. In Experiment II, embryos were vitrified using one of the three treatments (Treatment A, 40% ethylene glycol (EG); treatment B, 40% EG + 11.3% trehalose; and treatment C, 40% EG + 11.3% trehalose + 20% PVP and rehydrations) was performed directly in mPBS. Highest development (84.1%) and hatching rate (68.2%) were obtained when embryos were vitrified with the vitrification solution used in treatment C. In Experiment III, embryos were vitrified as in Experiment II (treatment C). The development and hatching rates were compared after rehydration in different rehydration solutions. No significant difference was observed among the development and hatching rates when rehydration was carried out in different concentrations of trehalose. Five vitrified-warmed bovine embryos were transferred directly to five recipients and three recipients gave birth to three normal calves.

Animals↗
PubMed2001

The effect of prefreezing the diluent portion of the straw in a step-wise vitrification process using ethylene glycol and polyvinylpyrrolidone to preserve bovine blastocysts.

A total of 678 bovine blastocysts, which had been produced by in vitro maturation, fertilization, and culture, were placed into plastic straws and were vitrified in various solutions of ethylene glycol (EG) + polyvinylpyrrolidone (PVP). Part of the straw was loaded with TCM199 medium + 0.3 M trehalose as a diluent; the diluent portions of the straw were prefrozen to either -30 or -196 degrees C. Then, the embryos suspended in the vitrification solution were pipetted into the balance of the straw and vitrified by direct immersion into liquid nitrogen. For thawing, the straws were warmed for 3 s in air and 20 s in a water bath at 39 degrees C and then agitated to mix the diluent and cryoprotectant solution for 5 min followed by culture in TCM199 + 10% FCS + 5 + microg/ml insulin + 50 microg/ml gentamycin sulfate for 72 h. Variables that were examined were the time of exposure to EG prior to vitrification, the PVP concentration, and the temperature of exposure to EG + PVP prior to vitrification. Survival and hatching rates of the blastocysts exposed to 40% EG in four steps at 4 degrees C were higher than those of embryos exposed in two steps (81.3 +/- 4.3% and 80.2 +/- 3.4% vs 67.6 +/- 4.5% and 71.5 +/- 4.7%, respectively; P < 0.05). The same indices were superior following vitrification-thawing of the blastocysts in 40% EG + 20% PVP than it was in 40% EG + 10% PVP (76.1 +/- 5.5% vs 63.7 +/- 1.8%; P < 0.05; and 61.6 +/- 6.0% vs 70.5 +/- 4.7%; P < 0.01, respectively). Exposure to the vitrification solution (40% EG + 20% PVP) at higher temperatures (37.5 degrees C vs 4 degrees C) reduced both survival and hatching rates (45.8 +/- 6.9% vs 83.9 +/- 4.4% and 41.5 +/- 1.8% vs 64.0 +/- 4.7%, respectively; P < 0.001). These results indicate that blastocysts vitrified after prefreezing the diluent portions of the straws do favor developmental competence of in vitro produced embryos.

Animals↗
PubMed2000

Polyvinylpyrrolidone Adsorption on Na-Montmorillonite. Effect of the Polymer Interfacial Conformation on the Colloidal Behavior and Binding of Chemicals.

Adsorption behavior of polyvinylpyrrolidone (PVP) on sodium montmorillonite, a swelling clay mineral, was investigated in diluted solutions at an ionic strength of 0.01 M, representative of environmental soil solution conditions. Physicochemical methods such as microcalorimetry, light scattering absorbance, photon correlation spectroscopy, microelectrophoresis, X-ray diffraction, and sedimentation volume measurements were used to characterize the colloidal behavior of montmorillonite particles with various PVP loadings. The extent and properties of the adsorbed PVP train, loop, and end fractions in the particle-stabilizing process have been specified. The interaction study of chemicals such as anionic surfactant sodium dodecyl sulfate and nonionized 4-monochlorophenol as well as their mixture also underlines the importance of the PVP interfacial conformations for the adsorbent capacity of this organoclay. Copyright 2000 Academic Press.

Journal Article↗
PubMed2001

Physicochemical Investigations on the Interaction of Surfactants and Salts with Polyvinylpyrrolidone in Aqueous Medium.

Microcalorimetric investigations have been carried out onthe interaction of the surfactants sodium cholate, sodium deoxycholate, tetradecyltrimethylammonium bromide, cetyl(hexadecyl)trimethylammonium bromide, and p-tert-octylphenoxy polyoxy-ethylene ether (Triton X-100) and the salts potassium iodide, sodium benzoate, sodium bromide, and sodium salicylate with the neutral polymer polyvinylpyrrolidone (PVP). The enthalpy of dilution of the surfactants has been measured in the absence and presence of the polymer and the results are compared to determine the effect of PVP on the micellization of the surfactants and the energetics of the process. As well, the micellization activity of the surfactants in the presence of the polymer has been studied by conductometric and fluorimetric methods. The enthalpy of dilution of the salts has been measured to provide an understanding of the nature and magnitude of their interaction with PVP. Copyright 2001 Academic Press.

Journal Article↗
PubMed2001

Investigation of the Interactions of Polyvinylpyrrolidone with Mixtures of Anionic and Nonionic Surfactants or Anionic and Zwitterionic Surfactants by Pulsed Field Gradient NMR.

The interaction of polyvinylpyrrolidone (PVP) with an anionic surfactant (sodium dodecyl sulfate, SDS), a nonionic surfactant (pentaethylene glycol monodecyl ether, C(10)E(5)), and a zwitterionic surfactant (lauryl amido propyl betaine, LAPB) has been investigated by means of pulsed gradient spin-echo NMR (FT-PGSE NMR), allowing self-diffusion coefficients to be determined. The results confirm the strong interaction prevailing in the PVP/SDS system, whereas no association has been observed in the PVP/C(10)E(5) and PVP/LAPB systems. Mixing PVP with two surfactants, namely SDS and C(10)E(5) or SDS and LAPB, results in the formation of ternary aggregates between the polymer and the mixed micelles. Copyright 2001 Academic Press.

Journal Article↗