Influence of water-soluble nonionic polymers adsorption on colloidal properties of nanosilica dispersions

The relationships between the adsorption of poly(vinyl alcohol) (PVA), poly(ethylene oxide) (PEO), and poly(vinyl pyrrolidone) (PVP) of various molecular weights onto nanosilica and the stability and rheological properties of the aqueous dispersions were analyzed. The adsorption isotherms for the polymers correspond to the Langmuir-type isotherms. The adsorption maximum slightly increases with increasing molecular weight of the polymers. The sedimentation and aggregative stability of the silica dispersion decreased at a low amount of an adsorbed polymer (less than a monolayer). At this polymer content, a significant increase in the viscosity of dispersions is observed due to the formation of polymeric bridges between silica nanoparticles from neighboring aggregates of them. If the amount of adsorbed polymer exceeds the monolayer then the stabilizing effect is observed due to the steric factor preventing the bridge formation and the viscosity of dispersion decreases slightly compared with systems with a low polymer content.

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Testing the Performance of Various Polymeric Antiscalants for Mitigation of Sb-Rich Precipitates Mimicking Stibnite-Based Geothermal Deposits

Geofluids ◽

10.1155/2020/8867084 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Celal Çiftçi ◽

Emre Karaburun ◽

Serhat Tonkul ◽

Alper Baba ◽

Mustafa M. Demir ◽

...

Keyword(s):

Power Plants ◽

Vinyl Pyrrolidone ◽

Poly Vinyl Alcohol ◽

Poly Ethylene Glycol ◽

Molecular Weights ◽

Geothermal Fields ◽

The World ◽

Testing Potential ◽

Poly Ethylene ◽

Poly Vinyl Pyrrolidone

Scaling is frequently observed in geothermal fields and reduces the energy harvesting of power plants. Recently, Sb-rich deposits have developed in many fields around the world. Various polymeric macromolecules have been used as antiscalants to mitigate the formation of scale. Testing potential commercial antiscalants in field conditions is a tedious and costly process. The artificial synthesis of geothermal deposits in the lab is a more practical and economical way to test the performance of antiscalants. This study obtained a Sb-rich deposit by refluxing SbCl3 and Na2S·3H2O in 18 h. The product was found to be a mixture of Sb2O3 and Sb2S3. We examined the performance of antiscalants such as poly(ethylene glycol), poly(vinyl pyrrolidone), Gelatin, and poly(vinyl alcohol) of various molecular weights at 5 to 100 ppm. The formation of Sb2S3 is suppressed in the presence of the polymeric antiscalants. The dosage was found to be critical for the solubilization of Sb-rich deposits. Gelatin of 5 ppm showed the highest performance under the conditions employed in this study. While low dosages improve the concentration of [Sb3+], high dosages are required to increase the solubility of [S2-]. Moreover, the amount of deposit is reduced by 12.4% compared to the reference (in the absence of any polymeric molecules). Thus, comparatively, Gelatin shows the most promising performance among the molecules employed.

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In Vitro Drug Release, Permeability, and Structural Test of Ciprofloxacin-Loaded Nanofibers

Pharmaceutics ◽

10.3390/pharmaceutics13040556 ◽

2021 ◽

Vol 13 (4) ◽

pp. 556

Author(s):

Luca Éva Uhljar ◽

Sheng Yuan Kan ◽

Norbert Radacsi ◽

Vasileios Koutsos ◽

Piroska Szabó-Révész ◽

...

Keyword(s):

Amorphous State ◽

Physical Mixture ◽

Water Soluble ◽

Vinyl Pyrrolidone ◽

Amorphous Solid Dispersion ◽

Release Mechanism ◽

Dissolution Studies ◽

In Vitro Diffusion ◽

Poly Vinyl Pyrrolidone

Nanofibers of the poorly water-soluble antibiotic ciprofloxacin (CIP) were fabricated in the form of an amorphous solid dispersion by using poly(vinyl pyrrolidone) as a polymer matrix, by the low-cost electrospinning method. The solubility of the nanofibers as well as their in vitro diffusion were remarkably higher than those of the CIP powder or the physical mixture of the two components. The fiber size and morphology were optimized, and it was found that the addition of the CIP to the electrospinning solution decreased the nanofiber diameter, leading to an increased specific surface area. Structural characterization confirmed the interactions between the drug and the polymer and the amorphous state of CIP inside the nanofibers. Since the solubility of CIP is pH-dependent, the in vitro solubility and dissolution studies were executed at different pH levels. The nanofiber sample with the finest morphology demonstrated a significant increase in solubility both in water and pH 7.4 buffer. Single medium and two-stage biorelevant dissolution studies were performed, and the release mechanism was described by mathematical models. Besides, in vitro diffusion from pH 6.8 to pH 7.4 notably increased when compared with the pure drug and physical mixture. Ciprofloxacin-loaded poly(vinyl pyrrolidone) (PVP) nanofibers can be considered as fast-dissolving formulations with improved physicochemical properties.

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Influence of Water on Room-Temperature Preparation of Silver Nanoparticles Using Poly(vinyl pyrrolidone) as Reducing Agent

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2013.7142 ◽

2013 ◽

Vol 13 (6) ◽

pp. 4084-4089 ◽

Cited By ~ 2

Author(s):

Dan Wu ◽

Wei Wang ◽

Fatang Tan ◽

Huixin Zhang ◽

Xiaolin Qiu ◽

...

Keyword(s):

Silver Nanoparticles ◽

Room Temperature ◽

Reducing Agent ◽

Vinyl Pyrrolidone ◽

Influence Of Water ◽

Poly Vinyl Pyrrolidone ◽

Temperature Preparation

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Poly(vinyl alcohol) and poly(vinyl pyrrolidone) blended films for local nitric oxide release

Biomaterials ◽

10.1016/j.biomaterials.2003.10.035 ◽

2004 ◽

Vol 25 (17) ◽

pp. 3773-3782 ◽

Cited By ~ 109

Author(s):

Amedea Barozzi Seabra ◽

Marcelo Ganzarolli de Oliveira

Keyword(s):

Nitric Oxide ◽

Vinyl Alcohol ◽

Vinyl Pyrrolidone ◽

Poly Vinyl Alcohol ◽

Nitric Oxide Release ◽

Poly Vinyl Pyrrolidone

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PREPARATION AND CHARACTERIZATION OF POLY (VINYL ALCOHOL)–POLY (VINYL PYRROLIDONE) MUCOADHESIVE BUCCAL PATCHES FOR DELIVERY OF LIDOCAINE HCL

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2018v10i1.23208 ◽

2018 ◽

Vol 10 (1) ◽

pp. 115 ◽

Cited By ~ 5

Author(s):

Napaphak Jaipakdee ◽

Thaned Pongjanyakul ◽

Ekapol Limpongsa

Keyword(s):

Vinyl Alcohol ◽

Vinyl Pyrrolidone ◽

Poly Vinyl Alcohol ◽

Scanning Calorimetry ◽

X Ray ◽

Casting Technique ◽

In Vitro Permeation ◽

Lidocaine Hcl ◽

Poly Vinyl Pyrrolidone

Objective: The objectives of this study were to prepare and characterize a buccal mucoadhesive patch using poly (vinyl alcohol) (PVA), poly (vinyl pyrrolidone) (PVP) as a mucoadhesive matrix, Eudragit S100 as a backing layer, and lidocaine HCl as a model drug.Methods: Lidocaine HCl buccal patches were prepared using double casting technique. Molecular interactions in the polymer matrices were studied using attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and X-ray diffractometry. Mechanical and mucoadhesive properties were measured using texture analyzer. In vitro permeation of lidocaine HCl from the patch was conducted using Franz diffusion cell.Results: Both of the free and lidocaine HCl patches were smooth and transparent, with good flexibility and strength. ATR-FTIR, DSC and X-ray diffractometry studies confirmed the interaction of PVA and PVP. Mechanical properties of matrices containing 60% PVP were significantly lower than those containing 20% PVP (*P<0.05). Mucoadhesive properties had a tendency to decrease with the concentration of PVP in the patch. The patch containing 60% PVP had significantly lower muco-adhesiveness than those containing 20% PVP (*P<0.05). In vitro permeation revealed that the pattern of lidocaine HCl permeation started with an initial fast permeation, followed by a slower permeation rate. The initial permeation fluxes follow the zero-order model of which rate was not affected by the PVP concentrations in the PVA/PVP matrix.Conclusion: Mucoadhesive buccal patches fabricated with PVA/PVP were successfully prepared. Incorporation of PVP in PVA/PVP matrix affected the strength of polymeric matrix and mucoadhesive property of patches.

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