Polyvinylpyrrolidone Solution Research Articles

The Nanostructure of Polymer-Active Principle Microparticles Produced by Supercritical CO2 Assisted Processing.

Traditional and supercritical CO2 assisted processes are frequently used to produce microparticles formed by a biopolymer containing an active principle to improve the bioavailability of the active principle. However, information about the internal organization of these microparticles is still scarce. In this work, a suspension of dextran + Fe3O4 nanoparticles (model system) and a solution of polyvinylpyrrolidone (PVP) + curcumin were used to produce spherical microparticles by supercritical CO2 processing. Periodic dynamic light scattering measurements were used to analyze the evolution of the microparticles dissolution, size, and size distribution of the guest active principle in the polymeric matrix. It was found that curcumin was dispersed in the form of nanoparticles in the PVP microparticles, whose size largely depended on its relative concentration. These results were validated by transmission electron microscopy and scanning electron microscopy of the PVP microparticles and curcumin nanoparticles, before and after the dissolution tests.

A Hydrogen Bonds-Crosslinked Hydrogels With Self-Healing and Adhesive Properties for Hemostatic.

Hydrogels with adhesive properties have the potential for rapid haemostasis and wound healing in uncontrolled non-pressurized surface bleeding. Herein, a typical hydrogen bond-crosslinked hydrogel with the above functions was constructed by directly mixing solutions of humic acid (HA) and polyvinylpyrrolidone (PVP), in which the HA worked as a crosslinking agent to form hydrogen bonds with the PVP. By altering the concentration of HA, a cluster of stable and uniform hydrogels were prepared within 10 s. The dynamic and reversible nature of the hydrogen bonds gave the HA/PVP complex (HPC) hydrogels injectability and good flexibility, as well as a self-healing ability. Moreover, the numerous functional groups in the hydrogels enhanced the cohesion strength and interaction on the interface between the hydrogel and the substrate, endowing them with good adhesion properties. The unique chemical composition and cross-linking mechanism gave the HPC hydrogel good biocompatibility. Taking advantage of all these features, the HPC hydrogels obtained in this work were broadly applied as haemostatic agents and showed a good therapeutic effect. This work might lead to an improvement in the development of multifunctional non-covalent hydrogels for application to biomaterials.

Synthesis of Ni/Y2O3 Nanocomposite through USP and Lyophilisation for Possible Use as Coating.

The Ni/Y2O3 catalyst showed high catalytic activity. Based on this, the aim of this study was to create Ni/Y2O3 nanocomposites powder with two innovative technologies, Ultrasonic Spray Pyrolysis (USP) and lyophilisation. In the USP process, thermal decomposition of the generated aerosols in an N2/H2 reduction atmosphere caused a complete decomposition of the nickel (II) nitrate to elemental Ni, which became trapped on the formed Y2O3 nanoparticles. The Ni/Y2O3 nanocomposite particles were captured via gas washing in an aqueous solution of polyvinylpyrrolidone (PVP) in collection bottles. PVP was chosen for its ability to stabilise nano-suspensions and as an effective cryoprotectant. Consequently, there was no loss or agglomeration of Ni/Y2O3 nanocomposite material during the lyophilisation process. The Ni/Y2O3 nanocomposite powder was analysed using ICP-MS, SEM-EDX, and XPS, which showed the impact of different precursor concentrations on the final Ni/Y2O3 nanocomposite particle composition. In a final step, highly concentrated Ni/Y2O3 nanocomposite ink (Ni/Y2O3 > 0.140 g/mL) and test coatings from this ink were prepared by applying them on a white matte photo paper sheet. The reflection curve of the prepared Ni/Y2O3 nanocomposite coating showed a local maximum at 440 nm with a value of 39% reflection. Given that Ni is located on the surface of the Ni/Y2O3 nanocomposite in the elemental state and according to the identified properties, tests of the catalytic properties of this coating will be performed in the future.

Technical note: Temperature and concentration dependence of water diffusion in polyvinylpyrrolidone solutions.

ObjectiveThe goal of this work is to provide temperature and concentration calibration of water diffusivity in polyvinylpyrrolidone (PVP) solutions used in phantoms to assess system bias and linearity in apparent diffusion coefficient (ADC) measurements.MethodADC measurements were performed for 40 kDa (K40) PVP of six concentrations (0%, 10%, 20%, 30%, 40%, and 50% by weight) at three temperatures (19.5°C, 22.5°C, and 26.4°C), with internal phantom temperature monitored by optical thermometer (±0.2°C). To achieve ADC measurement and fit accuracy of better than 0.5%, three orthogonal diffusion gradients were calibrated using known water diffusivity at 0°C and system gradient nonlinearity maps. Noise‐floor fit bias was also controlled by limiting the maximum b‐value used for ADC calculation of each sample. The ADC temperature dependence was modeled by Arrhenius functions of each PVP concentration. The concentration dependence was modeled by quadratic function for ADC normalized by the theoretical water diffusion values. Calibration coefficients were obtained from linear regression model fits.ResultsMeasured phantom ADC values increased with temperature and decreasing PVP concentration, [PVP]. The derived Arrhenius model parameters for [PVP] between 0% and 50%, are reported and can be used for K40 ADC temperature calibration with absolute ADC error within ±0.016 μm2/ms. Arrhenius model fit parameters normalized to water value scaled with [PVP] between 10% and 40%, and proportional change in activation energy increased faster than collision frequency. ADC normalization by water diffusivity, D W, from the Speedy–Angell relation accounted for the bulk of temperature dependence (±0.035 μm2/ms) and yielded quadratic calibration for ADCPVP/D W = (12.5 ± 0.7) ·10−5·[PVP]2 − (23.2 ± 0.3)·10−3·[PVP]+1, nearly independent of PVP molecular weight and temperature.ConclusionThe study provides ground‐truth ADC values for K40 PVP solutions commonly used in diffusion phantoms for scanning at ambient room temperature. The described procedures and the reported calibration can be used for quality control and standardization of measured ADC values of PVP at different concentrations and temperatures.

Використання полівінілалкоголю та полівінілпіролідону для підготовки деконсервованих еякульованих сперматозоїдів кнурів до запліднення методом ICSI

The aim of the study was to explore the effect of PVP (polyvinylpyrrolidone) and PVA (polyvinyl alcohol) media on deconserved ejaculated boar sperm and their preparation for artificial insemination to optimize biotechnological approaches. The studies used ejaculated cryopreserved sperm of a boar of the Myrhorod breed Dnipro 641. Genetic material was stored in the Bank of Genetic Resources of Animals IABG nnamed after M.V. Zubets NAAS for eight years. The sperm suspension was thawed in a water bath at +37 °C for 5 min until completely thawed. Separation of sperm from cryopreservative agent and diluent was performed using the swim up method in Sp-TALP medium. After the presence of sperm in the 10.0% solution of PVP for 10 min, motility decreased by 68.2% (P < 0.05) and amounted to 3.4%, and after the next 10 min of incubation decreased to 1.4% (P <0.01), which is 10 times lower than the initial mobility. In 10.0% of PVA mobility after 10 min of incubation decreased by 37.4% (P <0.05) and amounted to 6.7%, and after 10 min decreased to 5.7% (P < 0.01), which is 1.8 times lower than the initial mobility. It was found that in the case of 10.0% of PVP solution ejaculated deconserved boar sperm lose motility by 86.9% (P <0.01) from the initial motility, which makes it impossible to select a suitable sperm for fertilization by ICSI (intracytoplasmic sperm injection). It is shown that 10.0% PVA solution can be used for immobilization of boar sperm, as it reduces motility by 46.7% (P <0.01) of the initial sperm motility. It is proved that the mobility in the case of incubation of deconserved ejaculated boar sperm in 5.0% PVA solution decreases only by 28.0% (P <0.05) from the initial, which is optimal when using cryopreserved boar sperm, material which are limited and convenient for the operator and safe for oocytes.

Stress and Distortion of 100Cr6 Steel after Quenching in Aqueous 4% Polyvinylpyrrolidone Solution

Stress and Distortion of 100Cr6 Steel after Quenching in Aqueous 4% Polyvinylpyrrolidone Solution

The effect of various electrospinning parameter and sol-gel concentration on morphology of silica and titania nanofibers

Nano scale fibers of SiO2 and TiO2 with various compositions of viscosity and parameter have been prepared by electrospinning the precursor of tetraethyl orthosilicate (TEOS) and titanium (IV) isopropoxide (TiP). Different concentrations of polymer precursor polyvinylpyrrolidone (PVP) and applied voltages were studied. Distance tip to collector of 15 cm and flow rate of 0.003 mL/h were fixed for entire electrospinning process. The morphology of nanofibers was evaluated versus different solution concentrations as well as different applied voltages. Concentration focused in this study included 5 %wt, 10 %wt and 15 %wt of PVP along with 15 kV – 17.5 kV of voltages applied. The as-spun nanofibers were characterized by SEM. Results showed that the average fiber diameter decreases with decreasing of polyvinylpyrrolidone (PVP) solution concentration.

Fabrication of multilayer Graphene-coated Copper nanoparticles for application as a thermal interface material

A process to fabricate a thermal interface material (TIM) was developed to coat graphene, which is chemically stable and thermally conductive, on the surface of copper nanoparticles (CNPs) to prevent their oxidation while promoting heat dissipation. The CNPs were synthesized using the polyol method to convert polyvinylpyrrolidone (PVP) into multilayer graphene (MLG) via chemical vapor deposition (CVD). For optimization, CVD temperature, the amount of additional PVP solution, and PVP molecular weight (MW) in polyol process were varied. The results showed that thermal properties degraded with increasing residual PVP, and an increasing ID/IG ratio confirmed improved MLG quality. The optimal MLG coating conditions were found to be a CVD temperature of 880℃, 50 wt% additional PVP solution and using K30 PVP in polyol process (MW: 45,000). These conditions provided the highest thermal conductivity of 19.66 W/m∙K. Thermogravimetric analysis established that oxidation began at 150℃, which is higher than the upper temperature limit of electronic components. Therefore, MLG-coated CNPs would be suitable as TIM.

Remarkable stability of dye in polymer-clay nanocomposite film

The immobilization of rhodamine 6G and polyvinylpyrrolidone in a purified bentonite was investigated. Hybrid films were prepared by mixing an aqueous rhodamine 6G-bentonite suspension with aqueous solution of polyvinylpyrrolidone and subsequent casting on the solid substrate. The successful intercalation of the dyes and the polymer into the interlayer space of the bentonite was confirmed by the systematic expansion of the interlayer space. The stability of the rhodamine 6G adsorbed on the purified bentonite with polyvinylpyyrolidone was examined by following the appearance and the spectroscopic characteristics to find superior stabilities upon heating at 300 °C and sunlight irradiation at 150 °C in air if compared with the dye on the purified bentonite (without polymer) and that in the polymer (without bentonite).

Experimental and theoretical studies of cross-stream migration of non-spherical particles in a quadratic flow of a viscoelastic fluid.

We experimentally investigate the cross-stream migration of spherical, prolate, and oblate particles in a circular tube flow of a weakly viscoelastic fluid (De = O(10-2)) with negligible inertia (Re ≈ 0). From our previous theoretical studies, we developed mathematical models based on a second order fluid (i.e., retarded expansion for De ≪ 1) to characterize the migration trajectory of the particles in the absence of wall effects. The theory shows that the particle migration speed is proportional to the length the particle spans in the shear gradient direction (Lsg), and furthermore quantifies how particle shape alters the migration timescale. For particles with identical volume, spherical particles show the fastest migration speed among all the particles. The distinctive orientation behavior of prolate and oblate spheroids leads to a faster migration speed for an oblate particle compared to a prolate particle of the same aspect ratio. In this work, we verify our theory with microfluidic flow experiments using a model suspension of polystyrene (PS) micro-particles in a density-matched polyvinylpyrrolidone (PVP) solution (a Boger fluid). The experimental results show good qualitative and quantitative agreement with the theoretically predicted particle migration speed, indicating that the theory is able to provide reasonable predictions for real microfluidic systems.

HYDROGEN GAS PRODUCTION FROM WASTE WATER BY TiO2 AND NITROGEN- DOPED TiO2 NANO FIBERS WITH SIMULTANEOUS POLLUTANTS REMOVAL

At this work we synthesized electrospun titanium oxide (TiO2) and nitrogen-doped titanium oxide (N-doped TiO2) for producing hydrogen (H2) in the same time pollutant removal from waste water by photocatalytic oxidation at room contitions.We use titanium isopropoxide (TiP)/polyvinylpyrrolidone (PVP) solution to prepare dispersed titanium oxide in polymer nanofibers by sol–gel processing and electrospinning techniques. TiO2 is a very effective and brillant photocatalyst for water treatment, but it has drawbacks like absorbing UV light and fast backward reaction and recombination between electrons and generated holes pairs, there are much effort has been devoted to overcome its problems, like doping with metals and non-metals. Advantage of N-doped TiO2 nano fiber is expanded the utilization of a large part of the solar spectrum. This might be useful for environmental and energy applications, such as the photocatalytic degradation of organic pollutants, solar cells, sensors, and water splitting reactions.The photocatalytic activity of TiO2 and N-doped TiO2 nanofibers was carried out in the waste and dye water-splitting reaction to produce H2 and water treatment using mercury light irradiation. The doping of TiO2 with Nitrogen, which should improve the electronic properties, leading to activation as a photocatalyst under visible light irradiation.several characterization techniques are employed for studying the surface morphology, phase of structure, and binding energy for TiO2 and N-TiO2 nanofibers (Scanning electron microscopy, X-ray diffractometry, transmission electron microscope).

Противовоспалительное и анальгетическое действие ингибитора индуцируемой синтазы оксида азота в эксперименте

Introduction. Nitric oxide plays a key role in the development of inflammation. In this regard, it is promising to create a drug that reduces the production of nitric oxide in the focus of inflammation. Aim. To study experimentally the anti-inflammatory and analgesic effects of an inducible nitric oxide synthase inhibitor of an aminoguanidine derivative (LIS-M). Materials and methods. The compound LIS-M in 1% aqueous solution of polyvinylpyrrolidone was administered intramuscularly at doses of 5, 10 and 20 mg/kg to 150 male Sprague Dawley rats and 50 male CD-1 mice with experimental models of inflammation and pain. The animals of the comparison group received diclofenac at a dose of 10 mg/kg, the animals of the control group received 1% aqueous solution of polyvinylpyrrolidone in an equivalent volume. The effect of the LIS-M compound on the course of experimental pathology and its analgesic potential ulcerogenic effect were evaluated. Results. In male Sprague Dawley rats, the LIS-M compound reduces acute exudative inflammation caused by injection of carrageenan, histamine or serotonin in plantar aponeurosis, inhibits the proliferation of granulation tissue and exudation around a cotton swab implanted under the skin, does not have an ulcerogenic effect. In male CD-1 mice, it weakens the pain reaction and increases the time before it occurs. Conclusion. The LIS-M compound at doses ranging from of 5 to 20 mg/kg has a pronounced antiexudative, antiproliferative and analgesic effect, not inferior to the action of diclofenac at a dose of 10 mg/kg, and does not have an ulcerogenic effect.

In situ generated Ligand-Free gold nanoparticles in polyvinylpyrrolidone solution assisted laser in liquid method for green oxidation of cyclohexane to adipic acid with high yield

Here in we report a very simple method to create gold nanoparticles coated-double silica shells by using a three step process containing pulse laser ablation (PLAL) of metallic gold target in aqueous solution of polyvinylpyrrolidone, well-known stober process and calcination at high temperature respectively for achieving of Au@SiO2@SiO2 nanoparticles with narrow size distribution. Final structure was characterized by techniques such STEM, FESEM, BET, XPS, XRD, TGA, ICP-OES and FT-IR and shows the activity of 26 % conversion in aerobic oxidation of cyclohexane to adipic acid with the 92 % selectivity in mild conditions. More over the catalyst has saved its activity until 6 cycles without any dominant losing.

Prediction of quality attributes (mechanical strength, disintegration behavior and drug release) of tablets on the basis of characteristics of granules prepared by high shear wet granulation.

High shear wet granulation is commonly applied technique for commercial manufacturing of tablets. Granulation process for tablets manufacturing is generally optimized by hit and trial which involves preparation of granules under different processing parameters, compression of granules and evaluation of the resultant tablets; and adjustment is made in granulation process on the basis of characteristics of tablets. Objective of the study was to optimize the process of high shear wet granulation and prediction of characteristics of tablets on the basis of properties of granules. Atenolol granules were prepared by high shear wet granulation method, using aqueous solution of polyvinyl pyrrolidone (PVP k-30) as binder. Concentration of binder solution and granulation time were taken as process variables, both studied at three levels. Different combinations of process variables were determined by Design Expert software. Granules were evaluated for different parameters on the basis of SeDeM-ODT (Sediment Delivery Model-Oro Dispersible Tablets) expert system. Granules from all the trials were compressed using round (10.5 mm) flat faced punches at compression weight of 250 mg/tablet. Tablets were evaluated of different quality control parameters as per USP. Results showed that both the process variables had positive effect on mechanical strength of tablets and negative effect on disintegration and dissolution rate. Granule prepared with highest level of binder concentration (15%) and highest granulation time (60 sec) resulted in tablets with highest crushing strength (11.8 kg), specific crushing strength (0.328 kg/mm2), tensile strength (0.208 kg/mm2), lowest value of friability (0.19%) and highest disintegration time (10.9 min), as predicted from granules characteristics on the basis of SeDeM-ODT expert system. Drug release from Trial-13 (processed under highest level of both process parameters) was also lower than rest of the trials. It is concluded from the study that quality characteristics of tablets can be predicted from granules characteristics using SeDeM-ODT expert system. Furthermore, SeDeM-ODT expert system can also be used for optimization of the process of high shear wet granulation.

A novel composite binder design for direct ink writing alumina-based ceramics with enhanced strength at low sintering temperature

Direct ink writing (DIW), an extrusion-based additive manufacturing method, has been proposed as a versatile process for preparing ceramics for structural and functional applications. However, controlling the strength of ceramics during processing remains a challenge. In this study, a novel composite binder system consisting of aqueous polyvinylpyrrolidone solution and Al(H2PO4)3 gel was adopted for the DIW of alumina ceramics. Throughout the process, the mechanical performance, dimensional shrinkage, phase compositions and microstructure of samples were evaluated. The results indicate that the composite binder improves green strength by generating hydrogen bonding, which considerably enhances the strength of alumina ceramics under low-temperature sintering due to the reaction between Al(H2PO4)3 gel and nanosized clay particles. This also promotes the high-temperature sintering performance of Al2O3-based ceramics. Overall, the current composite binder is anticipated to be promising for DIW of alumina ceramics, providing sufficient strength for post-processing and greatly improving strength after low-temperature sintering.

The influence of ZrO2 addition on the morphological, structural, vibrational, and optical characteristics of composite fibers based on ZnO

In this work, pure ZnO and ZrO2 /ZnO composite fibers with different molar ratios (1: 3, 1: 1, 3: 1) were fabricated from homogeneously mixed zinc acetate, zirconium oxychloride and polyvinylpyrrolidone solution by electrospinning technique followed by heat treatment at 500 °C. The effects of ZrO2 concentration on the morphological, vibrational, structural, and optical features of the samples were investigated by diverse analyses. The beads-free and smooth structure of the composite nanofibers were examined by scanning electron microscopy. The crystallization of ZnO wurtzite and tetragonal ZrO2 structures were demonstrated using the Zn-O and Zr-O stretching vibrations in the Fourier transform infrared spectra and X-ray diffraction patterns. Also, the influence of ZrO2 concentration on the microstructure parameters of nanostructured samples was determined by the whole powder pattern modeling mean. The diffuse reflectance and photoluminescence spectroscopies were applied to investigate the optical properties of samples. The band gap value was estimated from the first derivative of the absorbance data with respect to the photon energy. The blue emissions (400–460 nm) in photoluminescence spectra were caused by defects like Zn interstitial/vacancy, Zr interstitial/vacancy, and O interstitial/vacancy. The characteristic blue emission shoulder at 2.59 eV may be raised of the electron transition from Zn interstitial to Zn vacancy.

Effect of glass nanofibers on mode I interlaminar fracture toughness of glass/epoxy composites

The idea of using glass nanofibers was proposed to overcome the weakness of out-of-plane properties of glass/epoxy composites. Glass nanofibers were produced by electrospinning solution of tetraethyl orthosilicate and polyvinylpyrrolidone as carrying polymer and dispersing the nanofibers in resin using an ultrasonic mixer. Various percentages of glass nanofibers were mixed with the resin and its effect on the tensile properties was investigated. Based on the tensile strength, the optimal percentage of nanofiber in the matrix was optimized. Finally, the hybrid composite was produced with unidirectional glass fabric using the optimized glass nanofibers content in resin. Interlaminar fracture toughness in mode I test was performed to investigate the effect of the addition of glass nanofibers on composites' mechanical properties. Results showed a significant increase (up to 91%) in interlaminar fracture toughness at the crack initiation state and caused a slight increase in the crack propagation load.

DEVELOPMENT OF A TECHNOLOGY FOR PRODUCING A STABLE INJECTABLE DOSAGE FORM OF A HYDROPHOBIC INDOLOCARBAZOLE DERIVATIVE

Objective: Development of a technology for the production of a stable injectable dosage form (IDF) of indolocarbazole derivative LHS-1269. Methods: LHS-1269 is an active pharmaceutical ingredient that was synthesized in the N. N. Blokhin National Medical Research Center of Oncology of the Ministry of Health of the Russian Federation. The IDF includes dimethyl sulfoxide (DMSO), 95% ethanol, Kollidon® 17PF and water for injection. Magnetic stirrer and overhead stirrer with a propeller stirring element were used to prepare the model solution of the IDF of LHS-1269. Sterilizing filtration of the solution was performed with 0.2−0.22 um polycarbonate, cellulose, polyvinylidene fluoride, polyethersulfone and nylon membrane filters. The aqueous solution of LHS-1269 was lyophilized in Edwards Minifast DO.2 freeze dryer. Assay of LHS-1269 was performed by spectrophotometry at 320±3 nm. Potentiometry was used to measure pH, a viscosimetry method was used to measure the viscosity of the solutions. The average weight was estimated by weighing a sample of 10 vials with the concentrate. Results: 0.5% aqueous solution of LHS-1269 was produced by mixing the solution of the active substance in DMSO and ethanol with an aqueous solution of polyvinylpyrrolidone gradually at the ratio of LHS-1269/DMSO/ethanol/Kollidon® of 1/11/32/40 by weight. The aqueous solution of the study substance cannot be lyophilized, so a sequence of technological operations was presented to produce an anhydrous concentrate “LHS-1269, concentrate for solution for injection and infusion 25 mg”. Conclusion: A technology was developed to produce a stable IDF of a hydrophobic indolocarbazole derivative LHS-1269, a high-potential antitumor drug.

Development of Antimicrobial Nitric Oxide-Releasing Fibers.

Nitric oxide (NO) is a highly reactive gas molecule, exhibiting antimicrobial properties. Because of its reactive nature, it is challenging to store and deliver NO efficiently as a therapeutic agent. The objective of this study was to develop NO-releasing polymeric fibers (NO-fibers), as an effective delivery platform for NO. NO-fibers were fabricated with biopolymer solutions of polyvinyl pyrrolidone (PVP) and ethylcellulose (EC), and derivatives of N-diazeniumdiolate (NONOate) as NO donor molecules, using an electrospinning system. We evaluated in vitro NO release kinetics, along with antimicrobial effects and cytotoxicity in microorganisms and human cell culture models. We also studied the long-term stability of NONOates in NO-fibers over 12 months. We demonstrated that the NO-fibers could release NO over 24 h, and showed inhibition of the growth of Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA), without causing cytotoxicity in human cells. NO-fibers were able to store NONOates for over 12 months at room temperature. This study presents the development of NO-fibers, and the feasibility of NO-fibers to efficiently store and deliver NO, which can be further developed as a bandage.

Investigation of the influence of calcination temperature on morphology and structure of electrospun 1D SnO2 nanostructures

The aim of the study was to manufacture the SnO2 one-dimensional nanostructures via the sol-gel technique and electrospinning methods from a solution of polyvinylpyrrolidone (PVP), tin chloride pentahydrate (SnCl4-5H2O), N, N-dimethylformamide (DMF) and ethanol (EtOH). The as obtained fibrous mats consisting of polymer and precursors particles were subjected to the heat treatment in air in the following temperatures 500, 600 °C to obtain pristine tin oxide nanowires. The scanning electron microscope (SEM) was used to determine the effect of calcination temperature on the morphology and structure of produced 1D SnO2. The energy dispersive spectrometry (EDX) and Fourier-Transform Infrared spectroscopy (FTIR) were performed to investigate the chemical composition and structure of manufactured nanomaterials, respectively.