Polyvinylpyrrolidone Solution Research Articles

Incorporation of composite metal-PVP derived carbon membranes for the percrystallisation of salt water

In this research using supported metal‑carbon membranes in a membrane percrystallisation application, we investigated the influence of metal ions on the formation of carbon during carbon membrane synthesis by combining polyvinylpyrrolidone (PVP) with various metal compounds, including zinc, potassium, barium, sodium, magnesium, calcium, and strontium, through calcination at 700 °C in a nitrogen atmosphere for the first time. These carbon membranes were then subjected to continuous percrystallisation experiments to produce dry salt crystals from salt solutions. The feed solution (3.5, 10, 20 wt% of salt) were used at 30, 50, and 70 °C for the performance evaluation. Intriguingly, the addition of metal elements to the PVP solution resulted in an enhancement in the total pore volume and surface area of the resulting carbon membranes. The PVP-Zn precursor exhibited the highest increase with a maximum improvement of 99 fold. Moreover, when compared to the PVP membranes alone, the composite membranes also exhibited higher fluxes. Among the tested composite carbon membranes, PVP-Ca, PVP-Zn, and PVP-Mg demonstrated the highest flux values, reaching an impressive 55 kg.m−2.h−1. Additionally, these membranes exhibited self-elimination, where salt was effectively removed from the membrane surface during percrystallisation testing. Thus, these membranes have the potential to be employed in desalination applications.

Incorporation of composite metal-PVP derived carbon membranes for the percrystallisation of salt water

In this research using supported metal‑carbon membranes in a membrane percrystallisation application, we investigated the influence of metal ions on the formation of carbon during carbon membrane synthesis by combining polyvinylpyrrolidone (PVP) with various metal compounds, including zinc, potassium, barium, sodium, magnesium, calcium, and strontium, through calcination at 700 °C in a nitrogen atmosphere for the first time. These carbon membranes were then subjected to continuous percrystallisation experiments to produce dry salt crystals from salt solutions. The feed solution (3.5, 10, 20 wt% of salt) were used at 30, 50, and 70 °C for the performance evaluation. Intriguingly, the addition of metal elements to the PVP solution resulted in an enhancement in the total pore volume and surface area of the resulting carbon membranes. The PVP-Zn precursor exhibited the highest increase with a maximum improvement of 99 fold. Moreover, when compared to the PVP membranes alone, the composite membranes also exhibited higher fluxes. Among the tested composite carbon membranes, PVP-Ca, PVP-Zn, and PVP-Mg demonstrated the highest flux values, reaching an impressive 55 kg.m−2.h−1. Additionally, these membranes exhibited self-elimination, where salt was effectively removed from the membrane surface during percrystallisation testing. Thus, these membranes have the potential to be employed in desalination applications.

Elasto-inertial particle focusing in sinusoidal microfluidic channels.

Dean flow existing in sinusoidal channels could enhance the throughput and efficiency for elasto-inertial particle focusing. However, the fundamental mechanisms of elasto-inertial focusing in sinusoidal channels are still unclear. This work employs four microfluidic devices with symmetric and asymmetric sinusoidal channels to explore the elasto-inertial focusing mechanisms over a wide range of flow rates. The effects of rheological property, flow rate, sinusoidal channel curvature, particle size, and asymmetric geometry on particle focusing performance are investigated. It is intriguing to find that the Dean flow makes a substantial contribution to the particle elasto-inertial focusing. The results illustrate that a better particle focusing performance and a faster focusing process are obtained in the sinusoidal channel with a small curvature radius due to stronger Dean flow. In addition, the particle focusing performance is also related to particle diameter and rheological properties, the larger particles show a better focusing performance than smaller particles, and the smaller flow rate is required for particles to achieve stable focusing at the outlet in the higher concentration of polyvinylpyrrolidone solutions. Our work offers an increased knowledge of the mechanisms of elasto-inertial focusing in sinusoidal channels. Ultimately, these results provide supportive guidelines into the design and development of sinusoidal elasto-inertial microfluidic devices for high-performance focusing.

Formulation, in vitro and in vivo evaluation of olanzapine nanoparticles dissolving microneedles for transdermal delivery

Olanzapine (OLZ) is classified as a typical antipsychotic drug utilized for the treatment of schizophrenia. Its oral bioavailability is 60% due to its low solubility and pre-systemic metabolism. Hence, the present work aims to formulate and evaluate OLZ nanoparticles dissolving microneedles (MNs) for transdermal delivery to overcome the problems associated with drug administration orally. OLZ nanoparticles were prepared by the nanoprecipitation method. The optimized OLZ nanoparticle formula was utilized for the fabrication of dissolving MNs by loading OLZ nanodispersion into polydimethylsiloxane (PDMS) micromould cavities, followed by casting the polymeric solution of polyvinylpyrrolidone(PVP-K30) and polyvinyl alcohol (PVA) to form MN matrix. The results revealed that the optimized OLZ nanoparticle formula (NP-5) exhibited particle size 115.76±5.45 nm, entrapment efficiency 78.4±5.46, and zeta potential -19.01±1.6 mV. The results of MNs revealed that MN-4 exhibits a high drug content of 98.52%, and ex vivo permeation through rabbit skin exhibited that MN-4 permeates more effectively than a simple patch by approximately 5.16 fold. In vivo pharmacokinetics study revealed that the area under curve AUC 0-∞ of MN-4 was 6054.56±376 ng. h/ml as compared with AUC0-∞ of marketed OLZ tablet was 3975.77±373 ng. h/ml. It can be concluded that the dissolving MN-4 patch is considered a promising formula to overcome the problems associated with drug administration orally and could improve drug bioavailability, in addition to the ease of administering the medication to schizophrenic patients.

Polyvinylpyrrolidone can prevent oolemma lysis caused by abnormal rupture of the plasma membrane in Piezo-ICSI.

The aim of this study was to investigate whether it is possible to prevent oolemma lysis after Piezo-assisted intracytoplasmic sperm injection (Piezo-ICSI) caused by abnormal membrane rupture. A total of 489 mature oocytes were obtained from 85 patients who underwent Piezo-ICSI in an infertility clinic. Inseminated oocytes were classified into the following two groups: normal rupture and abnormal rupture, and a portion of abnormally ruptured oocytes was randomly exposed to 7% PVP solution. Normal fertilization rate, degeneration rate, proportion of high-quality embryos on day 3, blastocyst formation, and morphologically high-quality blastocysts were compared. Abnormal rupture was defined as cytoplasmic membrane rupture before piezo pulse driving. Among the abnormal rupture groups, the normal fertilization and degeneration rates were compared between the high-stretched (ruptured at ≥ 50% during oocyte membrane stretching) and low-stretched (< 50% position) oocytes.The degeneration rate was significantly higher in abnormally ruptured oocytes than in normally ruptures oocytes (14.3% vs 1.3%, p < 0.001), and there was no significant difference in embryonic development after fertilization. PVP treatment immediately after oolemma rupture significantly decreased the degeneration rate (6.0% vs 19.7%, p = 0.031) and increased the normal fertilization rate. Similarly, there were no significant differences in the developmental potential. Furthermore, pregnancy outcome data showed no significant differences in pregnancy and live birth rates. The degeneration rate was reduced by treating low-stretched oocytes with PVP.Exposure to polyvinylpyrrolidone (PVP) immediately after abnormal membrane rupture represents an effective strategy to prevent oocyte degeneration. This is the first study to propose a strategy for the prevention of oocyte degeneration in Piezo-ICSI. These findings are expected to reduce the oocyte degeneration rate and increase normal fertilization rate as well as assist patients who can only acquire oocytes with weak plasma membranes.

Features of the Formation of a Reinforcing Coating on Hydrogel Membranes Based on Polyvinylpyrrolidone Copolymers

This paper presents the study results of formation features of composite hydrogel/polyamide membranes obtained by modification of hydrogel films based on 2-hydroxyethylmethacrylate (HEMA) and polyvinylpyrrolidone (PVP) copolymers. The formation process of composite two-layer membranes was carried out in two stages: obtaining hydrogel membrane substrates followed by their modification with an ultra-thin layer based on a mixture of polyamide (PA) with PVP. The main task of the work was to investigate the possibility of forming a modifying PA/PVP coating on the surface of hydrogel films and to obtain composite hydrogel membranes with the required strength and osmotic permeability based on them. For the formation of composite two-layer membranes, PVP with MM = 12 × 103 g/mol and MM = 360 × 103 g/mol were used. Additional use of PVP in the modifying solution contributes to the process of its penetration into the hydrogel substrate. Together with the formation of a reinforcing layer, this ensures the obtainment of hydrogel films of increased strength, with the possibility of directional regulation of their diffusion permeability. It was found that the main factors affecting the nature of the interaction between the layers of the obtained composite films, as well as their physico-mechanical and sorption–diffusion properties, are the HEMA:PVP ratio in the original polymer–monomer composition (PMC), the formulation of the reinforcing layer, the duration of the modification process and the molecular weight of PVP in PMC and in the modifying solution. The strength and water content of two-layer composite hydrogel/polyamide membranes, as well as their salt and water permeability coefficients, are the highest in the case of using high-molecular weight PVP (MMPVP = 360 × 103 g/mol) and low-molecular weight (MMPVP = 12 × 103 g/mol) during the synthesis of the hydrogel substrate to obtain a PA-6/PVP solution for forming a reinforcing layer.

Mass Spectrometry Imaging and Histology for the Analysis of Budding Intestinal Organoids.

Three-dimensional (3D) organoids have been at the forefront of regenerative medicine and cancer biology fields for the past decade. However, the fragile nature of organoids makes their spatial analysis challenging due to their budding structures and composition of single layer of cells. The standard sample preparation approaches can collapse the organoid morphology. Therefore, in this study, we evaluated several approaches to optimize a method compatible with both mass spectrometry imaging (MSI) and immunohistological techniques. Murine intestinal organoids were used to evaluate embedding in gelatin, carboxymethylcellulose (CMC)-gelatin-CMC-sucrose, or hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) solutions. Organoids were assessed with and without aldehyde fixation and analyzed for lipid distributions by MSI coupled with hematoxylin and eosin (H&E) staining and immunofluorescence (IF) in consecutive sections from the same sample. While chemical fixation preserves morphology for better histological outcomes, it can lead to suppression of the matrix-assisted laser desorption/ionization (MALDI) lipid signal. By contrast, leaving organoid samples unfixed enhanced MALDI lipid signal. The method that performed best for both MALDI and histological analysis was embedding unfixed samples in HPMC and PVP. This approach allowed assessment of cell proliferation by Ki67 while also identifying putative phosphatidylethanolamine (PE(18:0/18:1)), which was confirmed further by tandem MS approaches. Overall, these protocols will be amenable to multiplexing imaging mass spectrometry analysis with several histological assessments and help advance our understanding of the biological processes that take place in district subsets of cells in budding organoid structures.

THE EFFECT OF ESSENTIAL OIL ON FIBER MORPHOLOGY AND SURFACE PROPERTIES IN COAXIAL NANOFIBERS

In this study, core-shell nanofibers were produced by using hydrophilic polyvinylpyrrolidone (PVP) polymer in the core and hydrophobic poly(e-caprolactone) (PCL) polymer in the shell. Essential oil added nanofiber structures were developed by adding thyme oil (TEO) and borage oil (BO) in the PVP core part by using Triton X 100 (TX-100) as the surfactant. 8% PVP-8% PCL nanofibers were produced by adding TEO, BO and a 1:1 volume/volume mixture of these two (TEO:BO) to the PVP solution. Addition of essential oil and surfactant to the solutions resulted in different conductivity and viscosity values. SEM images were analyzed and it was observed that nanofiber diameters increased when essential oil and surfactant were added to the core of the coaxial nanofibers. Pristine, TEO-added, TEO:BO added and BO-added nanofibers were calculated as 145 ± 66, 233 ± 150, 245 ± 165 and 300 ± 124 nm, respectively. Besides, water contact angle measurements showed that TX-100 and essential oil additives caused high hydrophilization of nanofiber by changing the hydrophobic nature of PCL. While the contact angle of the 8% PVP-8% PCL sample without additives were 98°, the contact angle of the oil and surfactant containing samples were measured as 0°. In conclusion, it was observed that the nanofiber morphology and surface properties changed when different essential oils and surfactant were added to the core-shell nanofibers.

Facile and Low Temperature Synthesis of Nd1.8Sr0.2NiO4-δ Cathode Nanofibers for Intermediate Temperature Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are usually operated at high temperatures (800-1000 °C). As the overall efficiency of SOFC is governed by thermodynamics and kinetics during operation, reducing the operating temperature to 500-650 °C causes significant increase in the electrode polarization losses especially at cathode due to high activation energy towards oxygen reduction reaction (ORR) at cathode, which eventually reduces the overall cell performance. Addressing increased polarization losses at relatively low temperatures (500-650 °C) has been the key issue and a focus of many groups over past couple of decades. Conventional cathode materials lose their ORR activity and so discarded for intermediate temperature (IT)-SOFC application. In this regard, mixed ionic-electronic conductors (MIECs) offer high thermal and chemical stability along with high oxygen diffusion and good electronic conductivity at IT [1,2]. In addition, Ruddlesden-Popper (RP) type MIECs with A2BO4 structure have been demonstrated as promising cathode for IT- SOFCs due to their unique structure, rapid oxygen surface exchange kinetics, and excellent stability in atmosphere. Particularly Nd2NiO4+δ oxides offer an excellent oxygen diffusion coupled with high surface exchange coefficients and comparable thermal expansion coefficients with those of oxygen-ion conductors (YSZ and CGO) [2]. Enhanced electronic conductivity and electrochemical performance have been demonstrated for partial replacement of Nd with Sr in our previous reports [3].Albeit, the intrinsic material properties such as electrochemical catalytic activity and electrical conductivity are of primary importance, an actual electrode performance strongly depends on its microstructure. Therefore, in addition to using high catalytic and conductive materials, achieving an extremely high-power density, thus, requires a finely controlled electrode microstructure, to expand the electrochemically active triple-phase boundary (TPB). Recently, electrospinning has been considered as an efficient, cost effective and promising method for synthesis of ceramic nanofibers. Pertinent literature suggests that SOFC with cathode nanofiber has superior/better performance (nearly doubled power density and significant reduced polarization resistance) compared to powder type electrodes. Selection of suitable cathode materials with modified microstructure (nanofibers) would facilitate more electrochemically active sites for the oxygen reduction at relatively low temperatures <650 °C.In this paper we synthesized Nd1.8Sr0.2NiO4-δ (NSNO) cathode nanofibers using electrospinning technique and compared its electrochemical performance with NSNO nanopowder. Practically, 10 wt.% Polyvinylpyrrolidone (PVP) solution was prepared by dissolving it in ethanol, to which stoichiometric amounts of Nd-nitrate, Sr-nitrate, Ni-nitrate (total weight percentage of metal salts- 3 wt%) were added, together with some deionized water. The mixture was then stirred for 10 h at room temperature on a magnetic stirrer to obtain a homogeneous sol. The sol was loaded into the electrospinning syringe. Distance between the spinneret and the collector was fixed at 25 cm and the high-voltage supply was maintained at 30 kV. The spinning rate was controlled at 5 ml h- 1 by a syringe pump. The obtained nanofibers were dried at 80 °C for 12 h, then sintered at 900 °C for 2 h in air to obtain single-phase NSNO.The obtained nanofibers were characterized using room temperature XRD, XPS, SEM and dc electrical conductivity (400-650 °C). In addition, electrochemical impedance spectroscopy studies on symmetric cells were carried out as a function of temperature (400-650 °C). Improved electrochemical performance is attributed to enhanced electrochemical active sites for ORR due to nanofibers and optimum porosity.

Vac-and-fill: A micromoulding technique for fabricating microneedle arrays with vacuum-activated, hands-free mould-filling

We report a simple and reproducible micromoulding technique that dynamically fills microneedle moulds with a liquid formulation, using a plastic syringe, triggered by the application of vacuum (‘vac-and-fill’). As pressure around the syringe drops, air inside the syringe pushes the plunger to uncover an opening in the syringe and fill the microneedle mould without manual intervention, therefore removing inter-operator variability. The technique was validated by monitoring the plunger movement and pressure at which the mould would be filled over 10 vacuum cycles for various liquid formulation of varying viscosity (water, glycerol, 20% polyvinylpyrrolidone (PVP) solution or 40% PVP solution). Additionally, the impact of re-using the disposable syringes on plunger movement, and thus the fill pressure, was investigated using a 20% PVP solution. The fill pressure was consistent at 300–450mbar. It produced well-formed and mechanically robust PVP, poly(methylvinylether/maleic anhydride) and hydroxyethylcellulose microneedles from liquid formulations. This simple and inexpensive technique of micromoulding eliminated the air entrapment and bubble formation, which prevent reproducible microneedle formation, in the resultant microneedle arrays. It provides a cost-effective alternative to the conventional micromoulding techniques, where the application of vacuum (‘fill-and-vac’) or centrifugation following mould-filling may be unsuitable, ineffective or have poor reproducibility.

Microheater with copper nanofiber network via electrospinning and electroless deposition

In this report, we present the development of a copper nanofiber network-based microheater, designed for applications in electron microscopes, gas sensing, and cell culture platforms. The seed layer, essential for electroless deposition, was fabricated through the electrospinning of a palladium-contained polyvinylpyrrolidone solution followed by a heat treatment. This process minimized the contact resistance between nanofibers. We successfully fabricated a microheater with evenly distributed temperature by controlling the electrospinning time, heat treatment conditions, and electroless deposition time. We assessed the electrical and thermal characteristics of the microheater by examining the nanofiber density, sheet resistance, and transmittance. The microheater’s performance was evaluated by applying current, and we verified its capacity to heat up to a maximum of 350 °C. We further observed the microheater’s temperature distribution at varying current levels through an infrared camera. The entire manufacturing procedure takes place under normal pressure, eliminating the need for masking or etching processes. This renders the method easily adaptable to the mass production of microdevices. The method is expected to be applicable to various materials and sizes and is cost-effective compared to commercially produced microheaters developed through microelectromechanical system processes, which demand complex facilities and high cost.

Evaluation of Red Cell Deformability in Sickle Cell Disease Patients, Sickle Cell Carriers, and Healthy Controls Using Lorrca-Derived Parameters

BACKGROUND Red blood cell (RBC) deformability plays a critical role in RBC elongation and viscosity, and when reduced, perfusion of peripheral tissues and oxygen delivery are impaired. Intracellular ATP maintains water and ion homeostasis in RBCs; reduced ATP leads to water and ion loss, dehydration and loss of RBC elasticity. RBC dehydration increases mean corpuscular hemoglobin concentration (MCHC) and also affects distribution of RBC width (RDW). Patients with sickle cell disease (SCD) have reduced RBC ATP, and markedly reduced RBC deformability when compared to healthy individuals. Here, we employed Laser-Optical Rotational Red Cell Analyzer (LORRCA, RR Mechatronics) to evaluate deformability in RBCs from patients with SCD (HbSS) compared to RBCs from sickle cell carriers (HbAS) and ethnic-matched healthy controls (HbAA). We further analyzed how these LORRCA-derived parameters correlate with ATP, MCHC, and RDW. METHODS We enrolled adult subjects (age ≥ 18 years) of African-descent, and not recently transfused (within 8 weeks) under protocol NCT03685721 approved by the NHLBI Institutional Review Board. Fresh whole blood in EDTA was processed on the same day of collection. Cells were counted and diluted in polyvinylpyrrolidone (PVP) solution before undergoing LORRCA assays including deformability, osmoscan, and oxygenscan (HbSS subjects). The deformability assay uses the elongation Index (EI) to measure the cells' ability to undergo deformation with increasing shear stress at 0.95, 3, and 30 Pascals (Pa). The osmoscan assay measures the deformability under continuous osmotic changes (0-600mOsm/kg) and has several parameters: O min (RBC fragility); El max (maximum deformability and membrane flexibility); O max (osmolality where EI max is achieved) and O hyper (intracellular viscosity and maximum deformability in the hypertonic region). The oxygenscan assay measures the oxygen pressure at the time when RBCs start to become rigid (point of sickling). Whole blood levels of ATP were measured using LC-MS/MS with LLOQ at 50.0 μg/mL and converted to intracellular concentrations by dividing by the hematocrit (as a fraction). Descriptive statistics and correlation (Spearman) of ATP, RDW, and MCHC with each LORRCA parameter were performed using R (v4.2.3) and Prism(v9). RESULTS We studied 156 subjects which comprised of 63 HbSS (33 males), 61 HbAS (23 males) and 32 HbAA (8 males) genotypes. The average age in years (range) in HbSS was 32 (18-58); in HbAS, 43 (18-70), and in HbAA, 38 (19-72). As shear stress and osmotic pressure increased, the mean EI and osmolality were significantly (p&amp;lt;0.001, unpaired two-sample t-test) lower in the HbSS cohort compared to HbAS and HbAA (Figure 1). There was no significant difference in the mean EI and osmolality between HbAA and HbAS with increasing shear stresses and osmotic pressures. As shear stress increased, the correlation of deformability with reduced ATP got significantly stronger in the HbSS cohort (r= -0.351 at 0.95 Pa to r=-0.401 at 30 Pa) but the trend was reversed for the HbAS and HbAA cohort (Table 1). Under increasing osmotic pressure, a significant correlation was found between reduced ATP and maximal deformability (EI Max) in HbSS (p=0.008) compared to HbAS (p=0.896) and HbAA (p=0.114). MCHC was significantly correlated with RBC hydration state (O Hyper) in all 3 genotypic groups (HbSS, HbAS and HbAA). Similarly, RDW correlated with maximal deformability (EI Max) under increasing osmotic pressure in all 3 cohorts. In the HbSS subjects, there was a significant positive correlation of ATP and RDW with point of sickling (oxygenscan); MCHC was negatively correlated but was not significant. CONCLUSION RBC deformability was reduced in HbSS patients compared to HbAS and HbAA under increasing shear stress and osmotic pressure. ATP levels showed significant correlation with RBC deformability as measured by LORRCA, particularly in patients with SCD, suggesting increasing ATP levels as an important therapeutic strategy in patients with SCD. In keeping with published data, our analyses showed that RBC volume and size as well as intracellular hemoglobin concentration can affect deformability.

Study of Structural, Optical and Acoustical Properties of Sodium Sulfate Incorporated Polyvinyl Pyrrolidone (PVP) Composite

The structural, optical and acoustical properties of a polymer composite of sodium sulfate (Na2SO4) doped polyvinyl pyrrolidone (PVP) were studied. The simple chemical route method was utilized for the preparation of the polymer composite by varying the concentration of Na ions in the PVP. The pure 3% PVP solution was mixed with five different concentrations of Na2SO4 solutions in the ratio of 80:20. X-ray diffraction (XRD) spectra of PVP/Na2SO4 (1.0% of Na2SO4 in 3.0% of PVP) confirmed the crystalline nature of the PVP/Na2SO4 polymer composite. The identification of several chemical functional groups contained in the PVP/Na2SO4 was demonstrated by Fourier transform infrared (FTIR) spectroscopy. The FTIR showed the excellent interaction between the polymer (PVP) and the dopant Na2SO4. Optical studies were performed by utilizing a UV-visible absorbance spectrophotometer. The UV-VIS spectroscopy results indicated that absorption increased in an asymmetric manner and the absorption peak showed a red shift with increasing Na ions concentration in the host PVP. The optical band gaps (direct and indirect) were found to decrease with increase in Na ions concentration in the polymer due to increase in the density of localized states in the band-gap. The activation and Urbach energies were evaluated from the conductivity measurements and the absorption coefficient, respectively. Several acoustical parameters, viz. ultrasonic velocity, density, viscosity, adiabatic compressibility, intermolecular free length, acoustic impedance, and surface tension, were also computed. The ultrasonic velocity, acoustic impedance, density, viscosity, and surface tension of the polymer solutions were found to increase while the adiabatic compressibility and intermolecular free length decreased with the addition of increasing amounts of Na ions in PVP.

Blend of polyvinylpyrrolidone/thermally reduced graphene for adsorption of heavy metal ions in water

This paper presents the preparation of a modified polyvinylpyrrolidone (PVP)/graphene mixture and evaluates its adsorption capacity for heavy metal ions in water. Graphene with a high specific surface area of about 362 m2 g−1 was obtained through the thermal separation of graphite oxide (GO), which had been synthesised from graphite by the Hummer method. The graphene-PVP blend was prepared by dispersing the graphene into a PVP solution and then crosslinking it to prevent washout by water. This crosslinking ensured a well-dispersed and stable graphene-PVP blend. The maximum adsorption capacity of graphene-PVP for Cu2+ and Cd2+ ions was found to be 158 mg g−1 and 134 mg g−1, respectively, at pH 3 and a contact time of 30 min. The experimental results were found to be consistent with Langmuir and pseudo-second-order kinetic models. The study further reveals that the adsorption mechanism of Cu2+ and Cd2+ ions on graphene-PVP follows an ion exchange mechanism, driven by strong interactions between PVP and metal ions. The study provides an easy, low-cost, and eco-friendly method to produce highly adsorptive graphene-PVP materials.

Development of olanzapine solid dispersion by spray drying technique using screening design for solubility enhancement.

Olanzapine (OLZ) is a psychotropic class drug commonly used to treat schizophrenia, bipolar disorder, and acute manic episodes. It has less water solubility, resulting in a slow dissolution rate and oral bioavailability. Therefore, the development in oral dosage forms is required to enhance the drug solubility. The solid dispersion of olanzapine is prepared by spray drying technique. The solution of polyvinylpyrrolidone K-30 (PVP K-30), mono amino glycyrrhizinate pentahydrate (GLY), OLZ and silicon dioxide were dissolved in distilled water and ethanol and spray dried to get the solid dispersion. Solid dispersion was characterized for surface morphology, solubility, encapsulation efficiency (EE), X-ray diffraction (X-RD), Differential Scanning Calorimeter (DSC) and drug-polymer interaction by Fourier transforms infrared spectroscopy. The amorphous nature of the drug's incorporation in solid dispersion was confirmed by X-RD analysis. Prepared solid dispersion showed higher solubility, 11.51 mg, than pure OLZ (0.983 mg ml-1), while the range of EE was found to be between 64 to 90 %. The solubility and dissolution rate of the OLZ can effectively increase by spray-dried solid dispersion. Plackett-Burman screening design plays a vital role in understanding the effect of independent variables on EE and solubility.

Study of montmorillonite modification technology using polyvinylpyrrolidone

In this work, a new method of modifying montmorillonite (Mt) with polyvinylpyrrolidone (PVP) was developed, which makes it possible to obtain modified Mt with different structures and modifier content simultaneously. The essence of the method consists in mixing colloidal solutions of Mt and PVP, processing the mixture with ultrasound, settling, and selecting individual layers of the final solution. Several methods, such as scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetry (TG), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, have been used to characterize pure substances and to study the structure and thermal behavior of the composites. It was established that PVP macromolecules could both intercalate in the interlayer space of Mt and form exclusively exfoliated Mt. In addition, under certain conditions, Mt flocculated with PVP can be obtained. It is shown that during intercalation, PVP macromolecules displace and replace montmorillonite water in the interlayer space of clay mineral.

Preparation of high-purity gallium oxide via gallium hydrolysis

Gallium oxide (Ga2O3), a promising semiconductor material, has attracted significant attention in recent years. This study focuses on a method for rapidly obtaining high-purity Ga2O3 through the one-step hydrolysis of gallium in an alkaline environment to address the challenges of complex experimental equipment and the high-pressure condition of the traditional method. Uniformly dispersed rod-like GaOOH with a length of 2 µm is prepared using a 5 mM polyvinylpyrrolidone solution. Additionally, Ga2O3 (500 °C α-Ga2O3 and 800 °C β-Ga2O3) with different crystal forms is prepared by calcinating GaOOH at different temperatures. Compared with conventional methods, this approach offers a fast, safe, and cheap process for preparing high-purity Ga2O3.

Iron Oxide Nanoparticles Produced by a Low-Energy Nd: YAG Laser Ablation Technique and Their Application as Contrast Agent for Magnetic Resonance Imaging

A magnetic resonance imaging contrast agent is proposed using iron oxide nanoparticles (IONPs) synthesized by a pulsed laser ablation technique. Experimentally, an Nd: YAG laser (1064 nm, 7 ns, 30 mJ) was directed and focused on a high-purity iron plate immersed in a liquid solution of deionized water and polyvinylpyrrolidone (PVP). After a few minutes of laser bombardment, iron oxide nanoparticles dispersed in the liquid were homogeneously produced. A reddish yellow color-colloidal IONPs are produced in the water, while its color changes to dark brown for the PVP solution. The characterization results demonstrated that IONPs in the form of Fe2O3 and Fe3O4 made in the PVP have an excellent dispersibility with a spherical shape that is significantly smaller than that of IONPs made in the deionized water at the same laser repetition rate. The produced IONPs are further applied as a contrast agent for the magnetic resonance imaging (MRI) modality by varying concentrations from 0.05 mM to 2.31 mM. The results demonstrated that images of the IONPs sample with a concentration of 2.31 mM showed the highest contrast enhancement (Cenh), with an enhancement factor of 221.875 % for T1-weighted images and 91.227 % for T2-weighted images. IONPs with a concentration of 2.31 mM had the highest signal-to-noise ratio (SNR) for a T1-weighted picture of 52.92, while IONPs with a concentration of 0.05 mM had the highest SNR for a T2-weighted image of 179.117.

Polyaniline/polyvinylpyrrolidone nanofibers via nozzle‐free electrospinning

AbstractPolyaniline (PANI) in its emeraldine base (PANI‐EB) and salt (PANI‐ES) forms was combined with polyvinylpyrrolidone (PVP) to produce nanofibers in a one‐step electrospinning process using a nozzle‐free electrospinning setup for the first time. The surface morphologies and chemical structure of the composite nanofibers were characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy—attenuated total reflectance (FTIR‐ATR), and energy‐dispersive X‐ray spectroscopy (EDX). Four PANI/PVP electrospun nanofibers with different PANI concentrations were prepared to investigate the effect of PANI concentration on the structure and properties of the nanofibers. The incorporation of different contents of PANI‐EB and PANI‐ES in the PVP solution and their impact on the fiber morphology were investigated.

The Influence of Wet Granulation Parameters on the Compaction Behavior and Tablet Strength of a Hydralazine Powder Mixture.

The aim of this paper was to describe the influence of high-shear wet granulation process parameters on tablet tensile strength and compaction behavior of a powder mixture and granules containing hydralazine. The hydralazine powder mixture and eight types of granules were compacted into tablets and evaluated using the Heckel, Kawakita and Adams analyses. The granules were created using two types of granulation liquid (distilled water and aqueous solution of polyvinylpyrrolidone), at different impeller speeds (500 and 700 rpm) and with different wet massing times (without wet massing and for 2 min). Granulation resulted in improved compressibility, reduced dustiness and narrower particle-size distribution. A significant influence of wet massing time on parameters from the Kawakita and Adams analysis was found. Wet massing time had an equally significant effect on tablet tensile strength, regardless of the granulation liquid used. Granules formed with the same wet massing time showed the same trends in tabletability graphs. Tablets created using a single-tablet press (batch compaction) and an eccentric tablet press showed opposite values of tensile strength. Tablets from granules with a higher bulk density showed lower strength during batch compaction and, conversely, higher strength during eccentric tableting.