Polyvinyl Pyrrolidine Research Articles

Co-delivery of gentiopicroside and thymoquinone using electrospun m-PEG/PVP nanofibers: In-vitro and In vivo studies for antibacterial wound dressing in diabetic rats

Nanofibers (NFs) provide several delivery advantages like their great flexibility and similarity with extracellular matrix (ECM) which qualify them to be the unique model of a wound dressing. NFs could create mats of polymeric matrix loaded with an active agent enhancing its solubility and stability. In our study, Gentiopicroside (GPS) and Thymoquinone (TQ) loaded in NFs polymeric mats composed of coblended polyvinyl pyrrolidine (PVP) and methyl ether Polyethylene glycol (m-PEG) were fabricated via electrospinning technique. A morphological study using Scanning Electron Microscopy (SEM) was performed for all formulae as well as in vitro release study using High-performance Liquid chromatography (HPLC) for sample analysis. The optimized formula (F3) was chosen for further assays using Fourier-Transform Infrared Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC). Study of the antibacterial effect, and in vivo healing action for diabetic infected wounds to quantify Tumor necrosis factor-alpha and Cyclooxygenase-2 were also investigated. F3 achieved the highest % cumulative release (99.79 ± 6.47 for GPS and 96.89 ± 6.87 for TQ) at 60 min, and a smaller diameter (200 nm) showing significant anti-bacterial effects with well-organized skin architecture demonstrating great healing signs. Our results revealed that m-PEG/PVP NFs mats loaded with GPS and TQ could be considered an optimal wound care dressing.

Performance investigation of silica gel based consolidated composite adsorbents effective for adsorption desalination systems

Performance of an adsorption desalination system is mostly influenced by the type of adsorbent and their thermo physical properties such as thermal stability, thermal conductivity, surface area and pore volume. Silica gel and zeolite are the most widely employed conventional adsorbents in an adsorption desalination system. But they are characterised by low thermal stability, high desorption temperature and low percentage of water productivity. These limited adsorption capabilities of conventional adsorbent lead to low system performance. The motivation of this work is to synthesis a consolidated composite adsorbent using conventional adsorbent and other highly porous material such as metal organic frame work (MoFs) for a better adsorption capability. The introduction of such materials in adsorption desalination system is expected to significantly improve the performance due to their better adsorption/desorption capacity. Present study introduces three different combination of composite adsorbents synthesised from silica gel and MOFs with poly vinyl pyrrolidine as binder. Silica gel is used as the parent adsorbent in all three combinations. Aluminium fumarate and nickel based MoFs (CPO-27Ni) are used as the secondary adsorbents. Three combination are namely, composite 1 (silica gel and CPO-27Ni MOF), composite 2 (silicagel and aluminium fumarate) and composite 3 (silica gel, CPO-27-Ni and aluminium fumarate). Surface area, pore volume, thermal stability and adsorption capacity of composite adsorbents are evaluated in this study. It is found that the composite 2 gives maximum BET surface area of 590 ± 10 m2/g with a pore volume of 0.279cc/g. It also exhibit superior adsorption capacity than other composite adsorbents. Maximum adsorption capacity of composite 2 is found to be 0.315 kg/kg of adsorbent. Performance evaluation of composite adsorbents in a single bed adsorption desalination system is also included in this study. A single bed adsorption desalination system is designed, fabricated and tested under the meteorological condition of Kollam, Kerala, India. Performance evaluation reveals that the three composite adsorbent can co generate potable water and cooling effect in the adsorption desalination system. At an evaporation temperature of 200 C, composite 2 exhibits comparatively better desalination and cooling effect. Water productivity and coefficient of performance of composite 2 is found to be 1.12 kg/kg of adsorbent and 0.315 respectively. Composite 1 and composite 3 gives moderate or more minor desalination and cooling effect in the system. The yield of adsorption desalination system using composite 2 is found to be 16% higher than that of conventional adsorbent such as silica gel. Results highlight that composite adsorbent composed of conventional adsorbent and MOF can be a potential candidate for adsorption desalination application.

Evaluation of Dissolution Behavior of Cefuroxime Axetil as Affected by Polymeric Interaction Using Mixture Design Experiment

The objective of this project was to improve the solubility of poorly water soluble drugs, namely cefuroxime axetil by formulating solid dispersions with hydrophilic polymer. Hydroxypropyl methyl cellulose (HPMC), polyvinyl pyrrolidine (PVP) and polyethylene glycol (PEG) were used as polymeric carriers for the preparation of solid dispersion. Solid dispersions were prepared by the solvent extraction method. Interaction effect of HPMC, PVP and PEG was investigated using a simplex mixture design. A fitted mathematical model was used to express each response as a function of the proportion of the blend components that are able to empirically predict the response to any blend of combination of the components. The synergistic interaction effect of the ternary HPMC: PVP: PEG blend was shown to be strongest among the experimental blends. Nevertheless, an antagonistic interaction effect becomes significant as the HPMC proportion increases in the blends. The study revealed that a mixture design could be a valuable tool in better elucidating and predicting the effects on dissolution beyond the conventional one component blend. Dhaka Univ. J. Pharm. Sci. 20(3): 317-324, 2022 (June) Centennial Special Issue

EVALUATION OF DIFFERENT GRADES OF GUAR GUM, ACACIA GUM, AND POLYVINYL PYRROLIDONE AS CROSS-LINKERS IN PRODUCING SUBMICRON PARTICLES

Objective: The main goal of this research is to evaluate using of guar gum (GG), Arabic gum, and poly-vinylpyrrolidone, each of two viscosity grades, as crosslinking agents in producing nanoparticles and submicron particles. Methods: The method used is the preparation of nanoparticles of carbamazepine using two viscosity grades of polymers (GG, acacia gum, and polyvinyl pyrrolidine) by emulsification/solvent evaporation technique. Based on a statistical design composed of mixed 32-levels factors and 13-levels factor was selected for screening and preliminary optimization purposes. The collected nanoparticles from the first portion of all 24 runs were subjected to the following qualifications, particle diameter, polydispersity index (PDI%), zeta potential, entrapment efficiency (EE%), and drug loading. Results: The study revealed that based on the obtained findings and the associated statistical analysis, influences of stirring rate, polymer type, polymer grade, and polymer loading in different formulation runs resulted in produced particles with different characteristics such as particle size of different formulation series are in sub-micron (0.13–91.83 μm) with EE% (max 52.28%), reduced EE observed in this study can be attributed to lower polymer load in the dispersed phase (1% and 10%) and zeta potential values were small (range 35.69–41.68), all preparation factors have no significant effect on zeta potential, PDI values (close to zero) showed that all the samples formed monodispersions in water and its due to steric hindrance than a surface charge. Conclusion: The study recommends that different polymers need special techniques for producing cross-linked particles with sub-micron particles, no universal technique can be applied. Keywords: Polymer, Guar gum, Acacia gum, Polyvinyl pyrrolidine, Carbamazepine, Emulsification/solvent evaporation technique, Stirring rate.

Preparation and Bio Pharmaceutical Evaluation of Chrono Pharmaceutical Drug Delivery System of Atenolol

A time-adjustable pulsatile release system containing atenolol as an active pharmaceutical agent was developed for bedtime dosage administration and release of medicine in the early morning to manage elevated blood pressure. The system contained an immediate release (IR) core, a sustained-release (SR) plug, and a mucoadhesive cup layer and it was designed by the cup and core technique. The immediate-release layer was composed of atenolol, croscarmellose sodium, microcrystalline cellulose (MCC), sorbitol, talc, and magnesium stearate. The SR plug was composed of hydroxyl propyl methylcellulose (HPMC), polyvinyl pyrrolidine (PVP), MCC, Lactose, talc, and magnesium stearate. The mucoadhesive cup contains polycaprolactone and mucoadhesive polymer chitosan. Bilayer tablets were punched by applying different compressive forces. Based on the Release data of the drug from each layer F5 and S5 were selected for the preparation of the bilayer tablet. Cup composition containing 3% of chitosan provided the highest mucoadhesion time up to 10h. Pulsatile delivery of the drug from the formulation was observed at 300 min after the administration of the drug. The constructed pulsatile delivery systems were compared to that of commercially available atenolol IR tablet. The comparison demonstrated that the formulation is suitable for the intended chronopharmaceutical delivery of antihypertensive drugs. Keywords: Chronopharmaceuticals, Pulsatile Drug Delivery, Hypertension, Mucoadhesive Polymer, Atenolol

The use of pectin to synthesis and characterize hydrogel (composite, grafting and blending) and study of some water retention properties

This research was conducted to purpose preparing and characterization various types of hydrogels such as blending, composite and grafting. This was done by reacting monomers such as acrylamide (A.M), methyl acrylate (M.A) and polymers. Polyvinyl Pyrrolidine (PVP) and carboxymethyl cellulose (CMC) with pectin was prepared from citrus peels. Hydrogel polymers (graft, blend and composite) were characterized using different techniques such as Fourier Transformed Infrared spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM). The results of the reactions were identical to the theoretical expectations. The study was conducted to find out some properties such as swelling in water and absorption at different temperatures 25 °C and 20 °C, and the results were shown as a (559.9%, 429.2%) and (515.2%, 363.2%) respectively.

Facile Co3O4 nanoparticles deposited on polyvinylpyrrolidine for efficient water oxidation in alkaline media

AbstractTo develop an inexpensive, earthabundant, efficient, and stable catalyst is very crucial for the realization of renewable energy for practical applications, but it is a difficult task. In this research study, we have deposited Co3O4 nanoparticles on polyvinylpyrrolidine (PVP) through electro‐spun technique followed by carbonization. The structure and composition studies were carried by scanning electron microscopy, energy‐dispersive spectroscopy, and powder X‐ray diffraction techniques. The Co3O4 nanoparticles are deposited on the nanofibers of PVP with improved surface area and conductivity; therefore, the hybrid material has shown an excellent oxygen evolution reaction (OER) in alkaline media. The onset potential for the presented OER catalyst is about 1.46 V versus reversible hydrogen electrode, and an overpotential of 280 mV is needed to reach a current density of 10 mAcm−2. The Co3O4 nanoparticles are highly durable for 20 hr and very stable. The low charge transfer resistance of 29.23 Ω is offered by the Co3O4 hybrid material, which facilitated the OER kinetics in alkaline media. These obtained OER results may be utilized for the overall water splitting and the synthetic strategy is low cost, thus it favors the mass production of functional materials for diverse electrochemical applications.

Bioavailability Enhancement of Ritonavir by Solid Dispersion Technique

Ritonavir is an antiretroviral agent used in the treatment of HIV-infection. It is a BCS class IV drug having poor aqueous solubility leading to poor bioavailability. Bioavailability is the amount of drug that enters the systemic circulation. The bioavailability is affected by various factors like solubility, dissolution and stability. In order to improve bioavailability, many techniques like solid dispersions, nanoparticles, liposomes, encapsulation methods were present. The main aim of this study is to improve the bioavailability of ritonavir with the help of Polyvinyl Pyrrolidone (PVP) K-30 by using solid dispersion technique. Different formulations were made with varied concentrations of polymer. Characterization of solid dispersion was done by phase solubility, drug content, Fourier transformed infrared spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and in-vitro dissolution studies. From phase solubility studies that apparent solubility constant was found to be 42.227M-1. The drug content of the binary system of ritonavir and PVP was found to be ranging from 99.17% to 103.06%. %. FT-IR studies revealed that there was no drastic change in the wave number indicating polymer compatibility with drug. In-vitro dissolution studies proved that there was an increase in drug release of ritonavir with incremental ratios of polymer and F5 formulation has shown almost 95% of drug release.
 Keywords: Bioavailability, Solid dispersion, Polyvinyl pyrrolidine, Solvent evaporation, Dissolution.

Synergetic influence of F-MWCNTS on polyvinylpyrrolidone sodium alginate composite membrane for reverse osmosis

In this study, novel composite membrane of functionalized multi-walled carbon nanotubes (F-MWCNTs) polyvinyl pyrrolidine (PVP) and sodium alginate (Na-Alg) with unique characteristics were synthesized for the application of reverse osmosis (RO) desalination. The MWCNTs in different amounts were systematically and uniformly dispersed in PVP/Na-Alg polymer matrix during the synthesis of membranes by dissolution casting method. The effect of F-MWCNTs content in the performance of the composite membrane was investigated for RO desalination process compared to PVP/Na-Alg blended membrane. The spectral studies were carried out by Fourier transform infrared spectroscopy (chemical bonding) and scanning electron microscopy (surface morphology). The thermogravimetric analysis (TGA) of membranes also recommended that composite membrane with the highest content of F-MWCNT has more excellent thermal stability compared to PVP/Na-Alg blended membrane and other modified membrane samples. The most striking experimental results show that the incorporation of F-MWCNTs improved the general RO performance of the composite membranes. The modified composite membrane surface became rough as compared to the PVP/Na-Alg blend membrane surface. The PVP/Na-Alg blended membrane shows a maximum permeation flux of 5.5 L/m2h and high-water content. This experimental analysis also presented that tethered F-MWCNTs/PVP/Na-Alg polymer matrix membrane, with stronger F-MWCNTs/polymer matrix interactions, enhanced the composite membrane's salt rejection performance by 85.4% for the highest content of F-MWCNTs. Therefore, it can be concluded that all the membrane samples presented excellent capacity to resist the growth of gram-negative E. coli bacteria.

(Invited) Critical Effect of Particle Size in Ru-Catalyzed Electrosynthesis of Ammonia

Electrochemical reduction of N2 to NH3 has recently received considerable attention, because it may enable sustainable, distributed production of NH3 when powered by solar- or wind-generated electricity. However, typical catalysts show a low activity and selectivity for N2 reduction reaction (NRR) due to the barrier for N2 activation and the competing hydrogen evolution reaction (HER). A rational design of NRR catalysts relies on our understandings of structure-activity relationships and active sites for the NRR, and such study requires model catalysts with well-defined structures. Here we present a study of size-dependent activity for the NRR on Ru nanoparticle catalysts. We first tried colloidal synthesis method with polyvinylpyrrolidine (PVP) as a surfactant to control the size of Ru nanoparticles, while the derived Ru catalysts showed negligible activity for NRR, which was attributed to residual surfactant molecules that blocked catalyst surfaces. Therefore, we used atomic layer deposition (ALD) method to prepare Ru nanoparticles with controlled sizes and clean surfaces. We also quantified the electrochemical active surface areas of Ru samples and measured surface-area-normalized activity for the NRR. Consequently, the effect of Ru nanoparticle size on the NRR activity and Faradaic efficiency was revealed, which can provide insights into the active sites for the NRR and guidance on the design of NRR catalysts via surface site engineering.

Evaluation of antioxidant and anticancer effects of Piper betle L (Piperaceae) leaf extract on MCF-7 cells, and preparation of transdermal patches of the extract

Purpose: To determine the antioxidant and anticancer effects of Piper betle (P. betle) leaf extract on human breast cancer MCF-7 cells, and to develop transdermal patches containing the extract.
 Methods: The leaf extract of P. betle was prepared by maceration method, and its antioxidant activity was evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Cytotoxicity and suppression of cell migration (indices of anticancer activity) were also assessed in MCF-7 cells by sulforhodamine B (SRB) and wound healing assays, respectively. Transdermal patches were developed using the casting method, and the resultant patches were evaluated with regard to their physical appearance and mechanical properties before and after a stability test.
 Results: The extract exhibited antioxidant activity with half-maximal inhibitory concentration (IC50) of 30.0 ± 0.1 µg/mL. It also showed cytotoxicity with an IC50 of 114.3 ± 14.9 µg/mL, and significantly suppressed the migration of MCF-7 cells at a dose of 25 µg/mL. Based on desirable characteristics, patch base formulations containing 4.2 % pectin, 0.4 % hydroxyl propyl methylcellulose (HPMC), 0.4 % polyvinyl pyrrolidine K-90 (PVP-K90) and 3 % propylene glycol (PG) were selected for incorporation into the extract.
 Conclusion: Leaf extract of P. betle exhibits potential anti-breast cancer properties. A transdermal patch containing 0.03 % of the extract can be successfully developed for treatment of breast cancer.

The effect of PVP: BaTiO3 interlayer on the conduction mechanism and electrical properties at MPS structures

In this paper, the influence of doping barium titanate in the polyvinyl pyrrolidine polymer sandwiched between the metal-semiconductor on the conduction mechanism and the electrical properties of the formed diode has been examined. The barium titanate nanostructure is prepared by microwave assisted method. The TGD/DTA, x-ray diffraction pattern (XRD), Field Emission Scanning Electron Microscope (FE-SEM), Electron Dispersive x-ray (EDX) and UV-Vis spectroscopy analyses are performed in order to determine the calcination temperature, average crystalline size, surface morphology, purity specification, and optical properties of the prepared barium titanate nanostructure, respectively. The main electrical parameters such as the ideality factor (n), barrier height (BH), leakage current (I0), shunt (Rsh) and series (Rs) resistances of the Al/PVP: BaTiO3/p-Si (MPS) and Al/p-Si (MS) structures are calculated by Thermionic Emission (TE), Norde, and Cheung methods by measuring the I–V characteristics of the both diodes at ±6 V and compared with each other. Moreover, the surface states density (Nss) as a function of energy at forward bias and the current conduction mechanisms at forward and revers bias are investigated. The rectifying ratio of MPS diode is enhanced by reducing the n, Rs, Nss, I0 and by increasing shunt resistance (Rsh), BH due to presence of interfacial layer. Therefore, PVP: BaTiO3 interlayer can be a suitable alternative replacement of intrinsic interlayer for utilization in the nanoscale electronic and optoelectronic devices and circuits.

Investigations on Al2O3 dispersed PEO/PVP based Na+ ion conducting blend polymer electrolytes

In this current study, Na+ ion conducting solid blend polymer electrolytes (NCSBPEs) based on polyethylene oxide (PEO) / polyvinyl pyrrolidine (PVP) / sodium nitrate (NaNO3) with the addition of different wt.% aluminum oxide (Al2O3) as filler were prepared using solution casting technique. The prepared solid blend polymer electrolytes are subjected to X-ray diffraction (XRD), Fourier transforms infrared (FTIR), and AC-impedance techniques. The complexation has been studied using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) measurements. AC-impedance spectroscopy has been used to analyze the ionic conductivity of the solid blend polymer electrolytes. The higher ionic conductivity $$(\sigma )$$ ~10–7 S/cm−1 is obtained for PEO: PVP: NaNO3 film and it was enhanced to ~ 10–5 S/cm−1 with the addition of Al2O3 filler at the ambient temperature. The dielectric and tan δ values were also calculated using the impedance analysis. In LSV (linear sweep voltammetry) studies, a broad electrochemical stability window was observed for polymer electrolytes besides CV (cyclic voltammetry) studies confirm the electrochemical behavior of the electrolytes.

Tailoring the photoluminescent and electrical properties of tin-doped ZnS@PVP polymeric composite films for LEDs applications

Abstract In the present work, tailoring the photoluminescent and electrical properties of Zn1-xSnxS@PVP polymeric composite films has been achieved for LEDs applications. Un-doped and 1.0 wt % of Sn-doped ZnS in polyvinyl pyrrolidine (Zn1-xSnxS@PVP) polymeric composite films were prepared using solution casting technique. The effect of Sn molar ratio x (x: 0 to 0.3) on the morphological, structural, photoluminescent and electrical properties is explored using a scanning electron microscope, X-ray diffraction (XRD), photoluminescence (PL) and DC electrical conductivity studies. XRD measurements reveal the amorphous nature of both bare PVP and Zn1-xSnxS@PVP polymeric composite films. The PL spectra measurements of the prepared films exhibit broad emission peaks with maxima intensities ranged from 400 to 417 nm. The Gaussian fitting method is used to de-convolute the PL emission bands of bare PVP and Zn1-xSnxS@PVP polymeric composite films. Three emission peaks for ZnS@PVP polymeric film are noticed at 392, 430 and 476 nm. An extra emission peak located at the green light region (480–502 nm) is observed for Zn1-xSnxS@PVP composite films. The electrical conductivity of the prepared Zn1-xSnxS@PVP polymeric composite films is enhanced thirty times more than that of bare PVP one. The prepared Zn1-xSnxS@PVP polymeric composite films could play an important role in LEDs applications.

Preliminary Characterization and Comparison of Mucilage from Leaves of Hibiscus Sabdariffa L. as A Tablet Binder

The present research dealt with the extraction and characterization of mucilage from the Hibiscus sabdariffa leaves. Compared with normal binding agents such as starch and Poly Vinyl Pyrrolidine (PVP), the mucilage of Hibiscus sabdariffa (HSM) was assessed for its binding properties in tablet formulations. Tablets were formulated using HSM, starch and PVP as binders at a various concentration to evaluate its comparative binding efficiency. The compressed tablets were analyze for their quality control tests as per IP. The extracted HSM showed the characteristics of mucilage and good physicochemical properties. The FTIR and thermal analysis compatibility tests showed that there were no significant reactions between the drug and mucilage. Granule properties of various formulations were found to be comparable and have excellent flow characteristics. Post compression parameters suggested that tablets formulated with mucilage had better hardness and friability as that of the tablets prepared with starch and PVP. The formulations exhibited a better and more consistent release as compared to standard formulations using starch and PVP as a binder. The statistical analysis of in vitro dissolution profile by using DD solver software for difference factor (f1), similarity factor (f2), and Rescigno index (ξ) values also indicated promising results. The results notably indicate that binding property of HSM was at par with starch and PVP.

Assessing magnetic and inductive thermal properties of various surfactants functionalised Fe3O4 nanoparticles for hyperthermia

This work reports the fabrication of magnetite (Fe3O4) nanoparticles (NPs) coated with various biocompatible surfactants such as glutamic acid (GA), citric acid (CA), polyethylene glycol (PEG), polyvinylpyrrolidine (PVP), ethylene diamine (EDA) and cetyl-trimethyl ammonium bromide (CTAB) via co-precipitation method and their comparative inductive heating ability for hyperthermia (HT) applications. X-ray and electron diffraction analyses validated the formation of well crystallined inverse spinel structured Fe3O4 NPs (crystallite size of ~ 8–10 nm). Magnetic studies confirmed the superparamagnetic (SPM) behaviour for all the NPs with substantial magnetisation (63–68 emu/g) and enhanced magnetic susceptibility is attributed to the greater number of occupations of Fe2+ ions in the lattice as revealed by X-ray photoelectron spectroscopy (XPS). Moreover, distinctive heating response (specific absorption rate, SAR from 130 to 44 W/g) of NPs with similar size and magnetisation is observed. The present study was successful in establishing a direct correlation between relaxation time (~ 9.42–15.92 ns) and heating efficiency of each surface functionalised NPs. Moreover, heat dissipated in different surface grafted NPs is found to be dependent on magnetic susceptibility, magnetic anisotropy and magnetic relaxation time. These results open very promising avenues to design surface functionalised magnetite NPs for effective HT applications.

The Effect of Poly (Vynil Pyrrolidine) (PVP) Added in Variation of Ca2+ and PO43- Concentration in Microbial Cellulose-Hydroxyapatite Composite As Scaffold For Bone Healing

In Indonesia, the traffic accident causing 6 million people suffered injuries, particularly injuries fractures. 46.2% incidence of fractures occur in the lower extremities, 25% of them dying, 45% had a physical disability, 15% experienced psychological pressure and only 10% were healed well. Implant (graft) are used to support and accelerate the healing process of broken bones (bone healing). This study was done to make microbial cellulose-hydroxyapatite scaffold as a candidate for bone healing. Microbial cellulose obtained from culturing Acetobacter xylinum is used as a matrix and hydroxyapatite as a filler that is synthesized using the method of immersion in a solution of CaCl2 and KH2PO4, to increase the formation of apatite crystals, added polyvinyl Pyrrolidine (PVP). Scaffold synthesized using methods of freeze dried. Formation of composites varied in the concentration of Ca2+ and PO 3- of 25:125; 50:100; 75:75; 100:50 mM. The samples were then characterized using FTIR spectroscopy which shows the phosphate groups and the carbonate indicates the formation of hydroxyapatite in the eighth sample. Furthermore, to determine the morphology and identify the elements in the scaffold used SEM-EDAX, it was found that the pore formed measuring about 150-300 μm and obtained ratio of Ca / P best on microbial cellulose scaffold-PVP-hydroxyapatite with a variation of the concentration of Ca2+ and PO43- of 100 : 50 mM is equal to 0.6046 with an average degradation rate of 18.617% and the percentage of porosity contained in the sample amounted to 88.4%. This proves that microbial cellulose scaffold-PVP-hydroxyapatite with a variation of the concentration of Ca2+ and PO43- of 100:50 mM potential as a candidate for bone healing.

Influence of calcination temperature on the growth of electrospun multi-junction ZnO nanowires: A room temperature ammonia sensor

Chemiresistive gas sensors play a significant role in human exhaled breath analysis for non-invasive disease diagnosis applications. Ammonia has been considered as one of the prominent biomarkers, which is present in the exhaled breath of persons affected by chronic kidney disease (CKD). In this context, polyvinyl pyrrolidine (PVP) - zinc oxide (ZnO) nanofibers based chemiresistive gas sensor has been developed for the detection of ammonia at room temperature. PVP-ZnO nanofibers were synthesized using electrospinning technique with an applied potential of 20 kV. The synthesized nanofibers were calcined in the temperature range of 200–700°C in steps of 100°C. The influence of calcination temperature on the structural, morphological, electrical and optical properties were investigated using various characterization techniques. Further, calcinated samples were drop cast onto the Ag/Pd electrode for sensing studies using a homemade gas chamber integrated with high resistance electrometer. The sample calcined at 500°C showed a selective response towards ammonia with a response of 20 towards 50 ppm, and response and recovery times of 88 and 65 s.

Electrospun nanofiber-based niflumic acid capsules with superior physicochemical properties

The aim of this study was to assess whether nanofibrous drug mats have potential as delivery systems for poorly water-soluble drugs. Amorphous nanofiber mats from a model poorly water-soluble active pharmaceutical ingredient (API), niflumic acid, together with the polymer excipient, polyvinyl pyrrolidine, were prepared by nozzle-free electrospinning. This technique offers a scalable way for drug formulation, and by increasing the surface area of the drug, the dissolution rate and therefore bioavailability of the API can be improved. In this study, both the amount of the dissolved active ingredient and the dissolution kinetics has been improved significantly when the nanofibrous mats were used in the drug formulation. A 15-fold increase in the dissolved amount of the produced amorphous niflumic acid nanofiber was observed compared to the dissolved amount of the raw drug within the first 15 min. Capsule formulation was made by mixing the electrospun nanofibers with a microcrystalline cellulose filler agent. When comparing the dissolution rate of the capsule formulation on the market with the nanofibrous capsules, a 14-fold increase was observed in the dissolved drug amount within the first 15 min.

Electrocatalytic oxidation of water at a polyoxometalate nanoparticle modified gold electrode.

Spherical polyoxometalate nanoparticles, [HPMo]NPs, were synthesized from a very well known Keggin-type polyoxometalate [H3PMo12O40] in the presence of sodium dodecyl sulphate (SDS) and polyvinyl pyrrolidine (PVP) in aqueous medium and characterized by UV-Vis spectroscopy and Transmission Electron Microscopy (TEM). The [HPMo]NPs were used to modify a gold working electrode and they were characterized by SEM, EDX, elemental mapping, cyclic voltammetry and electrochemical impedance spectroscopy and applied for the electrocatalytic oxidation of water in a phosphate buffer solution at neutral pH. The modified electrode showed excellent electrocatalytic activity towards oxidation of water at an impressively low overpotential ∼350 mV with a high current density of around 1.7 mA cm−2, good stability under exhaustive electrolysis conditions and also showed long term stability.