Addition Of Ethylcellulose Research Articles

Fabrication and characterization of a novel polysaccharide based composite nanofiber films with tunable physical properties

In this study, the pullulan/ethyl cellulose composite nanofiber films with tunable physical properties were fabricated by blend electrospinning process. The solution properties of polysaccharide polymers were investigated and related with the morphology of the nanofiber films, and the results showed that the addition of ethyl cellulose caused decreasing viscosity and conductivity of solutions, which gave rise to the smaller fiber diameter. The Fourier transform infrared spectroscopy indicated that pullulan and ethyl cellulose chains interacted with each other through hydrogen bonding. X-ray diffraction analysis showed that electrospinning process retarded the crystallization of polysaccharide molecules. Thermal analysis showed that the composite nanofiber films possessed higher melting temperature and degradation temperature than the pure pullulan nanofiber film. Water contact angle and water stability test proved that the composite nanofiber films possessed tunable surface wettability (94.6°–120.1°) and improved water stability. The mechanical test showed that the composite nanofiber films had enhanced mechanical strength.

23 Full factorial design for optimization of stable amorphous host–guest-based mirabegron complex for extended-release action

The current study was to develop a stable amorphous mirabegron complex with improved solubility, stability, and extended-release of action. HPβCD was screened as a suitable complexing agent, which exhibited an entrapment efficiency of 91.2 ± 3.4% and facilitated transformation of drug into the amorphous state. The addition of ethylcellulose extended the release of the complex by 81.4 ± 2.8% for 12 h. The influence of HPβCD and ethyl cellulose on the crystal habit of mirabegron was analyzed by XRPD, DSC, ATR FTIR and morphological behavior were analyzed by SEM. 23 Full factorial design was used to optimize the mirabegron complex. The outcomes of stability studies illustrated amorphous complex was stable for 6 months at long-term and accelerated storage conditions, where content uniformity came under the accepted range of 98–102%. Thus, HPβCD-based inclusion complex represents a futuristic approach to design mirabegron formulation with improved solubility and extended-release of action in over active bladder syndrome. Host-guest complex of HPβCD and mirabegron.

A Preliminary result on the rGO functionalization as counter-electrode in dye-sensitized solar cells (DSSC)

In the effort of replacing Platinum (Pt) based counter-electrode (CE) for reducing fabrication cost in the dye-sensitized solar cell (DSSC), we synthesized rGO powder from graphite bar (commercially available) using modified Hummer’s method with an introduction of microwave irradiation. rGO was attached to the FTO surface by dissolving it in the solvent with the addition of ethyl cellulose (ES) following by two-step annealing process. rGO solution was deposited by spin coating technique with different thickness namely 1 layer rGO (A1), 5 layer rGO (A2), 10 layer rGO (A3) and 15 layer rGO (A4) followed by an annealing process, and the reference cell was assigned as A5 (using Pt). From the thin film resistance measurement using the four-probe method and conductivity calculation, the conductivity decreased as the rGO layer becomes thicker, namely from (0.58 to 0.42, 0.07 and 0.03) S/cm for A1, A2, A3, and A4 in consecutive order. From the photovoltaic measurement, we found that the utilization of rGO as a catalyst in CE increased the efficiency of the cell from 3.82% (A5) to 4.52% (A1). Furthermore, increasing the thickness of rGO layer from A1 (2.1 μm) to A2 (10.5 μm) also increased the efficiency from 4.52% to 5.89%, further increasing on the layer thickness A3 (21 μm) to A4 (31.5 μm) reduced the conversion efficiency to 2.57% and 0.33%. The highest conversion efficiency achieved for the cell with 10.5 μm thickness of CE, specifically A2. Further investigation of the influence of CE thickness and conductivity to the internal parameters of the DSSC must be done in order to gain a much better understanding of this result.

Development of enhanced ethanol ablation as an alternative to surgery in treatment of superficial solid tumors

While surgery is at the foundation of cancer treatment, its access is limited in low-income countries. Here, we describe development of a low-cost alternative therapy based on intratumoral ethanol injection suitable for resource-limited settings. Although ethanol-based tumor ablation is successful in treating hepatocellular carcinomas, the necessity for multiple treatments, injection of large fluid volumes, and decreased efficacy in treatment of non-capsulated tumors limit its applicability. To address these limitations, we investigated an enhanced ethanol ablation strategy to retain ethanol within the tumor through the addition of ethyl cellulose. This increases the viscosity of injected ethanol and forms an ethanol-based gel-phase upon exposure to the aqueous tumor environment. This technique was first optimized to maximize distribution volume, using tissue-simulating phantoms. Then, chemically-induced epithelial tumors in the hamster cheek pouch were treated. As controls, pure ethanol injections of either four times or one-fourth the tumor volume induced complete regression of 33% and 0% of tumors, respectively. In contrast, ethyl cellulose-ethanol injections of one-fourth the tumor volume induced complete regression in 100% of tumors. These results contribute to proof-of-concept for enhanced ethanol ablation as a novel and effective alternative to surgery for tumor treatment, with relevance to resource-limited settings.

Engineering chemically exfoliated dispersions of two-dimensional graphite and molybdenum disulphide for ink-jet printing

Stable ink dispersions of two-dimensional-layered-materials (2DLMs) MoS2 and graphite are successfully obtained in organic solvents exhibiting a wide range of polarities and surface energies. The role of sonication time, ink viscosity and surface tension is explored in the context of dispersion stability using these solvents, which include N-methyl-2-pyrrolidone (NMP), N,N-Dimethylacetamide (DMA), dimethylformamide (DMF), Cyclohexanone (C), as well as less-toxic and more environmentally friendly Isopropanol (IPA) and Terpineol (T). The ink viscosity is engineered through the addition of Ethyl-Cellulose (EC) which has been shown to optimize the jettability of the dispersions. In contrast to prior work, the addition of EC after sonication—instead of prior to it—is noted to be effective in generating a high-density dispersion, yielding a uniform film morphology. High-quality inks are obtained using C/T and NMP as solvents for MoS2 and graphite, respectively, as gauged through optical absorption spectroscopy. Electronic transport data on the solution-cast inks is gathered at room temperature. Arrays of 2D graphite-rod based inks are printed on rigid Si, as well as flexible and transparent polyethylene terephthalate (PET) substrates. The results clearly show the promise of ink-jet printing for casting 2DLMs into hierarchically assembled structures over a range of substrates for flexible and printed-electronics applications.

Optimization of fluid characteristics of 2D materials for inkjet printing

ABSTRACT2D materials have shown to be the next step in semiconductor use and device manufacturing that can allow us to reduce the size of most electronics. One of the novel ways to obtain 2D materials is through liquid exfoliation, in which these materials can be obtained by dispersing the smallest possible particles in different solvents. Once obtained, the solutions can be used to manufacture devices via different processes, one of which is inkjet printing. This process relies in selecting “jettable” fluids, which need to have the necessary combination of viscosity and surface energy or “wettability”. In this work we have modified the viscosities and surface energies of five solvents: IPA (Isopropanol), NMP (N-methyl – 2 pyrrolidone), DMA (Dimethylacetamide), DMF (Dimethylformamide) and a mixture of Cyclohexanone / Terpineol 7:3. We have found an avenue to tailor the viscosity of these solvents though the addition of Ethyl Cellulose (EC), where the viscosity has been increased by up to 15 times at an EC concentration of 6%. For inkjet printing, ideally a viscosity of 4 – 10 cP is recommended, which we have been able to achieve with all of the solvents studied. It has been found that the different solvents present different susceptibilities to the EC addition, with DMA and DMF being the least sensitive to the EC addition. We have also studied the change in the drop dynamics and interactions of the 2D solutions with the substrate. Through this analysis we have found solvents that appear to be attractive for inkjet printing of MoS2 and graphite.

Processing and electromechanical properties of lead zirconate titanate thick films by electrophoretic deposition

Electrophoretic deposition (EPD) was used for the fabrication of piezoelectric [lead zirconate titanate (PZT)] thick films on alumina substrates. The EPD was performed in constant current mode from an ethanol based suspension consisting of PZT and PbO particles. The influence of addition of ethyl cellulose (EC) and sintering temperature on the thickness, density, homogeneity and functional response of PZT thick films is studied. Results show that the highest electromechanical performance is obtained for the PZT thick films sintered at 900 or 950°C, with a thickness coupling factor kt of 50%. The addition of EC influenced the thickness of the PZT thick films but had only minor effect on the porosity content for sintering temperatures over 900°C. Moreover, elastic constants of the thick films based on the suspension with EC were lower, which leads to lower acoustic impedance (15 MRa) while maintaining high (kt) value. In this last case, a better acoustic matching can be expected with propagation media such as water or biological tissues for ultrasound medical imaging applications.

Low-Cost CZTSSe Solar Cells Fabricated with Low Band Gap CZTSe Nanocrystals, Environmentally Friendly Binder, and Nonvacuum Processes

High quality Cu2ZnSn(SSe)4 (CZTSSe) for solar cells can be fabricated with Cu2ZnSnS4 (CZTS) nanocrystals, followed by a selenization process. However, the use of toxic and environmentally unfriendly solvents such as toluene or hexanethiol to disperse the nanocrystals and the use of the harsh selenization process to promote the grain growth are not environmentally benign. We present here an environmentally friendly, sustainable, and scalable route to fabricate CZTSSe with Cu2ZnSnSe4 (CTZSe) nanocrystals by a sulfurization process. The CZTSSe film has been doped with S to optimize the device performance, exhibiting an enhancement in the open-circuit voltage (Voc) and short circuit current density (Jsc). In addition, by developing a robust precursor film with the addition of ethyl cellulose, the loss of Sn associated with the conversion of CZTSe to CZTSSe during the grain growth process has been mitigated, leading to an increase in the conversion efficiency compared to that of the precursor film without usin...

Molecular interactions of ethylcellulose with sucrose particles

Heat resistance in chocolate upon ethylcellulose addition is due to the formation of a jammed sugar network.

Preparation of hydroxypropylmethyl cellulose-based porous matrix for gastroretentive delivery of gabapentin using the freeze-drying method

The aims of the present study were to prepare hydroxypropylmethyl cellulose (HPMC)-based porous matrix tablets for gastroretentive drug delivery and to characterize their physicochemical properties. Gabapentin (GBP) was used as a model drug. Paste containing GBP, HPMC and water was molded and freeze-dried to prepare freeze-dried gastroretentive matrix tablet (FD-GRT). In vitro drug release and erosion studies were also performed. Although FD-GRT exhibited porous structure, they had good tablet strength and friability. Density of FD-GRT ranged from 0.402 to 0.509 g/cm3 and thus they could float on the medium surface without any lag time. FD-GRT was remained floated until the entire matrix erosion or end of drug release during in vitro release test. Release behavior of GBP could be modulated by the amount and the viscosity grade of HPMC. However, large amount and high viscosity of HPMC caused trouble in molding prior to freeze-drying. Addition of ethylcellulose could retard the release rate of GBP, with relatively low increase in viscosity of paste. Since pores generated by freeze drying imparted buoyancy for gastric retention to FD-GRT, additional materials for buoyancy was not necessary and FD-GRT had no lag time for buoyancy due to low density. Therefore it could be a promising tool for gastroretentive drug delivery.

Development of Matrix-Type Transdermal Delivery of Lornoxicam: In Vitro Evaluation and Pharmacodynamic and Pharmacokinetic Studies in Albino Rats

A matrix-type transdermal drug delivery system of lornoxicam was prepared with the addition of combination of hydrophilic and hydrophobic polymers in different ratios. Transdermal patches of lornoxicam were designed with ethyl cellulose:polyvinylpyrrolidone and Eudragit RL 100:Eudragit RS 100 in different ratios with propylene glycol as plasticizer (5%) and tween 80 as permeation enhancer using the solvent evaporation technique. Evaluation of these formulations was performed through mechanical characterization and in vitro permeation studies. From the physicochemical and in vitro permeation data, the two formulations showing the best result (A3 and B3) were selected for further in vivo studies. The anti-inflammatory and analgesic effects of the patches were studied using the carrageenan paw edema model and hot plate test, respectively. The pharmacokinetic parameters were studied and recorded on animals. Formulations A3 and B3 exhibited greatest (311.04 μg and 306.32 μg, respectively) cumulative amount of drug release. The Higuchi model seemed to be the most appropriate model describing release kinetics from all patches (r(2) = 0.9847-0.9971). It was observed that both the patches significantly controlled inflammation and showed analgesic effect from the first hour (P < 0.05). Formulations A3 and B3 were found to enhance the bioavailability of lornoxicam by 3.1 and 2.7 times, respectively, with reference to the oral dosage form. Hence, lornoxicam can be formulated into transdermal patches to sustain its release characteristics and to avoid the disadvantages of oral routes. Formulations A3 and B3 were found to be the best choice to manufacture a lornoxicam transdermal drug delivery system. The objective of the present work was to develop a matrix-type transdermal drug delivery system of lornoxicam with the addition of ethyl cellulose:polyvinylpyrrolidone and Eudragit RL 100:Eudragit RS 100 in different ratios with propylene glycol as plasticizer (5%) and tween 80 as permeation enhancer using the solvent evaporation technique. Lornoxicam is a non-steroidal anti-inflammatory drug that is used for the treatment of pain, inflammation, and arthritis. The prepared patches were evaluated for mechanical characterization and in vitro permeation studies. The formulations showing best results (A3 and B3) were selected further for in vivo and pharmacokinetic studies on animals. From the results, it was found that formulations A3 and B3 exhibited greatest cumulative amount of drug release, controlled inflammation, and showed analgesic effect from the first hour. Hence, lornoxicam can be formulated into transdermal patches, and formulations A3 and B3 were found to be the best choice to manufacture a lornoxicam transdermal drug delivery system.

Solution-based β-diketonate silver ink for direct printing of highly conductive features on a flexible substrate

The novelty of this study is the laboratory formulation of silver ink adapted for the inkjet printing of conductive metallic features on flexible polyimide (PI) substrates with potential integrated circuit applications ranging from large-area electronics to low-end applications. A new silver precursor for printing conductive patterns with the empirical formula [Ag(dien)](tmhd), where tmhd = 2,2,6,6-tetramethyl-3,5-heptanedionato and dien = diethylenetriamine, was synthesised using a simple and environmentally friendly method. The viscosity and surface tension of the organic solvent system were optimised through the addition of ethyl cellulose and hexylamine, yielding potential printing ink of high Ag wt%. Silver patterns on a flexible PI substrate were produced by thermal annealing of silver features prepared either by spin-coating or by directly drawing with a piezoelectric inkjet printer. Films were produced using a silver precursor (60 wt%) dissolved in hexylamine (39 wt%) and ethyl cellulose (1 wt%) with a viscosity of 9–11 mPa and annealed in air at 250 °C. They displayed resistivity values in the range of 4.625–9.376 × 10−6 Ω cm. The composition of printing ink is [Ag(dien)](tmhd) : hexylamine : ethyl cellulose = 45 : 54 : 1 by wt%. A resistivity of 7.44 × 10−6 Ω cm was found for a silver line with a width of 177 μm and a thickness of 106 nm. The silver patterns were characterised by scanning electron microscopy, FT-IR, X-ray photoelectron spectroscopy and X-ray diffraction. The resistivities of our silver patterns are lower than those previously prepared by other research groups using water-based silver salts as ink. We propose that the high Ag wt% achievable with an organic solvent-based system may explain this lower resistivity.

SYNTHESIS AND CHARACTERIZATION OF LSM/SDC FILMS AS COMPOSITE CATHODES FOR SOLID OXIDE FUEL CELLS

The study of the strontium-doped lanthanum manganites in the form of films covers a large area of technological applications, such as ceramics semiconductors and solid oxide fuel cell cathode. Strontium-doped lanthanum manganite and samarium-doped ceria has been used as composite cathode of solid oxide fuel cells (SOFCs) because of its excellent performance in electronic and ionic conductivity. In this work, we produced films of the cathode LSM / SDC on yttria stabilized zirconia (YSZ) electrolytes. La0.8Sr0.2MnO3 (LSM) and Ce0.8Sm0.2O1.9 (SDC) powders were synthesized by a synthesis route similar to the Pechini method, in which the gelatin replaced the ethylene glycol as polymerizing agent. Precursor powders of LSM and SDC phases were calcined at 900 ºC. In the step of films production were prepared suspensions of the LSM and SDC powders with addition of ethyl cellulose as a pore-forming agent. The ceramic suspensions were deposited on YSZ electrolyte using the spin coating method. After sintering to 1150 °C for 4 h the films were characterized by XRD and SEM. The film with 10 wt.% ethyl cellulose presented porous and strongly adhered to the YSZ substrate.

Porous photocatalytically active ZnO films obtained from ethylcellulose modified solutions by spray pyrolysis

Nanocrystalline porous ZnO films are deposited onto alumina foil substrates by polymer-modified spray pyrolysis of zinc nitrate and zinc acetate solutions. The dependence of the concentration of added ethylcellulose and the type of zinc precursor on both the photocatalytic properties and films morphologies is investigated. It is established that the addition of ethylcellulose as a modifier in the spray solution leads to the formation of a porous structure with crystallites sizes about 15 nm, when zinc acetate is used as precursor. These films show better photocatalytic activity for degradation of Malachite Green (MG) dye than the films obtained from zinc nitrate modified solution. The zinc nitrate films exhibit weaker activity for degradation of MG regardless of their smaller crystallite size (8–12 nm). This can be explained with their lower porosity than that of polymer-modified zinc acetate films. It is established that 450 °C is the limit temperature of treatment for the preparation of ZnO films with good photocatalytic activities. This photocatalytic activity in films shows a drop in the comparison to the films treated at lower temperature, due to decreasing of the pore number and deterioration of the surface morphology.

Biodegradable Polymer for Demulsification of Water-in-Bitumen Emulsions

Removal of residual water from a solvent-diluted bitumen is a challenging task because the water drops, in the emulsified form of a few micrometers, are extremely stable. A nontoxic and biodegradable polymer, ethylcellulose, was used to break up emulsified water from naphtha-diluted bitumen. It was found that the ethylcellulose polymer at 130 ppm dosage removed up to 90% of the emulsified water in the diluted bitumen by gravity settling after 1 h at 80 °C. The tests, extended to bitumen froth containing about 10% solids by weight, showed a 90% removal of the water in the diluted bitumen froth. The addition of ethylcellulose also assisted the removal of fine solids with the water. However, for bitumen froths containing 30% or more solids, the efficiency of water removal by ethylcellulose addition was found to be less effective. Micrographic images revealed that ethylcellulose broke up the water-in-bitumen emulsions by flocculation and coalescence.

Physicochemical properties of film-coated melt-extruded pellets

The purpose of this study was to investigate the physicochemical properties of poly(ethylene oxide) (PEO) and guaifenesin containing beads prepared by a melt-extrusion process and film-coated with a methacrylic acid copolymer. Solubility parameter calculations, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), modulated differential scanning calorimetry (MDSC), X-ray powder diffraction (XRPD) and high performance liquid chromatography (HPLC) were used to determine drug/polymer miscibility and/or the thermal processibility of the systems. Powder blends of guaifenesin, PEO and functional excipients were processed using a melt-extrusion and spheronization technique and then film-coated in a fluidized bed apparatus. Solubility parameter calculations were used to predict miscibility between PEO and guaifenesin, and miscibility was confirmed by SEM and observation of a single melting point for extruded drug/polymer blends during MDSC investigations. The drug was stable following melt-extrusion as determined by TGA and HPLC; however, drug release rate from pellets decreased upon storage in sealed HDPE containers with silica desiccants at 40°C/75% RH. The weight loss on drying, porosity and tortuosity determinations were not influenced by storage. Recrystallization of guaifenesin and PEO was confirmed by SEM and XRPD. Additionally, the pellets exhibited a change in adhesion behaviour during dissolution testing. The addition of ethylcellulose to the extruded powder blend decreased and stabilized the drug release rate from the thermally processed pellets. The current study also demonstrated film-coating to be an efficient process for providing melt-extruded beads with pH-dependent drug release properties that were stable upon storage at accelerated conditions.

Effects of Ethylcellulose and 2-Octyldodecanol Additives on Skin Permeation and Irritation with Ethylene-Vinyl Acetate Copolymer Matrix Patches Containing Formoterol Fumarate

Skin permeation of formoterol fumarate (FF) and irritation with ethylene-vinyl acetate (EVA) copolymer matrix patches was investigated using rat and human skin in vitro and different species of experimental animal, respectively. Skin permeation of FF increased remarkably without addition of ethylcellulose (EC) and was remarkably enhanced by incorporation of 2-octyldodecanol (OD) instead of hydrogenated rosin glycerol ester (Ester Gum H). Effects on skin permeation of FF with EVA matrix patches were similar in rat and human skin, but rat skin was 1000 times more permeable than human skin after 24 h. The primary irritation indices for matrix patches without EC and with EC (OD-0), EC and 0.5 mg OD per square centimeter (OD-0.5), and EC and 1.0 mg OD per square centimeter (OD-1) were 1.46, 1.13,1.29 and 1.38. The results suggested that the irritation induced by these patches was rather mild, but significantly greater than the 0.21 observed with the control. No significant effects were noted for either EC or OD alone. Skin irritation intensity with EVA matrix patches was observed to be in the order of rabbits, guinea pigs, rats and miniature swine.

Release Behavior of Ketoprofen from Chitosan/Alginate Microcapsules

Chitosan/alginate microcapsules were prepared continuously by an air extrusion method. The influences on loading efficiency and release, such as air flow-rate, chitosan molecular weight and concentration, alginate concentration, pH of chitosan solution, ethyl cellulose, and freezing drying the capsules were studied. Freezing drying chitosan/alginate microcapsules was important for controlled release of ketoprofen. High molecular weight and high concentration of chitosan did not increase loading of ketoprofen, but reduced the release of the ketoprofen. The addition of ethyl cellulose increased the loading of ketoprofen and the release time was prolonged. Increasing sodium alginate concentration reduced the loading efficiency with no clear distinction on the release of ketoprofen. The ketoprofen entrapped in the pH sensitive chitosan/alginate microcapsules gave controlled release in intestinal fluid.

Effect of Adjuvants on Tackiness of Polyvinylpyrrolidone Film Coating

Two formulations were developed using polyvinylpyrrolidone for the film coating of tablets by the pan-coating method. The addition of ethylcellulose and shellac eliminated the tackiness sometimes associated with polyvinylpyrrolidone coating due to the hygroscopicity of the film former. The film coats increased the resistance of the tablet to mechanical stress, did not significantly increase the weight of the tablet, and were physically acceptable after storage at 2 and 45°. The film coats did not interfere with the disintegration and dissolution of the tablet since the film coats were rapidly removed from the tablet in water, simulated gastric fluid, and simulated intestinal fluid.