Effect of carboxymethyl cellulose on dissolution kinetics of carboxymethyl cellulose-sodium carbonate two-component tablet

Sodium carbonate and carboxymethyl cellulose powders are compressed into two-component tablets with three mass ratios,97%:3%,95%:5% and 93%:7%.The dissolution tests for two-component tablets and reference pure sodium carbonate tablets are carried out at various temperatures.The dissolution process of each tablet is measured by electrical conductivity tracking method and the concentration of dissolved sodium carbonate is quanti fied with calibrated conductivity-concentration converting equation of sodium carbonate.The quanti fied dissolution data is fitted with both surface reaction model and diffusion layer model and the results clearly show that surface reaction model is suggested as the appropriate dissolution model for all measured tablets.Therefore,it is determined that carboxymethyl cellulose is a stable element to remain the dissolution mechanism of tablet unchanged.The dissolution rate constant quanti fied with surface reaction model presents that carboxymethyl cellulose-sodium carbonate two-component tablets obtain signi ficant higher dissolution rate constant than pure sodium carbonate tablet and higher proportion of carboxymethyl cellulose leads to apparent higher dissolution rate constant.The results prove for the usage of carboxymethyl cellulose in most practical applications at a relative low-level,the effect of carboxymethyl cellulose is effective and positive for two-component tablet to enhance the dissolution process and improve dissolution rate constant and this effect is speculated coming from its dynamic physical transforming process in water including dilation and conglutination.

Preparation of Waterborne Nanoscale Carbon Black Dispersion with Sodium Carboxymethyl Cellulose

Waterborne nanoscale carbon black dispersion （NCBD） was widely used in inkjet printing, spun.dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose （CMC） as dispersant. Effects of CMC viscosity, ultrasonic time and oxidation with hydrogen peroxide on carbon black （CB） particle size were discussed. The results showed that CB particle size decreased by mechanical agitation while it Increased by ultrasonic with the increase of CMC viscosity. Uitrasonk is a more effective method to disperse CB particles than that of mechanical agitation. CB particle size lbviously decreased with itcreasing ultrasonic time and arrived at about 160 nm for 60min.In addition,oxidation with 2 mol/L of H2O2 and 0.2wt% of CMC300 reduced CB particle size to 160nm at 90℃ for 2.5h.

Crosslinked carboxymethyl cellulose-sodium borate hybrid binder for advanced silicon anodes in lithium-ion batteries

Silicon anodes have drawn ever-increasing attention in lithium-ion batteries(LIBs) owing to their extremely high theoretical capacity and abundance in the earth. Despite promising advantages, the wide use of silicon anodes in LIBs is highly hindered by their fast capacity fading and low Coulombic efficiency arising from their substantial volumetric variation(>300%). Herein, we report a novel aqueous hybrid gel binder for silicon anodes via crosslinking sodium carboxymethyl cellulose(NaCMC) by an inorganic crosslinker-sodium borate. Not only this gel polymer binder can chemically bond to silicon nanoparticle, but also the deformable framework of this crosslinked binder is capable of maintaining electrode integrity, thus buffering dramatic volume change of silicon. Consequently, the silicon anode with this gel binder exhibits good cycle life(1211.5 mAh/g after 600 cycles) and high initial Coulombic efficiency(88.95%).

Cu(OH)_(2)/CMC one-dimensional composite-nanofiber-based electrochemical sensor for aspirin detection

Copper-based nanomaterials have been widely used in catalysis,electrodes,and other applications due to their unique electron-transfer properties.In this work,an efficient electrochemical sensor based on an electrode modified with one-dimensional Cu(OH)_(2)/carboxymethyl cellulose(CMC)composite nanofibers was fabricated and investigated for the detection of aspirin.Scanning electron microscopy was employed to examine the morphological characteristics of these composite nanofibers.Cyclic voltammetry and electrochemical impedance spectroscopy were used to assess the electrochemical performance of a Cu(OH)_(2)/CMC composite nanofiber-modified electrode.The findings indicate that the modified electrode has a very high sensitivity to aspirin.The observed enhanced performance could be a result of the high surface-to-volume ratio of the composite nanofibers and their superior electron-transport characteristics,which may hasten electron transfer between aspirin and the surfaces of the modified electrode.This detection technique also demonstrated strong selectivity for aspirin.These findings imply that the technique can be applied as a highly effective and selective approach to aspirin measurement in biological science.

Size-controlled Pd Nanoparticles Supported on α-Al_2O_3 as Heterogeneous Catalyst for Selective Hydrogenation of Acetylene

Size-controlled Pd nanoparticles （PdNPs） were synthesized in aqueous solution, using sodium car-boxymethyl cellulose as the stabilizer. Size-controlled PdNPs were supported onα-Al2O3 by the incipient wetness impregnation method. The PdNPs onα-Al2O3 support were in a narrow particle size distribution in the range of 1-6 nm. A series of PdNPs/α-Al2O3 catalysts were used for the selective hydrogenation of acetylene in ethylene-rich stream. The results show that PdNPs/α-Al2O3 catalyst with 0.03%（by mass） Pd loading is a very effective and sta-ble catalyst. With promoter Ag added, ethylene selectivity is increased from 41.0%to 63.8%at 100 ＆#176;C. Comparing with conventional Pd-Ag/α-Al2O3 catalyst, PdNPs-Ag/α-Al2O3 catalyst has better catalytic performance in acety-lene hydrogenation and shows good prospects for industrial application.

Determination of trace calcium by solid substrate-room temperature phosphorimetry

A new method for the determination of trace calcium by solid substrate-room temperature phosphorimetry is established. It is based on the fact that chromeazurols azurol S-phenanthroline-NaCMC (CAS-phen-NaCMC) system can emit strong and stable room temperature phosphorescence (RTP) on the solid substrate in the filter paper. Ca(2+) and phenanthroline can form complex ion Ca(phen)3(2+), which will form complex [Ca(phen)3(CAS)2] with CAS. In the result, the number of CAS molecules in each spot increased, causing sharp increase of the RTP signal of the CAS-phen-NaCMC system.

In situ wound sprayable double-network hydrogel: Preparation and characterization

In clinical settings the wound-dressing was required easy to use and can match the wound area immediately, at the same time they need to have the properties of hemostats, anti-inflammation and promoting wound healing. To get an ideal wound dressing, we developed a type of gel-like wound adhesive patch from spraying double-network hydrogel, which own the properties of self-antibacterial and can promote wound healing. By spraying, the gel-like wound adhesive patch can match the wound area immediately and form a gel-film in 10 s. Sodium carboxymethyl cellulose as p H sensitive materials accelerated the speed to form the gel-film and enhanced ductility of the wound adhesive patch. In vitro experiments show that, this gel-like wound adhesive patch can promote cell proliferation and reduce cell apoptosis.In vivo studies show that, compared with commercialized wound dressings in clinic using, the spraying gel-like wound adhesive patch from our work has a better effect on wound healing. In conclusion, the spraying gel-like wound patch in our work is easy to use and can form a gel-film match on wound area in a short time, also it has the properties of hemostats, anti-inflammation and promoting wound healing.Its feasibility for mass production shows a good potential for commercial use.

Mucoadhesive microparticles as potential carriers in inhalation delivery of doxycycline hyclate:a comparative study

The present work compares and evaluates the suitability of different polymer-based microparticles for inhalation delivery of doxycycline hyclate.Mucoadhesive polymers,such as sodium carboxymethyl cellulose,sodium alginate,polyvinyl alcohol,polyvinylpyrolidone,starch,and carbopol were selected as carriers for inhalation delivery.Microparticles were prepared by spray drying and evaluated in terms of yield,moisture content,morphology,tapped density,encapsulation efficiency,in vitro mucoadhesion,thermal properties and in vitro aerosolization performance.Additionally,the cytotoxicity of the microparticles on H1299 human alveolar cell line was examined.Smooth spherical to collapsed doughnut shaped particles were formed.They exhibited tap densities of 0.202-0.502 g/cm^(3) and mass median aerodynamic diameter of 3.746.54 um.Mucoadhesion was highest in case of carbopol-based microparticles.Drug release from these microparticles exhibited biphasic Fickian type of diffusion.Only at the highest concentration of microparticles(1 mg/mL)less than 90% cell viability was seen in DX loaded sodium alginate microparticles(DXSA,87.2%),starch microparticles(DXST,85.1%)and carbopol microparticles(DXCP,82.7%)preparations after 48 h of exposure to alveolar cells.The results clearly indicate that sodium carboxymethyl cellulose-based microparticles may serve as an ideal carrier for inhalation delivery of doxycycline hyclate.

In vitro assessment of the effect of microencapsulation techniques on the stability,bioaccessibility and bioavailability of mulberry leaf bioactive compounds

Mulberry(Morus alba L.)leaf extract is well-known for its health-promoting features.However,food processing conditions affect its bioactive profile,which could be limited by encapsulation.Nevertheless,assessing the impact of encapsulating techniques on the digestibility of embedded biocompounds requires further knowledge.Hence,the aimed of this study was to assess the effects of carrier materials and drying techniques on(i)bioaccessibility and bioavailability indexes,(ii)stability of nutraceuticals,and(iii)changes in antioxidant activities of mulberry leaf extract powder by using an in vitro oral-gastrointestinal digestion.Digestion was performed out at 37°C in darkness by shaking encapsulated extract with human saliva during 2 min,followed by 2 h of incubation with a pepsin-HCl mixture,then mixed for 2 h with bile salts and pancreatin.After digestion the samples were acidified and HPLC assayed.A significant(p<0.05)decrease in nutraceuticals content was noted during the intestinal phase with more reduction in gamma-aminobutyric acid(34.91–51.14%)compared to that of flavonols(16.58–28.90%),1-deoxynojirimycin(17.56–20.42%)and phenolic acids(0.53–0.67%)in the gastric digesta.Although encapsulation was observed to enhance the bioaccessibility,negative effects were found in terms of the bioefficiency and bioavailability.Furthermore,encapsulation techniques mostly affected the ion reducing capacity than the radical scavenging capacity.The outcomes suggested that carriers had a major effect on the digestibility and antioxidative activity,whilst the drying techniques mostly affect the bioaccessibility and bioavailability of the flavonols.