共查询到20条相似文献,搜索用时 296 毫秒
1.
José R. Bresolin Maria-Claudia T. Largura Camila C. Dalri Geórgia Hoffer Clóvis A. Rodrigues 《Drug development and industrial pharmacy》2014,40(4):503-510
Objective: The aim of the present investigation was to evaluate the use of spray-dried O-carboxymethyl chitosan (OCMCS) as potential hydrophilic matrix excipient for sustained release of drug.Methods: The polymer was synthesized from chitosan, then spray-dried and characterized. Tablets with different OCMCS concentrations (80, 50, 30, 5 and 2% w/w), containing diltiazem (DTZ) as model drug, were prepared for direct compression (DC) and after the wet granulation method (WG).Results: The spray-dried OCMCS powder was spherical, with a smooth surface and an average size of 2.2?µm. The tablets prepared for WG disintegrated in time less than 30?min. The tablets obtained for DC presented high retention of the drug, with zero order or Higuchi release kinetic. There was a direct relationship between the OCMCS concentration and the release ratio, swelling degree and water uptake behavior. DC tablets containing 80% OCMCS presented behavior as an effective swelling-control system. The DC tablets with 5% OCMCS showed a similar release profile at formulations with 30% HPMC.Conclusion: Spray-dried OCMCS showed great potential as hydrophilic matrices for drug-sustained release. 相似文献
2.
Piyasi Mukhopadhyay Kishor Sarkar Mousumi Chakraborty Sourav Bhattacharya Roshnara Mishra P.P. Kundu 《Materials science & engineering. C, Materials for biological applications》2013,33(1):376-382
We have developed self-assembled chitosan/insulin nanoparticles for successful oral insulin delivery. The main purpose of our study is to prepare chitosan/insulin nanoparticles by self-assembly method, to characterize them and to evaluate their efficiency in vivo diabetic model. The size and morphology of the nanoparticles were analyzed by dynamic light scattering (DLS), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The average particle size ranged from 200 to 550 nm, with almost spherical or sub spherical shape. An average insulin encapsulation within the nanoparticles was ~ 85%. In vitro release study showed that the nanoparticles were also efficient in retaining good amount of insulin in simulated gastric condition, while significant amount of insulin release was noticed in simulated intestinal condition. The oral administrations of chitosan/insulin nanoparticles were effective in lowering the blood glucose level of alloxan-induced diabetic mice. Thus, self-assembled chitosan/insulin nanoparticles show promising effects as potential insulin carrier system in animal models. 相似文献
3.
《Drug development and industrial pharmacy》2013,39(7):1010-1019
The aim of this research is to develop novel chitosan nanoparticles including cyclodextrins complexes for docetaxel (DTX), evaluate the performance of nanoparticles which could enhance the oral permeability and bioavailability of DTX in vitro and in vivo. DTX/sulfobutylether-β-cyclodextrin inclusion complexes were made and it was the main ingredient to prepare the DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles due to their promising physicochemical properties. DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles were prepared by the ionic gelation of chitosan with tripolyphosphate in the presence of cyclodextrins. Results indicated that DTX/sulfobutylether-β-cyclodextrin inclusion complexes and docetaxel/sulfobutylether-β-cyclodextrin/chitosan nanoparticles both had good performances in the studies of release and the rat small intestinal absorption in vitro. DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles showed preferable capability in improving the small intestinal absorption and inhibiting the efflux of DTX. In pharmacokinetics study, the DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles increased the AUC0→t and decreased the clearance significantly, and the oral relative bioavailability of the DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles was as high as 1447.53% compared to the pure DTX formulation. The DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles prepared in this study have a good prospect for oral administration as an alternative of current DTX formulations. 相似文献
4.
Joseph Shailender Mrinalini Reddy Sirukuri Avantika Dalvi Odapalli Keerthi Priya 《Drug development and industrial pharmacy》2018,44(7):1109-1119
Objective: Design chitosan based nanoparticles for tenofovir disoproxil fumarate (TDF) with the purpose of enhancing its oral absorption.Significance: TDF is a prodrug that has limited intestinal absorption because of its susceptibility to gut wall esterases. Hence, design of chitosan based polymeric novel nanocarrier systems can protect TDF from getting metabolized and also enhance the oral absorption.Methods: The nanoparticles were prepared using the ionic gelation technique. The factors impacting the particle size and entrapment efficiency of the nanoparticles were evaluated using design of experiments approach. The optimized nanoparticles were characterized and evaluated for their ability to protect TDF from esterase metabolism. The nanoparticles were then studied for the involvement of active transport in their uptake during the oral absorption process. Further, in vivo pharmacokinetic studies were carried out for the designed nanoparticles.Results: The application of design of experiments in the optimization process was useful to determine the critical parameters and evaluate their interaction effects. The optimized nanoparticles had a particle size of 156?±?5?nm with an entrapment efficiency of 48.2?±?1%. The nanoparticles were well characterized and provided metabolic protection for TDF in the presence of intestinal esterases. The nanoparticles were able to increase the AUC of tenofovir by 380%. The active uptake mechanisms mainly involving clathrin-mediated uptake played a key role in increasing the oral absorption of tenofovir.Conclusions: These results show the ability of the designed chitosan based nanoparticles in enhancing the oral absorption of TDF along the oral route by utilizing the active endocytic uptake pathways. 相似文献
5.
Folate (FA) modified carboxymethyl chitosan (FCC) has been synthesized and the hydrogel nanoparticles can be prepared after
the sonication. Formation and characteristics of nanoparticles of FCC were studied by fluorescence spectroscopy and dynamic
light scattering methods. The critical aggregation concentration value of FCC in water was 9.34 × 10−2 mg/ml and the mean hydrodynamic diameter of particle was 267.8 nm. The morphology of nanoparticles was observed by transmission
electron microscopy which had spherical shape. Loading capacity (LC), loading efficiency (LE) and the in vitro release profiles
of nanoparticles were investigated by doxorubicin (DOX) as a model drug. When the initially added amount of DOX versus the
constant amount of FCC polymer was increased, the LC in the nanoparticles was gradually increased and the LE decreased. The
in vitro release profile of the DOX from the FCC nanoparticles exhibited sustained release. Cellular uptake of FCC nanoparticles
was found to be higher than that of nanoparticles based on linoleic acid (LA) modified carboxymethyl chitosan because of the
FA-receptor-mediated endocytosis, thereby providing higher cytotoxicity against Hela cells. 相似文献
6.
Fang Li Jianing Li Xuejun Wen Shenghu Zhou Xiaowen Tong Pingping Su Hong Li Donglu Shi 《Materials science & engineering. C, Materials for biological applications》2009,29(8):2392-2397
Chitosan nanoparticles containing the anticancer drug paclitaxel were prepared by a solvent evaporation and emulsification crosslinking method. The physicochemical properties of the nanoparticles were characterized by various techniques, and uniform nanoparticles with an average particle size of 116 ± 15 nm with high encapsulation efficiencies (EE) were obtained. Additionally, a sustained release of paclitaxel from paclitaxel-loaded chitosan nanoparticles was successful. Using different ratios of paclitaxel-to-chitosan, the EE ranged from 32.2 ± 8.21% to 94.0 ± 16.73 %. The drug release rates of paclitaxel from the nanoparticles were approximately, 26.55 ± 2.11% and 93.44 ± 10.96% after 1 day and 13 days, respectively, suggesting the potential of the chitosan nanoparticles as a sustained drug delivery system. Cytotoxicity tests showed that the paclitaxel-loaded chitosan had higher cell toxicity than the individual paclitaxel and confocal microscopy analysis confirmed excellent cellular uptake efficiency. TEM images showed the ultrastructure changes of A2780 cells incubated with paclitaxel-loaded nanoparticles. Flow cytometric analysis revealed two subdiploid peaks for the cells in the paclitaxel-loaded nanoparticles and paclitaxel treated groups, respectively, with the intensity of the former higher than that of the latter. Moreover, the cell cycle was arrested in the G2-M phase, which was consistent with the action mechanism of the direct administration of paclitaxel. These results indicate that chitosan nanoparticles have potential uses as anticancer drug carriers and also have an enhanced anticancer effect. 相似文献
7.
Reza Mahjub Moojan Radmehr Farid Abedin Dorkoosh Seyed Naser Ostad 《Drug development and industrial pharmacy》2014,40(12):1645-1659
Objective: The purpose of this research was the development, in vitro, ex vivo and in vivo characterization of lyophilized insulin nanoparticles prepared from quaternized N-aryl derivatives of chitosan.Methods: Insulin nanoparticles were prepared from methylated N-(4-N,N-dimethylaminobenzyl), methylated N-(4 pyridinyl) and methylated N-(benzyl). Insulin nanoparticles containing non-modified chitosan and also trimethyl chiotsan (TMC) were also prepared as control. The effects of the freeze-drying process on physico-chemical properties of nanoparticles were investigated. The release of insulin from the nanoparticles was studied in vitro. The mechanism of the release of insulin from different types of nanoparticles was determined using curve fitting. The secondary structure of the insulin released from the nanoparticles was analyzed using circular dichroism and the cell cytotoxicity of nanoparticles on a Caco-2 cell line was determined. Ex vivo studies were performed on excised rat jejunum using Frantz diffusion cells. In vivo studies were performed on diabetic male Wistar rats and blood glucose level and insulin serum concentration were determined.Results: Optimized nanoparticles with proper physico-chemical properties were obtained. The lyophilization process was found to cause a decrease in zeta potential and an increase in PdI as well as and a decrease in entrapment efficiency (EE%) and loading efficiency (LE%) but conservation in size of nanoparticles. Atomic force microscopy (AFM) images showed non-aggregated, stable and spherical to sub-spherical nanoparticles. The in vitro release study revealed higher release rates for lyophilized compared to non-lyophilized nanoparticles. Cytotoxicity studies on Caco-2 cells revealed no significant cytotoxicity for prepared nanoparticles after 3-h post-incubation but did show the concentration-dependent cytotoxicity after 24?h. The percentage of cumulative insulin determined from ex vivo studies was significantly higher in nanoparticles prepared from quaternized aromatic derivatives of chitosan. In vivo data showed significantly higher insulin intestinal absorption in nanoparticles prepared from methylated N-(4-N, N-dimethylaminobenzyl) chitosan nanoparticles compared to trimethyl chitosan.Conclusion: These data obtained demonstrated that as the result of optimized physico-chemical properties, drug release rate, cytotoxicity profile, ex vivo permeation enhancement and increased in vivo absorption, nanoparticles prepared from N-aryl derivatives of chitosan can be considered as valuable method for the oral delivery of insulin. 相似文献
8.
Nguyen Ngoc Thinh Pham Thi Bich Hanh Le Thi Thanh Ha Le Ngoc Anh Tran Vinh Hoang Vu Dinh Hoang Le Hai Dang Nguyen Van Khoi Tran Dai Lam 《Materials science & engineering. C, Materials for biological applications》2013,33(3):1214-1218
A simple method was introduced to prepare magnetic chitosan nanoparticles by co-precipitation via epichlorohydrin cross-linking reaction. The average size of magnetic chitosan nanoparticles is estimated at ca. 30 nm. It was found that the adsorption of Cr(VI) was highly pH-dependent and its kinetics follows the pseudo-second-order model. Maximum adsorption capacity (at pH 3, room temperature) was calculated as 55.80 mg·g? 1, according to Langmuir isotherm model. The nanoparticles were thoroughly characterized before and after Cr(VI) adsorption. From this result, it can be suggested that magnetic chitosan nanoparticles could serve as a promising adsorbent for Cr(VI) in wastewater treatment technology. 相似文献
9.
Rangrong Yoksan Suwabun Chirachanchai 《Materials science & engineering. C, Materials for biological applications》2010,30(6):891-897
The fabrication of silver nanoparticles was accomplished by γ-ray irradiation reduction of silver nitrate in a chitosan solution. The obtained nanoparticles were stable in the solution for more than six months, and showed the characteristic surface plasmon band at 411 nm as well as a positively charged surface with 40.4 ± 2.0 mV. The silver nanoparticles presented a spherical shape with an average size of 20–25 nm, as observed by TEM. Minimum inhibitory concentration (MIC) against E. coli, S. aureus and B. cereus of the silver nanoparticles dispersed in the γ-ray irradiated chitosan solution was 5.64 µg/mL. The silver nanoparticle-loaded chitosan–starch based films were prepared by a solution casting method. The incorporation of silver nanoparticles led to a slight improvement of the tensile and oxygen gas barrier properties of the polysaccharide-based films, with diminished water vapor/moisture barrier properties. In addition, silver nanoparticle-loaded films exhibited enhanced antimicrobial activity against E. coli, S. aureus and B. cereus. The results suggest that silver nanoparticle-loaded chitosan–starch based films can be feasibly used as antimicrobial materials for food packaging and/or biomedical applications. 相似文献
10.
Ya-fei Zhang Pei Yin Xue-qin Zhao Jūn Wang Jùn Wang Cai-ding Wang Lei Ren Qi-qing Zhang 《Materials science & engineering. C, Materials for biological applications》2009,29(6):2045-2049
Polymeric non-viral vectors, such as chitosan nanoparticles show good biocompatibility, but low transfection efficiency. The objective of this study was to improve the transfection efficiency of chitosan based non-viral vectors by using o-carboxymethyl-chitosan which is a kind of water-soluble chitosan derivative and also has good biocompatibility. O-Carboxymethyl-chitosan-organosilica hybrid nanoparticles (CMG NPs) were synthesized through a rapid one-step aqueous synthetic approach for gene delivery. The size of nanoparticles was 276 ± 25 nm and zeta potential was 31.6 ± 0.4 mV in deionized water. Zeta potential increased with the decrease of pH, and it had been discovered that pH = 5.5 is the best point for CMG NPs to bond with plasmid DNA. DNA inclusion and integrity was evaluated by gel electrophoresis, and it is indicated that CMG NPs could protect DNA against DNase I and serum degradation. The results of MTT for cell viability and in vitro transfection also support the idea that CMG NPs could be used as efficient and safe vectors for gene delivery. 相似文献
11.
D. A. Silva J. S. Maciel J. P. A. Feitosa H. C. B. Paula R. C. M. de Paula 《Journal of Materials Science》2010,45(20):5605-5610
Polyelectrolyte complex nanoparticles of chitosan and carboxymethyl cashew gum (CMCG) were prepared with CMCG with two different
degrees of substitution (DS = 0.16 and 0.36). The effects of polymer concentration, molar mixing ratio (n
+/n
−) and mixing order of reactants on particle size distribution and zeta potential were investigated. Nanoparticle structure
was elucidated by Fourier transform spectroscopy. Particle size of CH/CMCG DS = 0.16 dispersions was smaller than with DS
0.36 for all n
+/n
− ratio investigated. Particle size smaller than 200 nm was obtained when CMCG with DS = 0.16 was used for particle formation.
The polydispersity index values were small when CMCG DS 0.36 was used. Increasing the concentration of CMCG led to larger
particle size. Zeta potential values for almost all molar mixing ratios were found to be positive (10–32 mV). 相似文献
12.
The Fe3O4–chitosan nanoparticles with core-shell structure have been prepared by crosslinking method. Oleic acid modified Fe3O4 nanoparticles were firstly prepared by co-precipitation then chitosan was added to coat on the surface of the Fe3O4 nanoparticles by physical absorption. The Fe3O4–chitosan nanoparticles were obtained by crosslinking the amino groups on the chitosan using glutaraldehyde. Transmission electron microscopy showed that the Fe3O4–chitosan nanoparticles were quasi-spherical with a mean diameter of 10.5 nm. X-ray diffraction pattern and X-ray photoelectron spectra indicated that the magnetic nanoparticles were pure Fe3O4 with a cubic inverse spinel structure. The modification using chitosan did not result in a phase change. The binding of chitosan to the Fe3O4 nanoparticles was also demonstrated by the measurement of fourier transform infrared spectra and thermogravimetric analysis. Magnetic measurement revealed that the saturation magnetization of the composite nanoparticles was 30.7 emu/g and the nanoparticles were superparamagnetic at room temperature. Furthermore, the inductive heating property of the composite nanoparticles in an alternating current magnetic field was investigated and the results indicated that the heating effect was significant. The Fe3O4–chitosan nanoparticles prepared have great potential in hyperthermia. 相似文献
13.
Yue Tian Ji-Cheng Yu Xiao-Hui Qi Xiao-Wei Wu Rui-Nian Hua Sheng-Di Fan 《Journal of Materials Science: Materials in Electronics》2009,20(5):439-444
CaF2:Eu nanoparticles capped with chitosan and bio-conjugation of CaF2:Eu/chitosan nanoparticles with bovine serum albumin (BSA) were synthesized via microemulsion method. As a surfactant, chitosan
was employed to cap the nanoparticles during the synthesis process and provided functional groups, such as amino group for
further bio-conjunction with BSA. CaF2:Eu and CaF2:Eu/chitosan–BSA nanoparticles were characterized by means of X-ray powder diffraction (XRD), field-emission scanning electron
microscopy (FE-SEM), ultraviolet spectrophotometer (UV), infrared spectrophotometer (IR) and photoluminescence spectrophotometer
(PL). The XRD results indicated that the CaF2:Eu and CaF2:Eu/chitosan-BSA nanoparticles have crystallized well and the average sizes were about 16 and 19 nm, respectively. Images
of FE-SEM showed that the average grain sizes of the CaF2:Eu and bio-conjunction of CaF2:Eu/chitosan nanoparticles with BSA were about 19 and 20 nm. The patterns of UV spectra and IR spectra showed that BSA was
linked to CaF2:Eu/chitosan nanoparticles. In the emission spectrum of the CaF2:Eu/chitosan–BSA nanoparticles, characteristic emission peaks of Eu3+ within the wavelength ranging from 500 to 700 nm were observed, corresponding to the transitions from the excited 5D0 levels to 7FJ levels. This confirmed that the Eu3+dopant ion is located in a Ca2+ crystal site with Td symmetry. 相似文献
14.
Artesunate-loaded chitosan/lecithin nanoparticles: Preparation,characterization, and in vivo studies
《Drug development and industrial pharmacy》2013,39(12):1538-1546
Artesunate (AST), the most widely used artemisnin derivative, has poor aqueous solubility and suffers from low oral bioavailability (~40%). Under these conditions, nanoparticles with controlled and sustained released properties can be a suitable solution for improving its biopharmaceuticals properties. This work reports the preparation and characterization of auto-assembled chitosan/lecithin nanoparticles loaded with AST and AST complexed with β-cyclodextrin (β-CD) to boost its antimalarial activity. The nanoparticles prepared by direct injection of lecithin alcoholic solution into chitosan/water solution have shown the particle size distribution below 300?nm. Drug entrapment efficiency was found to be maximum (90%) for nanoparticles containing 100?mg of AST. Transmission electron microscopy images show spherical shape with contrasted corona (chitosan) surrounded by a lipidic core (lecithin + isopropyl myristate). Differential scanning calorimeter thermograms demonstrated the presence of drug in drug-loaded nanoparticles along with the disappearance of decomposition exotherm suggesting the increased physical stability of drug in prepared formulations. Negligible changes in the characteristic peaks of drug in Fourier-transform infrared spectra indicated the absence of any interaction among the various components entrapped in the nanoparticle formulation. In vitro drug release behavior was found to be influenced by pH value. Increased in vivo antimalarial activity in terms of less mean percent parasitemia was observed in infected Plasmodium berghei mice after the oral administration of all the prepared nanoparticle formulations. 相似文献
15.
Elaheh Mortazavian Farid Abedin Dorkoosh 《Drug development and industrial pharmacy》2014,40(5):691-698
The purpose of this study is to optimize and characterize of chitosan buccal film for delivery of insulin nanoparticles that were prepared from thiolated dimethyl ethyl chitosan (DMEC-Cys). Insulin nanoparticles composed of chitosan and dimethyl ethyl chitosan (DMEC) were also prepared as control groups. The release of insulin from nanoparticles was studied in vitro in phosphate buffer solution (PBS) pH 7.4. Optimization of chitosan buccal films has been carried out by central composite design (CCD) response surface methodology. Independent variables were different amounts of chitosan and glycerol as mucoadhesive polymer and plasticizer, respectively. Tensile strength and bioadhesion force were considered as dependent variables. Ex vivo study was performed on excised rabbit buccal mucosa. Optimized insulin nanoparticles were obtained with acceptable physicochemical properties. In vitro release profile of insulin nanoparticles revealed that the highest solubility of nanoparticles in aqueous media is related to DMEC-Cys nanoparticles. CCD showed that optimized buccal film containing 4% chitosan and 10% glycerol has 5.81?kg/mm2 tensile strength and 2.47?N bioadhesion forces. Results of ex vivo study demonstrated that permeation of insulin nanoparticles through rabbit buccal mucosa is 17.1, 67.89 and 97.18% for chitosan, DMEC and DMEC-Cys nanoparticles, respectively. Thus, this study suggests that DMEC-Cys can act as a potential enhancer for buccal delivery of insulin. 相似文献
16.
Aihua Yao Fanrong Ai Deping Wang Wenhai Huang Xiaochuan Zhang 《Materials science & engineering. C, Materials for biological applications》2009,29(8):469-2529
Gd-substituted zinc ferrite nanoparticles with low Curie temperatures (Tc) were synthesized by a chemical co-precipitation method. The magnetic properties and heat generation characteristics of these magnetic nanoparticles were investigated. The Tc of ZnGdxFe2 − xO4 nanoparticles increased with increasing Gd3+ substitution, and was ~ 318 K at x = 0.02, which was a suitable Curie temperature for thermal seeds implanted in human body. The study on heat generation ability under external alternating magnetic field showed that the temperatures of these nanoparticles could be safely controlled around Tc without the temperature probe and controller. Furthermore, in vitro cytotoxicity of the ferrite nanoparticles was assessed using MTT assay. The results demonstrated that exposure to the bare ferrite nanoparticles for 48 h resulted in concentration-dependent toxicity. Cell growth inhabitation was observed when 4.0 mg/ml of bare ferrite nanoparticles was used. In contrast, PEG-capped nanoparticles had no significant effect on cell viability at any of the concentrations tested. 相似文献
17.
Divyanka Shrikant Bodas 《Drug development and industrial pharmacy》2013,39(7):1193-1204
Budesonide is a BCS class II drug with low water solubility (0.045?mg/mL) and low oral bioavailability (6–8%) due to high first pass effect. The aim is to prepare cross-linked chitosan–dextran sulfate nanoparticles and/or nanodispersion. Nebulizable cross-linked nanodispersion was prepared by the solvent evaporation technique and characterized through XRPD, FTIR, mean particle size (MPS), polydispersity index (PDI), zeta potential (ZP), drug loading, entrapment efficiency, SEM, % production yield, in vitro diffusion, aerodynamic and stability study. The optimization of formulation was done by using central composite rotatable design to study the effect of independent variables, concentration of chitosan (X1) and concentration dextran sulfate (X2) on the dependent variables, MPS (Y1), drug loading (Y2) and % CDR (% cumulative drug release) (Y3). The MPS, PDI, and ZP of budesonide-loaded nanoparticles were 160.8?±?0.27?nm, 0.36?±?0.04, and 13?±?0.894?mV, respectively. The percent drug loading of all the batches was found in range of 10–16%. The emitted drug in target region (alveoli) was measured by using HPLC and it was found to be 18.26%. It was found that, nanodispersion had the optimum in vitro aerodynamic behavior. Stability study results showed no significant change in MPS, PDI, ZP, and % CDR after three month storage. In conclusion, cross-linked chitosan–dextran sulfate nanoparticles had properties suitable for nebulizable dispersion of increased drug loading, in vitro drug release and avoiding the first pass effect. 相似文献
18.
Hoang Vinh Tran Lam Dai Tran Thinh Ngoc Nguyen 《Materials science & engineering. C, Materials for biological applications》2010,30(2):304-310
A simple and effective process has been proposed to prepare chitosan/magnetite nanocomposite beads with saturation magnetization value as high as uncoated Fe3O4 nanoparticles (ca. 54 emu/g). The reason was that the coating chitosan layer was so thin that it did not affect magnetic properties of these composite beads. Especially, chitosan on the surface of the magnetic Fe3O4 nanoparticles is available for coordinating with heavy metal ions, making those ions removed with the assistance of external magnets. Maximum adsorption capacities for Pb(II) and Ni(II), occurred at pH 6 and under room temperature were as high as 63.33 and 52.55 mg/g respectively, according to Langmuir isotherm model. These results permitted to conclude that chitosan/magnetite nanocomposite beads could serve as a promising adsorbent not only for Pb(II) and Ni(II) (pH = 4–6) but also for other heavy metal ions in wastewater treatment technology. 相似文献
19.
Au nanoparticles deposited on chitosan were readily prepared from aqueous solution of NaAuCl4 containing chitosan powder by the reaction with sonochemically formed reducing species. The average size of the formed Au particles was measured to be 22 nm with a relatively narrow size distribution, although there was no specific stabilizer for Au nanoparticles. 相似文献
20.
A novel method was developed to obtain N-(2-hydroxy)-propyl-3-trimethylammonium chitosan chloride (HTCC) using glycidyl trimethyl ammonium chloride (GTMAC) and chitosan
in a homogeneous system. The factors affecting the degree of substitution (DS) of HTCC, including the amount of perchloric
acid, the reaction temperature, and the reaction time, were especially investigated. Under optimal conditions (i.e., with
2.0, 1.9, and 15 g of chitosan, perchloric acid, and GTMAC, respectively), chitosan was pre-reacted with GTMAC at 60 °C, and
then the reaction was continued at 80 °C for 8 h. The as-produced HTCC had a DS of 86.9%. Its structure was characterized
by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Moreover, it had a good solubility in water within
a wide pH range. Besides, the composite was formed from HTCC loaded on bentonite surface. 相似文献