Preparation and release behavior of carboxymethylated chitosan/alginate microspheres encapsulating bovine serum albumin

Microspheres were prepared from carboxymethylated chitosan (CM‐chitosan) and alginate by emulsion phase separation. Their structure and morphology were characterized with IR spectroscopy and scanning electron microscopy. Bovine serum albumin (BSA) was encapsulated in the microspheres to test the release behavior. The swelling behavior, encapsulation efficiency, and release behavior of BSA from the microspheres at different pHs and with a pH‐gradient condition were investigated. The BSA encapsulation efficiency was calculated to be 80%. The degree of swelling of the microspheres without BSA loaded at pH 7.2 was much higher than that at pH 1.0. The encapsulated BSA was quickly released in a Tris–HCl buffer (pH 7.2), whereas a small amount of BSA was released under acid conditions (pH 1.0) because of the strong electrostatic interaction between ? NH₂ groups of CM‐chitosan and ? COOH groups of alginic acid and a dense structure caused by a Ca²⁺ crosslinked bridge. For the simulation of the processing of the drug under the conditions of the intestine, the microspheres were tested in a pH‐gradient medium, in which an acceleration of the release occurred at pH 7.4 after a lag time at a low pH (5.8–6.8). At pH 7.4, a large amount of BSA was released from the microspheres in a short time because of the rapid swelling of the microspheres. However, the release only depended on the diffusion of BSA at relatively low pHs, this resulted in a relatively low release. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 878–882, 2004     

Synthesis of pH-responsive isolated soy protein/carboxymethyl chitosan microspheres for sustained pesticide release

In order to improve the utilization rate of avermectin (AVM), a complex was prepared by electrostatic self-assembly using isolated soy protein (ISP) and carboxymethyl chitosan (CMCS) for loading AVM to obtain ISP/CMCS@AVM microspheres. The encapsulation efficiency (EE), sustained release property, ultraviolet (UV) protective ability, and toxicity of the microspheres were evaluated, and the release kinetics of AVM from the microsphere at different pHs were investigated. The results demonstrated that the average particle size of ISP/CMCS@AVM was 283.95 nm, and the EE reached 88.42% for AVM after denaturation. After 70 h of exposure to UV light, the residual rate of AVM in ISP/CMCS@AVM was 78.12%, which was significantly higher than 35.18% in the AVM emulsion. Moreover, the formulation imparted pH sensitivity and sustained-release property to AVM and was consistent with the Korsmeyer–Peppas model, controlled by Fick diffusion. Finally, the insecticidal toxicity of ISP/CMCS@AVM did not differ significantly from that of unmodified AVM. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48358.     

Elaboration of a feather keratin/carboxymethyl cellulose complex exhibiting pH sensitivity for sustained pesticide release

Feather keratin (FK) and carboxymethyl cellulose (CMC) were used as raw materials to prepare a FK/CMC polyelectrolyte complex via electrostatic interactions. Using avermectin (AVM) as a model drug and elevated temperature, an FK/CMC@AVM drug-carrying complex was obtained. The structure and morphology of FK/CMC@AVM were both analyzed by Fourier transform infrared spectroscopy, dynamic light scattering, and scanning electron microscopy (SEM). Furthermore, the encapsulation efficiency, anti-ultraviolet, sustained release, and toxicity properties of FK/CMC@AVM were studied. The results showed that the average particle size of FK/CMC@AVM was 386.57 nm and the encapsulation efficiency was 67.06%. Under UV light irradiation, FK/CMC@AVM significantly improved the stability of AVM and the half-life of AVM was found to be delayed from 354 to 1800 min. Moreover, the sustained release of AVM featured pH sensitivity and was consistent with the Korsmeyer–Peppas model. Upon increasing the pH from 1.5 to 9.5, the release mechanism of AVM changed from Fick diffusion to non-Fick diffusion. Finally, the toxicity characteristics of FK/CMC@AVM were not significantly different from those of nonmodified AVM. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47160.     

Controlled release of berberine hydrochloride from alginate microspheres embedded within carboxymethyl chitosan hydrogels

Berberine hydrochloride is a natural medicine with wide clinical application. In this article, berberine hydrochloride was entrapped into alginate microspheres via an emulsification/gelation method. The size distribution of the microspheres was determined by a laser particle sizer. Drug distribution within the microspheres was determined by confocal laser scanning microscopy. Those drug‐loaded microspheres were further entrapped into carboxymethyl chitosan (CMC) hydrogel to form a new drug‐delivery system (DDS). The surface morphology of the DDS was observed using metallographic microscopy and scanning electron microscopy (SEM). The compression strength of the DDSs with alginate microspheres was found significantly higher than that of the pure hydrogel. The drug‐release performances of the DDS in phosphate buffer solution (PBS, pH 7.4), saline solution (pH 6.3), and hydrochloric acid solution (HAS, pH 1.2) were also studied. Decay of the DDS in PBS within 72–80 h results in a faster release; however, the steady release in saline solution could last for all the testing period without cleavage of the DDS. In HAS, because of the shrinkage of the DDS, release is fast in the first period and remains steady later. The DDS exhibits prospective in controlled steady release of drugs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Sorption and desorption of water vapour by membranes of the polyelectrolyte complex of chitosan and carboxymethyl cellulose

Sorption of water vapour by chitosan/carboxymethyl cellulose polyelectrolyte complex membranes prepared at two different pHs was studied. A linear dependence of the water uptake (W) on time was observed for W values lower than 0.5 g of water per gram of membrane. For higher values of W diffusion becomes controlled by the relaxation of the chains, and second-order kinetics is observed. An equation that satisfactorily reproduces this behaviour is proposed. Desorption experiments were carried out at different temperatures and the W versus time curves obtained exhibited the same general pattern and were also adjusted by this equation. The approximate average diffusion coefficients were evaluated at each temperature and the apparent activation energy for the diffusion process is reported.     

羧甲基纤维素钠/凹凸棒石纳米复合材料的制备与表征

以羧甲基纤维素钠(CMC-Na)为基体,凹凸棒石(AT)为增强材料,采用溶液共混法制备了标题物。研究了凹凸棒石用量对纳米复合材料结构和性能的影响。通过FT-IR、TG、SEM对复合材料进行了表征。试验结果表明,当凹凸棒石用量为羧甲基纤维素钠质量的0.22%时,复合材料的力学性能最佳。由于纳米凹凸棒石的引入,CMC-Na分子某些特征峰的波数发生了变化,复合材料的形貌也发生了改变;羧甲基纤维素钠/凹凸棒石纳米复合材料的热稳定性高于纯羧甲基纤维素钠膜。     

羧甲基纤维素钠和羟乙基纤维素在日化产品中的应用

羧甲基纤维素钠(CMC)和羟乙基纤维素(HEC)是纤维素醚类产品中使用范围最广的产品,它们是纤维素链上葡萄酐单元的羟基与醚化基团(氯乙酸或环氧乙烷)反应而成的。其水溶液是非牛顿性流体,黏度随剪切速率变化而与时间无关。溶液的黏度随浓度增大迅速增加,是使用范围最广的增稠剂和流变助剂。介绍了CMC和HEC的分子结构、合成制备、溶液特性和在日化产品应用的配方。     

糠醛渣制备羧甲基纤维素的研究

以糠醛渣为原料,采用Milox法提取纤维素,经漂白处理后制备羧甲基纤维素(CMC),对纤维素提取工艺、漂白工艺及CMC的合成进行了初步研究。实验结果表明,纤维素提取工艺优化条件:甲酸80mL,过氧化氢14mL,反应时间2.5h—2.5h—2.5h,反应温度80℃—95℃—80℃;漂白工艺条件:可选择过氧化氢10mL,氢氧化钠质量浓度2.5g/L,反应温度45℃,反应时间60min。制得的CMC的取代度为0.901 2,黏度为45mPa·s。     

壳聚糖/羧甲基壳聚糖及其衍生物在日化方面的应用

壳聚糖及其衍生物含有大量的氨基和羟基,为壳聚糖的改性或者接枝反应提供了活性基团,壳聚糖/羧甲基壳聚糖因特殊的化学结构而使其具有优异的化学性质,如良好的生物相容性、无毒、生物可降解性以及抗微生物活性等性质,因此受到生物工程、医药、食品、化妆品以及其他一些领域的广泛关注,成为近年来研究开发的热点。对壳聚糖/羧甲基壳聚糖及其衍生物在日用化学中的应用进行了综述,并对其发展趋势进行了展望。     

废纸制备羧甲基纤维素的研究

以废纸为原料制备羧甲基纤维素(CMC),探讨了分散剂组成、碱化温度、时间、碱用量和醚化剂用量、醚化温度、时间对产品粘度的影响。结果表明,当废纸、氢氧化钠和醚化剂的质量比为1 0∶0 9∶1 2,以85%的乙醇水溶液为分散剂,35℃碱化90min,75℃醚化150min时,生成的CMC质量最好,取代度>0.6,有效成分>85%,水分<10%,氯化物<4%,其2%水溶液的粘度>500mPa·s。     

Biocompatibility and characteristics of theophylline/carboxymethyl chitosan microspheres for pulmonary drug delivery

The main aim was to evaluate the biocompatibility of theophylline/carboxymethyl chitosan/β‐cyclodextrin microspheres made by spray drying for pulmonary delivery. Haemolysis tests and cell culture experiments were used to determine blood and cell biocompatibility, and in vivo implantation experiments were used to examine tissue biocompatibility. The theophylline/carboxymethyl chitosan/β‐cyclodextrin microspheres were spherical in shape with a smooth or wrinkled surface, and showed no haemolysis activity. The cytotoxicity was dependent on concentration and showed no toxicity at low concentration. The results of implantation indicated that the inflammatory reaction gradually lessened and disappeared and had no significant difference from that of an operative suture. Therefore, theophylline/carboxymethyl chitosan/β‐cyclodextrin microspheres possess good biocompatibility and can be used as a promising carrier for pulmonary drug delivery. © 2013 Society of Chemical Industry     

Blend films of O‐carboxymethyl chitosan and cellulose in N‐methylmorpholine‐N‐oxide monohydrate

To introduce N‐methylmorpholine‐N‐oxide (NMMO) process to prepare antibacterial lyocell fiber, the blend films of O‐carboxymethyl chitosan (O‐CMCS) and cellulose were prepared. O‐CMCS in aqueous suspension with particles having a surface mean diameter of 2.24 μm was blended with cellulose in NMMO hydrate. The blend films with different O‐CMCS content were prepared with the blend solutions. SEM confirmed that O‐CMCS remained within the cellulose film in the particle. The mechanical properties of the blend films show little increased value when O‐CMCS was less 5%; however, it decreased sharply when O‐CMCS was over 8%. Thus, the optimum O‐CMCS content may give a good combination of antibacterial action and mechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4601–4605, 2006     

Studies on preparations and properties of drug-eluting embolization microspheres made from oxidated alginate and carboxymethyl chitosan

Embolization microspheres were prepared through two steps. The microspheres demonstrated regular sphericity with a main size distribution in the range of 100?µm?～?270?µm. An anticancer drug doxorubicin could be loaded into the microspheres with high loading rates from 21% to 32% due to physical and ionic interaction of carboxyl groups in the microspheres and amino groups in doxorubicin. The drug could be controlled released at different pH conditions. The blank microspheres were biodegradable, non-cytotoxic, and the drug-eluting embolization microspheres could be potentially applied as embolic agents in interventional therapy.     

反相微乳液法制备纳米银/羧甲基壳聚糖复合微粒

采用反相微乳液法,以水合肼为还原剂制备纳米银/羧甲基壳聚糖复合微粒,并用红外光谱、X射线衍射、透射电镜对制备的样品微粒进行表征,讨论了搅拌速度、AgNO_3用量以及乳液体系的组成对纳米银复合粒子形貌与尺寸的影响。结果表明,当搅拌速度为1400r/min,AgNO_3用量为0.52g,吐温-80/液体石蜡体积比为4:5时,可制得粒径在50nm左右的纳米银/羧甲基壳聚糖复合微粒,且粒子具有较好的面心立方晶体结构。     

Polyelectrolyte complexes of sodium alginate with chitosan or its derivatives for microcapsules

Chitosan, a cationic polysaccharide, was heterogeneously deacetylated with a 47% sodium hydroxide solution and followed by a homogeneous reacetylation with acetic anhydrides to control the N-acetyl content of the chitosan having a similar molecular weight. The chitosans having different degrees of N-acetylation were complexed with sodium alginate, an anionic polysaccharide, and the formation behavior of polyelectrolyte complexes (PECs) was examined by the viscometry in various pH ranges. The maximum mixing ratio (R_max) increased with a decrease in the degree of N-acetylation of the chitosan at the same pH, and with a decrease in pH at the same degree of N-acetylation. Similarly, N-acylated chitosans were also prepared. The N-acyl chitosans scarcely affected the formation behavior of PECs with sodium alginates. For the application of the PECs produced, the microencapsulation of a drug was performed and the release property of drug was tested. The microcapsules were prepared in one step by the extrusion of a solution of guaifenesin and sodium alginate into a solution containing calcium chloride and chitosan through interpolymeric ionic interactions. The drug release during the drug-loaded microcapsules storage in saline was found to depend on the pH where the microcapsules were formed and the kind of N-acyl groups introduced to the chitosan. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 425–432, 1997     

Controlled release of carbamazepine from carboxymethyl chitosan‐grafted‐ 2‐hydroxyethylmethacrylate matrix tablets

The aim of the study was to prepare the controlled release dosage of carbamazepine matrix tablets using wet granulation technique. The graft copolymerization of carboxymethyl chitosan (CMCH) with 2‐hydroxyethylmethacrylate (HEMA) was carried out. The product was characterized by Fourier‐transform infrared, scanning electron microscopy, transmission electron micrograph, and X‐ray diffraction anayses. CMCH‐g‐HEMA was used as binder to prepare the matrix tablets containing carbamazepine. The properties of tablets like hardness, friability, and dissolution influenced by binder were studied. In vitro release of the matrix tablets was carried out with the phosphate‐buffered solution (pH 7.4) at 37°C and 100 × g using USP dissolution test apparatus. Release rate of carbamazepine from controlled release matrix tablets was compared with the commercially marketed tablet, Tagretol 200. Results show that after 6 hrs percentage drug release of formulated tablet CGH₅ was 20.42% and that of Tegretol 200 was 18.32%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Micellar solutions of amphipathic copolymers based on carboxymethyl cellulose

A novel family of amphipathic copolymers based on carboxymethyl cellulose (CM‐cellulose) has been synthesized through ultrasonic irradiation. Their micellar conformation in aqueous solution was studied by dynamic laser scattering, environmental scanning electron microscopy and gel permeation chromatography. The results show that conformation of copolymer molecules is totally different from that of CM‐cellulose because of the introduction of the surface active macromonomers. Due to the influence of hydrophobic character and molecular weight, different amphipathic copolymers have different micellar conformations, such as cylindrical, spheroidal or ellipsoidal micelles. In the range of concentration tested, the normalized first‐order autocorrelation function g⁽¹⁾(τ) of a copolymer of CM‐cellulose and poly(ethylene oxide) dodecyl ether acrylate does not fit a single‐exponential decay, indicating a polydisperse system and the existence of species of different shapes and size. At different concentrations, the hydrodynamic radii of micelles (R) almost distribute into two regions of smaller and larger size. With increasing copolymer concentration, the region of smaller R remains in the range 30–100 nm and is considered to represent monomolecular micelles, while the larger R region increases gradually with concentration, which means that polymolecular micelles increase in size. © 2003 Society of Chemical Industry     

农作物秸杆制备羧甲基纤维素工艺的研究

本文以玉米秸秆为原料,讨论了制备羧甲基纤维素的工艺。它的最佳条件为;NaOH用量为8g,碱化温度30℃～35℃,碱化时间50min;醚化剂(一氯乙酸)用量为11g,醚化时间120min,醚化温度65℃;乙醇质量分数75%,其产品质量符合纺织行业上浆标准。     

“类乒乓球”状壳聚糖微球对环丙沙星的控制释放性能的研究

以甲醛作为交联剂,通过悬浮交联法得到单分散性的微米级微球。采用分光光度法研究了壳聚糖微球对环丙沙星的载药释药性能,考察了环丙沙星初始浓度、pH、微球粒径大小、载药时间及温度对饱和吸附量的影响。结果表明,在初始浓度为200 mg/L,pH为8.80和时间为65 min,温度为37℃的优化条件下,壳聚糖微球对环丙沙星的载药量最大,最大吸附量为325 mg/g。在pH为7.4,温度为37℃的模拟人体肠胃缓冲溶液(NaH2PO4/NaOH)中研究了初始浓度以及释放时间对释放结果的影响。实验表明,环丙沙星在担载时与环丙沙星的初始浓度有关,浓度越大,担载量越大,但是担载效率和浓度之间无确定的线性关系。在环丙沙星释放初期有明显的释放现象,但是随着时间的推移,药物释放逐渐稳定,释药效率可达97%左右。     

Preparation of sodium carboxymethyl cellulose from paper sludge

BACKGROUND: This paper describes the reuse of paper sludge, an industrial solid waste, for the preparation of sodium carboxymethyl cellulose (CMC). The process includes pretreatment, basification and etherification. RESULTS: The optimal pretreatment condition involved the addition of 6.7% hydrochloric acid to the paper sludge for 30 min at 70 °C. The order of factors influencing the effect of reaction was: etherification temperature > sodium hydroxide dose > basification temperature > etherification time > sodium chloroacetate dose. The optimal preparation condition of CMC was: m_papersludge: m_{sodiumhydroxide}: m_{sodiumchloroacetate} = 0.9:0.8:1.15; basification at 40 °C; etherification at 60 °C for 1 h. Under these conditions, certified CMC with viscosity less than 20 mPa· s, DS more than 0.50 and purity more than 90% was produced. The results of Fourier transform infrared (FTIR) and X‐ray diffraction (XRD) spectra analyses indicated that the product has characteristics of high degree of substitution (DS) and low crystallinity. The coated paper using CMC prepared from paper sludge as a water retention agent can meet the quality standards of GB/T 10335.1‐2005. CONCLUSION: Preparation of CMC from paper sludge can be considered a feasible alternative, generating value‐added product and contributing to solving environmental problems resulting from paper sludge. Copyright © 2008 Society of Chemical Industry