O-季铵化改性壳聚糖固载环糊精的制备及其载药性能

对壳聚糖进行O-季铵化改性,并与羧甲基-β-环糊精在均相条件下进行缩合反应,制得O-季铵化壳聚糖固载环糊精(QCSCD),用FTIR、EA和SEM对产物进行表征。以酮洛芬为模型药物,研究其载药及药物释放行为。结果表明,季铵盐基团的引入提高了QCSCD的载药量,为3.97mg/mg,并且改变了QCSCD的pH响应性能。与壳聚糖固载环糊精相反,QCSCD在模拟胃液中的释放速率很快,而在模拟肠液中具有缓释性能。     

季铵化改性壳聚糖的制备及其凝血性能研究

为了对壳聚糖进行化学改性及探究其凝血性能,以来源丰富的壳聚糖为起始原料,通过亲核取代反应,开展季铵化改性,采用紫外-可见光谱、红外光谱及X-射线衍射进行结构表征,并在体外探索其凝血性能。化学结构表征结果表明,季铵化壳聚糖已经成功制备得到;季铵化壳聚糖(50 mg)的体外凝血时间为128.2 s,凝血指数为43.6%,血浆复钙时间为102.1 s,制备得到的季铵化壳聚糖具有较强的促凝血性能。     

壳聚糖的季铵化改性及其应用

阐述了壳聚糖季铵化改性的常用改性剂,改性后的壳聚糖理化性能的改善情况及其应用领域。     

季铵化壳聚糖-聚苯乙烯共混膜的制备及表征

以十六烷基三甲基溴化铵(CTAB)为表面活性剂,过硫酸钾为引发剂制备了聚苯乙烯微乳液,用共混法制备了3种不同质量比的季铵化壳聚糖和聚苯乙烯微乳液的共混膜.研究了该膜的温度和pH的敏感性及力学强度.结果表明,共混膜的拉伸强度与纯壳聚糖膜相比有较大提高,而且该膜仍然具有一定的温度敏感性和pH敏感性,有较好的应用价值.     

壳聚糖载药微球的制备方法及在医药领域的应用

壳聚糖是唯一的天然碱性多糖,其优异的生物学特性使之成为药物载体领域研究的热点.综述了壳聚糖微球常见的制备方法,阐述了壳聚糖微球作为药物载体在医药领域的应用,介绍了药物包覆在微球中后,不仅达到了药物缓释控释的目的,还增加了其靶向性、降低了药物毒副作用.因此,对新型药物载体材料的研究及新型医药产品的开发有着重要意义.     

丝素-羟丙基壳聚糖微球的结构和释药性能

以胰岛素为目标药物,以丝素(SF)和羟丙基壳聚糖(HPCS)为包药材料,复凝聚法制备SF-HPCS载药微球。采用红外光谱(FTIR)、扫描电镜(SEM)、X射线衍射(XRD)、热重分析(TGA)等对载药微球的结构、外部形貌及热性能等进行了表征。结果表明,所制备的载药微球表面密实,平均粒径22.4μm,呈正态分布;载药微球对胰岛素的包埋率达73.6%,大于HPCS载药微球(64.3%)及壳聚糖(CS)载药微球(57.1%);SF-HPCS载药微球在人工胃液中4h内累计释药率为21.3%,在人工肠液中24h内累计释药率达81.2%,48h累计释药率为92.2%,释放过程平稳、缓慢。     

季铵化壳聚糖止血海绵制备工艺的研究

以表观特征及吸水率为考察指标,探究不同因素对季铵化壳聚糖止血海绵制备工艺的影响。以季铵化壳聚糖为原料,戊二醛为交联剂,采用冷冻干燥工艺制备安全的止血海绵医用生物材料。该方法制得的止血海绵呈雪白色,质地柔软、均匀,结构疏松多孔,且具有一定的弹性。该止血海绵可在酸性、中性和碱性条件下制备,在中性条件下制得的止血海绵吸水率最大;中性条件下,分别考察了戊二醛浓度、温度及季铵化壳聚糖浓度对吸水率的影响,结果表明,当戊二醛质量分数为1.5%,温度为35℃,季铵化壳聚糖质量分数为3%时,制备的止血海绵吸水率最高。所研制的止血海绵安全、稳定,可为季铵化壳聚糖止血海绵的进一步应用研究与临床开发提供实验依据。     

季铵化壳聚糖及其絮凝六价铬性能的研究

以3-氯-2-羟丙基三甲基氯化铵(CTA)为改性剂接枝改性了壳聚糖,制备得到了2-羟丙基三甲基壳聚糖季铵盐(CTA-CTS),用红外光谱和核磁共振表征了产物的结构;用得到的产品处理含Cr2O72-的模拟电镀废水,研究了接枝时间、废水的pH值、CTA-CTS的质量浓度对Cr(Ⅵ)去除能力的影响。结果表明:接枝反应主要发生在—NH2上,并以反应时间为10.0h的产品对Cr(Ⅵ)的去除能力较强,在pH值为5.0,CTA-CTS的质量浓度为100mg/L左右时,对Cr(Ⅵ)的去除率可达95%。     

改性季铵化壳聚糖阴离子交换膜的制备与表征

以壳聚糖（CS）为原料,2,3-环氧丙基三甲基氯化铵（GTA）为醚化剂,通过亲核取代反应制备了季铵化壳聚糖（QCS）,用傅立叶变换红外光谱（FT-IR）表征了产物的结构,结果表明产物结构与目标产物的结构相符。以QCS为原料,醋酸溶液为溶剂,通过加入交联剂戊二醛（GA）和荷正电聚苯乙烯（PS）微球,制备了一系列改性QCS阴离子交换膜,并对其含水率、溶胀度、离子交换量等性能进行了测定。结果表明：交联剂的加入可有效抑制QCS膜的形变,降低了其溶胀度,微乳液的加入会在一定程度上提高复合膜的离子交换能力,交联度为4%、微乳液用量为15%（v/v）时离子交换膜的含水率趋于稳定。     

叶酸偶联N-季铵化壳聚糖的制备及其基因载体性能

首先对壳聚糖进行季铵化改性合成N-季铵化壳聚糖（HTCC）,再接枝叶酸基团制备了叶酸偶联N-季铵化壳聚糖（FA-HTCC）,用FTIR和1H NMR等对产物进行表征,并对其作为基因载体进行研究。结果表明,合成产物具有较好的水溶性,N/P为4的FA-HTCC/DNA复合物粒径为188 nm、Zeta电位为15.4 mV。与PEI和阳离子脂质体相比,FA-HTCC具有更低的细胞毒性和更高的转染效率。     

“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。     

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     

Glutaraldehyde‐crosslinked chitosan beads for controlled release of diclofenac sodium

An inexpensive and simple method was adopted for the preparation of chitosan beads, crosslinked with glutaraldehyde (GA), for the controlled release of diclofenac sodium (DS). The beads were prepared by varying the experimental conditions such as pH, temperature, and extent of crosslinking. The absence of any chemical interaction among drug, polymer, and the crosslinking agent was confirmed by FTIR and thermal analysis. The beads were characterized by microscopy, which indicated that the particles were in the size range of 500–700 μm and SEM studies revealed smooth surface and spherical shape of beads. The beads produced at higher temperature and extended exposure to GA exhibited lower drug content, whereas increased drug loading resulted in enhanced drug release. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 211–217, 2007     

Electroactive polyacrylamide/chitosan/polypyrrole hydrogel for captopril release controlled by electricity

The demand for the development of new therapies and devices for controlled drug release has been continuously increasing, especially those based on materials sensitives to external stimuli, such as electricity. Therefore, in this work, acrylamide was polymerized in the presence of chitosan (CS), using N,N′-methylenebisacrylamide as cross-linking, followed by immersion in pyrrole aqueous solution and chemical polymerization to obtain an electroactive hydrogel of polyacrylamide/CS/polypyrrole (PA/CS/PPy) (67.5/7.5/25% wt.); this electroactive hydrogel was later used in drug delivery controlled by electricity studies. The synthesized PA/CS/PPy hydrogel was characterized by scanning electron microscopy, FTIR spectroscopy, and thermogravimetric analysis. It was observed that the hydrogel presented pores in the range of 50–200 μm with CS and PPy well incorporated to the cross-linked PA. The hydrogel swelling percentage (S) was determined at different pHs. It was observed that S was independent of pH, with S = 700% and a swelling kinetics described by the Fickian diffusion mechanism at alkaline pH. PA/CS/PPy hydrogel was used to absorb captopril (a drug for hypertension control), and its kinetics release at different applied potentials and pH was studied. Release kinetics were described by the Korsmeyer–Peppas model, while release mechanism was a Case-II transport without current at alkaline pH; under electrical stimuli, the mechanism presented an anomalous transport with ON–OFF profile, increasing the release rate with the applied voltage showing its electroactivity in the captopril release.     

Preparation of porous chitosan/agarose microsphere and its R‐phycoerythrin release properties

The chitosan microspheres (CS‐CL) were prepared by suspension crosslinking method and used as carriers of R‐phycoerythrin (R‐PE). In this study, R‐PE was loaded in the microspheres and released in vitro. The effects of pH value, temperature, ionic strength, and R‐PE concentration on loading efficiency and release behavior were discussed. A novel microsphere that contained agarose (CS‐AR MP) was prepared and the basic loading and releasing behavior for R‐PE of this kind of new microspheres were also investigated. The results showed that all these chitosan microspheres have the ability to control‐release R‐PE. The addition of agarose may somewhat accelerate the release rate of R‐PE from microspheres and reduce the capacity of adsorption for R‐PE. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2759–2766, 2007     

Synthesis and characterization of chitosan/cloisite 30B film for controlled release of ofloxacin

In this research program, chitosan film was prepared by blending chitosan with Cloisite 30 B at different concentrations 0 wt %, 1 wt %, and 2.5 wt %. The blends were characterized by Fourier transmission infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X‐ray diffraction (XRD) analysis. From the FTIR spectra the various groups present in chitosan/C 30 B blend were monitored. The homogeneity, morphology, and crystallinity of the blends were ascertained from SEM and XRD data, respectively. The most suitable form of blend was taken and used as a carrier for the controlled release of ofloxacin. The swelling studies have been carried out at different drug loading. Drug release kinetics was analyzed by plotting the cumulative release data versus time by fitting to an exponential equation which indicated the occurrence of non‐Fickian type of kinetics. The drug release was investigated at different pH medium and it was found that the drug release depends upon the pH medium as well as the nature of matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

药物控释用智能水凝胶研究进展

智能水凝胶在药物控释方面具有智能化、效率高和安全方便等优点.近年来,研究开发药物控释用智能水凝胶非常活跃,展示了广阔的应用前景.本文综述了药物控释用温度、pH值、葡萄糖、电场、磁场及光敏感水凝胶的最新研究进展.     

Preparation and evaluation of chitosan‐coated polyphosphazene hydrogel beads for drug controlled release

Chitosan‐coated polyphosphazene‐Ca²⁺ hydrogel beads were fabricated by dropping polyphosphazene into CaCl₂/chitosan gelling solution. Polyphosphazene used here was a water‐soluble degradable polyanion (PCPAP), which carried almost two carboxylatophenamino groups on each phosphorus atom of the polymer backbone. Two kinds of turbidimetric titration were applied in this study to reveal the interaction between PCPAP and chitosan within the pH range of 4.57≈7.14. The effect of gelling solution pH on the properties of chitosan‐coated PCPAP beads was especially emphasized. It was found that the PCPAP/chitosan complex prepared at relatively high pH (pH 6.5) dissociated most slowly in pH 7.4 phosphate‐buffered solution (PBS). The erosion of chitosan‐coated beads and the release of model drug (Coomassie brilliant blue and myoglobin) in PBS were both obviously prolonged with the increase of gelling solution pH, exhibiting perfect accordance with the behavior of complex dissociation. In addition, the coating of PCPAP/chitosan complex on the bead surface facilitated the improvement of drug loading efficiency. The higher the gelling solution pH, the more the drug loading efficiency improved. At pH 6.5 (PCPAP 5%, CaCl₂ 7%, chitosan 0.3%), the loading efficiency of myoglobin in beads reached as high as 93.2%. These results indicate that the chitosan‐coated polyphosphazene‐ Ca²⁺ bead is a potential formulation for drug controlled release. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1993–1999, 2004     

Destruction of chitosan capsules based on host–guest interaction and controllable release of encapsulated dyes

This article describes a new and simple method to control the release of payloads encapsulated in chitosan capsules. The capsules with the liquid core and rigid shell are performed by drop‐wisely adding chitosan solution into anionic surfactant solution. The capsules can be destroyed by β‐CD because β‐CD binds and sequesters surfactant from the shell through the host‐guest interaction. The destruction process is studied by optical microscopy and scanning electron microscopy. The capsules can swell in acid solution and shrink in alkaline solution. It is found that the destruction speed increases with increasing acidity or alkalinity of β‐CD solution. Rhodamine B encapsulated in the liquid‐core of chitosan capsules can be released from the capsules in β‐CD solution. The release rate can be adjusted by the pH value of β‐CD solution. The release speed of the capsule increases with the increase of acidity or alkalinity in β‐CD solution. The above concept can provide more versatility for controlled release of a variety of payloads such as drugs, cosmetics, and so on. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45229.