共查询到16条相似文献，搜索用时 62 毫秒
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海藻酸钠(sodium alginate,SA)是从褐藻类中提取的一种具有生物活性、可生物降解的聚阴离子电解质;壳聚糖(chitosan,CS)是一种天然的、含有氨基的亲水性多糖,是一种聚阳离子电解质。SA/CS微载体是一种天然的高分子材料,具有无毒性、生物相容性、生物降解性,且能够与生物大分子药物结合,使其所载药物可缓慢且稳定地释放,从而实现药物的靶向作用,因此SA/CS微载体在生物医学领域具有广阔的应用前景。本文就SA/CS微载体的生物特性、制备方法、体外释放特性及其作为药物载体的相关应用作一综述。 相似文献
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以壳聚糖和海藻酸钠为载体、4A沸石为性能改良剂,采用锐孔法制备了4A沸石/海藻酸钠/壳聚糖复合微球,利用显微镜、SEM、FTIR和XRD对复合微球进行了表征,考察了4A沸石对复合微球成球率和溶胀性能的影响。结果表明:随着4A沸石添加量的增加,复合微球的质量和粒径均增大,添加4A沸石有利于复合微球成球,成球率最高为98.5%(添加4A沸石1 g),且冷冻干燥后微球具有均匀的粒径和规则的球形形状。在不同pH(3、5、7)和温度下,4A沸石能有效抑制微球的过度溶胀,但仍然保持良好的pH和温度敏感性。 相似文献
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为了得到一种对啶虫脒具有高负载率和良好的缓释性能的农药载体,以膨润土作为吸附剂,利用壳聚糖的成膜性,采用挤出外源凝胶法制备了啶虫脒凝胶微球。并通过FTIR、SEM、TG、溶胀实验和释药实验对其结构、形貌和性能进行表征。结果表明,所制得的凝胶微球的粒径为1.42～1.71 mm,膨润土可提高微球粒径与球形度,使啶虫脒的载药率和包封率分别由原来的4.16%和36.36%提升为4.91%和63.01%。壳聚糖与海藻酸钠通过静电作用形成了聚电解质复合物,辅助了钙离子交联,使啶虫脒的载药率和包封率分别由原来的4.16%和36.36%提升为5.23%和54.29%。膨润土表面含有大量的羟基,与海藻酸钠和壳聚糖形成氢键作用,可有效抑制海藻酸钙的大量溶胀,提高其缓释性能。 相似文献
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以壳聚糖为基质,通过共混法引入海藻酸钠,采用乳液冷冻干燥法,并结合正戊醇和醋酸铵作致孔剂,制备海藻酸钠/壳聚糖多孔微载体,并在该微载体上培养人肝细胞L-02。通过扫描电子显微镜来观察微载体的微观结构形貌,并通过红外光谱、溶胀性、吸水率、体外降解率、MTT比色法等手段来综合评价海藻酸钠/壳聚糖微载体的性能及生物活性。结果表明,致孔剂不同,则得到的微载体的表观形貌也不同。以正戊醇为致孔剂进行冻干得到的微载体孔径为3～50μm,孔隙率为93%;以正戊醇和醋酸铵2种致孔剂来制孔得到的微载体孔径为15～55μm,孔隙率为94%。且2种方法得到的微载体硬度高,溶胀性良好,吸水率高,空白海藻酸钠/壳聚糖微载体在体外可完全降解。红外光谱显示,海藻酸钠/壳聚糖微载体中,壳聚糖分子链上的氨基和乙酰胺基都与海藻酸钠分子链上的羧酸盐官能团存在很强的静电相互作用。光学显微镜观察L-02人肝细胞在海藻酸钠/壳聚糖微载体上生长良好。 相似文献
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为隔绝饲用碘酸钙在贮存、使用过程中与还原性物质，如维生素c (VC)的反应。以碘酸钙(Ca(IO3)2)为芯材，海藻酸钠(SA)为壁材，纳米碳酸钙(Nano-CaCO3)为交联钙源，采用改良的内源乳化法制备了碘酸钙/海藻酸钠凝胶微球(Ca(IO3)2/SAMS)。利用FTIR、SEM、TG、XRD对Ca(IO3)2/SAMS进行了表征，同时测定了其在VC溶液中的稳定性，探讨了Ca(IO3)2/SAMS形成机制。结果表明，Ca(IO3)2/SAMS呈球形，粒径约为20~40 μm，其表面有大量碘酸钙晶体。Ca(IO3)2和Ca(IO3)2/SAMS在VC溶液中VC分解50%用时(t50%)分别为54.8 min和78.3 min，Ca(IO3)2在饲料中的稳定性得到明显提升。 相似文献
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Carboxymethyl chitosan sodium salt (CMCS)/sodium alginate (SA), a pH-sensitive hydrogel composed of CMCS and SA crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide, has been evaluated in vitro as a potential carrier for protein drug delivery of bovine serum albumin (BSA). The crosslinked structures, pore morphologies, and mechanical properties of the composite CMCS/SA hydrogel at different pH have been characterized by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA). The swelling behavior of the prepared hydrogel was assessed at different pH values, 1.2, 4.0, 6.86, 7.4, and 9.0. The in vitro slow release ability of the CMCS/SA hydrogel was assessed at 37°C and pH 1.2 or pH 7.4 to simulate gastrointestinal and mouth environments in vivo. The efficiency was found to be greater than 90% at pH 7.4. The composite CMCS/SA hydrogel showed no cytotoxic effect toward L-929 cells according to the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test. These findings demonstrate that the composite hydrogel has promising potential for drug delivery. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46911. 相似文献
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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 相似文献
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Sodium alginate/chitosan (SA/CS) two ply composite membranes were prepared by casting and solvent evaporation technique. NaHCO3 was used as a porogen additive to form pores in the interior of the composite membranes and glycerol was introduced as a plasticizer. The water uptake capacity, mechanical strength, oxygen permeation property, and in vitro cytotoxicity were evaluated to test the feasibility to utilize the composite membranes for wound dressing. The average pore size, water uptake capacity, and oxygen permeation property of the composite membranes could be adjusted by the ratio of NaHCO3 in the SA solution. The SA/CS two ply composite membranes showed high water uptake capacity, suitable mechanical strength, excellent oxygen permeability, and good biocompatible. It indicates that the SA/CS two ply composite membranes are suitable for wound dressing application. It provides a simple but promising platform to fabricate wound dressing using natural polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献