Microcapsules of alginate-chitosan.: II.: A study of capsule stability and permeability
Microcapsules of alginate-chitosan.: II.: A study of capsule stability and permeability
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DOI：
10.1016/s0142-9612(98)00230-0
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发表时间：
1999-04-01
期刊：
影响因子：
14
通讯作者：
Skjåk-Bræk, G
中科院分区：
文献类型：
--
作者：
Gåserod, O;Sannes, A;Skjåk-Bræk, G
海藻酸盐-壳聚糖胶囊的稳定性强烈依赖于与胶囊结合的壳聚糖的量。当通过将海藻酸钠溶液滴入壳聚糖溶液（一步法）来制备胶囊时，所有的壳聚糖位于表面上的薄海藻酸盐-壳聚糖膜中。这些胶囊比通过使海藻酸钙珠在壳聚糖和氯化钙的水溶液中反应（两阶段程序）制成的胶囊弱得多。当壳聚糖的数均分子量降低到约15000时，当胶囊制得更均匀时，当胶囊直径降低到约300 μ m时，在较短的反应时间后获得具有高机械强度的胶囊。当这些胶囊在藻酸钙凝胶正常溶解的条件下用钙螯合剂如柠檬酸盐处理时，它们仍然具有凝胶芯，表明壳聚糖在整个胶囊基质中的存在。当壳聚糖分子量增加和乙酰化程度增加时，以及当胶囊变得更不均匀时，两阶段胶囊的渗透性降低。另外几层藻酸盐和壳聚糖的添加导致胶囊几乎不能渗透IgG，表明平均胶囊孔径小于90埃。(C)1999 Elsevier Science Ltd.保留所有权利。
The stability of alginate-chitosan capsules was shown to depend strongly on the amount of chitosan bound to the capsules. When the capsules were made by dropping a solution of sodium alginate into a chitosan solution (one-stage procedure), all the chitosan was located in a thin alginate-chitosan membrane on the surface. These capsules were much weaker than the capsules made by reacting calcium alginate beads in an aqueous solution of chitosan and calcium chloride (two-stage procedure). Capsules with high mechanical strength were obtained after shorter reaction times when the number-average molecular weight of the chitosan was reduced to around 15 000, when the capsules were made more homogeneous and when the capsule diameter was reduced to around 300 mu m. When these capsules were treated with calcium sequestrant such as citrate under conditions when calcium alginate gels normally dissolve, they still had a gel core indicating the presence of chitosan throughout the capsule matrix. The permeability of the two-stage capsules was reduced when the chitosan molecular weight was increased and the degree of acetylation was increased, and when the capsules were made more inhomogeneous. The addition of another several layers of alginate and chitosan resulted in capsules virtually impermeable to IgG, suggesting an average capsule pore diameter less than 90 Angstrom. (C) 1999 Elsevier Science Ltd. All rights reserved.