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采用先辐射后冻融的方法制备了一系列聚乙烯醇(PVA)/水溶性壳聚糖/甘油水凝胶,通过浸泡法在水凝胶中载入云南白药,并且研究了溶液pH值、离子强度、冻融次数和PVA浓度对水凝胶溶胀性能和云南白药释放性能的影响.研究发现水凝胶的溶胀度随溶液离子强度的增大而下降,且酸性溶液大于中性溶液.水溶性壳聚糖的加入有利于云南白药载入凝胶,同时使云南白药的释放具有pH和离子强度敏感性.云南白药的释放量在模拟体液中最大,在中性溶液中次之,在水和酸性溶液中最小,与溶胀度变化关系相反.而水凝胶的溶胀度和云南白药释放量均随冻融次数和PVA浓度的增大而下降.分析表明,云南白药在不同介质中的释放量主要取决于药物和溶液中离子的交换能力;在相同介质中,不同凝胶的药物释放量受溶胀度影响明显.凝胶溶胀速率远大于药物释放速率说明后者主要由扩散过程控制.药物释放的pH敏感性表明该水凝胶具备用作云南白药的口服载体的潜力.
A series of polyvinyl alcohol (PVA) / water-soluble chitosan / glycerol hydrogels were prepared by means of freeze-thaw after radiation first, and then loaded into Yunnanbaiyao by immersion method. The effects of pH, Ionic strength, the number of freeze-thaw cycles and PVA concentration on the swelling properties of hydrogel and the release properties of Yunnan Baiyao.The results showed that the swelling degree of hydrogel decreased with the increase of the ionic strength of the solution, and the acidic solution was larger than the neutral solution. The addition of chitosan was beneficial to the loading of Yunnan Baiyao gel, at the same time, the release of Yunnan Baiyao was sensitive to pH and ionic strength.The release of Yunnan Baiyao was the largest in simulated body fluid, followed by that in neutral solution, And acidic solution, but the relationship between swelling degree and the swelling degree of the hydrogel decreased, while the swelling degree of the hydrogel and the release amount of Yunnan Baiyao decreased with the increase of freeze-thaw times and PVA concentration.The analysis showed that the release of Yunnan Baiyao in different media The quantity depends mainly on the exchange capacity of the ions in the drug and the solution. In the same medium, the drug release amount of different gels is significantly affected by the degree of swelling. The swelling rate of the gel is far greater than the drug release rate, Process control drug release indicated that the pH-sensitive hydrogels have the potential to be used as an oral carrier Yunnanbaiyao.