聚乙烯醇/葡聚糖复合凝胶的制备及药物释放规律的研究

Research on Preparation of the Poly (vinyl alcohol) (PVA)/Dextran Blend Hydrogel and its Drug Release

目的:采用冷冻-解冻物理交联方法制备聚乙烯醇(PVA)和葡聚糖(Dextran)混合凝胶。并考察复合凝胶药物释放规律。方法:含有胰岛素的PVA/Dextran溶液置于-20℃条件下冷冻8h,在室温下解冻4h,反复冷冻-解冻数次制备得到胰岛素PVA/Dextran复合凝胶,反相高效液相色谱法考察了胰岛素的体外释放行为。结果:胰岛素复合凝胶体外释放模式符合Higuchi扩散方程。当PVA/Dextran比例从100/0降到80/20,胰岛素释放速率明显增加,最大释放率从45%增加到65%。当冷冻-解冻循环次数从2增加到6,胰岛素达到最大释放的时间从24h增加到45h,最大释放率从70%降到50%。释放介质的温度的升高能显著增加胰岛素的释放速率。结论:PVA/Dextran制备的胰岛素复合凝胶具有良好的缓释效果。PVA/Dextran复合凝胶是一种较有前景的水凝胶药物载体。

Objective： To prepare a blend hydrogel based on a physically cross-linked poly （vinyl alcohol） （PVA）/Dextran by repetitive freeze-thaw procedures and investigate its drug release behavior. Methods： Insulin-loaded blend hydrogel was created by freezing an aqueous solution of PVAfDextran/Insulin at -20℃ for 8 h and thawing it at room temperature for 4 h （repeat the freeze-thaw cycle several times as needed）. Insulin release kinetics from blend hydrogel was investigated by RP-HPLC in vitro. Results： Release profile of Insulin followed Higuchi equation. As PVA/Dextran ratio dropped from 100/0 to 80/20, the rate of Insulin release increased markedly, and the maximum Insulin depletion increased from 45 % to 65 % of the total loading. As the freeze-thaw cycle increased from 2 to 6, the time for Insulin release to cease increased from 24 h to 45 h, and the maximum depletion decreased from 70 % to 50 % of the total loading. The increase of release medium temperature could enhance the release rate. Conclusions： Insulin-loaded blend hydrogel made of PVA and Dextran could offer sustained release of Insulin. PVA/Dextran blend hydrogel is a potentially useful system as drug delivery carrier.