直接缩聚法海藻酸钠/乳酸低聚物接枝共聚物的合成及释药性能研究

Synthesis and Drug Release Behavior of Polylactic Acid Grafting from Alginate(ALG-g-PLA)Prepared by Direct Polycondensation.

通过直接缩聚法使乳酸与海藻酸钠接枝聚合,实现了对海藻酸钠的疏水改性。结果发现,疏水改性后的海藻酸钠水溶液中出现粒径为80~110nm的颗粒,说明海藻酸钠接枝改性成功。将改性后的海藻酸钠溶液滴入到氯化钙溶液中制备成直径1.5mm左右凝胶微球。以布洛芬为药物模型进行释放研究,结果表明,所得凝胶微球对药物的载药率和包封率较改性前得到提高,缓释效果增强。药物在弱碱性溶液中释放比较快,而在酸性环境中基本不释放。利用此特点,可将共聚物制备成药物载体,用于肠道内的控制释放。

Alginate was hydrophobically modified through a direct polycondensation of lactic acid grafting from sodium alginate.The results showed that nano particles with the diameters of 80~110nm were formed and uniformly distributed in the system.The nano particles were formed by hydrophobic interactions of polylactic acid segment.The modified alginate solution was dropped into calcium chloride solution to form microspheric beads.The release results showed that the newly prepared drug vehicle had enhanced drug loading rate and encapsulation efficiency,and it displayed slow release behavior.Drug release was fast in the weak alkaline solutions,but the release was nearly invisible in the acidic medium.The copolymer could be prepared as a pharmaceutical carrier for controlled release in the intestine.