纯亲水无规共聚物pH响应自组装及活性物控释

Study on pH⁃dependent Self⁃Assembly Behavior of Purely Hydrophilic Random Copolymers for Controlled Release of Active Substances

纯亲水无规聚合物由于无规链段分布以及纯亲水性,其在水中自组装驱动力来源更加难以获得,对于自组装的研究更加复杂。通过特殊设计poly(NVF⁃co⁃AA)的分子结构pH响应可控自组装,在pH=9.0~7.4时候可形成球状自组装体,而降低pH=5.0时自组装体解体成小的自组装聚集体,升高温度至38℃时自组装体依然稳定。利用这种可控的自组装结构可以实现α⁃熊果苷的包埋与控释,结果表明,在pH=9.0~7.4,温度为20~38℃时α⁃熊果苷可以稳定包埋90%以上,在皮肤环境下(pH=5.0,38℃),100 min内α⁃熊果苷累计释放率达95%以上。

It is very difficult to obtain a driving force from purely hydrophilic random copolymers self⁃assembly in water,and therefore the research on self⁃assembly is more complex due to random segment distribution and purely hydrophilici⁃ty.The molecular structure of poly(NVF⁃co⁃AA)was specially designed,and the controllable self⁃assembly could be obtained via a variation of pH responsiveness.The results indicated that the spherical self⁃assembly aggregates could be formed at pH 9.0~7.4.When pH value decreased to 5.0,these spherical self⁃assembly aggregates disintegrated into some small aggregates.The morphology of self⁃assembly aggregates was still stable with the temperature rising up to 38℃.The embedding and controlled release of alpha⁃arbutin were realized by using this controllable self⁃assembly struc⁃ture.The results indicated that more than 90%of alpha⁃arbutin could be entrapped stably at pH 9.0~7.4 and 20~38℃,and the cumulative release rate of alpha⁃arbutin was over 95%within 100 min under a skin environment of pH 5.0 and 38℃.