pH响应性可降解聚膦腈的合成和表征

SYNTHESIS AND CHARACTERIZATION OF pH-RESPONSIVE DEGRADABLE POLYPHOSPHAZENE

采用亲核取代引入侧基再进一步修饰的方法合成了一种新型的可降解聚膦腈 ,红外光谱、氢核磁共振谱、元素分析证实了聚合物的化学组成 .体外降解实验表明当侧基修饰达一定比例时 ,聚合物降解行为表现出强烈的pH响应性 ,即聚合物的降解在pH6 0～ 7 4之间迅速加快 ,这类聚合物可望作为口服药物控释制剂的载体材料 .

The method. of substitution reaction followed by modification was used to synthesize a novel polyphosphazene containing amino acethydroxamic acid benzyl esters. By changing the feed ratio of reactants during the polymer modification, two resultant polymers with different contents of amino acethydroxamic acid benzyl ester were obtained,. IR,H-1-NMR and. elemental analysis were applied to characterize these polymers. The degradation test in vitro was carried out in phosphorous-free buffer solutions in the pH range of 5.0 similar to 8.0. The result revealed that the polymer with certain amount of amino acethydroxamic acid side groups (80%) exhibited strong pH-responsive degradation property. After 1.5 d, the sample dissolved completely in the solution of pH7.4, but lost only about 8% and 4% in solutions of pH6.0 and pH5.0, respectively. The degradation rate of polymer accelerated suddenly in the pH range 6.0 similar to 7.4. These features are feasible for polymers to act as carriers of oral enteric drug controlled delivery systems.