Zhang Jian Xiang, Qiu Li Yan, Jin Yi, Zhu Kang Jie
College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310031, China.
Colloids Surf B Biointerfaces. 2005 Jul 10;43(3-4):123-30. doi: 10.1016/j.colsurfb.2005.03.012.
An amphiphilic graft polyphosphazene (PNIPAm/EAB-PPP) composed of oligo-poly(N-isopropylacrylamide) (PNIPAm) as hydrophilic segments and ethyl 4-aminobenzoate (EAB) as hydrophobic groups was synthesized via ring-opening polymerization and subsequent substitution reaction. The molar ratio of the PNIPAm segment to EAB group was 1.85:0.15. The lower critical solution temperature (LCST) of copolymer was 32.6 degrees C as determined by turbidity method. Micellization behavior of PNIPAm/EAB-PPP in an aqueous phase was characterized by fluorescence technique, 1H NMR, dynamic light scattering (DLS) and transmission electron microscopy (TEM). The critical micelle concentration (CMC) of the graft copolymer in aqueous solution was 0.1mg/ml. The number-averaged particle size of spherical micelles was 80 nm at 25 degrees C with a narrow distribution. TEM also revealed that inter-micellar aggregation was induced in the micelle solution at temperature above LCST of graft copolymer. The thermosensitive PNIPAm/EAB-PPP micelles may be of help to regulate the loading and release of hydrophobic drugs.
通过开环聚合和后续取代反应合成了一种两亲性接枝聚磷腈（PNIPAm/EAB-PPP），其由低聚聚（N-异丙基丙烯酰胺）（PNIPAm）作为亲水性链段和4-氨基苯甲酸乙酯（EAB）作为疏水性基团组成。PNIPAm链段与EAB基团的摩尔比为1.85:0.15。通过浊度法测定，该共聚物的低临界溶液温度（LCST）为32.6℃。采用荧光技术、1H NMR、动态光散射（DLS）和透射电子显微镜（TEM）对PNIPAm/EAB-PPP在水相中的胶束化行为进行了表征。接枝共聚物在水溶液中的临界胶束浓度（CMC）为0.1mg/ml。在25℃下，球形胶束的数均粒径为80nm，分布较窄。TEM还显示，在高于接枝共聚物LCST的温度下，胶束溶液中会诱导胶束间聚集。热敏性PNIPAm/EAB-PPP胶束可能有助于调节疏水性药物的负载和释放。
