改性海藻酸钠活化SiO_2纳米粒子稳定载药Pickering乳液及释药性

Stability and Release Properties of Drug-loaded Pickering Emulsions by the Modified Sodium Alginate Activated SiO_2 Nanoparticles

以胆固醇疏水改性两亲性海藻酸钠衍生物表面,活化SiO2纳米粒子,再制得负载氯氟氰菊酯的O/W型Pickering乳液.通过傅里叶变换红外光谱(FTIR),氢核磁共振波谱(1H NMR)、荧光光谱、动态光散射、光学显微镜和释药实验分别对海藻酸钠衍生物和Pickering乳液的性能进行了表征.结果表明,胆固醇基接枝到了海藻酸钠分子链上,改性后的海藻酸钠临界聚集浓度由1.26 mg/L降为0.28 mg/L,表现出了良好的两亲性.将海藻酸钠衍生物(CSAD)和表面活性剂十六烷基三甲基溴化铵(CTAB)吸附于SiO2纳米粒子表面,得到活化SiO2纳米粒子,其Zeta电位分别为-30.7和16.4 mV,粒径分别增大到583.3和438.4 nm.由CSAD活化SiO2粒子制备的乳液释药速率更缓慢.CSAD的交联作用使吸附于油水界面的活化SiO2粒子形成了比较稳定的网络结构或界面膜.

Pickering emulsions（W/O） loaded cyhalothrins were prepared by SiO2 nanoparticles whose sur- face were activated using amphiphilic alginate derivative hydrophobically modified by cholesterol under the conditions of high speed stirring. And they were characterized by means of Fourier transform infrared spectroscopy（FTIR） , 1H nuclear magnetic resonance（ 1H NMR）, fluorescence spectrum, dynamic light scattering, optical microscope and release studies. Experimental results showed that cholesterol groups had successfully grafted to the alginate molecular chains. The critical aggregation concentration of modified alginate was re- duced from 1.26 mg/L to 0.28 mg/L, which showed good amphipathy. Alginate derivative（CSAD） and sur- factant CTAB could be also adsorbed on the surface of SiO2 nanoparticles with the corresponding zeta potential which were 16.4 and -30.7 mV, respectively. And the particle sizes were 583.3 and 438.4 nm, respective- ly. The release rate of the Picketing emulsions prepared by the SiO2 particles activated by CSAD was more slowly. That may be the cross-linking action of CSAD which made the activated SiO2 particles adsorbed on the oil-water interface form the relatively stable network structures or the interface membranes