改性海藻酸钠载药纳米胶囊对氯氟氰菊酯的释放

以DCC/DMAP偶联酯化反应将胆固醇基接枝到天然多糖海藻酸钠上，制备了胆固醇基接枝海藻酸钠衍生物(CSAD)，采用乳化法对氯氟氰菊酯进行了负载，得到载药纳米胶囊。通过FTIR、1H NMR、荧光光谱、动态光散射、TEM和释药实验分别对改性海藻酸钠的结构和疏水性能以及载药纳米胶囊的形貌结构和释药性能进行了表征。结果表明改性海藻酸钠的取代度为5.3%~7.9%，其临界聚集浓度由1.23mg/L降为0.26~0.63mg/L，且随着取代度的增大，疏水基的增多，临界聚集浓度降至更低。所制备的载药纳米胶囊的d50为576.4?.4nm。Zeta电位值为-32.3?.6mV，在水溶液中能够表现出极好的稳定性能。对比常规微乳剂CSAD的氢键作用是其具备缓释性能的关键所在。

The release of cyhalothrin by drug-loaded nanocapsules prepared by the modified sodium alginate

Cholesterol modified alginate (CSAD) was prepared by DCC/DMAP covalent attachment of hydrophobic cholesterol onto the nature polysaccharide alginate. And the nanocapsules loaded cyhalothrins were obtained by emulsification method. The structure and hydrophobic properties of the alginate derivative and the morphology and release properties of the nanocapsules were characterized by means of Fourier transform infrared spectroscopy (FTIR), 1H Nuclear Magnetic Resonance (1H NMR), fluorescence spectrum, dynamic light scattering, transmission electron microscopy (TEM) and release studies. Experimental results showed that the degree of substitutions of CSAD were 5.3%~7.9% and their critical aggregation concentration were reduced from 1.23 mg/L to 0.26~0.63mg/L. With increasing degree of substitution, the hydrophobic group increased and the critical aggregation concentration reduced. The d50 of the drug-loaded nanocapsules were 576.4 ?7.4nm, and the Zeta potential value of drug-loaded nanocapsules were -32.3 ?0.6mV, which could exhibit excellent stability in aqueous solution. Compared with conventional microemulsions, the hydrogen bonds were key to CSAD to possess the Slow-Release properties.