纳米缓释型阿维菌素粉剂新剂型研究

以空心多孔纳米SiO₂为缓释载体，利用超临界包埋法、结合球磨分散与喷雾干燥等工艺制备了具有缓释和防止紫外光降解双重特性的阿维菌素纳米缓释粉剂。液相色谱分析表明阿维菌素在制剂的制备前后性质未发生变化。所制缓释粉剂经水分散后粒径约为200～500nm，分布均匀。悬浮稳定性和热贮稳定性均符合国家农药制剂标准。未制剂化的载药微球因微囊团聚严重，药物释放过程阻力大，药物累积释放大概1400min后仅达60%；而缓释粉剂在溶出的前5min即释放70%，具有迅速灭杀害虫效果，而剩余的农药以较为平缓的速率释放，在100min后累积释药80%，并且可以受到载体的保护而不受紫外光降解影响。

A novel sustained-release nano powder formulation for avermectin

A sustained-release nano powder formulation for avermectin has been prepared from porous hollow silica nanoparticles by supercritical fluid drug loading, milling and spray drying. HPLC spectra indicated that the properties of avermectin were not affected by the formulation process, The mean diameter of the formulated powders after being re-dispersed in water was in the range of 200 - 500 nm, demonstrating the high water dispersibility of this formulation. The storage stability meets the requirements of the National Pesticide Formulation Standards. Furthermore, the formulation shows an excellent sustained-release pattern and, in addition, the carrier protects the entrapped avermectin against UV degradation.