Preparation of Silica Microparticles as Volatile Material Carrier and Their Sustained-Release Property

The aim of this study is to develop an effective delivery system (silica microparticles) encapsulating volatile essential oil (EO) by multiple emulsification process and sol-gel method. Depending on critical materials (Pluronic P123 and HPC) and process parameter (drying temperature), silica microparticles were prepared and evaluated. As results, the amount of EO inside microparticles increased in polymer-dependent manners. On the other hand, the amount of EO was reduced as drying temperature increased. Based on these data, the condition fabricating silica microparticles was optimized: drying temperature (25 degrees C), Pluronic P123 (1.2%) and HPC (1.2%). The size and morphology of microparticles were observed by scanning electron microscopy. Also, the loadings and release profiles of EO in these particles were quantitatively analyzed by HPLC. Optimized silica microparticles showed the high encapsulation efficiency (32.7%) and sustained-release profiles of EO for 3 days. Taken together, silica microparticles are effective carrier for encapsulating volatile materials and providing sustained-release.