| 초록 |
Microcapsules composed of alginate and nano-sized calcium carbonate cores and ethyl cellulose matrix were prepared by an emulsification and spray-drying method. In order to prepare water-in-oil emulsions, 0.0625%, 0.125%, 0.25, 0.5%, 1% and 2% (w/v) concentration of calcium carbonates were suspended in alginate solution (3%, w/v), respectively. And then alginate aqueous solutions were micronized in ethyl cellulose solution in dichloromethane. The emulsion was spray-dried around 50℃. The pH-dependent release property of microcapsule was observed in pH 4,5,7,9. At acidic pH such as pH 4 and pH5, calcium carbonate dissolved in acidic condition and alginate gel formed with Ca2+ of calcium carbonate inside microcapsules. Alginate gel would trap dye, leading to a suppressed release. In addition, higher calcium carbonate concentration in microcapsules with lower release rate was obtained in acidic pH. |
