Effect of β-cyclodextrin on physical properties of nanocapsules manufactured by emulsion-diffusion method

This study was carried out to investigate the effect of β-cyclodextrin (β-CD) as a cryoprotectant on the eugenol encapsulated nanocapsules. Nanocapsules (NCs) were prepared by emulsion-diffusion method and frozen at various temperatures (−30 °C to −10 °C). Physical stability of the NCs was determined by particle size analysis and morphological observation using scanning or transmission electron microscopy before and after freezing or freeze-drying process. Freeze-thawed and freeze-dried NCs without β-CD were remarkably aggregated. The particle size of NCs without β-CD was significantly increased as decreasing freezing temperature. On the contrary, NCs with β-CD were slightly increased in the range of 370-400 nm. Significant particle aggregation was not shown at NCs with β-CD at all freezing temperatures. In this study, β-CD could was effective as a cryoprotectant to maintain physical stability of NCs after freezing or freeze-drying. β-CD could be useful to protect NCs from freezing stress.