Preparation and characterization of chitosan/sodium alginate (CSA) microcapsule containing Cortex Moutan

CSA microcapsules were prepared to encapsulate Cortex Moutan using emulsion-chemical cross-linking method and the optimum preparation conditions were studied by orthogonal array analysis. Based on encapsulation efficiency, the optimum preparation conditions for CSA microcapsule were: core–shell ratio = 1:2; shell concentration = 6% (w/v); agitation speed = 1100 rpm and cross-linking time = 60 min. The microcapsules were characterised by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and laser diffraction particle size analysis. The in vitro drug release behaviour of Cortex Moutan from the microcapsules was studied by HPLC. The in vitro cytotoxicity test was studied by MTT assay and LDH release assay. Results showed that the microcapsules were in spherical form with diameter mostly in the range of 1–10 μm. The FTIR spectra indicated that Cortex Moutan was successfully encapsulated in the microcapsules. The experimental results showed that the release performance of the microcapsules was influenced by pH value of PBS and the cytotoxicity test showed that the microcapsules had no toxic effect on cells. These results indicate that Cortex Moutan loaded CSA microcapsule may possess potential application in clinical treatment of atopic dermatitis.