Preparation and characterisation of chitosan microcapsules loaded with Cortex Moutan

The process of preparation and characterisation of chitosan microcapsules loaded with Cortex Moutan was studied and the optimum condition for microcapsule preparation was investigated by orthogonal array analysis. Based on the yield percentage of microcapsule, the optimum condition for microcapsule preparation was (i) core–shell ratio = 1:2; (ii) chitosan concentration = 6% (w/v); (iii) agitation speed = 1100 rpm; and (iv) cross-linking time = 90 min. Meanwhile, relative importance of the preparation parameters was in the order: core–shell ratio, agitation speed, chitosan concentration and cross-linking time. The Fourier transform infrared spectroscopy analysis revealed that Cortex Moutan has been completely encapsulated into chitosan microcapsule. The release rate of Cortex Moutan from microcapsules in pH 5.4 phosphate buffered saline (PBS) was slightly better than that in pH 5.0 PBS after the initial 48 h and the release rate became steady after that.

► Chitosan microcapsules loaded with Cortex Moutan were prepared and characterised.
► Optimum condition for microcapsule preparation was obtained by orthogonal array analysis.
► The release rate of the microcapsules was good in pH 5.4 of phosphate buffered saline in the first 48 h.