Encapsulation of Geranium wilfordii Maxim (GWM) into polyvinyl alcohol (PVA) biodegradable microcapsules was performed using the interfacial polymerization method. The optimum synthesis conditions including the core/shell ratio and the emulsifier concentration were explored. The fabricated microcapsules were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The in-vitro release behaviour of the GWM microcapsules was studied by ultraviolet-visible spectroscopy (UV-VIS). The results show that when the core/shell ratio was 1:1 and the emulsifier concentration was 5%, the GWM microcapsules sizes have a normal distribution with a mean diameter of 23.94 μm. FTIR results show that the GWM was successfully encapsulated by the PVA polymer. TG results indicate that the GWM microcapsules are stable below 300 °C. Moreover, the release from the GWM microcapsules occurs according to a non-Fickian diffusion model.

Keywords: traditional Chinese medicine extractive; microcapsule; slow-release; interfacial polymerization