Evaluation of Nano and Microcapsules of Silymarin in Simulated Gastrointestinal Conditions for Animal Target Delivery

The main goal of this research was to compare the in vitro release rates of nano- and microcapsules of Silybum marianum extract (SME) in animal simulated gastric and intestinal medium conditions. The extract was encapsulated within sodium alginate carriers using emulsification/internal gelation method. Particle size, zeta potential, polydispersity index (PDI) and morphology of nanocapsules were analysed via dynamic light scattering (DLS) and transmission electron microscopy (TEM). In addition, the effect of ultrasonication on nanocapsule properties and the release profiles of SME-loaded nano/microcapsules were evaluated. Results showed that ultrasonication reduced the size of capsules from 657.5 nm to 169.1 nm which resulted in uniform particles with a low PDI. Encapsulation efficiency for nanocapsules was 61%. Alginate nano/microcapsules protected polyphenols in simulated gastric medium as observed by 10% and 12% release, respectively. Nanocapsules released their contents higher and faster than microcapsules in simulated intestinal fluid (P<0.05). In conclusion, alginate nanocapsules containing SME were made successfully with a release rate of over 90% of extract within simulated intestinal medium which can be used for animal target delivery purposes.