Preparation and properties of gelatin-tannic acid histidine metal complex microspheres

Tannin histidine metal complex is a type of synthetic analogues of superoxide dismutase. To make the most of its SOD-like activity and expand its value in medical field, the gelatin-tannic acid histidine metal complex microspheres were prepared by emulsion cross-linking method. The optimum conditions for preparation of microspheres are found based on encapsulation ratio and the encapsulation efficiency range of four types of complex microspheres is 89.90-93.57 % under these conditions. The microspheres were characterized by IF spectrum, SEM and particle size analysis. The results showed that the average particle size of the four kinds of microspheres ranged from 5.5 to 14.7 & mu;m. Certain properties of microspheres were investigated and results prove that they have a high antioxidant property and a good sustained release effect, meanwhile, the optimal storage temperature and stable kinetic model are obtained. The study provides a way for the application of superoxide dismutase mimics in the sustained release.