Preparation and characterization of ethyl cellulose-sodium alginate/chitosan microgels
The porous nature of microgels allows soluble active ingredients to diffuse into or out of the particles. As a result, the release performance of microgels usually can only sustain for 5 hours, which greatly limits their application. Therefore, to solve the problems of the poorly sustained releaseperformance of common microgel systems, a new type of (ethyl cellulose)-coated sodium alginate/chitosan (EC-Alginate/CS) microgel was prepared. An one-step emulsification method was employed to generate the new type of EC-Alginate/CS core-shell microgel. Ultra-depth microscope, scanning electron microscope (SEM), infrared spectroscopy (FT IR), thermogravimetric analysis (TGA), water contact angle (WCA) and swelling ratio were used to characterize the matrix hydrogels and microgels prepared at the same water phase composition to optimize the EC-Alginate/CS core-shell microgels. The cytotoxicity experiments showed that the cell viability of mouse mononuclear macrophages (RAW264.7) at 0.1 g/L was 89.3%, which could prove that the system had good biocompatibility at this concentration. It was found that the encapsulation efficiency (EE) of microgels could achieve 67.1%. The cumulative release effect of the model drug methyl blue (MB) showed that the system could achieve a sustained release of 15 h with a certain pH sensitivity. This study provided theoretical support and application reference for the bioavailable sustained-release system for water-soluble active substances, and it might be further applied to daily chemical products such as cosmetics and laundry detergents.