Preparation, Optimization and Release Behaviour Evaluation of Carbamide Peroxide Microcapsules Integrated with Eudragit RS

Abstract

Slow‐release microcapsules were prepared by solvent evaporation method under different conditions with carbamide peroxide (CP) and Eudragit RS (EuRS) as core material and shell material respectively. Encapsulation efficiency (EE), release control, particle size and particle surface were characterized by UV spectrophotometer, light microscope, laser diffraction analysis (LDA) and scanning electron microscope (SEM). The results showed that CP microcapsules possessed a relatively regular spherical morphology. The particle size of microcapsules was generally distributed between 150∼500 μm. CP was in EuRS microcapsules in crystal phase. And magnesium stearate (MS) was used as stabilizer agent in emulsion, and it would also prolong the release time. The optimum condition of preparation was under 20°C, stirring rate was slightly higher than 400 rpm, and to obtain better release control, the optimal ratio of CP/EuRS was 1/3, MS proportion was 9.3 g/100 mL, and MS particle size was smaller than 32 μm. The maximum %EE was 94.59 %, the longest release duration was about 180 min, and the longest available storage of CP microcapsules was about 20 days under refrigeration. The release behavior of CP microcapsules can be explained by First‐order‐kinetic model.