Synthesis and Sustained-Release Property of Drug-Loaded Chitosan Microspheres by Spray Drying Technique

In this paper, drug–loaded chitosan microspheres were prepared by spray drying technique, using glutaraldehyde as cross–linking agent and salicylic acid as model drug. Effects of formulation and process parameters on the morphology of chitosan microspheres were investigated. The drug loading and encapsulation efficiency were determined. In vitro release of the drug into phosphate buffer at 37 °C was determined as functions of cross–linking density of the microspheres, pH value, and mass ratio of salicylic acid/chitosan. The results showed that the as-prepared chitosan microspheres were highly spherical with size in the range of 1–5 μm. The encapsulation efficiency was between ranged from 95.12% to 99.17%. As the drug loading drug increased, the morphology of chitosan microspheres changed gradually from sphere, sphere with distorted surface, to flat bread bowl. The drug–loaded chitosan microspheres showed sustained release behavior in vitro and will play an important role in drug delivery system.