Preparation of chitosan microspheres by emulsion crosslinking method for biomedical application

Abstract

The emulsion crosslinking method using glutaraldehyde as a crosslinking agent was exploited to prepare chitosan microspheres. Effects of preparation factors such as homogenization speed, oil/emulsifier ratio (O/E), oil/water ratio (O/W), crosslinker concentration on the structure of products were investigated. Structure and morphology of the obtained products were determined by Fourier transform infrared spectroscopy (FT-IR), Trasmission Optical Microscope systems (TOM), and Dynamic Laser Scattering analysis (DLS). The results indicated that the obtained products were spherical in shape. The average diameter of chitosan microspheres decreased with the increase of homogenization speed, O/W ratio, crosslinker concentration or decrease of O/E ratio. When homogenization speed is 6000 rpm, O/E =1.5, O/W=15, and molar ratio of chitosan to glutaraldehyde R=1, the average diameter of the chitosan microspheres was about 2.40 μm with a narrow size distribution. Chitosan microspheres are able to be used as a polymer matrix for targeted drug delivery systems due to their pH-responsive property.