Preparation of surface‐modified,micrometer‐sized carboxymethyl chitosan drug‐loaded microspheres

Drug‐loaded microspheres have attracted much attention in embolization therapy for liver cancer in recent years. Carboxymethyl chitosan has obvious advantages for biomedical applications because of its exceptional biocompatibility and biodegradability. In this study, surface‐modified carboxymethyl chitosan microspheres were prepared by the crosslinking reactions of carboxymethyl chitosan in a reverse suspension system with poly(ethylene glycol diglycidyl ether) (PEGDE) as the crosslinking agent; this was followed by the grafting polymerization of 2‐acrylamido‐2‐methyl propane sulfonic acid on the surface of the microspheres. The microspheres showed regular spherical shapes with size distributions ranging from 300 to 600 μm. Ion‐exchange groups (? COOH, ? SO₃H) were introduced into the microspheres; these groups could load doxorubicin with a loading rate as high as 34.6% in 24 h. This was an increase of 49.8% compared to that of the pure carboxymethyl chitosan microspheres. Additionally, the microspheres possessed large network structures because macromolecular PEGDE was used as the crosslinking agent. The drug‐release profile showed that the surface‐modified microspheres displayed a sustained‐release manner compared with the nonmodified microspheres in phosphate‐buffered saline. These microspheres have promising applications as drug‐loaded arterial embolization agents for the interventional treatment of tumors. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45731.