Structure and control release of chitosan/carboxymethyl cellulose microcapsules

Microcapsules of chitosan/sodium carboxymethyl. cellulose (NaCMC) were successfully prepared using a novel method of emulation phase separation. Their structure and morphology were characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM), and X-ray diffraction. Bovine serum albumin (BSA) was encapsulated in the microcapsules to test their release behavior. The swelling behavior, encapsulation efficiency, and release behavior of the microcapsules with different chitosan contents and pH conditions were investigated. The results indicated that the microcapsules have a high encapsulation efficiency (75%) and a suitable size (20-50 Am). The BSA in the microcapsules was speedily released at pH 7.2, namely, in intestinal fluid. The BSA release was reduced with increase of the chitosan content from 17 to 38% in the microcapsules. Acid-treated microcapsules have a compact structure, owing to a strong electrostatic interaction caused by -NH2 groups of chitosan and -COOH groups of CMC, and the encapsulated BSA was hardly released at pH 1.0, namely, in gastric juice. (C) 2001 John Wiley & Sons, Inc.