Release behavior of ketoprofen from chitosan/alginate microcapsules

Chitosan/alginate microcapsules were prepared continuously by an air extrusion method. The influences on loading efficiency and release, such as air flow-rate, chitosan molecular weight and concentration, alginate concentration, pH of chitosan solution, ethyl cellulose, and freezing drying the capsules were studied. Freezing drying chitosan/alginate microcapsules was important for controlled release of ketoprofen. High molecular weight and high concentration of chitosan did not increase loading of ketoprofen, but reduced the release of the ketoprofen. The addition of ethyl cellulose increased the loading of ketoprofen and the release time was prolonged. Increasing sodium alginate concentration reduced the loading efficiency with no clear distinction on the release of ketoprofen. The ketoprofen entrapped in the pH sensitive chitosan/alginate microcapsules gave controlled release in intestinal fluid.