Evaluation of a microreservoir-type biodegradable microcapsule for controlled release of proteins

For the controlled release of a model protein bovine serum albumin, a biodegradable microreservoir-type microcapsule was prepared. BSA was incorporated into the microcapsules with high efficiency of 96.1 (±3.1)% The encapsulation did not cause any changes in the molecular weight and conformation of BSA, which was proven by biochemical analyses such as gel electrophoresis, circular dichroism, and HPLC. The compositions and fabrication technique of microcapsules were found to be closely related to the release of BSA from the microcapsules and their degradation. Depending on microcapsule formulations, the in vitro release profile of BSA was either monophasic or biphasic. The microcapsules provided various release rates. It was also possible to control the delay before the initiation of BSA release and total duration of its delivery.