Fibrin-based drug delivery systems III: The evaluation of the release of macromolecules from microbeads

In this study, fibrin beads containing macromolecules of different molecular weight were prepared in two different size distributions by varying the ratio of oleic acid to mineral oil in the oil phase of the emulsion system. The release characteristics were examined and compared. A dependence on the size of the fibrin microspheres for macromolecule release from fibrin microspheres was demonstrated: the smaller the size of the fibrin microspheres, the faster the release rate of the macromolecules. In addition, the apparent diffusion coefficient was found to be a function of the molecular size of the macromolecules. As a result, the larger the molecular weight of the macromolecules, the smaller the apparent diffusion coefficient. However, the release of lysozyme and insulin dissolved in 0.1 N HCl solution was undetectable.