Cross-linked chitosan matrix-based multiple-unit drug delivery systems

Matrix-based multiple-unit drug delivery systems were manufactured by the compression of conventional and cross-linked chitosan into mini-matrices, which were then loaded into hard gelatin capsules. Three different types of mini-matrices were manufactured by direct compression of chitosan powder (not cross-linked), cross-linked chitosan microparticles or cross-linked chitosan granules and were characterized in terms of their physical properties such as hardness, friability, dimensions as well as their swelling and dissolution characteristics. The mini-matrices were film coated with Eudragit polymers (i.e. Eudragit L100, S100 and L100-55) to allow for drug release to start at different pH values. Several combinations of the coated mini-matrices were loaded into hard gelatin capsules to provide for rapid release as well as for delayed-onset sustained release from each multiple-unit drug delivery system. Release kinetics of the matrices consisting of cross-linked chitosan microparticles are presented as well as the in vitro release profiles of the multiple-unit drug delivery systems.