Degradation studies of modified inulin as potential encapsulation material for colon targeting and release of mesalamine

Due to the potential to treat colon specific diseases with reduced side effects, colon targeting has become of high interest over the last decades. Chemical modified inulin was investigated for its potential as encapsulation material regarding its enzymatic degradability and its drug release behavior. Different degrees of acetylated inulin (degree of substitution, DS, 0.3-2.1) were synthesized. The chemical modification leads to a reduction in enzymatic degradability by inulinase and esterase, enzymes which can be expressed by the colon microbiota. Acetylated inulin was only hydrolyzed to fructose units up to DS of 1.3. Microparticles made of native inulin and acetylated inulin (DS 1.8) were loaded with the colon-specific drug mesalamine by spray drying. Compared to the burst release of mesalamine by inulin particles within 6 h, acetylated inulin particles showed less burst release followed by a continuous drug release phase caused by diffusion up to 30% mesalamine after 52 h.