Construction of butyrylated starch film-coated microspheres for colon-targeted delivery of Akkermansia muciniphila postbiotics.

Emerging evidence suggests that Akkermansia muciniphila postbiotics show promising potential in promoting metabolic health. Nevertheless, their bioactivity and colonic availability can be compromised during upper gastrointestinal transit. To address this limitation, a colon-targeted delivery system was developed, based on butyrylated starch (BS) film-coated microspheres (BSFCMs). BS with a tunable degree of substitution was synthesized. Films fabricated from BS exhibited enhanced hydrophobicity and digestion resistance, with the optimal performance observed at DS = 1.79. Under in vitro simulated gastrointestinal conditions, microspheres with 14% coating weight gain showed under 30% cumulative release in simulated gastric and intestinal fluids. Furthermore, tuning the postbiotic loading ratio increased the colon-targeted delivery of representative postbiotic-derived small molecules to about 50%-70%. Collectively, these findings support the feasibility of using DS-tunable BS films as robust coating materials for constructing microsphere systems to mitigate premature release of A. muciniphila postbiotics during gastrointestinal transit and improve oral delivery efficiency for colonic applications.