An enhanced bioactive chitosan-modified microemulsion for mucosal healing of ulcerative colitis.

The intestinal mucus layer plays a crucial role in the systemic absorption of drugs. While penetration through this layer traditionally constitutes a pivotal phase in drug absorption, the approach for treating ulcerative colitis (UC) shifts towards facilitating the direct delivery of drugs to the colon. In this study, we engineered a chitosan-modified microemulsion encapsulated nobiletin (NOB-CS-ME) characterized by small particle dimensions and positive charge specifically, designed to enable targeted delivery. In vitro experiments demonstrated that this NOB-CS-ME effectively became less into the intestinal mucus layer, thus achieving successful escape of the intestinal mucus barrier absorption. After circumventing this barrier, NOB-CS-ME exhibited heightened cellular uptake by colonic epithelial cells, displaying an approximately 1.3-fold increase compared to the unmodified microemulsion. Collectively, these observations imply enhanced drug bioavailability, potentially resulting in more efficacious mucosal healing, providing a promising avenue for natural small-molecule drug delivery in UC treatment.