Dual-Sensitive Carbohydrate-Based Nanosystem for Targeted Drug Delivery to Potentiate the Therapeutic Efficacy of Ulcerative Colitis.

Purpose: Conventional oral formulations for inflammatory bowel disease (IBD) treatment are less than satisfactory, due to the poor controllability of drug release and lack of specificity to the inflammation sites in the gastrointestinal (GI) tract. To overcome these limitations, we developed a multiple carbohydrate-based nanosystem with pH/ROS dual responsibility and charge-mediated targeting ability for IBD-specific drug delivery.

Methods: In view of the overproduction of ROS and overexpression of cationic proteins in the inflammatory colon, the designed nanosystem was composed of oxidation-sensitive cyclodextrin (OX-CD), chitosan (CS) and pectin (AHP). OX-CD was utilized to load dexamethasone (DM) by the solvent evaporation method. CS and AHP with opposite charges were sequentially coated onto OX-CD to generate the nanosystems by the electrostatic self-assembly method. The physicochemical properties, stability, dual-sensitive drug release behavior, cytotoxicity, cellular uptake and anti-inflammatory activity were investigated in vitro. In vivo bio-distribution and therapeutic efficacy of the nanosystem were further evaluated in the ulcerative colitis (UC) mice.

Results: The obtained AHP/CS/OX-CD-DM nanosystem (ACOC-DM) could maintain stability under the GI pH environments, and release drug in the inflammatory colon with pH/ROS sensitivity. Dual polysaccharide-coated ACOC-DM exhibited higher cellular uptake and anti-inflammatory efficacy in macrophages than single polysaccharide-coated CS/OX-CD-DM nanosystem (COC-DM). Orally administrated ACOC-DM could enhance inflammation targeting ability and therapeutic efficacy of DM in the UC mice.

Conclusion: This carbohydrate-based nanosystem with pH/ROS dual sensitivity and inflammation targeting capacity may serve as a safe and versatile nanoplatform for IBD therapy.