In situ self-spray coating system that can uniformly disperse a poorly water-soluble H₂S donor on the colorectal surface to treat inflammatory bowel diseases

Inflammatory bowel disease (IBD) is an intestinal inflammatory disorder. Exogenous hydrogen sulfide (H₂S) donors such as diallyl trisulfide (DATS) have been used as anti-inflammatory mediators. However, an ideal method of administering DATS has yet to be established owing to its poor water solubility. Herein, a self-spray coating system that is derived from a DATS-loaded capsule with foaming capability (CAP-w-FC) is proposed for treating colitis. Following the rectal administration of CAP-w-FC into rats bearing colitis and its subsequent dissolution in the intestinal fluid, a spray coating system is self-assembled in situ. This system greatly promotes the dissolution of the poorly water-soluble DATS by producing nano-scaled micellar particles that are sprayed onto the large luminal surface of the colorectal tract. Following the internalization of the micellar particles by colon epithelial cells, their loaded DATS reacts with intracellular glutathione to yield H₂S. This exogenous H₂S then diffuses through plasma membranes to carry out its biological functions, including suppressing the overproduction of pro-inflammatory cytokines, inhibiting the adhesion of macrophages on the vascular endothelium, and repairing colonic inflamed tissues. Analytical results demonstrate that this self-spray coating system may be used as a unique drug delivery technique for covering the large colorectal surface to treat IBD.