Treatment of ulcerative colitis via the in situ restoration of local immune and microbial homeostasis by oral administration of Tremella polysaccharide drug-carrying hydrogel

Ulcerative colitis (UC) is a prevalent inflammatory bowel disease, and conventional treatments, such as anti-inflammatory medications and surgery, often prove inadequate due to frequent recurrences and various complications. To alleviate patient suffering, there is an urgent need for a therapeutic system that specifically delivers drugs to the colon for wound healing, inflammation relief, and restoration of microbial homeostasis. In this paper, we developed a Tremella polysaccharide drug-carrying hydrogel that adheres to the inflamed colonic mucosa, forming an effective artificial barrier and releasing the drug in situ to restore local immune and microbial balance. The hydrogel backbone was synthesized through the chemical cross-linking of Tremella polysaccharide with 1,4-butanediol diglycidyl ether in an alkaline environment. During this process, Soluplus® and TPGS-encapsulated ginsenoside compound K adhered to the hydrogel backbone due to electrostatic attraction. The enhanced adhesion following cross-linking enables the hydrogel to stably attach to the inflamed colonic mucosa, releasing mixed micelles that improve drug penetration and absorption by inhibiting the cellular efflux protein P-glycoprotein. This mechanism promotes local immune recovery and eliminates harmful intestinal flora, providing significant relief from UC symptoms. This natural polysaccharide-based hydrogel represents a highly effective oral treatment for UC.