pH and redox dual response nano suppository for the treatment of ulcerative colitis

In order to improve treatment compliance and provide sustained and slow drug release in the colon, we developed a hollow mesoporous silica nano-suppository based on pH and redox dual response. Hollow mesoporous silica nanoparticles containing disulfide bonds (HMSN-SS) were prepared and 5-ASA was loaded into the pores of HMSN-SS. Then, polydopamine (PDA) and chitosan (CS) were modified on the surface of HMSN-SS, and the suppository was prepared by mould, named 5-ASA@HMSN-SS-PDA-CS (5-ASA@HSPC). 5-ASA@HSPC acts directly on the lesion by rectal administration, CS helped the nanoparticles adhere to the surface of the colon, PDA dissociated from the surface of HMSN-SS by protonation in the acidic environment of the ulcerative colon, S-S was destroyed by the reducing environment of the colon, resulting in a stable and slow release of encapsulated 5-ASA from the pores of HMSN. In vitro release experiments and in vivo pharmacokinetic and pharmacodynamic experiments have shown that 5-ASA@HSPC is able to act slowly and steadily at the colonic site, while having an excellent safety profile, showing great potential in the treatment of ulcerative colitis.