Mucus- and pH-mediated controlled release of core-shell chitosan nanoparticles in the gastrointestinal tract for diabetes treatment.

For the successful oral delivery of peptide drugs, considerable barriers created by the harsh environment of the gastrointestinal tract, mucus, and epithelial cells must be overcome. This study was to establish a core-shell structure with chitosan (CS) nanoparticles (NP) as the core and poly-N-(2-hydroxypropyl) methacrylamide (pHPMA) as the intelligent escape shell to overcome pH and mucus barriers and improve the delivery efficiency of peptide drugs. A core-shell system (COS) composed of pHPMA-AT-1002-cys-chitosan (LRA-PA-CNPs) was prepared and used for the treatment of type 2 diabetes mellitus with the large-molecule peptide drug liraglutide (LRA). The complete COS system was observed through electron microscopy; the particle size of the LRA-PA-CNPs was approximately 160 nm; the encapsulation efficiency was approximately 69% ± 5%; the zeta potential was close to neutral; the mucus and epithelial penetration of the COS system were increased; and animal experiments showed that the COS system enhanced the oral hypoglycaemic effect of LRA.HIGHLIGHTSIntelligent escape material of poly-N-(2-hydroxypropyl) methacrylamide as the shell.Core-shell nanoparticles penetrate the mucus layer and exposing the chitosan core.Overcome pH and mucus barriers to improve the delivery efficiency of peptide drugs.