Hydrophobic ion pairing formed semaglutide designed for oral self-microemulsifying delivery in diabetes treatment

Semaglutide (SET) is a glucagon-like peptide-1 (GLP-1) receptor agonist approved for the treatment of type 2 diabetes. Although injectable formulations offer high bioavailability, they are associated with poor patient compliance. In contrast, oral tablets are more convenient but suffer from limited absorption due to SET's hydrophilicity and enzymatic instability in the gastrointestinal tract. To address these challenges, we developed a hydrophobic ion pair (HIP) complex of SET and sodium docusate (SET-DOC), which was further incorporated into a self-emulsifying drug delivery system (SD@SEDDS) to facilitate oral delivery. The optimized SD@SEDDS produced a clear emulsion upon dilution, with a uniform particle size of 85.55  nm, high drug loading (2.64  mg/g), and excellent stability. In vitro transport studies using a Caco-2/HT-29 co-culture model demonstrated enhanced permeability and reduced P-glycoprotein-mediated efflux. In vivo studies in a type 2 diabetic rat model showed that SD@SEDDS significantly reduced blood glucose levels, improved lipid profiles, and exhibited good biocompatibility without observable toxicity. These findings suggested that the combination of HIP technology and SEDDS represented a promising strategy for enhancing the oral delivery efficiency of peptide drugs such as SET.