Oral Delivery of Liraglutide Formulated with PLGA for Sustained Obesity Management

Liraglutide (Lira), a glucagon-like peptide-1 (GLP-1) receptor agonist, has demonstrated substantial efficacy in improving glycemic control and reducing body weight. However, subcutaneous injection is poorly adherent for patients. To improve treatment compliance, we developed a poly(lactic-co-glycolic acid) (PLGA)-based nanovesicle (PLGA-Lira-NV) system for the oral delivery of Lira using a double-emulsion solvent evaporation technique. The optimized formulation yielded a narrow size distribution and high encapsulation efficiency (>95%). In vitro release studies showed that PLGA-Lira-NVs remained relatively stable under acidic conditions (pH 1.2 to 6.8) and exhibited sustained drug release in a neutral environment (pH 7.4), enabling protection of the fragile peptide in the stomach and controlled release after crossing the intestine. Following oral administration to obese mice (10 mg/kg), PLGA-Lira-NVs achieved prolonged glycemic control for up to 72 h. Notably, body weight decreased to 83% of baseline after 12 days, outperforming the subcutaneous injection (free Lira) group (88%). The consistent trend toward weight reduction confirms the sustained-release properties of PLGA nanocarrier for Lira, highlighting its potential to reduce dosing frequency and improve patient compliance. Collectively, these findings underscore the promising potential of PLGA nanovesicles as an oral delivery platform for peptide therapeutics.