Improved surface adhesion and wound healing effect of madecassoside liposomes modified by temperature -responsive PEG-PCL-PEG copolymers

Madecassoside (MA) exhibits excellent therapeutic effects in wound healing and scar management. However, its high hydrophilic nature and low permeability through skin tissue limits its topical application. Liposomes are widely used to deliver drugs due to their high structural similarity and biocompatibility with cell membranes. However, normal liposome formulations are too fluid to maintain sufficient adhesion to the wound surface. In this study, in order to make an MA formulation conducive to topical administration, poly(ethylene glycol) -poly (epsilon-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE), a biodegradable and temperature -responsive co- polymer material, was synthesized and applied to improve the adhesion properties of MA liposomes. The mean particle size of the PECE-modified MA liposomes was 213.43 +/- 4.68 nm, and the zeta potential was -23.80 +/- 15.37 mV under the optimal conditions of EPC (egg yolk lecithin) to PECE at a mass ratio of 1:1. Additionally, PECE-modified MA liposomes maintained a hydrogel state for better adhesion until the tempera- ture reached 43 degrees C. Furthermore, the PECE-modified MA liposomes showed superior wound contraction effects relative to the MA liposomes in second-degree burn experiments using a rat model. These results indicated that PECE-modified MA liposomes have better surface adhesion performance and healing effects than unmodified MA liposomes.