Bioactive polydioxanone filaments functionalized with Olea europaea extract: Supercritical solvent impregnation, characterization and release profile

Abstract

The development of polymeric systems loaded with natural compounds is gaining momentum as a strategy for designing therapeutic materials, especially when combined with environmentally friendly technologies such as supercritical solvent impregnation (SSI). Olive leaf extract (OLE), particularly rich in oleuropein, offers potent antioxidant and anti-inflammatory effects. This study explores for the first time the SSI of OLE into polydioxanone (PDO) filaments, a biocompatible polymer commonly used in biomedical applications. The extract used, with 181.08 mg g−1 of oleuropein, demonstrated robust biological activity (DPPH IC50: 16.8 ± 1.4 mg L−1; LOX IC50: 207.2 ± 22.8 mg L−1). Processing conditions (pressure and temperature) were optimized to maximize extract incorporation, achieving the highest loading (15.05 ± 2.88 mg g−1) at 400 bar and 75 °C. Release assays performed in simulated physiological fluid (pH 7.4) revealed a diffusion-dominated mechanism. The active molecules retained their bioactivity post-release, with the in situ generation of the highly potent derivative, hydroxytyrosol. These findings support the potential of SSI as a platform for producing functional PDO-based systems with enhanced long-term therapeutic properties.