Paclitaxel-eluting silicone airway stent with sustained drug release and potent anti-fibrotic activity

Benign central airway stenosis (BCAS) remains difficult to manage because restenosis is frequently driven by fibroproliferative responses after intervention. To address this challenge, we developed a long-acting paclitaxel (PTX)-eluting silicone airway stent that integrates hydrophilic modification, a porous drug-reservoir structure, and ultrasound-responsive release.

Three hydrophilic modifiers (PEG-600, HM-530, and PVP-K17) were screened to improve matrix wettability and drug diffusivity. Coating thickness, pore formation, and cyclic ultrasound stimulation were further optimized. Drug release behavior, release kinetics, and mechanical performance were characterized systematically. In vitro cytocompatibility and anti-fibrotic activity were evaluated using L929, HFL-1, BEAS-2B, and HBE135 cells.

PVP-K17-modified porous stents combined with cyclic ultrasound showed the optimal release profile, achieving 22.85% cumulative PTX release over 90 days while retaining mechanical integrity. Drug release was well fitted by a comprehensive kinetic model (R² > 0.99) incorporating pore-forming (Kt) and ultrasound-enhancement (St) coefficients. Extracts of the modified silicone material met ISO 10993-5 cytocompatibility criteria, and PTX treatment selectively inhibited fibroblasts while showing relatively limited effects on epithelial cell viability.

These findings establish an integrated design framework for hydrophilic-modified, ultrasound-activated drug-eluting silicone airway stents that combine sustained local drug delivery, mechanical reliability, and selective anti-fibroproliferative activity.