Site-specific porous hydrogel coating and characterization for tunable drug- eluting ureteral stent

This study presents a strategy for localized chemotherapy delivery via the development of drug-eluting ureteral stents coated with a site-specific, microporous hydrogel. The hydrogel, synthesized from gelatine-hydroxyphenyl propionic acid (Gtn-HPA) and carboxymethylcellulose-tyramine (CMC-Tyr), was applied using a custom-designed 3D printed mould to ensure uniform thickness and precise coating. High-resolution Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM) imaging revealed a highly interconnected porous hydrogel architecture that facilitates controlled drug diffusion. Model compounds, including lysozyme, bovine serum albumin (BSA) and chemotherapeutic agent mitomycin C (MMC), were embedded within the hydrogel matrix. In vitro studies demonstrated an initial burst release within the first 12 h, followed by sustained drug release over a 15-day period. The release profiles were adjustable by modifying hydrogel composition and microstructure, and could be further regulated by introducing an additional drug-free hydrogel layer. A dynamic flow setup simulating urinary flow validated the feasibility of controlled, site-specific drug delivery. Overall, the proposed technique offers a customizable and clinically adaptable platform with the potential to improve therapeutic outcomes in the treatment of upper tract urothelial carcinoma.