Electron-Beam Crosslinked Hydrogels as Reproducible Platforms for Localized Doxorubicin Delivery: Irradiation Stability, Post-Loading, and In Vitro Evaluation

This study validates a multicomponent collagen/CMCNa/PVP/PEO hydrogel, synthesized via e-beam crosslinking at 25 kGy for localized doxorubicin (DOX) delivery. Fabrication reproducibility, drug stability, loading efficiency, and preliminary in vitro biological activity were investigated. Batch-to-batch reproducibility was demonstrated across three independent preparations. Three independent preparations showed reproducible gel fractions (90.4–94.0%), equilibrium swelling (1550–1950% at pH 6.4 and 1600–1850% at pH 7.4), and predominantly elastic behavior (tg δ = 0.014–0.03). Long-term degradation testing confirmed structural integrity, with only 8.24% mass loss after 84 days in physiological conditions. LC-MS analysis revealed considerable DOX degradation post-irradiation, supporting the adoption of a diffusion-based post-loading approach. The DOX-diffusion-loaded hydrogels exhibited high loading efficiency (>72%) and a loading capacity of ~3.88 µg/g. In vitro, the hydrogels provided biphasic yet sustained, diffusion-controlled DOX release (60–68% over 58 h pH-dependent). Biological assays showed concentration-dependent cytotoxicity of free DOX against A375 melanoma cells (IC50 = 0.038 µg/mL), while directly irradiated DOX-loaded hydrogels (H-DOX) at low exposure concentrations demonstrated cytocompatibility with VERO epithelial and CCD-1070Sk fibroblast cells, and a moderate, time-dependent antiproliferative effect on A375 cells. Collectively, these results establish crosslinked hydrogels with post-loading as a reproducible, stable, and cytocompatible platform for localized DOX delivery, highlighting their potential for adjuvant melanoma therapy.