In vitro evaluation of doxorubicin-eluting porous titania microspheres for transcatheter arterial chemoembolization

Preparing drug-eluting beads (DEBs) from radiopaque materials such as titania (TiO₂) can meet clinical need for directly visualizing DEBs during drug-eluting bead transcatheter arterial chemoembolization (DEB-TACE). Porous anatase-type TiO₂ microspheres with mean volume diameters of approximately 30 µm were obtained when silica nanoparticles (SiNPs) were introduced into the TiO₂ matrix by a sol–gel process involving a water-in-oil emulsion, and the SiNPs were then dissolved by subsequent treatment with NaOH solution. Of special note, microspheres prepared using SiNPs of approximately 20–25 nm in diameter had a high specific surface area of ~120 m²·g⁻¹ and a high doxorubicin (DOX)-adsorption capacity of ~150 mg·mL⁻¹, and they gradually released ~10% of the adsorbed DOX within 5 days. The DOX-loaded microspheres were non-cytotoxic, moreover, and exerted anticancer effects on HeLa cells. We propose that the present TiO₂ microspheres are potentially useful as novel radiopaque embolic materials for DEB-TACE.