Facile fabrication of diatomite biosilica-based nasal drug delivery vehicle for enhanced treatment of allergic rhinitis

Nanostructured silica-based materials have great potential as drug delivery vehicles for precise and personalized medical applications. As natural nanostructured silica, diatomite biosilica (DB) is recognized as a novel carrier to construct oral/parenteral smart drug delivery systems due to high surface area, biocompatibility, and applicability at low cost, yet the related studies on its use in local delivery routes are still scarce. Herein, we proposed a novel strategy to develop multifunctional nasal drug delivery vehicles based on DB, and demonstrated their versatile performance for enhanced treatment of allergic rhinitis (AR). As a proof of concept, the purified DB microparticles were loaded with budesonide as an anti-inflammatory model drug, and further processed via surface modification to graft polydopamine and carboxymethyl chitosan layers. The synthesized microcapsules exhibited remarkable mucin binding capacity and antibacterial activity against Staphylococcus aureus. Besides, toxicity evaluation with human skin fibroblast cells and hemolysis tests indicated their high biocompatibility. Moreover, in vitro drug release results demonstrated pH-responsive release performance of the microcapsules under simulated AR environment (pH 5.0, 35 °C). Hence, this study provides a facile and reliable approach to construct DB-based mucoadhesive nasal drug delivery vehicles, showing great potential for treatment of allergic airway inflammatory diseases.