Hyaluronic Acid-Based Hybrid Nanoparticles as Promising Carriers for the Intranasal Administration of Dimethyl Fumarate.

Purpose: Dimethyl fumarate (DMF), the first-line oral therapy for relapsing-remitting multiple sclerosis, is rapidly metabolized into monomethyl fumarate. The DMF oral administration provokes gastrointestinal discomfort causing treatment withdrawal. The present study aimed to develop an innovative formulation for DMF nasal administration. Lipid-polymer hybrid nanoparticles (LPNs) were developed to improve DMF stability, limiting gastrointestinal side effects and increasing brain bioavailability by nose-to-brain targeting application. Methods: DMF-loaded and unloaded LPNs with or without hyaluronic acid (HA) were prepared using the nanoprecipitation via magnetic/mechanical stirring technique. Particle morphology and surface properties were evaluated; drug content, viscosity, and mucoadhesion were determined. Physico-chemical stability of LPNs and DMF in the LPNs was also explored. In vitro DMF permeation experiments were performed utilizing the PermeaPad Results: LPNs with average sizes of 120-250 nm and a negative zeta potential -17.3 to -43 mV were obtained, primarily influenced by the presence of HA. HA assured drug stability up to 60 days and promoting the in vitro permeation of DMF compared to the free-DMF. HA greatly improved the viscosity and mucoadhesive properties. LPNs with and without HA did not exhibit any cytotoxicity and showed a rapid cell uptake starting from 15 min to 2 h with a best internalization after 1 h of treatment in both epithelial and neuronal cell lines. Nasal administration of DMF-loaded LPNs allowed to quantify up to about 12 μg/mL of DMF in the rat cerebrospinal fluid. Conclusion: The results highlight the role of HA in improving LPNs properties and performance as carrier of DMF for nasal administration. In particular, LPNs appear able to enter neurons and monolayers of epithelial cells, allowing to promote the nose-to-brain DMF delivery.