Gliomas, particularly glioblastoma multiforme, are highly aggressive brain tumors characterized by poor prognosis, mainly due to the blood-brain barrier limiting drug delivery. The intranasal route has been identified as a promising strategy for bypassing this barrier. Silibinin (SLB) is a natural flavonoid that inhibits glioma cell growth and invasion while inducing apoptosis, highlighting its potential as a therapeutic agent for glioblastoma. Hyaluronic acid (HA), a naturally occurring glycosaminoglycan, is recognized for its mucoadhesive, biocompatible, and targeting properties, mainly through its interaction with the CD44 receptor and other proteins overexpressed in tumor cells. In this context, HA-based hybrid lipid/polymeric nanoparticles (LPNs) were developed using HA of varying molecular weights for the intranasal delivery of SLB targeted to glioma tumors. Formulations were produced using low-, medium-, and high molecular-weight hyaluronate salts.

LPNs were prepared using a nanoprecipitation method. Physicochemical characterization included measurements of particle size and stability over 30 days, surface charge (ζp), morphology (via Cryo-TEM), thermal properties (DSC and ITC), total drug content in dispersion (DC), and encapsulation efficiency (EE). Mucoadhesive and viscosity properties were assessed to determine the potential for adhesion to nasal mucosa. In-vitro SLB- release kinetics studies were carried out. Cytotoxicity assays and cellular uptake tests were performed in RPMI 2650 nasal epithelial cells and T98-G glioblastoma cells to evaluate the potential of HA-SLB-loaded LPNs for targeted glioma therapy via intranasal administration.

Blank LPNs had an average size of approximately 100 nm, while SLB-loaded LPNs measured about 160 nm. The LPNs exhibited a negative ζp around -44.4 mV, indicative of good colloidal stability and confirming the presence of HA on the surface. Cryo-TEM analysis revealed spherical particles with an internal multilayer bilayer structure and a well-defined membrane thickness. ITC and DSC analyses suggested increased stability and an amorphous state of SLB within the LPN matrix, particularly when using low molecular weight HA. The formulations demonstrated good physicochemical stability over 30 days. DC and EE in the dispersions were approximately 100% and 60%, respectively. In-vitro release studies indicated that LPNs achieved a higher SLB release (85%) compared to free SLB (20% in 1 hour), highlighting the influence of low molecular weight HA on nanoparticle performance. The LPNs showed appropriate viscosity and mucoadhesive properties for nasal administration, regardless of HA molecular weight. Cellular uptake studies in RPMI 2650 cells confirmed efficient internalization, while cytotoxicity assays in T98-G glioblastoma cells demonstrated promising therapeutic efficacy through significant glioma cell growth inhibition.

The findings highlight the fundamental role of hyaluronic acid molecular weight in optimizing hybrid nanoparticles (LNPs), demonstrating their strong potential for intranasal delivery of hydrophobic natural compounds to overcome limitations of conventional routes and enhance therapeutic efficacy in glioma treatment.