In vitro assessment of the transport of Poly D, L Lactic-Co-Glycolic Acid (PLGA) nanoparticles across the nasal mucosa

The nasal mucosa provides a rapid, noninvasive route for drug administration to the systemic circulation and even potentially to the CNS. Nanoparticles made from the biodegradable polymer, PLGA, are of great interest for use in drug delivery systems due to PLGA’s relative safety and ease of surface modification. Nanoparticles may provide improved targeting and transport through the nasal mucosa. However, the optimal nanoparticle sizes and surface properties for intranasal delivery are unknown. In this study, we prepared PLGA nanoparticles within a size range of 50-70 nm containing the lipophilic fluorescent dye, Nile Red, using a surfactant-free nanoprecipitation method. The resulting nanoparticles were evaluated using dynamic light scattering and scanning electron microscopy. Nanoparticle uptake into the nasal mucosa was determined by exposing the tissues to nanoparticle dispersions for 30 or 60 minutes. The in vitro uptake of the nanoparticles by the nasal mucosal tissues revealed that the Nile Red-loaded PLGA nanoparticles were transported across the epithelial layer and accumulated in the sub-mucosal connective tissues. Nanoparticle uptake in the full thickness tissues was time dependent where 2% of the total loads of nanoparticles exposed to the tissues were measured in the mucosal tissue after 30 minutes and 4% were present in the tissues after 60 minutes. The rapid and measurable transfer of PLGA nanoparticles into the nasal mucosal tissues indicate that they may be an efficient delivery vehicle for drugs with either local or systemic activities.