Multicomponent nasal spray delivered via penetration-enhancer containing vesicles (PEVs) for antioxidant and antibacterial protection

Abstract

In this study, a nasal spray was formulated and tested co-loading grape seed extract, thymol, and camphor in penetration enhancer containing vesicles (PEVs) tailored to synergistically protect the nasal mucosa against oxidative stress and bacterial colonization. Based on their previously demonstrated effects, PEVs were prepared with propylene glycol (PG) and further enriched with carrageenan to promote muco-adhesion. The mean diameter of PG-PEVs was similar to 177 nm, and that of carrageenan PG-PEVs was similar to 194 nm. The polydispersity index ranged from 0.25 to 0.27, confirming the homogeneity of the dispersions. The zeta potential was significantly negative (similar to- 63 mV) and the entrapment efficiency was similar to 88 %, irrespective of vesicle composition. Sprayability studies disclosed that both PG-PEVs and carrageenan-PG-PEVs generated droplets larger than 10 mu m, thus appropriate for the deposition in the nasal cavity. Regional nasal deposition studies, carried out with a realistic nasal replica, highlighted that formulation droplets were deposited in the vestibule and turbinate areas of the nose. The ability of formulations to inhibit protein denaturation confirmed their anti-inflammatory effects. In vitro study with A549 and CuFi-1 cells, underlined that PG-PEVs and especially carrageenan PG-PEVs were nontoxic (viability similar to 140 %) and effectively counteracted cell apoptosis caused by hydrogen peroxide, restoring healthy conditions. The in vivo study in mice demonstrated that grape seed extract, thymol, and camphor-loaded carrageenan PG-PEVs were highly effective in counteracting the proliferation of Staphylococcus aureus.