Safety and efficacy of dissolvable microneedles embedded with dexamethasone-loaded nanoparticles for treating ocular inflammation

This study evaluates the ocular toxicity and therapeutic efficacy of a dissolvable microneedle (MN) system containing PLGA nanoparticles loaded with dexamethasone (Dex) using a rabbit model of endotoxin-induced uveitis. Previous research by our group demonstrated the potential of MN systems in delivering PLGA microparticles to scleral tissue. Building on this, we conducted an in-vivo study to assess the irritancy and therapeutic activity of Dex-loaded nanoparticles in MN patches. Results showed that both Blank-MN and Dex-MN patches caused minimal irritation, with no mechanical injury upon insertion. Dex-MN patches had a lower irritation score, and faster recovery compared to Blank-MN patches. In the uveitis model, Dex-MN patches significantly reduced clinical scores of uveitis and levels of pro-inflammatory markers (TNF-α, IL-6, MPO), and normalized apoptosis mediators (Bax, BCL2, NF-κB, Caspase3). Histopathological assessments confirmed reduced inflammatory reactions and cellular in-filtrate in Dex-MN treated eyes. These findings indicate that the Dex-loaded dissolvable MN system is a safe and effective platform for ocular drug delivery, offering significant therapeutic benefits in treating ocular inflammation.