Anti-oxidative mesoporous polydopamine-based hypotensive nano-eyedrop for improved glaucoma management

Conventional hypotensive eye drops remain suboptimal for glaucoma management, primarily due to their limited intraocular bioavailability and the growing concern regarding ocular surface side effects. Therefore, there is an urgent need to develop innovative intraocular pressure (IOP)-lowering formulations that not only possess enhanced corneal penetration ability but also provide ocular surface protection. Herein, anti-oxidative mesoporous polydopamine nanoparticles (MPDA NPs) were explored as a nano-carrier for Brimonidine to address the above issues. Nearly monodisperse MPDA NPs with obvious nanopores were successfully prepared by template-removal method and used for encapsulation of Brimonidine benefiting from their high specific surface area. Interestingly, the PEGylated and drug loaded MPDA-PEG@Brim NPs showed a near neutral surface charge, which is expected to enhance intraocular drug delivery. Consequently, much higher concentration of Brimonidine in the aqueous humor was found after topical administration of MPDA-PEG@Brim nano-dispersion as compared to free Brimonidine solution. Accordingly, superior IOP reduction effect was achieved for the nano-formulation in both hypertensive and normotensive rat eyes. Moreover, MPDA-PEG NPs showed good capability in scavenging diverse free radicals, alleviating intracellular oxidative stress, and mitigating ocular surface oxidative level in a mouse model of preservative-induced dry eye. In addition, the excellent biosafety of this novel Brimonidine nanodrug was confirmed both in vitro and in vivo. Therefore, the present work may shed light on the development of next generation hypotensive formulations for extended ocular surface protection and glaucoma management.