Drug delivery systems for ROS scavenging in hearing loss treatment

Hearing loss is the third most prevalent disabling disease in the world, impacting approximately one-fifth of the global population. Studies have shown that hearing loss is closely related to the accumulation of reactive oxygen species (ROS), and antioxidant therapy has been widely used to counteract ROS. However, this approach presents several limitations, including potential systemic side effects and insufficient drug accumulation in the inner ear. Moreover, the inner ear's complex anatomy and physiological barriers lead to unstable pharmacokinetics and susceptibility to environmental influences that affect therapeutic efficacy. Research into inner ear drug delivery systems has gained significant momentum recently. Drug delivery systems designed to deliver drugs to the inner ear can circumvent these problems and achieve improved therapeutic outcomes. Here, we summarize the traditional antioxidant therapeutic strategies and their inherent limitations and introduce the emerging antioxidant inner ear drug delivery systems such as hydrogels, microcarriers and nanoparticles. Finally, we discuss the challenges and look to the future directions of engineered ROS removal strategies for treating hearing loss.