Improved inner ear drug delivery using hydrogel carriers

The management of inner ear disorders is troubled with obstacles, such as the precise delivery of drug molecules to diseased cells. Due to the blood-labyrinth barrier (BLB), systemic therapy, the first line of treatment, frequently results in sub-optimal inner ear drug concentration. Although currently preferred local drug delivery methods such as intratympanic and intracochlear administration may result in a higher inner ear drug concentration, drainage via the Eustachian tube poses a challenge. The undesirable requirement for multiple doses to maintain therapeutic levels of the drug has prompted the investigation of improved local delivery methods for inner ear therapy. Using hydrogels to deliver drug molecules to the round window membrane via the intratympanic route is one of the novel methods of drug delivery to the inner ear. Various types of hydrogels may be developed in this line using natural polymers such as chitosan, hyaluronic acid, and gelatin, as well as synthetic polymers such as poloxamers. This article aimed to provide an in-depth analysis of drug delivery to the inner ear and discuss the impact of hydrogel-based formulations.