Possibilities of Inner Ear Barrier Models for Otologic Drug Development

The development of efficient drug delivery systems for the treatment of inner ear diseases remains a significant challenge because of the intricate anatomy and physiology of the inner ear. Conventional in vitro and in vivo models are limited in their ability to accurately recapitulate the inner ear microenvironment and drug pharmacokinetics. The emergence of organ‐on‐chip technology provides a promising alternative for studying inner ear drug delivery by enabling the reconstruction of key inner ear barriers, such as the round window membrane, blood‐labyrinth barrier, and perilymph‐endolymph barrier, in a microfluidic platform. This review discusses the current strategies for inner ear drug delivery, the challenges associated with each approach, and the potential of an inner ear barrier organ chip to overcome these limitations. Incorporating relevant cell types, extracellular matrix components, and biomechanical cues, the inner ear organ chips offer a valuable platform for drug screening, efficacy assessment, and disease modeling. The validation of these models and their successful application in otologic drug development will require a multidisciplinary approach involving tissue engineering, microfabrication, and cell and molecular biology. As inner ear organ chip technology advances, it is expected to accelerate the development of targeted and efficient drug delivery systems for the treatment of hearing disorders.