In the typical inner ear, also known as the cochlea, sensory cells detect sound and transmit information via the auditory neurons to the brain, where sounds are perceived. Age-related and noise-induced damage can occur to the connections (synapses) between these sensory cells and their neurons. This limits the information that can get from the ears to the brain, and therefore impairs speech interpretation in noisy situations, which can have devastating consequences for communication. Hearing aids and cochlear implants cannot address the underlying synapse damage, and past attempts to develop a drug therapy have been limited by difficulties delivering regenerative therapies into the cochlea. This project will test and validate the therapeutic potential of combining two novel regenerative drugs to repair cochlear synapse damage. These drugs will be delivered to the cochlea via a nanotechnology-based drug delivery system that can be implemented clinically. If successful, this project would support a first-in-human clinical trial, advancing the development of this technology towards the world's first successful drug therapy and delivery method to treat hearing loss.