Hearing loss has a tremendous impact on our quality of life. The ability to hear is a vital part of our overall sensory experience and our connection to the world around us. The impact of hearing loss may be profound, with consequences for the social, functional, and psychological well-being of the person. A hearing impairment limits our engagement and affects our self-identity. Because many people with hearing loss neglect treatment due to the options available, a pharmaceutical approach to treatment may be the answer. New research is focusing on the inner ear for effective drug delivery.
Although there are 466 million people worldwide who have hearing loss, there are no FDA-approved drugs available for preventing and treating inner ear disorders. A lack of clinical experience involving the inner ear creates challenges for the pharmaceutical companies that are developing inner ear medications. With indications such as ototoxicity and Meniere’s disease, these companies are developing therapies such as otoprotection, hair cell regeneration, and gene therapy. Selecting the most appropriate delivery method that will transport the medication is of vital importance.
Inner ear drug delivery involves three routes of administration: intratympanic, intracochlear, and systemic. Intratympanic uses a syringe injection to the tympanic membrane to deliver a drug across the middle ear and into the cochlea. This route is beneficial for administering drug solutions, drug suspensions, and injectable gels. Intracochlear is the transfer of the drug into the cochlea. Although this method is precise, it is also high-risk. An injection, a perfusion system, or a cochlear implant device are the delivery methods for this route. Systemic delivery is the favored route for future delivery as it poses a low risk for complications and is more comfortable for patients. Research is focusing on finding new systemic administration methods for ear therapy.
There is progress in the improvement of inner ear drug delivery systems. Drug targeting, gene and stem cell therapy, and hair cell regeneration are making effective inner ear drug delivery a reality. Collaboration is vital for translating lab bench results into viable treatment options. Researchers feel confident that partnership will overcome the challenges of administering therapy directly to the inner ear.
There are obstacles to be cleared in the development of efficient inner ear drug delivery systems. The main problem is not knowing the exact drug formulation for the intended drug delivery system. Another issue is the conversion of clinical findings that utilized animal models to applications for humans. What works in a rat may not be successful in a human. For systemic drug delivery, achieving a therapeutic dose in the inner ear after crossing the blood-labyrinth barrier without side-effects is the goal.
Inner ear therapies will encourage patients to seek care for their hearing loss. As an alternative to a hearing device, drugs provide a long-lasting, convenient, and efficient treatment option. The research team hopes that inner ear drug delivery systems will lay the groundwork for effective prevention and treatment with medications.