How Inner Ear Drug Delivery Will Change Hearing Loss Treatment

If you were to begin experiencing hearing loss tomorrow and visited an audiologist, what treatment recommendation do you expect to receive? If you are like most people, you would probably expect to be recommended an amplification device, like a hearing aid.
However, if you were to begin experiencing the symptoms of an infection tomorrow and went to see your primary care physician, what would you expect? Probably an antibiotic that would help to fight the infection and hopefully begin to relieve your symptoms.
Why should hearing loss be any different? If you think about it, you have probably never heard of someone being prescribed a drug in order to treat hearing loss. That’s because there are currently no FDA-approved drugs available for the treatment or prevention of inner ear disorders, like those that result in hearing loss.
All of that might change in the future – and it might be even sooner than you think. Many scientists, medical researchers, and pharmaceutical companies are now exploring the possibility of using drugs to treat and prevent inner ear disorders, and several products and therapies are in development. This research aims to address a variety of hearing disorder causes, ranging from ototoxicity from medication to genetic or hereditary hearing loss.
The therapeutic approaches utilized by these researchers also vary – including gene therapy, hair cell regeneration, and otoprotection. The goal is that, in the future, drugs will be a reliable and effective option for preventing or treating inner ear disorders and improving a patient’s quality of life.
The exact method for delivering these drugs to the inner ear has posed a challenge to researchers. Three methods are now available: intratympanic, intracochlear, and systemic. Intratympanic delivery involves using a syringe to inject the drug into the middle ear through the tympanic membrane. The drug can then be absorbed across the round window membrane and into the cochlea. Intracochlear administration focuses on delivering the drug directly to the cochlea. This provides greater precision for drug delivery, but it also requires a high-risk procedure.
Systemic delivery is the most desired route, but it is perhaps the most challenging at the moment because of the blood labyrinth barrier. Further research must be done to improve systemic delivery. It remains, however, a promising administration method.
While the local administration methods – intratympanic and intracochlear – hold risks for temporary or even permanent hearing loss, there are still great strides being made in these forms of drug delivery. For example, researchers recently developed a thermosensitive gel that can be injected through the tympanic membrane and into the middle ear. The gel solidifies at body temperature, so it will ideally stay on the round window membrane until it is absorbed into the cochlea.
Researchers hope to be able to, one day, help patients maintain or restore healthy auditory performance thanks to these new drugs and delivery methods. Some even feel optimistic that certain drugs, like otoprotectants, may later be available over the counter. This would allow audiologists and other medical professionals to easily recommend such products to their patients.
Another great goal of this developing research is that of reducing the number of cases or even ending genetic hearing loss altogether. With gene therapy, stem cell therapy, hair cell regeneration, and many other exciting new developments, hearing loss prevention and treatment are on the brink of a new age.
To learn more about this intriguing new research on drug therapies and inner ear delivery systems, we welcome you to contact our audiology office.


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