Sonoporation for Drug Delivery to the Inner Ear

Jan 26, 2022 | House Institute Foundation, Research

 
Professor David Bakhos

The House Institute Foundation (HIF) adjunct faculty Professor David Bakhos, MD, PhD (University of Tours, France) has been awarded a development grant for a 3-year study focused on the safety and efficacy of sonoporation for drug delivery to the inner ear. Collaborators include Pr. Helene Blasco, PhD, Dr. Jean-Michel Escoffre, PhD, and Dr. John Galvin, PhD.  

For individuals with hearing loss, medication is often used to treat inner ear disease. Historically, different approaches have been used to deliver medication. In “systemic” delivery, medication is delivered orally or by injection. However, this delivery method does not provide sufficient concentration of medication and may cause undesirable side effects. In “trans-tympanic” delivery, medication is delivered to the inner ear via injection. Trans-tympanic delivery of corticosteroids is often used to treat various inner ear diseases. While trans-tympanic delivery has greater efficacy than systemic delivery, it can also result in highly variable concentrations of the medicine in the inner ear, requiring multiple treatments that may or may not be successful.  

A new method of drug delivery has been proposed – “sonoporation”, in which ultrasound is used to excite microbubbles that then permeate cell membranes. If successful, sonoporation may allow for greater and more precise concentrations of medicine to be delivered to the inner ear. While sonoporation holds great promise as a method for drug delivery, more research is needed to evaluate its safety and efficacy. 

Professor Bakos plans to evaluate the safety and efficacy of sonoporation as a drug delivery system in a sheep model. Sheep will be used because they have similar inner ear anatomy and physiology as in humans; also, it is necessary to establish the safety and efficacy in an animal model before testing in humans.  

The study has two objectives: First, to evaluate the feasibility and safety of sonoporation by measuring the ototoxicity associated with sonoporation using objective auditory measurements and metabolomic analysis of perilymph extracted from the inner ear. Second, to compare the concentration of medication in the inner ear between sonoporation and trans-tympanic delivery. Pharmaco-metabolomic analysis of perilymph fluid will be used to compare the two approaches.  


Bakhos (second from left) and a team of physicians and scientists at his lab at the University of Tours, France.

If results are promising, Professor Bakos will develop a clinical ultrasonic probe in collaboration with engineers. The possibility of delivering medications to the inner ear using sonoporation may lead to new ways to treat people with hearing loss.