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Updated: Jun 27, 2025

Trans-Tympanic Drug Delivery for the Treatment of Ototoxicity
Published on: March 16, 2018
Sound Exposure Promotes Intratympanic Drug Delivery to the Inner Ear
Omer J Ungar1,2, Yumai Situ2, Jennifer L Spiegel1,2,3
1Department of Otolaryngology-Head and Neck Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
Objective:
To investigate the impact of sound exposure, with the resultant windows vibration on perilymphatic concentrations following intratympanic (IT) dexamethasone and gentamicin in an animal model.
Study Design:
Animal model blinded study.
Setting:
Animal facility of a tertiary medical center.
Methods:
Bilateral IT dexamethasone or gentamicin was applied to 15 tested rats. Following injections, each rat was exposed for 3 minutes to free field 30 dB sound pressure level (SPL), 512 vHz noise, with 1 external auditory canal plugged (contralateral control). Following noise exposure, perilymph was obtained from both ears. Drug concentrations were measured using ultrahigh-performance liquid chromatography-mass spectrometer.
Results:
For dexamethasone, the average (±SD) perilymphatic steroidal concentration was 0.417 µg/mL (±0.549) in the control ears versus 0.487 µg/mL (±0.636) in the sound-exposed ears (P = .008). The average (±SD) gentamicin perilymphatic concentration was 8.628 µg/mL (±2.549) in the sound-exposed ears, compared to 4.930 µg/mL (±0.668) in the contralateral control (nonsound exposed) ears. Sound exposure promoted steroidal and gentamicin diffusion to the inner ear by an averaged (±SD) factor of 1.431 and 1.730 (±0.291 and 0.339), respectively.
Conclusion:
Low-intensity noise (30 dB SPL) was found to enhance dexamethasone phosphate and gentamicin diffusion to the inner ear (by an averaged factor of ∼1.4 and 1.7, respectively) in a murine model.
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