Comparison of gentamicin distribution in the inner ear following administration via the endolymphatic sac or round window.

Abstract

The distribution of gentamicin in the inner ear via the endolymphatic sac (ES) or round window (RW) routes was investigated. Experimental study. A fluorescent gentamicin-Texas Red conjugate (GTTR) was adopted to visualize the gentamicin. Adult guinea pigs were treated with GTTR applied to the ES or RW, the animals were allowed to recover for 3 days, then confocal microscopy was used to observe and quantify GTTR distributions in cochlear and vestibular sensory epithelium. When GTTR was applied via the ES, strong GTTR labeling was observed in the vestibule while little GTTR was detected in the cochlea (P < .0001). However, distinct GTTR fluorescence was observed in the cochlea and vestibule following RW application (P = .7967). There was less GTTR labeling in cochlea via ES application than through RW administration (P < .0001). ES drug application may be preferable for the treatment of intractable Meniere's disease. Laryngoscope, 2010.