Intraotic drug delivery following gentamicin Infusion using the an osmotic pump in chinchilla / 대한이비인후과학회지

ABSTRACT

BACKGROUNDS AND OBJECTIVES: We developed a method of intraotic treatment using gentamicin (GM) in chinchillas. MATERIALS AND METHOD: An osmotic pump, connected near the round window by a Teflon tube (0.13mm ID X 0.18mm OD) through an opening in the scala tympani, continuously perfused 12microliter of GM per day for a week. In the three experimental groups (n=12), each animal was treated with a total dose of 0.1mg of GM for a week. Animals in the control group (n=4) were immediately sacrificed after perfusion with saline for a week. RESULTS: In the control group, there was no damage in any of the hair cells. In the treatment group, the hair cells were more severely damaged at 4 weeks than at 1 week. The outer hair cells were more sensitive to GM than the inner hair cells. Among the outer hair cells, the first rows were damaged first. The basal part of cochlea was damaged earlier than the apical. The ototoxic effect continued even after perfusion had ceased. CONCLUSIONS: This pump system limits drug distribution to the target tissue, minimizing systemic side effects while permitting precise control of delivery rate, volume, concentration and duration.