title: Ototoxicity of aluminum acetate/benzethonium chloride otic solution in the chinchilla animal model.
abstract: OBJECTIVE
  To determine the ototoxic potential of aluminum acetate (0.5%)/benzethonium chloride (0.03%) otic solution in the chinchilla animal model.
  
  
  METHODS
  A randomized, prospective, controlled study was conducted in the chinchilla animal model.
  
  
  METHODS
  Fourteen female chinchillas were used. After an incision was made in each tympanic membrane, baseline auditory brainstem response measurements were performed at 16, 20, and 25 kHz. One ear was randomized to receive aluminum acetate (0.5%)/benzethonium chloride (0.03%), whereas the other ear served as the control and received 0.9% NaCl. Solutions were applied transtympanically once a day for 3 consecutive days. Postapplication auditory brainstem response measurements were done at day 7 and day 30. In half of the animals, scanning electron microscopy was done following the last auditory brainstem response measurement.
  
  
  RESULTS
  A statistically significant difference was found between the mean threshold shifts in the experimental and control ears at all frequencies on both 7 and 30 days postapplication (P < .02). Increased ossification of the cochleae was seen in experimental ears (n = 12). Scanning electron microscopy study demonstrated outer hair cell damage and/or loss in the experimental ears. No significant morphological changes were detected on scanning electron microscopy obtained from the control ears.
  
  
  CONCLUSIONS
  Application of aluminum acetate (0.5%)/benzethonium chloride (0.03%) otic solution causes hearing loss in chinchillas when a tympanic membrane perforation exists. Further studies are needed to test the effect of this otic solution on hearing.
  
  
  METHODS
  4.
authors.affiliation: McGill Auditory Sciences Laboratory, Division of Pediatric Otolaryngology-Head and Neck Surgery, The Montreal Children's Hospital, Montreal, Quebec, Canada.
authors.forename: Jacob
authors.initials: J
authors.lastname: Pitaro
authors.forename: Zhoobin A
authors.initials: ZA
authors.lastname: Mood
authors.forename: Sam J
authors.initials: SJ
authors.lastname: Daniel
mesh_terms: D000085:Acetates / Q000008:administration & dosage / Q000009:adverse effects*; D000818:Animals; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000009:adverse effects*; D001309:Auditory Threshold; D001558:Benzethonium / Q000008:administration & dosage / Q000009:adverse effects*; D002682:Chinchilla; D003051:Cochlea / Q000648:ultrastructure; D004195:Disease Models, Animal; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D008855:Microscopy, Electron, Scanning; D010032:Otitis Externa / Q000188:drug therapy*; D011446:Prospective Studies
chemical_list: D000085:Acetates; D000891:Anti-Infective Agents, Local; D001558:Benzethonium; C013396:aluminum acetate
keywords: External otitis; aluminum acetate; benzethonium chloride; chinchilla; ototoxicity