Effects of common topical otic preparations on the morphology of isolated cochlear outer hair cells

Otic drops are commonly used not only for otitis externa but also for otorr hea in the presence of tympanostomy tube or tympanic membrane perforation. Many studies have demonstrated the ototoxicity of common otic preparations such as Cortisporin(R) otic drops. Recent studies have suggested the use of fluoroquinolone antibiotic drops as an alternative owing to their excellen t antimicrobial coverage and no ototoxic effect. The purpose of this study was to assess the relative ototoxicity of four common otic preparations by direct exposure to isolated cochlear outer hair cells (OHCs). OHCs from adu lt chinchilla cochlea were exposed to standard bathing solution (control), Cortisporin, Cipro HC(R), Ciloxan(R), and Floxin(R). The cells were observe d using an inverted microscope, and the images recorded in digital still-fr ame and video, and analyzed on the Image Pro-Plus(R) 3.0 program. As measur ed by time to cell death and change in morphology of OHCs, Cortisporin was most toxic to OHCs. Among the fluoroquinolone drops, Floxin was more toxic than Ciloxan or Cipro HC.