title: Single Administration of a Sustained-Release Formulation of KB-R7785 Inhibits Tympanic Membrane Regeneration in an Animal Model.
abstract: OBJECTIVE
  A pressure equalization tube placed within the tympanic membrane is the only clinically available method for inhibiting tympanic membrane regeneration. Problems associated with this include associated otorrhea, biofilm formation, medial migration of the tube, tube retention, induction of granulation tissue, and a small but significant rate of cholesteatoma. We aimed to demonstrate that a single administration of a sustained-release polymer formulation of KB-R7785 maintains tympanic membrane perforation for at least 6 months.
  
  
  METHODS
  Sustained-release KB-R7785 was delivered within a novel polymer hydrogel to 20 mice with bilateral acute tympanic membrane perforations (a total of 40 perforations). The perforations were monitored at 3-month intervals until 9 months.
  
  
  RESULTS
  At 3 months, 90% of perforations were open (n=36/40). At 6 months, 75% of perforations were open (total n=30/40). At 9 months, 22.5% of perforations were open (total n=6/40). The majority of tympanic membrane perforations (75%) were open (not healed) beyond 6 months and close (fully healed) prior to 9 months (77.5%). Once healed, tympanic membranes resembled their normal histological appearance.
  
  
  CONCLUSIONS
  This study demonstrates that a single administration of a sustained-release polymer formulation of KB-R7785 inhibits tympanic membrane regeneration for 6-9 months.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Stanford University, California, USA. peterlsantamaria@gmail.com.
authors.forename: Peter Luke
authors.initials: PL
authors.lastname: Santa Maria
authors.forename: Chloe
authors.initials: C
authors.lastname: Santa Maria
authors.forename: Sungwoo
authors.initials: S
authors.lastname: Kim
authors.forename: Yunzhi Peter
authors.initials: YP
authors.lastname: Yang
mesh_terms: D000818:Animals; D003692:Delayed-Action Preparations; D004195:Disease Models, Animal; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006877:Hydroxamic Acids / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D012038:Regeneration / Q000187:drug effects*; D018058:Tympanic Membrane Perforation / Q000473:pathology*
chemical_list: D003692:Delayed-Action Preparations; D006877:Hydroxamic Acids; C107086:KB R7785; D005998:Glycine