title: Drug delivery to the cochlea using PLGA nanoparticles.
abstract: OBJECTIVE
  This study aimed to investigate the efficacy of encapsulating therapeutic molecules in poly lactic/glycolic acid (PLGA) nanoparticles for drug delivery to the cochlea.
  
  
  METHODS
  An experimental study.
  
  
  METHODS
  We examined the distribution of rhodamine, a fluorescent dye, in the cochlea, liver, and kidney of guinea pigs. Intravenous injection of rhodamine or rhodamine-encapsulated PLGA nanoparticles was used to target the fluorescent dye systemically to the liver, kidney, and cochlea, and these molecules were applied locally to the round window membrane (RWM) of the cochlea. The localization of rhodamine fluorescence in each region was quantitatively analyzed.
  
  
  RESULTS
  After systemic application of rhodamine nanoparticles, fluorescence was identified in the liver, kidney, and cochlea. The systemic application of nanoparticles had a significant effect on targeted and sustained delivery of rhodamine to the liver but not the kidney or cochlea. Rhodamine nanoparticles placed on the RWM were identified in the scala tympani as nanoparticles, indicating that the PLGA nanoparticles can permeate through the RWM. Furthermore, the local application of rhodamine nanoparticles to the RWM was more effective in targeted delivery to the cochlea than systemic application.
  
  
  CONCLUSIONS
  These findings indicate that PLGA nanoparticles can be an useful drug carrier to the cochlea via local application.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tamura
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kita
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Endo
authors.forename: Tae-Soo
authors.initials: TS
authors.lastname: Kim
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ishihara
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Mizushima
authors.forename: Megumu
authors.initials: M
authors.lastname: Higaki
authors.forename: Juichi
authors.initials: J
authors.lastname: Ito
mesh_terms: D000818:Animals; D003051:Cochlea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004333:Drug Administration Routes; D004337:Drug Carriers; D016503:Drug Delivery Systems / Q000295:instrumentation*; D005456:Fluorescent Dyes / Q000008:administration & dosage* / Q000493:pharmacokinetics; D006168:Guinea Pigs; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019344:Lactic Acid; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008856:Microscopy, Fluorescence; D049329:Nanostructures; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D012235:Rhodamines / Q000008:administration & dosage* / Q000493:pharmacokinetics
chemical_list: D004337:Drug Carriers; D005456:Fluorescent Dyes; D011108:Polymers; D012235:Rhodamines; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid