title: Nanoporous silica coatings as a drug delivery system for ciprofloxacin: outcome of variable release rates in the infected middle ear of rabbits.
abstract: OBJECTIVE
  The present study was performed to examine the impact of the release rate of ciprofloxacin from prostheses coated with nanoporous silica layers on the outcome of an acute bacterial infection of the middle ear of rabbits.
  
  
  BACKGROUND
  Middle ear prostheses are often implanted in an infectious environment because of chronic otitis media and cholesteatoma. Bacterial colonization leads to healing disorders after surgery and may lead to the extrusion of the implants. Nanoporous silica layers appear promising as a drug delivery system for antibiotics placed on implants. Before clinical applications can be envisioned, it is necessary to find an optimal release rate.
  
  
  METHODS
  White New Zealand rabbits were provided unilaterally with either a "slow release" or a "burst release" ciprofloxacin-containing middle ear Bioverit II prosthesis. After implantation, the middle ears were infected with a solution of Pseudomonas aeruginosa. Afterwards, animals were monitored clinically and, after 3 months, sacrificed to perform necropsy and microbiologic examinations.
  
  
  RESULTS
  In the "slow release" group, 7 of 12 animals had to be euthanized preterm because of their poor clinical condition compared with 2 of 12 animals of the "burst release" group (p < 0.05). Clinical and microbiologic examination also showed a better outcome for animals of the burst release group.
  
  
  CONCLUSIONS
  A burst release of ciprofloxacin from middle ear implants is important to combat a perioperative infection with Ps. aeruginosa in the middle ear model of the rabbit.
authors.affiliation: ENT Department, Hannover Medical School, Hannover, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Hesse
authors.forename: Nina
authors.initials: N
authors.lastname: Ehlert
authors.forename: Tammo
authors.initials: T
authors.lastname: Lüenhop
authors.forename: Anna
authors.initials: A
authors.lastname: Smoczek
authors.forename: Silke
authors.initials: S
authors.lastname: Glage
authors.forename: Peter
authors.initials: P
authors.lastname: Behrens
authors.forename: Peter Paul
authors.initials: PP
authors.lastname: Müller
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Esser
authors.forename: Thomas
authors.initials: T
authors.lastname: Lenarz
authors.forename: Martin
authors.initials: M
authors.lastname: Stieve
authors.forename: André
authors.initials: A
authors.lastname: Bleich
authors.forename: Nils Kristian
authors.initials: NK
authors.lastname: Prenzler
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D001522:Behavior, Animal / Q000502:physiology; D002516:Ceramics; D002939:Ciprofloxacin / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems; D004343:Drug Implants; D004427:Ear Diseases / Q000188:drug therapy* / Q000382:microbiology; D004432:Ear, Middle / Q000601:surgery; D005260:Female; D053208:Kaplan-Meier Estimate; D008422:Materials Testing; D053758:Nanoparticles; D009460:Neurologic Examination; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology; D011817:Rabbits; D012822:Silicon Dioxide; D016019:Survival Analysis
chemical_list: D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D004343:Drug Implants; D002939:Ciprofloxacin; D012822:Silicon Dioxide