title: Rapid pulmonary delivery of inhaled tobramycin for Pseudomonas infection in cystic fibrosis: a pilot project.
abstract: BACKGROUND
  Patients with cystic fibrosis spend as much 30 min a day inhaling tobramycin. Could a new rapid system deposit the equivalent amount of tobramycin faster?
  
  
  METHODS
  Six healthy adult males inhaled 5 ml (300 mg) of tobramycin from a breath enhanced nebulizer and either 125 mg (n = 3) or 150 mg (n = 3) from a vibrating membrane system with a large or small aerosol mixing chamber respectively. A radiolabel was added to the solution and shown to "track" with the tobramycin. Imaging was done with a dual headed gamma camera. Because the radiolabel will be cleared by mucociliary action during administration, algorithms were developed to allow the comparison of a slower system to a faster one.
  
  
  RESULTS
  Both formulations were well tolerated. The lung deposition was 16.6 +/- 3.2% (mean +/- SD) of the charge dose delivered in 10.9 +/- 1.0 min for the breath enhanced nebulizer versus 32.0 +/- 5.1% delivered in 2.5 +/- 0.4 min from the vibrating membrane system. The absolute pulmonary delivery of tobramycin was 49.9 +/- 9.6 versus 43.9 +/- 4.8 mg for the two systems respectively, differences that were statistically significant (pair t-test) but unlikely to be clinically significant. There was a similar deposition of tobramycin for the 125 and 150 mg dose.
  
  
  CONCLUSIONS
  It is possible to deliver an equivalent amount of tobramycin in a shorter period of time with the new vibrating membrane system and a more concentrated formulation. These data will allow the design of a comparison in patients with CF.
authors.affiliation: Division of Nuclear Medicine, Hospital for Sick Children Research Institute, University of Toronto, Toronto, Canada. allan.coates@sickkids.ca
authors.forename: Allan L
authors.initials: AL
authors.lastname: Coates
authors.forename: Maria
authors.initials: M
authors.lastname: Green
authors.forename: Kitty
authors.initials: K
authors.lastname: Leung
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Chan
authors.forename: Nancy
authors.initials: N
authors.lastname: Ribeiro
authors.forename: Emily
authors.initials: E
authors.lastname: Louca
authors.forename: Felix
authors.initials: F
authors.lastname: Ratjen
authors.forename: Martin
authors.initials: M
authors.lastname: Charron
authors.forename: Markus
authors.initials: M
authors.lastname: Tservistas
authors.forename: Manfred
authors.initials: M
authors.lastname: Keller
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D003550:Cystic Fibrosis / Q000188:drug therapy* / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D010865:Pilot Projects; D011552:Pseudomonas Infections / Q000188:drug therapy*; D013997:Time Factors; D014031:Tobramycin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D014031:Tobramycin