title: Characterization of respiratory deposition of fluticasone-salmeterol hydrofluoroalkane-134a and hydrofluoroalkane-134a beclomethasone in asthmatic patients.
abstract: BACKGROUND
  Fixed combination fluticasone-salmeterol is the most used anti-inflammatory asthma treatment in North America, yet no studies report the actual respiratory tract dose or the distribution of drug within the lungs. Inflammation due to asthma affects all airways of the lungs, both large and small. Inhaled steroid delivery to airways results from a range of drug particle sizes, with emphasis on smaller drug particles capable of reaching the peripheral airways. Previous studies suggested that smaller drug particles increase pulmonary deposition and decrease oropharyngeal deposition.
  
  
  OBJECTIVE
  To characterize the dose of fluticasone-salmeterol hydrofluoroalkane-134a (HFA) (particle size, 2.7 μm) delivered to asthmatic patients and examine the drug distribution within the lungs. The results were compared with the inhalation delivery of HFA beclomethasone (particle size, 0.7 μm).
  
  
  METHODS
  A crossover study was conducted in asthmatic patients with commercial formulations of fluticasone-salmeterol and HFA beclomethasone radiolabeled with technetium Tc 99m. Deposition was measured using single-photon emission computed tomography/computed tomography gamma scintigraphy.
  
  
  RESULTS
  Two-dimensional planar image analysis indicated that 58% of the HFA beclomethasone and 16% of the fluticasone-salmeterol HFA were deposited in the patient's lungs. The oropharyngeal cavity and gut analyses indicated that 77% of the fluticasone-salmeterol HFA was deposited in the oropharynx compared with 35% of the HFA beclomethasone.
  
  
  CONCLUSIONS
  The decreased peripheral airway deposition and increased oropharyngeal deposition of fluticasone-salmeterol HFA was a result of its larger particle size. The smaller particle size of HFA beclomethasone allowed a greater proportion of lung deposition with a concomitant decrease in oropharyngeal deposition.
authors.affiliation: Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87108, USA. cleach@lrri.org
authors.forename: Chet L
authors.initials: CL
authors.lastname: Leach
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Kuehl
authors.forename: Ramesh
authors.initials: R
authors.lastname: Chand
authors.forename: Loren
authors.initials: L
authors.lastname: Ketai
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Norenberg
authors.forename: Jacob D
authors.initials: JD
authors.lastname: McDonald
mesh_terms: D000280:Administration, Inhalation; D000335:Aerosol Propellants; D000420:Albuterol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D000730:Androstadienes / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000627:therapeutic use; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D001249:Asthma / Q000000981:diagnostic imaging / Q000188:drug therapy*; D001507:Beclomethasone / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000627:therapeutic use; D018592:Cross-Over Studies; D004338:Drug Combinations; D000068297:Fluticasone-Salmeterol Drug Combination; D006801:Humans; D006845:Hydrocarbons, Fluorinated; D008168:Lung / Q000000981:diagnostic imaging / Q000187:drug effects*; D010316:Particle Size; D011877:Radionuclide Imaging; D005466:Fluorocarbons
chemical_list: D000335:Aerosol Propellants; D000420:Albuterol; D000730:Androstadienes; D018927:Anti-Asthmatic Agents; D001507:Beclomethasone; D004338:Drug Combinations; D000068297:Fluticasone-Salmeterol Drug Combination; D006845:Hydrocarbons, Fluorinated; C094049:apaflurane; D005466:Fluorocarbons