title: Evaluation of particle size distribution of albuterol sulfate hydrofluoroalkane administered via metered-dose inhaler with and without valved holding chambers.
abstract: BACKGROUND
  Administration of inhaled medications via metered-dose inhaler (MDI) to pediatric patients younger than 4 years usually requires use of a holding chamber or spacer with an attached face mask.
  
  
  OBJECTIVE
  To determine the particle size distribution and overall dose of albuterol from the albuterol sulfate hydrofluoroalkane delivered in conjunction with 2 US-marketed valved holding chambers (VHCs) compared with the dose delivered via MDIs without VHCs.
  
  
  METHODS
  Cascade impaction methods with high-performance liquid chromatography were used to evaluate the fine particle mass (FPM) of albuterol administered without and with the use of 2 commercially available VHCs.
  
  
  RESULTS
  Particle size distributions for the 2 VHCs and the control were similar. The mean FPM values for the 2 VHCs and the control were 32, 28, and 30 microg, respectively. Statistical comparison of the FPM shows a similar profile when differences from the albuterol hydrofluoroalkane without a spacer were evaluated.
  
  
  CONCLUSIONS
  In vitro results obtained under these test conditions demonstrate that all the FPM values for the VHCs tested were within 15% of the control range, a difference that is unlikely to be clinically meaningful. These results do not warrant a change in the recommended dose of albuterol hydrofluoroalkane administered when using the VHCs tested. The use of an MDI in conjunction with a VHC provides a reasonable therapeutic approach for administration of albuterol hydrofluoroalkane to young children and other patients who have difficulty administering the MDI alone.
authors.affiliation: GlaxoSmithKline Inc, Research Triangle Park, North Carolina 27709, USA. Courtney.C.Crim@gsk.com
authors.forename: Courtney
authors.initials: C
authors.lastname: Crim
authors.forename: Mark
authors.initials: M
authors.lastname: Holmes
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lee
authors.forename: Robb
authors.initials: R
authors.lastname: Cavanaugh
authors.forename: William
authors.initials: W
authors.lastname: Lincourt
mesh_terms: D000420:Albuterol / Q000008:administration & dosage* / Q000737:chemistry; D001249:Asthma / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000008:administration & dosage* / Q000737:chemistry; D002675:Child, Preschool; D006801:Humans; D006845:Hydrocarbons, Fluorinated / Q000008:administration & dosage; D036501:Metered Dose Inhalers / Q000592:standards*; D010316:Particle Size; D005466:Fluorocarbons
chemical_list: D000420:Albuterol; D001993:Bronchodilator Agents; D006845:Hydrocarbons, Fluorinated; C094049:apaflurane; D005466:Fluorocarbons