title: Measurements of droplet size distribution and analysis of nasal spray atomization from different actuation pressure.
abstract: BACKGROUND
  To evaluate the deposition efficiency of spray droplets in a nasal cavity produced from a spray device, it is important to determine droplet size distribution, velocity, and its dispersion during atomization. Due to the limiting geometric dimensions of the nasal cavity airway, the spray plume cannot develop to its full size inside the nasal vestibule to penetrate the nasal valve region for effective drug deposition.
  
  
  METHODS
  Particle/droplet image analysis was used to determine local mean droplet sizes at eight regions within the spray plume under different actuation pressures that represent typical hand operation from pediatric to adult patients.
  
  
  RESULTS
  The results showed that higher actuation pressure produces smaller droplets in the atomization. Stronger actuation pressure typical of adult users produces a longer period of the fully atomized spray stage, despite a shorter overall spray duration. This produces finer droplets when compared with the data obtained by weaker actuation pressure, typical of pediatric users.
  
  
  CONCLUSIONS
  The experimental technique presented is able to capture a more complete representation of the droplet size distribution and the atomization process during an actuation. The measured droplet size distribution produced can be related to the empirically defined deposition efficiency curve of the nasal cavity, allowing a prediction of the likely deposition.
authors.affiliation: 1 School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University , Bundoora, Victoria, Australia .
authors.forename: Kiao
authors.initials: K
authors.lastname: Inthavong
authors.forename: Man Chiu
authors.initials: MC
authors.lastname: Fung
authors.forename: William
authors.initials: W
authors.lastname: Yang
authors.forename: Jiyuan
authors.initials: J
authors.lastname: Tu
mesh_terms: D000281:Administration, Intranasal; D003198:Computer Simulation; D004867:Equipment Design; D008953:Models, Anatomic; D009038:Motion; D009296:Nasal Cavity / Q000033:anatomy & histology*; D059085:Nasal Sprays; D009330:Nebulizers and Vaporizers; D009716:Numerical Analysis, Computer-Assisted; D010316:Particle Size; D011312:Pressure; D013997:Time Factors; D014867:Water / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: D059085:Nasal Sprays; D014867:Water
keywords: automated actuation; nasal drug delivery; particle/droplet image analysis; spray atomization; spray pattern