title: Impact of holding position during inhalation on drug release from a reservoir-, blister- and capsule-type dry powder inhaler.
abstract: OBJECTIVE
  To determine whether drug release may be impaired by tilting some dry powder inhalers (DPIs).
  
  
  METHODS
  Using an inhalation simulator, we measured drug release from Turbuhaler® (TBH), Diskus® (DKS) and Breezhaler® (BZH) at several peak inhaled flow rates (PIFs) while the DPIs were held at level and tilted (80°). Drug release was then measured from all three DPIs at 0, 30, 60 and 90° of tilt, and capsule rotation was also recorded.
  
  
  RESULTS
  Drug release from TBH was flow-dependent while that from DKS and BZH was flow-independent. With TBH, the plot of drug release vs. PIF either at level or at tilted position scattered along approximately the same regression lines. With DKS and BZH, drug release at tilted position was significantly lower than that while at level. With DKS the decrease was almost 20%, while with BZH, drug release frequently failed. With BZH, significant reductions in drug release were observed while the device was tilted by 30-90°.
  
  
  CONCLUSIONS
  The position in which the DPI is held may affect drug delivery, especially when using BZH.
authors.affiliation: a Department of Respiratory Medicine , Shonan Fujisawa Tokushukai Hospital , Fujisawa , Japan.
authors.forename: Tetsuri
authors.identifier: http://orcid.org/0000-0001-5975-1886
authors.initials: T
authors.lastname: Kondo
authors.affiliation: b Division of Respiratory Medicine , Atsugi Circulation Clinic , Atsugi , Japan.
authors.forename: Toshimori
authors.initials: T
authors.lastname: Tanigaki
authors.affiliation: c Department of Clinical Evaluation of Drug Efficacy , School of Pharmacy, Tokyo University of Pharmacy and life Sciences , Hachioji , Japan.
authors.forename: Haruko
authors.initials: H
authors.lastname: Yokoyama
authors.affiliation: a Department of Respiratory Medicine , Shonan Fujisawa Tokushukai Hospital , Fujisawa , Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hibino
authors.affiliation: d Department of Medicine , Tokai University Oiso Hospital , Oiso , Japan.
authors.forename: Sakurakao
authors.initials: S
authors.lastname: Tajiri
authors.affiliation: a Department of Respiratory Medicine , Shonan Fujisawa Tokushukai Hospital , Fujisawa , Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Akazawa
authors.affiliation: c Department of Clinical Evaluation of Drug Efficacy , School of Pharmacy, Tokyo University of Pharmacy and life Sciences , Hachioji , Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: e Department of Medicine , Stanford University , Stanford , CA , USA.
authors.forename: Stanley M
authors.initials: SM
authors.lastname: Cassan
mesh_terms: D000280:Administration, Inhalation; D001249:Asthma / Q000188:drug therapy*; D058995:Dry Powder Inhalers / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D001239:Inhalation
keywords: Drug release; flat; peak inhaled flow; simulation; tilt