title: Comparison of Aerodynamic Particle Size Distribution Between a Next Generation Impactor and a Cascade Impactor at a Range of Flow Rates.
abstract: Wide variation in respiratory flow rates between patients emphasizes the importance of evaluating the aerodynamic particle size distribution (APSD) of dry powder inhaler (DPI) using a multi-stage impactor at different flow rates. US Pharmacopeia recently listed modified configurations of the Andersen cascade impactor (ACI) and new sets of cut-off diameter specifications for the operation at flow rates of 60 and 90 L/min. The purpose of this study was to clarify the effect of these changes on the APSD of DPI products at varied flow rates. We obtained APSD profiles of four DPIs and device combinations, Relenza®-Diskhaler® (GlaxoSmithKline Co.), Seebri®-Breezhaler® (Novartis Pharma Co.), Pulmicort®-Turbuhaler® (Astrazeneca Co.), and Spiriva®-Handihaler® (Nippon Boehringer Ingelheim Co.) using Next Generation Impactors (NGIs) and ACIs at flow rates from 28.3 to 90 L/min to evaluate the difference in the use of previous and new sets of cut-off diameter specifications. Processing the data using the new specifications for ACI apparently reduced large differences in APSD obtained by NGI and ACI with the previous specifications at low and high flow rates in all the DPIs. Selecting the appropriate configuration of ACI corresponding to the flow rate provided comparable APSD profiles of Pulmicort®-Turbuhaler® to those using NGIs at varied flow rates. The results confirmed the relevance of the current US Pharmacopeia specifications for ACI analysis in obtaining APSD profiles of DPI products at wide flow rates.
authors.affiliation: Division of Drugs, National Institute of Health Sciences, Kamiyoga 1-18-1, Setagaya-ku, Tokyo, 158-8501, Japan. h.yoshida@nihs.go.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Division of Drugs, National Institute of Health Sciences, Kamiyoga 1-18-1, Setagaya-ku, Tokyo, 158-8501, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Kuwana
authors.affiliation: Division of Drugs, National Institute of Health Sciences, Kamiyoga 1-18-1, Setagaya-ku, Tokyo, 158-8501, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Shibata
authors.affiliation: Division of Drugs, National Institute of Health Sciences, Kamiyoga 1-18-1, Setagaya-ku, Tokyo, 158-8501, Japan.
authors.forename: Ken-Ichi
authors.initials: KI
authors.lastname: Izutsu
authors.affiliation: Division of Drugs, National Institute of Health Sciences, Kamiyoga 1-18-1, Setagaya-ku, Tokyo, 158-8501, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Goda
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000737:chemistry*; D058995:Dry Powder Inhalers / Q000379:methods*; D036501:Metered Dose Inhalers; D009330:Nebulizers and Vaporizers; D010316:Particle Size
chemical_list: D000336:Aerosols
keywords: Andersen cascade impactor; Next Generation Impactor; aerodynamic particle size distribution; cut-off diameter; dry powder inhaler