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Updated: Dec 9, 2025

Author Spotlight: Developing a Disposable Dosator for Preclinical Testing of Dry Powder Inhalers in Small Animal Models
Published on: August 18, 2023
Analysis of Drug Release Dynamics of the Reservoir-type Dry Powder Inhalers
Sakurako Tajiri1, Tetsuri Kondo, Toshimori Tanigaki
1Department of Medicine, Tokai University Oiso Hospital, 21-1 Gakkyo, Oiso, Kanagawa 259-0198, Japan. sakurako@is.icc.u-tokai.ac.jp.
Objective:
Dry powder inhalers (DPIs) are classified as capsule, blister, and reservoir types. Currently, two reservoir-type DPIs, i.e., TurbuhalerTM (TBH) and GenuairTM (GNA), are available, but their physical characteristics differ. Therefore, we compared their drug release patterns.
Methods:
An inhalation f low simulator was set to reach peak inhalation f low (PIF) at two time points, 0.4 s (rapid) or 1.5 s (moderate), and then the drug release from both the DPIs were compared.
Results:
The amount of drug release from the TBH increased linearly with increase in PIF, and the amounts were higher during rapid inhalation than during moderate inhalation. The GNA had a threshold flow for drug release, above which the flow was PIF-dependent (rapid) or independent (moderate). With rapid inhalation, drug release was dependent on the peak value and releasing time in both the DPIs. With moderate inhalation, the peak flow dependency of the TBH was attenuated, whereas that of the GNA remained time-dependent.
Conclusion:
Rapid and strong inhalation are best for drug release in both the DPIs, but a longer inhalation was required for the GNA. Therefore, if a patient cannot inhale rapidly, then a moderately rapid and long inhalation could be considered, but strong inhalation is still mandatory for TBH.
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