Analysis of Drug Release Dynamics of the Reservoir-type Dry Powder Inhalers.

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.

Satisfaction, preference and error occurrence of three dry powder inhalers as assessed by a cohort naïve to inhaler operation.

Background: Inhaled medication is central to the treatment of COPD. Various types of inhaler devices, which directly deliver medication to the lung, have been developed. However, patients often exhibit incorrect techniques of inhaler usage. Effectiveness of therapy may be affected by the ease of device usage, size, convenience of use, durability, clarity of instructions and device preferences of patients. This study compares the satisfaction and preference, as well as error occurrence, with the use of Genuair®, Ellipta™ and Breezhaler™ by healthy subjects in Hong Kong. Subjects and methods: One hundred and thirty healthy Hong Kong Chinese subjects aged ≥40 years without a previous diagnosis of COPD and asthma and with no experience of using dry powder inhalers (DPIs) were recruited. Subjects learned to use the three DPIs by initially reading the instructions and then observing a demonstration with verbal explanation. The number of errors committed was evaluated. Subjects also completed a questionnaire to indicate their satisfaction and preference. Results: The satisfaction score of comfort for Breezhaler was significantly higher than that for Ellipta (p≤0.05), while the satisfaction score on confidence to have inhaled the entire dose was highest for Genuair compared with Ellipta (p≤0.0001) or Breezhaler (p≤0.05). The overall satisfaction score was significantly higher for Genuair than Ellipta (p≤0.05) or Breezhaler (p≤0.01). After reading the instructions, the highest number of subjects committing one or more critical errors was with Breezhaler (97) followed by Genuair (70) and then Ellipta (33). Demonstration reduced the number of critical errors made by subjects for each DPI to one third or lower. Conclusion: Breezhaler seemed to be more comfortable and easy to carry, but users made less critical errors when using Ellipta after reading the instructions only. Genuair provided the clearest indication of correct dose preparation and inhalation.