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Analyzing 20 Years of Clinical Studies on Inspiration through Dry Powder Inhalers

Clark AR.

Respiratory Drug Delivery 2016. Volume 1, 2016: 99-108.

Abstract:

A literature review of maximum inspiratory pressures (MIP) and their role in determining peak inspiratory flow rates through dry powder inhalers (DPI) was performed. The main determinant of inspiratory pressure was shown to be age and gender. These trends, which are the result of the variations in respiratory muscle strength with age and gender, are used to explain similar trends in the peak inspiratory flow rates through DPIs. Lower peak flow rates in young cystic fibrosis (CF) patients and elderly chronic obstruction pulmonary disease (COPD) patients are shown to follow the natural development and decline of respiratory muscle strength with age. Generally, however, peak DPI pressure drops and hence, flow rates, are lower than MIPs determined under static conditions. There was no identifiable correlation with disease severity found in this review. It is concluded, in line with a 2010 publication by Malmberg et al. that with reference to inspiratory flows through DPIs it is “[a]ge and gender rather than severity that matters.”