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Insight into pressure drop dependent efficiencies of dry powder inhalers.
MedLine Citation:
PMID:  22586728     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
PURPOSE: The purpose of this study was to assess the effectiveness of three commercial capsule-based dry powder passive inhalers [Rotahaler® (RH), Monodose Inhaler® (MI) and Handihaler® (HH)] in de-agglomerating salbutamol sulphate (SS) and micronized lactose (LH300) powders and their sensitivity to air flow rate changes and air flow resistance.
METHODS: Aerosolisation was assessed in real-time using a laser diffraction method: this approach was possible as only single-component formulations were tested. Volume percent of the aerosolised particles with diameter less than 5.4 μm at air flow rates from 30 to 180 l min−1 was obtained with the RH, MI and HH and provided a parameter, relative de-agglomeration (RD), as a measure of de-agglomeration. The pressure drops across the device at various flow rates were obtained from a differential pressure meter.
RESULTS: The relationship between RD of SS and LH300 and air flow rate appeared substantially different between the devices. It was surprisingly found that in some cases RD dropped at the highest air flows: this indicates a device specific maxima in RD occurs, and this may in part be attributed to changes in capsule motion. It is proposed that this relationship between RD and pressure drop provides a patient focussed simple way to assess RD performance. This assessment indicated that MI was the most efficient relative de-agglomerator at lower pressure drops, while HH increases its effectiveness at higher pressure drops.
CONCLUSION: The approach of measuring RD as a function of pressure drop revealed instructive variations in the aerosolisation performances of different devices. This new approach helps compare device performances with different powders, and hence improve optimisation and consistency of performance.
Authors:
Srinivas Ravindra Babu Behara; Ian Larson; Paul Kippax; Peter Stewart; David A V Morton
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences     Volume:  46     ISSN:  1879-0720     ISO Abbreviation:  Eur J Pharm Sci     Publication Date:  2012 Jun 
Date Detail:
Created Date:  2012-05-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9317982     Medline TA:  Eur J Pharm Sci     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  142-8     Citation Subset:  IM    
Affiliation:
Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.
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