Inspiratory flow rate through a dry powder inhaler (Clickhaler®) in children with asthma

2003 ◽  
Vol 35 (3) ◽  
pp. 220-226 ◽  
Author(s):  
Mark Parry-Billings ◽  
Claire Birrell ◽  
Louise Oldham ◽  
Christopher O'Callaghan
Author(s):  
Ganga Srinivasan ◽  
Advait Shetty

The dry powder inhaler (DPI) has become widely known as a very attractive platform for drug delivery. DPIs are being used for the treatment of asthma and chronic obstructive pulmonary disease by many patients. There are over 20 devices presently in the DPI market. DPIs are preferred over nebulizers and pressurized metered dose inhalers. However, some of the challenges of DPI are dependence on inspiratory flow (unsuitable for young children, elderly people), systemic absorption due to deposition of drug in deep lung (unsuitable for local diseases treatment), and increase in upper airway deposition of a large fraction of coarse particles. Hence, there is a need to address these unmet issues. The interpatient variation can be minimized by developing devices independent of patient’s inspiratory flow rate or active based powder mechanism. This article reviews DPI devices currently available, advantages of newly developed devices, and formulation technologies. The platform technologies are developed to improve aerosolization and dispersion from the device and decrease the patient related factors. The DPI delivery system has been expanded to treatment of non-respiratory diseases such as migraine and diabetes. The development of innovative DPI device and formulation technologies for delivering therapeutic proteins such as insulin has been accelerated to overcome the problems associated with conventional insulin therapy.Keywords: Dry powder inhaler, Inspiratory flow rate, Insulin, Platform technologies.


2008 ◽  
Vol 121 (2) ◽  
pp. S158-S158
Author(s):  
W MANUYAKORN ◽  
C DIREKWATTANACHAI ◽  
S BENJAPONPITAK ◽  
W KAMCHAISATIAN ◽  
C SASISAKULPORN ◽  
...  

Author(s):  
Roberto W. Dal Negro

Dry powder inhalers (DPIs) are widely and increasingly used in clinical practice because they represent a substantial advancement in inhalation technology. The effectiveness of a powdered drug to inhale depends on the inspiratory flow rate generated by the patient and on the turbulence produced by the intrinsic resistance of the DPI. While the inspiratory flow is variable with the patient’s ability and conditions, the turbulence is differently sized within each device because depending of its technical design. There are higher - medium-, and low-resistance devices. With low-resistance DPIs, the disaggregation and the microdispersion of the drug highly depend on the patient’s inhalation airflow rate, because the role of the resistance-induced turbulence is obviously negligible in these cases. This flow-rate dependency is minimized in the presence of a sufficient regimen of turbulence as in the case of medium-resistance DPIs. Both the disaggregation and the micro-dispersion of the powdered drug are optimized in these circumstances even in the absence of a maximal inspiratory flow rate. The low resistance DPIs should not be regarded as the best performer DPIs because their intrinsic low-resistance regimen requires a higher inspiratory airflow rate and effort, which frequently cannot be achieved by subjects suffering from a disease-induced airflow limitation. Only when the ratio between the inhalation flow rate and the DPI intrinsic resistance is balanced, the speed of the particulate, the distribution of the drug within the lung, and the variability of the effective inhaled dose are optimized.


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