The Role Of Micronization With Dry Powder Inhaler Technologies

By Andrew Milner

Dry Powder Inhalers (DPIs) have many unique advantages that have contributed to the incredible growth of DPI pharmaceutical products. A relatively large number of DPI devices for various inhalable powder formulations are available to increase performance.  

The Aerosol Society (aerosol-soc.com) has carried out a study that shows that the inhalation performance of a dry powder inhaler (DPI) is strictly correlated with the critical quality attributes (CQA) of the active pharmaceutical ingredient (API). Particles typically need to be reduced in size within the aerodynamic diameter range of 1-5 µm in order to reach the airways. These dimensions are usually targeted when micronizing crystalline API. Jet mills are a widespread micronization technology, through which micronization is achieved by using air or nitrogen at very high pressure.

The two most important critical process parameters (CPP) which directly affect the API particle size are micronizing pressure and feed rate. Nowadays it is of fundamental importance for a manufacturer to rely on a technology able to achieve the desired DPI inhalation performance through direct control of the micronizing parameters.

Achieving high performance with conventional jet mills remains very difficult, therefore, Dec has set itself the task to develop, in close cooperation with global pharmaceutical partners, a new generation of spiral jet mills meeting specific particle size distribution (PSD) targets.