Quality by Design Considerations for Product Development of Dry-Powder Inhalers

Abstract

Abstract Quality by design (QbD) elements have been thoroughly outlined and discussed with emphasis on the mechanisms by which interactive powder mixtures of dry powder inhalers (DPIs) are formed, characterized, and quality assured. It should be emphasized that it is difficult to test the uniformity of dosage units containing minute amounts of potent drugs such as DPIs. Therefore, it is important to design both the formulation and the processing in order to guarantee the breakdown of the drug agglomerates and dispersion of individual particles into the excipients. Consequently, the design of an efficient content uniformity test and a proper formulation and processing should be considered in order to safeguard against the presence of unit doses having high drug contents. This is of particular relevance to QbD approach using process analytical technology (PAT) techniques which assure the product performance, the homogeneity of the final interactive powder mixtures, and safeguard against the presence of high dose units in DPIs.