The purpose of Quality by Design (QbD) is to design and develop formulations and manufacturing processes to ensure a predefined quality. The challenge of QbD is to accurately and quantitatively determine the functional relationship between material/physical Critical Quality Attributes (CQAs) with Unit Operation Critical Process Parameters (CPPs) and their impact on the finished dosage forms.
Particle size, material segregation-flow and water sorption can be key quantitative measures of the physical characteristics of APIs, excipients, additives, etc. used to manufacture the final dosage form. The information obtained can be correlated to control key variables within the manufacturing process, maintaining the manufacturing profile within the design space.