Introduction to Quality by Design (QbD)

This chapter introduces the principles of quality by design (QbD) to those who want to understand pharmaceutical QbD, and that may include readers from industry, academia, regulators or indeed anyone interested in finding out more about this important subject. QbD is not just about doing the science- and risk-based work; it is about explaining the story clearly, both verbally and in written form. QbD fundamentally links patient requirements to drug product and then drug substance. QbD normally starts in development and progresses through to manufacturing, with the intent of producing a control strategy for commercial-scale production. QbD can be applied to small and large molecules, to drug substance and drug product, to vaccines, to combination products, to all or parts of a process, to novel drugs or to generics. QbD is about gaining product and process understanding, communicating it and delivering it, such that patients can continue to benefit from the medicines they may take.