Quality by Design: an Overview of the Basic Concepts

The premise ofQuality byDesign (QbD) is that the quality of the pharmaceutical product should be based upon the understanding of the biology or the mechanism of action (MOA) and the safety of the molecule [1]. The manufacturing process should then be developed to meet the desired quality attributes of the molecule, hence the concept of “design” of the product quality versus “testing” the product quality. Although testing the product quality after manufacturing is an essential element of quality control, testing should be conducted to confirm the predesired product attributes and not to simply reveal the outcome of a manufacturing process. The ICHQ8 guideline provides an overview of some of the aspects of QbD [2]. The guideline clearly states that quality cannot be tested into products; that is, quality should be built in by design. Although the task of designing a complex biological molecule such as amonoclonal antibody may seem daunting, the experience gained in the past roughly 30 years of the biotechnology industry history has laid the foundation for the QbD initiative [3, 4]. The industry has come a long way in identifying and selecting viable drug candidates, in developing high-productivity cell culture processes, in designing purification processes that yield a high-purity product, and in analyzing the heterogeneity of complex