ABSTRACT
This chapter discusses the Quality by Design (QbD) elements and steps and the statistical concepts, methods, and tools such as mechanistic model, design of experiments (DoE), and multivariate analysis. QbD can improve the quality of a drug substance and a drug product. That is, a successful QbD approach can lead to a better understanding of products and more robustness of the manufacturing process and offers the potential for timely and flexible regulatory approval. This technical brief will focus on development and validation activities applicable to drug products, the benefit that well-developed analytical methods can contribute to the overall developmental time and cost efficiency of a program. In the past, a traditional approach for method development is non-systematic and thus decisions are made based on results from sequential runs of experiments. Especially, the benefit of DoE is the possibility to implement through simultaneously changing two or more parameters, reducing the number of experiments.
