Abstract
Quality by design is a systematic approach to drug product development and manufacturing that starts by defining the target product quality. It continues with an assessment of the risks to product quality that are involved in the characteristics of the raw materials and in the parameters of the manufacturing process.
At the following stage, the actual impact of the characteristics and parameters identified is found through experiments and the design space is defined on that basis. Design space is an abstract multidimensional space in which the desired product quality can be attained by changing and controlling the variables.
Based on the advanced knowledge of the product and the process obtained, the process can be optimized effectively and an appropriate control strategy set at points representing the greatest risk to quality or at points where information can be obtained well enough in advance to allow for reversing (by an appropriate adjustment of the process conditions) a potentially inappropriate course of the process. The information gained through the use of quality-by-design tools can then be used to accelerate the registration process of a new drug product and, in particular, for a substantial increase of manufacturing process efficiency and of the certainty that the desired product quality will be achieved.