Process development and scale-up of processes for the production of active pharmaceutical ingredients require the application of mixing theory and practice for successful operation in manufacturing operations. Mixing issues can be critical components of both homogeneous and heterogeneous reactions either in achieving the desired conversion rate or, of often greater importance, in achieving the predicted selectivity. In addition, many crystallization processes require consideration of mixing in order to realize the desired crystal attributes on scale-up.

Many of the ways mixing issues can impact these operations are discussed along with examples.