Quality by Design in Formulation Development

Formulation development moved to Quality-by-Design in recent years under the aegis of the FDA. Quality-by-Design allow manufacturers to build the quality into the process instead of simply testing the final product and it also allow to manage small changes of the final formulation or dosage form without a complete redesign of the production line. Quality-by-Design require the planning of experiments using Design-of-experiments in order to calculate the contribution of each factors and their interactions for the final products and what happened inside the space described by those experiments so that the outcome of every single variations will be known before doing the experiment itself. Besides Design-of-Experiments allows to include statistics inside the experiments rather than at end. Quality-by-Design require planning, rigorous testing and, if possible, prior knowledge of the subject to better guide the process. All those procedures need to be thoroughly documented and subjected to continuous improvement and discussion.