Biomedical Engineering Reference
In-Depth Information
11
QbD FOR RAW MATERIALS
Maureen Lanan
11.1 INTRODUCTION
Design of experiments (DOE) is one strategy used to simplify development of a
biological manufacturing process. The experiments are performed systematically using
combinations of factors and the results provide quantitativemodels that predict outcomes
given the inputs. When multiple factors are included in the design, multivariate
mathematical models are created that describe the “design space” for a process. Quality
by design (QbD) is the process used to define these multidimensional equations and,
ultimately, to translate these equations into an understanding of all the combinations of
discreet process conditions that can be used to give similar results from a manufacturing
process. Because it takes quite a few experiments to create and test these models, the
process of comparing factors and selecting manufacturing conditions takes place during
development, often in small scale, before manufacturing begins.
Once a process is transferred into a manufacturing plant, priority is shifted from
mapping the design space to making consistent product with a well-controlled process.
Fewer batches can be run in parallel because of cost and logistics. The emphasis
on making product for use in patients takes precedent. It is during this transition
to manufacturing that omissions or incorrect ranges chosen for the DOEs from
