By Daniel L. Kirschner, PhD, Executive Director, Analytical Services, and Tom Lovelace, Sr. Manager, Process Development and Manufacturing, Cambrex
Demonstrating control over the manufacturing process is a key element of the Quality by Design (QbD) model. In Part I of ‘Successful control strategies’, we discussed Cambrex’s capabilities in determining CPPs and PARs to pinpoint manufacturing steps that require tighter control. We continue our discussion of these late-stage QbD studies by exploring the importance of fate and purge studies, which measure the ability of the process to remove impurities and provide evidence of their removal. Often these studies are run in parallel because they generate related data; fate and purge studies can expose other CPPs or indicate the downstream removal of a CQA from a drug substance.
“While CPP and PAR range finding studies seek to understand their effect on the process as it relates to end product quality, here we use the process to understand the fate of impurities during each step in the process and where they are removed,” explains Dr. Daniel Kirschner, Executive Director of Analytical Services at Cambrex. Fate and purge studies also reveal how specifications at different process stages relate to each other, which is critical to understanding the formation of impurities throughout the manufacturing process as a whole.