PharmTech: What are the unique challenges of applying in-process controls and process analytical technologies (PAT) to multilayer tablets?

Behrens (IMA): PAT systems based on transmission or reflection are seldom used on monolayer tablets. The amount of validation is high, and even more complex for bilayer or multilayers. It is also difficult to repeat the measuring results on each layer. The industry has to put more efforts into this issue.

Kirsch (Natoli): PAT is best used during development to understand the variables involved in achieving the formulation design for a quality tablet.... However, PAT measurements can provide information for feedback control, which can offer the manufacturer an opportunity to move toward real-time release of a product. If traditional tablet press variables are properly controlled and a quality granulation is delivered to the tablet press, then the due diligence time spent in process development pays off with a robust manufacturing process that does not require process analytical instrumentation.