No. Neither the CGMP regulations nor FDA policy specifies a minimum number of batches to validate a manufacturing process. The current industry guidance on APIs (see ICH Q7A3 for APIs) also does not specify a specific number of batches for process validation.
FDA recognizes that validating a manufacturing process, or a change to a process, cannot be reduced to so simplistic a formula as the completion of three successful full scale batches. The agency acknowledges that the idea of three validation batches has become prevalent, in part due to language in its own guidance documents. However, FDA is now clarifying current expectations on process validation. The 1987 Guideline of General Principles of Process Validation is currently being revised to address this issue. The emphasis for demonstrating validated processes is placed on the manufacturer’s process design and development studies in addition to its demonstration
of reproducibility at scale, a goal that has always been expected.
However, a minimum number of conformance (a.k.a. validation) batches necessary to validate the
manufacturing processes is not specified. The manufacturer is expected to have a sound rationale for its choices in this regard. The agency encourages the use of science based approaches to process validation.
