This is common concept to validate three consecutive batches in pharmaceuticals. In process validation initial three batches are taken for validation. This is a basic question that concentrates everyone’s mind that why three batches are taken for validation?
Neither FDA nor any other regulation specifies the maximum number of batches to be considered as validation. The manufacturers have to choose the number of batches to be validate in this regard. The number of batches to be taken under validation depends upon the risk involved in the process of manufacturing. The less knowledge about the process requires the more statistical data to confirm the consistent performance. Consideration of validation batches fewer than three will require more statistical and scientific data to prove the consistency of process to meet quality standards.
FDA’s “Guidance for Industry on Process Validation: General Principles and Practices” provides the guideline for process validation, no longer consider the traditional three batch validation appropriate but also does not prescribe the number of batches to validate or suggests any other method to determine it.
Related: Guidance for Industry on Process Validation: General Principles and Practice
Generally it is considered if we get the desired quality in first batch, it is accidental, second batch quality is regulator and quality in third batch is Validation. When two batches are taken as validation the data will not be sufficient for evaluation and to prove reproducibility because statistical evaluation cannot be done on two points, it needs minimum three points because two points always draw a straight line. Therefore, minimum three consecutive batches are evaluated for validation of manufacturing process and cleaning procedures. More than three batches may be taken in validation but it involves the cost and time and the companies don’t want to do so.