Revalidation - Types of Process Validation

-Re validation is needed to ensure that changes in the process and/or in the process environment, whether intentional or unintentional, do not adversely affect process characteristics and product quality.
-Re validation will be performed mainly

• Re validation after changes
• Periodic re validation carried out at scheduled intervals.

Re validation after changes :
-Re validation must be performed on introduction of any changes affecting a manufacturing and/or standard procedure having a bearing on the established product performance characteristics. 

-Such changes may include those in starting material, packaging material, manufacturing processes, equipment, in-process controls, manufacturing areas, or support systems (water, steam, etc.). Every such change requested should be reviewed by a qualified validation group, which will decide whether it is significant enough to justify re validation and, if so, its extent.

-Re validation after changes may be based on the performance of the same tests and activities as those used during the original validation, including tests on sub processes and on the equipment concerned. Some typical changes which require re validation include the following:

-Changes in the starting material,Changes in the process which impact process steps and product quality, Changes in equipment,Changes in the production area and support system,

-Unexpected changes and deviations may be observed during self-inspection or audit, or during the continuous trend analysis of process data. 

Periodic Re validation:

-It is well known that process changes may occur gradually even if experienced operators work correctly according to establish methods. Similarly, equipment wear may also cause gradual changes. Consequently, re validation at scheduled times is advisable even if no changes have been deliberately made.
 

-The decision to introduce periodic revalidation should be based essentially on a review of historical data, i.e. data generated during in-process and finished product testing after the latest validation, aimed at verifying that the process is under control. During the review of such historical data, any trend in the data collected should be evaluated.

- In some processes, such as sterilization, additional process testing is required to complement the historical data. The degree of testing required will be apparent from the original validation.