Please clarify, Re-validation means its Re-prospective validation / Re-concurrent validation??
In Re-validation what we can do??


Revalidation is not same as Concurrent or Prospective validation.

Here is what a revalidation or Changecontrol means

To provide mechanisms for ongoing process optimization and ensure a continuing state of process control, a formal change control system should be established to evaluate and approve proposed changes to specifications, test procedures, raw materials, facilities, support systems, equipment (including computer hardware), processing steps, packaging materials, and computer software.

[b]The change-control/Revalidation program should include procedures to:

  1. Prevent unauthorized modifications to a validated system;

  2. Evaluate proposed changes against development and technology transfer documents;

  3. Identify and evaluate all proposed changes to assess their potential affects on the API process and determine if, and to what extent, revalidation is needed;

  4. Ensure that all documents affected by changes are promptly revised; and

  5. Determine the impact of changes on the critical chemical and physical attributes of the API (e.g., impurity profiles, stability, and particle size).

Any proposals for changes should be drafted, reviewed, and approved by the appropriate organizational units, and reviewed and approved by the quality control unit.[/b]

Changes implemented to improve process yields should be evaluated carefully to determine if these result in new or higher levels of impurities. The impurity profile of the resulting batches should be comparable to the impurity profile of the API batches used in drug safety and clinical testing. Process changes should also be evaluated to ensure that these do not have an adverse effect on analytical methods due to increased interference caused by new or higher levels of impurities and by-products. Analytical methods should be modified as necessary to ensure they are capable of detecting and quantifying impurities.

Dosage form manufacturers should be notified of changes in the API production process that could affect the critical attributes of the API (e.g., impurity profile, crystal form, particle size, residual solvent content, or stability) and thus have a significant impact upon the dosage forms produced from that API.

Change-Control Classification

The change-control program should provide for a classification scheme to evaluate changes in raw materials, manufacturing sites, scale of manufacturing, manufacturing equipment, and production processes. This classification procedure should be used in determining what level of testing, validation, and documentation is needed to justify changes to a validated process.

Changes should be categorized as minor or major depending on the nature and extent of the changes, and the effects these changes could impart on the process. In all cases, scientific judgement should determine what additional testing and validation studies are needed to justify a change in a validated process.

A minor change should be defined as one that is unlikely to have a detectable impact on the critical attributes of the API. Such changes would not shift the process in any discernible manner, and might be implemented with minimal testing and revalidation. For example, “like-for-like” equipment replacements where equipment is repaired to its initial validated state or in which identical or similar equipment is introduced into the process, would unlikely affect the process if adequately installed and qualified.

A major change should be defined as one that would likely significantly affect the critical quality attributes of the API. For example, a change in solvent used for the final crystallization could significantly affect the impurity profile, physical attributes, and other critical quality attributes of the API. Such changes should be justified by additional testing, and if appropriate, revalidation.