During the normal course of operations, it may become necessary to introduce changes in the process to improve the quality. Occasionally, new equipments or instruments may be installed, or there may be a change in the utility systems. Whenever any such changes are introduced, it is vital to prove that these changes do not have any adverse effect on the process or the product quality. Collecting such evidence is described as revalidation. The documentation and other requirements for revalidation match those of prospective validation.
Often, due to wear and tear, over the course of time, there
may be a drift from normal operating conditions. This makes it important for
manufacturers to make sure they schedule a periodic revalidation of their
systems, equipments, facilities, and processes to confirm that they continue to
perform as expected to meet the prescribed quality requirements.
Changes that Necessitate Revalidation
1. Change in raw materials (especially physical properties
such as particle size, moisture content, density, viscosity, etc. which tend to
affect product or process quality.
2. Change in vendor from whom APIs and other raw materials
are procured.
3. Change in the primary container or other packaging
material.
4. Process changes (such as drying temperature, mixing time,
batch size, etc.).
5. Substitution of equipment with a new type of equipment
(same equipment new model does not require validation; but the qualification
steps of DQ, IQ, OQ, and PQ must be performed and documented).
6. Any change in the facility/premises/plant.
If a decision is taken to not perform revalidation trials
despite a change in the process/equipment, the reason for this decision must be
explained and documented.