Requalification (often called periodic qualification) is a fundamental pillar in the GMP regulations.
In simple terms: It is not enough to demonstrate that a piece of equipment or system worked well the day it was installed. You must demonstrate that, over time, use, maintenance work and wear, it continues to be capable of producing consistent results within the required quality parameters.
Why periodic requalification is mandatory according to GMP (Annex 15 and FDA)
Periodic requalifications exist because GMP regulations (specifically Annex 15 of the EU Guidelines or FDA standards) require that critical equipment, facilities and systems maintain their validated status over time, not just at the time of commissioning. He continued use, natural wear of components and the maintenance interventions They can progressively alter the behavior of a team. Although these changes are not always evident, they can affect its accuracy, its functionality or its ability to operate within established quality parameters. Furthermore, in the day-to-day life of the plant, small modifications, repairs or updates are made that, considered in isolation, may seem irrelevant, but which together can introduce uncontrolled deviations in the process. Requalification is the mechanism that allows demonstrating, both internally and before an inspection, that the organization maintains a continuous and effective control on its critical infrastructure.
What equipment, facilities and systems must be requalified
Generally, it applies to everything that has a critical impact on product quality. This includes:
- Manufacturing equipment: Mixers, fillers, tableters, etc.
- Laboratory equipment: HPLC, analytical balances, autoclaves.
- Critical systems: Purified water systems (PW/WFI), HVAC air systems (air conditioning and filtration), and computerized systems.
What does the periodic requalification process consist of?
It is usually not as comprehensive as the initial qualification, but rather focuses on verifying that critical functions continue to operate as expected. Typically includes:
- Review of changes: Evaluate what modifications have been made since the last validation.
- Maintenance check: Verify that preventive maintenance has been carried out according to schedule.
- Functional tests: Perform simplified tests (often focused on critical process parameters or CPPs) to confirm that the equipment is responding as it should.
- Review of deviations: Verify that there are no recurring deviations.
Differences between revalidation and requalification of processes
It is common to confuse them, but technically:
- Requalification: It focuses on the equip the system (is the machine still working?).
- Revalidation: It focuses on the process (Do you still produce the same batch of medicine with the same quality?). “Periodic revalidation” is often referred to when process data is reviewed to ensure that the validated state is maintained.
Important note: If a piece of equipment undergoes a major modification (for example, changing the main motor or control software), you do not wait for periodic requalification. You must make a qualification of changes immediately.
How to define the frequency of requalification using a risk-based approach?
The frequency of requalifications It is not imposed by a fixed calendar defined by regulations. Instead, it should be set using a Risk -based approach, which technically and documentaryly justifies each selected interval. To do this, factors such as the frequency of use of equipment, are complexity technique, he failure history O deviations, los results obtained in previous calibrations and maintenance, as well as the changes that have been carried out since the last qualification. This evaluation allows you to define a periodicity consistent with the real impact of the system on product quality. Once established, said frequency must be clearly reflected in the Validation Master Plan (or VMP for its acronym in English), guaranteeing that it is not an arbitrary decision, but rather a strategy that can be defended against any audit.
The Validation Master Plan (VMP) as the axis of maintaining the validated state
This is the “parent” document that dictates the rules of the game. Without the VMP, requalifications would be isolated efforts, lacking coherence and difficult to defend before an auditor.
The VMP establishes the “validated state maintenance policy”
The VMP does not list each bolt, but establishes the methodology that will be applied to decide what, when and how to requalify. The VMP defines the risk criteria that you will use to determine frequency, as well as the minimum testing standards and the common framework that ensures that all critical equipment is treated under the same approach.
For example: “All critical systems (direct impact) will be requalified every 24 months, unless the risk analysis indicates a shorter period”.
Periodic requalification as evidence of compliance with the VMP
If the VMP represents the organization's formal commitment to keep its systems under control, requalification is tangible evidence that this commitment is fulfilled in practice.
Each requalification report demonstrates that the rules defined in the VMP do not remain on paper, but are applied systematically and consistently. When an audit detects that critical equipment has not been requalified as established, the problem is not limited to that specific equipment. The inspector will directly question the effectiveness of the VMP and, by extension, the plant's quality management system. In that context, An omitted or poorly executed requalification calls into question the entire validation strategy, not just a specific element.
The feedback loop between requalifications and the VMP
The VMP is not static. If during periodic requalifications you observe recurring failure patterns in certain systems, the VMP should be reviewed.
Example: If the VMP says that you requalify a system every 3 years, but your requalifications show that the system degrades in 18 months, the VMP must be modified to adjust the frequency of that equipment. The requalification informs the VMP about the technical reality.
Risks of lack of alignment between VMP and requalifications
| Aspect | Validation Master Plan (VMP) | Periodic Requalification |
| Nature | Strategic / Regulatory | Operational/Tactical |
| Role | Define the “rules” and the strategy. | Run the tests under those rules. |
| Periodicity | It is reviewed (annual or for major changes). | It happens according to the defined schedule. |
| Aim | Ensure global compliance. | Ensure that specific equipment remains “alive”. |
The danger of disconnection
The most serious mistake in the pharmaceutical industry is having a VMP that says one thing (e.g. “we will requalify everything every 2 years”) and a requalification practice that does another (e.g. “we do it when we have time or money”). That discrepancy is direct causality of a critical observation (or “Major”) in any quality inspection.
If there is undocumented maintenance, the requalification is automatically invalidated.
Documented maintenance as technical memory of the equipment
Requalification cannot be understood as an isolated exercise, since it depends entirely on the technical history of the team. Each maintenance intervention, no matter how small, is part of the “memory” of the system and conditions the interpretation of its current state. When the repairs, settings O component substitutions are correctly documented in work orders or logbooks, the quality team can evaluate the requalification with criteria, focusing on the most sensitive points introduced by these changes. On the contrary, when there are undocumented interventions, requalification is carried out blindly, based on an incomplete reality. In this scenario, any conclusion about the validated status of the equipment loses technical and regulatory soundness.
Why undocumented maintenance invalidates requalification
Imagine that a technician adjusted the pressure of a valve so that the machine would stop making errors, but did not write it down. Then comes the periodic requalification:
- False data: The validation team performs the tests and everything seems to be in order. However, the equipment is operating under conditions that were not originally validated.
- Quality risk: If something goes wrong with the final product months later, there is no trace in history as to why the machine behaves differently.
- Legal non-compliance: In the event of an audit by a health authority (FDA, EMA), if it is discovered that there was maintenance without registration, the quality system is considered committed. The previous requalification is void because it was based on a false premise (that the equipment was in a validated state).
The validated state chain of custody: maintenance, changes and requalification
The maintenance of the validated state must be understood as a continuous chain of information, in which each link depends on the previous one. It all starts with maintenance, where each intervention generates a record that describes what has been done and why. If this intervention involves a relevant change, the change management system comes into play, which evaluates whether a partial or immediate requalification is necessary. Periodic requalification is at the end of this chain and acts as a global assessment of the equipment's condition. When previous records are complete and coherent, requalification flows naturally.
When data is missing or document gaps exist, the chain is broken and the status validated cannot be credibly sustained.
How to detect and mitigate the risk of undocumented maintenance
If you suspect that there are undocumented maintenance tasks in your plant, the risk is high. Here are three steps to remedy it:
- History audit: Conduct a thorough review of the Logbooks comparing them with the inventory of spare parts used. If parts were purchased, but there is no record of installation, you have a hole in your traceability.
- Culture of “What is not written, does not exist”: It is a fundamental GMP mantra. You must reinforce that a quick repair without paper is a repair that technically never occurred, and therefore, is a serious offense.
- Make the registration process more flexible: Sometimes maintenance is not documented because the process is overly complicated. Simplify forms for minor changes (non-critical adjustments) without losing traceability.
Conclusion: periodic requalification as the last line of defense of the GMP system
In short, requalification is the final quality control; Documented maintenance is the guarantee that the equipment has not undergone hidden changes and the VMP is the document that dictates the rules of the game.
If you eliminate maintenance documentation, you are flying blind in your requalification.
Don't wait for a requalification to fail an inspection.
Identify gaps between maintenance, VMP and requalifications before they become critical observations.
Request a technical review of your validated state maintenance strategy.