This informal CPD article ‘Maintaining Control: Validation and Monitoring in Barrier Systems’, was provided by Pharmalliance Consulting, who offer specialist support to pharmaceutical companies to maintain and increase quality compliance levels.
Modern isolators and RABS promise a high level of protection, but only when they’re properly validated, monitored, and maintained. In inspections, regulators are consistently asking: is the system still performing as intended? And is the company actively proving it? Validation isn’t just a startup activity. It’s an ongoing discipline.
Smoke Studies: More Than a Qualification Checkbox
Airflow visualisation (smoke studies) are a foundational validation element for barrier systems. But a single static video isn’t enough anymore. Inspections now focus on whether airflow studies simulate actual interventions, with equipment running and personnel (or gloved arms) in position. It’s not just about proving unidirectional flow exists, it’s about demonstrating that flow isn’t disrupted during the most critical operations. EU Annex 1 also expects video documentation to be available for review, covering both “at rest” and “in operation” conditions. If airflow can’t protect open product during an intervention, that’s a failure, regardless of how clean your particle counts look.
Glove and Seal Integrity: Always in Focus
One of the most cited issues with barrier systems is glove leaks, both undetected and unaddressed. For isolators, routine leak testing is essential. This includes pressure hold testing of gloves and the isolator chamber, often before and after each campaign. Regulators now expect a written glove management program: defined test frequencies, acceptance criteria, change-out intervals, and training. It’s no longer acceptable to wait for gloves to fail before taking action. The same goes for RABS. Although they aren’t sealed like isolators, their gloves must still be sterilised before use, sanitised between operations, and inspected regularly. Failing to monitor glove condition is seen as a high-risk oversight.
Requalification and Maintenance
Barrier systems must be requalified at defined intervals. This includes repeat smoke studies, HEPA integrity testing, leak checks, and airflow measurements. FDA and EU guidance both suggest annual requalification as a baseline, more frequently if changes occur. Maintenance is also a hot topic. Regulators want to see that isolators and RABS are proactively maintained, gaskets replaced on schedule, filters changed before failure, gloves retired based on wear, not just damage. Deferred or reactive maintenance often signals poor control and triggers further scrutiny.
Alarm Management and Trending
Inspectors are now looking closely at how alarms tied to barrier systems are handled. For example, if pressure differentials fall outside their limits or if airflow alarms trigger repeatedly, is there a structured response? Sites are expected to have defined escalation pathways, root cause analysis, and documented follow-up. Recurrent alarms with no resolution plan indicate a breakdown not just in equipment control, but in overall quality oversight. Some firms are starting to trend alarm history across multiple campaigns to spot degradation before it leads to a critical event.
Contamination Recovery Plans
When barrier systems fail, the response must go beyond maintenance. Inspectors want to see predefined protocols that cover recovery from contamination events. This includes decontamination cycles, requalification steps, and impact assessment for any exposed product. Some advanced facilities include mock drills or tabletop exercises to train teams on how to respond when a glove fails mid-batch or when a door seal is compromised. These practices are not yet standard, but they are increasingly being viewed as best practice.
Lifecycle Integration with CCS
One final area of focus is how barrier system performance links back to the facility’s Contamination Control Strategy. EU Annex 1 is clear that all control elements should be part of an integrated lifecycle. This means the CCS should include maintenance history, glove failure rates, requalification records, and even airflow deviation trends. A standalone validation file isn’t enough. Inspectors want to see how these insights shape operational decisions and ongoing risk management.
Conclusion
Barrier systems offer powerful contamination control, but they demand active stewardship. Regulators expect that isolators and RABS be continuously validated, rigorously monitored, and thoughtfully maintained. Anything less invites risk, and questions about whether the barrier is protecting the product or just creating a false sense of security.
We hope this article was helpful. For more information from Pharmalliance Consulting, please visit their CPD Member Directory page. Alternatively, you can go to CPD Industry Hubs for more articles, courses and events relevant to your Continuing Professional Development requirements.
References
The European Commission, 2022. EU Guidelines for Good Manufacturing Practice for Medicinal Products for Human and Veterinary Use, Annex 1: Manufacture of Sterile Medicinal Products, Brussels, Belgium.
The European Commission, 2015. EU Guidelines for Good Manufacturing Practice for Medicinal Products for Human and Veterinary Use, Annex 15: Qualification and Validation, Brussels, Belgium.
U.S. Food and Drug Administration, 2004. Guidance for Industry: Sterile Drug Products Produced by Aseptic Processing – Current Good Manufacturing Practice, United States of America.
Pharmaceutical Inspection Co-operation Scheme, 2007. PI 014-3 – Isolators Used for Aseptic Processing and Sterility Testing, Geneva, Switzerland.
International Organisation for Standardisation, 2015. ISO 14644-2:2015 – Cleanrooms and Associated Controlled Environments – Part 2: Monitoring to Provide Evidence of Cleanroom Performance Related to Air Cleanliness by Particle Concentration, Geneva, Switzerland.
International Organisation for Standardisation, 2021. ISO 13408-6:2021 – Aseptic Processing of Health Care Products – Part 6: Isolator Systems, Geneva, Switzerland.
