Impact of EU GMP Annex 1 on the Adoption of Single-Use Systems – Exploring the Integrity Challenges
Background
Single-use systems (SUS) have established themselves in biotechnology and sterile pharmaceutical manufacturing, primarily due to their flexibility and cost-effectiveness compared to traditional stainless-steel systems (Figure 1). These advantages include lower expenses for cleaning and validation processes, as well as faster time-to-market due to reduced construction and reconstruction activities. For small batch products, such as clinical materials and advanced therapy medicinal products (ATMPs), SUS often represent the only viable option. However, there has historically been a lack of regulatory guidelines regarding the implementation and use of SUS. The revised EU GMP Annex 11 is the first guideline to specify expectations for SUS, particularly when used after the sterile boundary, such as following the sterile filtration step.
Specific Risks Associated with SUS
Annex 1 addresses the specific risks related to SUS that must be evaluated as part of the contamination control strategy (CCS). These risks include interactions between the drug product and the SUS surface, such as adsorption and potential leachables, particulate matter, as well as concerns regarding the integrity of SUS, which are characterized as "fragile" and "complex." The Annex 1 also provides a checklist that includes supplier qualification (with a focus on sterilization verification), integrity verification throughout the process, establishment of acceptance criteria, incoming control procedures, and operator training. Furthermore, it discusses closed systems, including intrinsic sterile connection devices (Figure 2), emphasizing that their placement should depend on design and process considerations. For aseptic processing, systems with integrity risks must be in a Grade A zone, systems demonstrating integrity (e.g., through pressure testing or monitoring) may be used in lower classified areas.
Understanding Supplier Responsibilities
The industry, encompassing both SUS suppliers and end-users, recognized integrity challenges associated with SUS even before the revised Annex 1 was published, leading to a holistic, risk-based approach to address these issues. Key risk factors include components, assembly design, manufacturing processes, packaging, shipping, and handling procedures. Suppliers are responsible for selecting appropriate components, such as durable bag films, implementing best design practices, and ensuring a validated manufacturing process with in-process controls and release tests. They must also maintain integrity during shipment through qualified packaging and transport validation.
Figure 1: Example of a single-use filling assembly (left part) including dosing tubes and filling needles (not visible as they are inside the isolator), pump tubes, and a header bag. The filling assembly is connected via a sterile connection devices to the single-use redundant filtration assembly (right part) which is designed to support the pre-use post sterilization integrity test (PUPSIT). Picture: Courtesy of PSM GmbH.
End-users are tasked with establishing incoming control, inspection, and handling procedures in collaboration with their suppliers. There has been a noticeable shift in critical quality controls, risk assessments, and mitigation strategies from drug manufacturers to SUS suppliers, resulting in heightened regulatory expectations regarding supplier qualification and integrity verification. If risks compromising integrity are identified, appropriate measures must be implemented (Annex 1, §8.130:
If the system can be shown to remain integral at every usage (e.g. via pressure testing and/or monitoring) then a lower classified area may be used ).
Recommendation
Barcelona, Spain23-25 September 2025
Modern Microbiology Laboratory
Onsite Integrity Testing: Yes or No?
Annex 1 does not provide specific guidance on the process, design considerations, or integrity issues that would require onsite integrity testing of SUS, leading to uncertainty about when such tests are necessary. In October 2023, Swiss Medic published a Technical Interpretation paper2 addressing questions related to Annex 1 §8.129, including whether suppliers' integrity tests can be accepted without additional onsite verification. The response remains ambiguous, stating that while the integrity of critical singleuse systems should ideally be tested on-site by the end-user before production, if no onsite test is conducted, a risk assessment must be performed. This assessment should be justified, integrated into the CCS, and include comprehensive supplier qualification and an evaluation of risks associated with potential damage during delivery and installation.
Figure 2: Aseptic connection of two sterile fluid pathways (single-use systems) using a sterile connection device. Integrity assurance measures include a robust design qualified by e.g., microbiological challenge tests, supplier’s integrity check, and consistent performance which should be verified periodically during the aseptic process simulation. An on-site pressure decay test before actuation is technically not possible for mechanical connectors. Picture: Courtesy of Merck KGaA Darmstadt Germany.
Batt et al.3 discusses the development and validation of a process-specific integrity test for SUS, highlighting the technical challenges involved. Design limitations for conducting onsite integrity tests include the use of sterile connection devices before actuation, bags that may not withstand high pressure (necessary for sensitivity), and open ends in filling applications that complicate testing. Additionally, applying pressure for integrity testing poses risks of damaging the single-use assembly and potential contamination when introducing gas into the sterile system. Conducting integrity tests post-use is also challenging, as residual process fluid can interfere with results.
Recommendation
Cologne, Germany21-23 October 2025
Lyophilization 2025 - Includes Workshop at GEA
Conclusion
The revised EU GMP Annex 1 represents a little step forward in establishing regulatory expectations SUS in sterile pharmaceutical manufacturing. Historically, the industry has rarely implemented onsite integrity tests for SUS, opting instead for holistic risk assessments.
As the adoption of SUS continues to grow, it is crucial for all stakeholders to understand their responsibilities, from supplier qualification to the implementation of effective handling procedures. The ambiguity surrounding onsite integrity testing necessitates further education for inspectors and end-users to clarify when such tests are appropriate and how they should be conducted. The successful integration of SUS into aseptic processing will depend on ongoing dialogue.
About the Author
Simone Biel is a Senior Regulatory Consultant at Merck Life Science KGaA, Darmstadt, Germany in the area of Single-Use Technology and filtration in biopharmaceutical manufacturing.
Noten:
1 European Commission (2022), EU Guidelines for Good Manufacturing Practice Medicinal Products for Human and Veterinary Use, Annex 1, Manufacture of Sterile Medicinal
2 Swissmedic (2023), I-SMI.TI.25e Interpretation of GMP Annex 1 2022 (Rev. 1),
https://www.swissmedic.ch/swissmedic/en/home/humanarzneimittel/bewilligungen_zertifikate/authorisations/inspectorates.html
3 Nicholas Batt, Simone Biel, Charles Raye, and Nicola Rutigliani (2022), Chem. Ing. Tech. 2022, 94, No. 12, 1985 1994
