This informal CPD article ‘Contamination Control Strategies in OSD Manufacturing’, was provided by Pharmalliance Consulting, who offer specialist support to pharmaceutical companies to maintain and increase quality compliance levels.
When the revised EU Annex 1 on sterile products was published, many oral solid dose (OSD) manufacturers assumed it had little relevance to their operations. Tablets and capsules are not sterile, and Annex 1 focuses heavily on aseptic processing (1).
Yet one principle in the guideline is highly relevant across the board: the expectation for every site to establish a Contamination Control Strategy (CCS) (1). Far from being a sterile-only concept, a CCS provides a structured, science-based approach to identifying risks, designing controls, and demonstrating that those controls are effective (6). For OSD facilities, often handling multiple products, including highly potent compounds, that kind of structure is essential.
Why OSD Facilities Cannot Ignore Contamination Risks
It is true that OSD plants do not face sterility requirements in the same way as injectable facilities, but they encounter challenges of their own.
- Cross-contamination. Powders are inherently mobile, and without robust controls they can migrate between rooms, equipment, or batches. Regulatory guidance highlights cross-contamination as a critical risk in shared facilities, particularly for potent compounds (5).
- Microbiological risks. Although OSD products are not sterile, they must meet defined microbiological quality standards. Failures in water systems, cleaning processes, or environmental control can lead to non-compliance (3).
- Operator protection. Modern OSD plants frequently handle highly potent APIs (HPAPIs), where inadequate containment presents direct risks to personnel through inhalation or dermal exposure (5).
Each of these risks reinforces why a CCS is just as vital for OSD manufacturing as it is for sterile production.
What Annex 1 Contributes
Annex 1 introduces a key expectation: contamination control should be addressed holistically rather than through isolated measures (1). A facility cannot rely solely on individual controls such as cleaning validation, HVAC design, or operator training in isolation. The CCS integrates these elements into a single, coherent framework.
For OSD, this means mapping the entire manufacturing lifecycle, from raw material receipt through blending, compression, coating, and packaging, and systematically identifying potential contamination risks and corresponding controls (6).
The Core Elements of a CCS for OSD
An effective CCS for an OSD facility will typically address:
- Facility and equipment design. Proper segregation, pressure cascades, and containment strategies are essential to prevent cross-contamination (2).
- Utilities. HVAC, water, and compressed air systems must be controlled and maintained to avoid acting as contamination sources (2).
- Cleaning validation. Cleaning processes must be validated and scientifically justified to ensure removal of residues and prevent carryover (4).
- Personnel practices. Gowning, hygiene, and material handling practices remain fundamental to contamination control (3).
- Raw material management. Supplier qualification and appropriate storage conditions are critical to maintaining material quality (3).
- Monitoring programmes. Environmental and particulate monitoring provide evidence that controls remain effective over time (8).
- Quality oversight. The pharmaceutical quality system should integrate the CCS with deviation management, CAPA, and change control processes (7).
Avoiding the “Paper-Only” Trap
A common weakness is treating the CCS as a static document prepared primarily for inspections. However, regulatory expectations emphasise that risk management and control strategies should be maintained and continuously improved throughout the product lifecycle (6,7).
A CCS should therefore be a living system, updated when new products are introduced, processes change, or monitoring data identifies emerging risks.
Benefits Beyond Compliance
When implemented effectively, a CCS delivers value beyond regulatory compliance:
- It provides inspectors with clear evidence that contamination risks are understood and actively controlled (1).
- It helps personnel understand how individual activities contribute to overall product quality and patient safety (7).
- It supports continuous improvement through ongoing review and risk evaluation (6).
- Most importantly, it reduces risks to patients by ensuring consistent product quality.
Bringing It All Together
Although the CCS concept originated in sterile manufacturing, its principles are directly applicable to OSD. Cross-contamination, microbiological risks, and operator safety all require a structured, risk-based approach.
In parallel, evolving regulatory frameworks such as the Modernisation of Cosmetics Regulation Act (MoCRA) highlight a broader global trend toward increased expectations for documented safety and control strategies across regulated industries (9). By adopting a CCS mindset, OSD facilities can move from fragmented controls to an integrated strategy. The result is not only alignment with Annex 1 expectations but a more robust and defensible approach to protecting both patients and operators.
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References
(1) 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.
(2) The European Commission, 2013. EU Guidelines for Good Manufacturing Practice for Medicinal Products for Human and Veterinary Use, Chapter 3: Premises and Equipment, Brussels, Belgium.
(3) The European Commission, 2014. EU Guidelines for Good Manufacturing Practice for Medicinal Products for Human and Veterinary Use, Chapter 5: Production, Brussels, Belgium.
(4) 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.
(5) Pharmaceutical Inspection Co-operation Scheme, 2018. PI 043-1 Aide-Memoire: Cross-Contamination in Shared Facilities, Geneva, Switzerland.
(6) International Council for Harmonisation, 2025. ICH Q9(R1) – Quality Risk Management, Step 5, Geneva, Switzerland.
(7) International Council for Harmonisation, 2008. ICH Q10 – Pharmaceutical Quality System, Geneva, Switzerland.
(8) 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.
(9) United States Congress, 2022. Modernization of Cosmetics Regulation Act (MoCRA), Washington, D.C., USA.
