This informal CPD article ‘Managing Cross-Contamination Risks in Multipurpose API Plants’, was provided by Pharmalliance Consulting, who offer specialist support to pharmaceutical companies to maintain and increase quality compliance levels.
Multipurpose plants are a cornerstone of small molecule API manufacturing. Instead of dedicating facilities to a single active ingredient, manufacturers often use shared equipment across multiple products and campaigns. This approach offers flexibility and cost efficiency in a market where demand for individual APIs can fluctuate (5).
However, this flexibility introduces one of the most significant risks in pharmaceutical production: cross-contamination. Even trace levels of carryover from one product to another can result in adulterated batches and potential patient harm (1,5). Consequences range from unexpected pharmacological effects to severe toxicity, as well as regulatory actions such as recalls or import alerts.
Why Multipurpose Facilities Carry Higher Risk
Unlike dedicated facilities, multipurpose plants rely heavily on cleaning, segregation, and procedural controls to prevent contamination. Regulatory guidance makes clear that these controls must be robust, validated, and consistently implemented (3,5).
Inspection findings frequently highlight recurring weaknesses:
- Superficial cleaning validation. Validation studies may not address worst-case compounds, particularly those that are highly potent or difficult to clean (4,7).
- Non-scientific residue limits. Acceptance criteria are sometimes not linked to toxicological data such as Health-Based Exposure Limits (HBELs) or Permitted Daily Exposure (PDE) values (7).
- Inadequate sampling. Poorly justified swab and rinse locations can fail to detect residues in hard-to-clean areas (3,5).
- Equipment design limitations. Dead legs, rough surfaces, and poor drainage can retain residues and hinder effective cleaning (2,5).
- Weak segregation controls. Shared facilities handling high-risk compounds without appropriate containment or zoning present significant cross- contamination risks (4).
Regulators consider these issues indicative of deficiencies in the overall contamination control strategy, rather than isolated technical gaps (4).
Cleaning Validation: The First Line of Defence
Cleaning validation remains the primary control for preventing cross-contamination in multipurpose facilities. Regulatory expectations are clear: firms must demonstrate that cleaning processes can consistently remove residues to safe levels (3,5).
Key expectations include:
- Worst-case product selection. Validation must include the most toxic and hardest-to-clean APIs, ensuring a conservative and protective approach (4,7).
- Science-based residue limits. Acceptance criteria should be derived from toxicological evaluations such as PDE or HBEL values (7).
- Robust sampling strategies. Sampling methods must target worst-case locations and be scientifically justified (3).
- Lifecycle approach. Cleaning validation must be maintained throughout the lifecycle, including revalidation following changes or deviations (6).
- Comprehensive documentation. All validation activities must be fully documented, attributable, and inspection-ready (3,5).
Both FDA and EU inspectors continue to cite inadequate cleaning validation as a critical deficiency, often requiring extensive remediation programmes (3,4).
The Role of Facility and Equipment Design
Effective contamination control cannot rely solely on cleaning. Facility and equipment design play a critical supporting role. Best practices include:
- Dedicated areas or equipment for highly potent, sensitising, or antibiotic APIs where risk cannot be adequately controlled (4,7).
- Closed systems to minimise airborne contamination and protect both product and personnel (2,5).
- Defined personnel and material flows to prevent cross-over between campaigns (2).
- Equipment designed for cleanability, with smooth surfaces, minimal dead spaces, and proper drainage (2,5).
Regulatory guidance is explicit that, in certain cases, shared facilities may not be appropriate. For high-risk compounds, dedicated facilities or equipment may be required to ensure patient safety (4,7).
Why Cross-Contamination Control Matters
Cross-contamination is fundamentally a patient safety issue.
- Patient risk. Exposure to unintended APIs can lead to adverse or toxic effects, particularly with potent or sensitising compounds (1,7).
- Regulatory impact. Failures can result in recalls, warning letters, import alerts, or suspension of manufacturing activities (3).
- Industry trust. Repeated contamination events undermine confidence in pharmaceutical manufacturing quality systems.
As a result, cross-contamination control remains a major focus during regulatory inspections, with expectations for robust risk assessments, validated controls, and strong quality oversight (3,4).
The Regulatory Message
Regulatory expectations are consistent: multipurpose manufacturing is acceptable only when supported by rigorous and science-based controls. Cleaning validation must be designed around worst-case scenarios. Facility and equipment design must support segregation and cleanability. Quality systems must ensure that contamination risks are continuously assessed and controlled.
Ultimately, while multipurpose plants provide operational flexibility, they also introduce elevated risk. Regulators have made it clear that cross-contamination control is central to API GMP compliance, and deficiencies in this area will not be tolerated (3,5).
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References
(1) The European Commission, 2014. EU Guidelines for Good Manufacturing Practice for Medicinal Products for Human and Veterinary Use, Chapter 5: Production, Brussels, Belgium.
(2) The European Commission, 2015. 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, Part II: Basic Requirements for Active Substances Used as Starting Materials, Brussels, Belgium.
(4) Pharmaceutical Inspection Co-operation Scheme, 2018. PI 043-1 Aide-Memoire: Cross-Contamination in Shared Facilities, Geneva, Switzerland.
(5) International Council for Harmonisation, 2000. ICH Q7 – Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients, Geneva, Switzerland.
(6) U.S. Food and Drug Administration, 2020. Q7 Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients (Guidance for Industry), United States of America.
(7) European Medicines Agency, 2014. Guideline on setting health based exposure limits for use in risk identification in the manufacture of different medicinal products in shared facilities, London, United Kingdom.
(8) International Society for Pharmaceutical Engineering (ISPE), 2017. ISPE Risk-Based Manufacture of Pharmaceutical Products (Risk-MaPP) Baseline Guide, Tampa, FL, United States of America.
