This informal CPD article ‘Open vs. Closed Processing in Biopharmaceuticals: A Guide to Effective Contamination Control’, was provided by Pharmalliance Consulting, who offer specialist support to pharmaceutical companies to maintain and increase quality compliance levels.
Introduction
In biopharmaceutical production, understanding the differences between open and closed processing systems is essential for ensuring product integrity and compliance. This differentiation impacts everything from contamination risk to operational efficiency and guides the appropriate environmental controls required to protect products from potential contaminants.
What Defines Open and Closed Processing?
The terms “open” and “closed” describe the extent to which a biopharmaceutical production process is isolated from its environment. In a closed system, the process is entirely shielded from outside exposure, either by design or through the application of specific sanitisation methods (PDA). These systems are effectively sealed off during production, preventing contamination from airborne particles, microbes, or other environmental factors.
In contrast, open systems involve some level of exposure to the surrounding environment, typically during stages of the production process (PDA). For example, when components are added manually to a vessel or when a product is transferred between containers without a fully contained pathway, the process is considered open. This difference between open and closed processes necessitates specific environmental controls to mitigate contamination risks in each scenario.
Why Process Closure Matters for Contamination Control
The classification of a system as open or closed significantly impacts the level of contamination risk and the required control measures. Closed systems, by design, shield products from environmental contamination, which often allows for operation in a less-stringent environment, such as a controlled non-classified (CNC) space (PDA). This benefit reduces the need for complex and costly cleanroom classifications.
Open processes, however, expose the product directly to the surrounding environment, thereby increasing the risk of contamination. Consequently, these processes require a more rigorous classification and control environment, typically within a cleanroom setting. Ensuring the correct classification and design of open and closed systems within production facilities is essential to maintaining a contamination-free environment and supporting product safety.
Practical Implications for Facility Design and Operation
Determining the open or closed status of processing systems influences the design and operational strategy of biopharmaceutical facilities. During facility design, engineers must decide which processes can remain in closed systems and which will be exposed, as this informs the layout and requirements for cleanroom spaces. Closed processes reduce the need for high-class environments and may also allow facilities to streamline operations by avoiding excessive cleanroom complexity.
From an operational standpoint, closed systems require fewer contamination control measures, allowing for simpler and more cost-effective maintenance and operation. Open systems, on the other hand, necessitate strict procedures to maintain cleanroom standards, including gowning protocols, environmental monitoring, and frequent sterilisation cycles.
Conclusion
Distinguishing between open and closed processing systems is a critical step in biopharmaceutical manufacturing, directly impacting contamination control strategies, facility design, and operational efficiency. By understanding the requirements and limitations of each system type, facilities can optimise their production environments, reducing costs associated with extensive classification while ensuring product safety.
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References
PDA (Parenteral Drug Association), 2021. Risk-Based Selection of Environmental Classifications for Biopharmaceutical Operations, Bethesda, MD.
