Published on 09/12/2025

Bags and Tubing: Worst-Case Selection for SUS Manifolds

Introduction to Extractables and Leachables (E&L)

In the pharmaceutical industry, the safety and efficacy of drug products are paramount. As organizations transition toward single-use systems (SUS), understanding extractables and leachables (E&L) becomes increasingly critical. The E&L studies evaluate the chemical constituents that may leach from container closure systems or materials that are in direct contact with the drug product. These materials include bags and tubing used in the manufacturing process.

The regulatory framework for E&L assessments is grounded in compliance with guidelines and standards issued by authorities such as the U.S. Food and Drug Administration (FDA), European Medicines Agency (EMA), and Medicines and Healthcare products Regulatory Agency (MHRA). These organizations expect manufacturers to demonstrate that container closure integrity (CCI) and the safety of the drug product are maintained throughout its lifecycle.

Identifying Worst-Case Scenarios for E&L Testing

The fundamental objective of an E&L risk assessment is to identify the worst-case scenario that can impact patient safety. This process must carefully consider various factors that influence E&L through a systematic evaluation:

• Material Compatibility: Assess the interaction between the drug product and the materials used in bags and tubing.
• Storage Conditions: Evaluate the temperature, light exposure, and contact time, as these parameters affect leaching.
• Manufacturing Process: Analyze the processing conditions under which the single-use systems are utilized.

As part of the E&L risk assessment, it is crucial to determine the analytical evaluation threshold (AET) and dose-based threshold (DBT). AET is the smallest concentration of compounds that can be reliably detected and characterized, while DBT is established to ensure that any leachable substances present do not pose a risk to the patient by correlating dosing of the drug product to the quantity intended for leaching.

Regulatory Expectations for E&L Studies

In the context of modern pharmaceutical development, the guidelines provided by both the FDA and the European Union Good Manufacturing Practices (EU GMP) Annex 1 significantly shape E&L testing protocols. The FDA emphasizes the need for comprehensive validation of all materials and systems used in drug production, ensuring strict compliance with cGMP regulations.

The EMA requires that E&L studies be executed and reported in a manner that demonstrates the acceptability of leachables, considering their toxicity. Both regulatory bodies emphasize scientifically sound methodologies and systematic approaches to documentation of E&L findings.

Step-by-Step Guide to Conducting E&L Risk Assessment

Step 1: Define the Scope of the Study

The first step in conducting an E&L risk assessment is to define the scope. This includes identifying the specific single-use systems (SUS) under evaluation and determining which materials (e.g., bags, tubing) require examination. Factors such as the intended use, expected shelf life, and storage conditions must also be taken into account.

Step 2: Material Characterization

Material characterization involves collecting information about the composition of the materials used in the SUS. Manufacturers often provide this data, which should include details of any additives, stabilizers, and other components that may influence E&L profile. Tools like Fourier-transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) are typically employed for this purpose.

Step 3: Conduct E&L Studies

E&L studies should be carried out using representative conditions, meaning the actual use conditions of the SUS in a controlled environment. This may also involve replicated studies under worst-case scenarios to ensure compliance with the AET and DBT. Additionally, the threshold levels outlined in the PQRI guideline should be considered to validate safety.

Step 4: Analyze Results

After conducting the E&L studies, results must be compiled and analyzed thoroughly. Analytical data should be evaluated against established safety thresholds, including AET and DBT calculations. This scientific analysis ensures that leachables are within acceptable limits for patient safety and complies with FDA and EMA expectations.

Step 5: Documentation and Reporting

All findings from the E&L studies must be documented comprehensively. This includes detailing the experimental methods, results, and conclusions. Documentation forms an integral part of the validation process and must be readily accessible during audits or inspections. Regulatory authorities expect clear reporting that provides a defensible rationale for material selection and acceptance criteria.

Case Studies of E&L Assessments

Real-world case studies provide insights into the application of E&L assessment frameworks in the pharmaceutical sector. For instance, a prominent biopharmaceutical company conducted an extensive E&L study on specific silicone tubing used in cell culture processes. Their findings indicated that silicone leachables were detected but were within acceptable limits established by the AET and DBT calculations.

Similarly, another organization assessed the E&L profile of custom bags used for biologics storage. They identified several leachables during their testing but successfully demonstrated through scientific evaluation that the compounds did not present toxicological concerns, in line with USP CCI guidelines.

Container Closure Integrity (CCI) Testing

In conjunction with E&L studies, CCI testing is vital. This testing ensures that the packaging maintains its integrity, preventing contamination and ensuring product quality. Various methods, such as vacuum decay testing and dye ingress testing, can be employed to evaluate container closure integrity.

The regulatory expectations surrounding CCI testing require robust evidence that single-use systems remain sealed under various conditions throughout their intended shelf life, further protecting the drug product from potential leachables or other contaminants.

Best Practices for E&L and CCI Studies

To ensure compliance with regulatory expectations and to establish a comprehensive validation strategy, pharmaceutical companies should adopt best practices for E&L and CCI studies:

• Engage with suppliers to gather comprehensive material specifications and data sheets.
• Incorporate holistic risk assessments that consider all operational variables.
• Utilize advanced analytical techniques to ensure accurate identification of leachables.
• Involve cross-functional teams, including Quality Assurance and Regulatory Affairs, in the validation process.
• Maintain a well-documented record that provides transparency to regulators in case of inspections.

Conclusion and Future Directions

As the pharmaceutical landscape evolves, especially with the increasing adoption of single-use systems, the need for robust E&L assessments and CCI testing will only grow more critical. Adherence to regulatory guidelines and standards set forth by entities like the EMA, FDA, and others ensures that patient safety and product integrity are maintained.

By following the step-by-step approach outlined in this article, pharmaceutical professionals can conduct thorough E&L risk assessments and CCI tests, leading to informed decisions regarding material selection and management of single-use systems within production processes.