Published on 03/12/2025

Single-Use System Qualification: Extractables/Leachables Hooks

In the rapidly evolving landscape of biologics and Advanced Therapy Medicinal Products (ATMPs), the complexity of validations surrounding single-use systems (SUS) is paramount. This article guides pharmaceutical professionals through the necessary steps to ensure effective extractables/leachables (E&L) assessments as part of the qualification and validation of single-use systems. It will cover a variety of critical components including viral clearance validation, spiking studies, and compliant processes based on regulatory standards such as the FDA, EMA, and ICH.

Understanding Single-Use Systems in Aseptic Processes

Single-use systems (SUS) have revolutionized the manufacturing landscape in the biopharmaceutical sector, particularly within aseptic environments. These systems reduce the risk of cross-contamination as they are designed for one-time use, simplifying cleaning and validation procedures. However, their introduction raises concerns about extractables and leachables which could potentially affect product safety and efficacy.

Aseptic processing, focused on maintaining sterility, demands strict adherence to regulatory guidelines. Given the intricacy of closed systems, validation scientists must ensure that all components are rigorously evaluated to mitigate any risks associated with E&L. Key guidelines, such as FDA’s Process Validation Guidance, outline critical expectations for the qualification of SUS and further establish that these systems must have predictable and manageable E&L profiles.

Step 1: Establishing the Framework for E&L Testing

Before initiating the testing of extractables and leachables, it is essential to establish a comprehensive quality framework. This framework should be built around the following core components:

• Risk Assessment: A risk-based approach to identify potential sources of extractables based on the materials used in the SUS is fundamental. Assess the combination of materials, processing conditions, and their intended application.
• Material Characterization: Each component in the single-use system—including tubing, bags, filters, and connectors—should be characterized to ascertain potential E&L.
• Selection of Test Conditions: Conditions simulating actual processes should be selected for E&L studies, including temperature, time, and chemical environments relevant to the intended use.

Step 2: Performing Extractables Studies

The next step is to execute extractables studies, aimed at quantifying the level of substances that may leach from the materials into the drug product. This process involves several key activities:

• Test Method Development: Identify and validate extraction methods suitable for the materials in question, including accelerated extraction tests that simulate the worst-case scenarios.
• Analysis of Extractables: Gather samples of the extracts for comprehensive chemical analysis using methodologies such as Gas Chromatography-Mass Spectrometry (GC-MS) or Liquid Chromatography-Mass Spectrometry (LC-MS).
• Data Interpretation: Analyze the data to identify the nature and concentrations of extractables, assessing their potential impact on product quality.

Step 3: Conducting Leachables Studies

Leachables studies are critical, specifically for ensuring that no harmful compounds migrate into the product during actual use. This phase is marked by specific processes:

• Leachable Testing During Stability Studies: Conduct leachables studies concurrently with actual stability testing of the drug product to provide real-world data on leachable behavior.
• Methods of Detection: Similar to extractables, utilize analytical techniques such as GC-MS or LC-MS to identify leachables during stability analysis.
• Impact Assessment: Assess the biological impact of detected leachables on product safety, efficacy, and overall quality.

Step 4: Ensuring Regulatory Compliance for E&L Testing

To align with regulatory expectations, comprehensive documentation must be prepared, illustrating a clear understanding of sample handling, testing methodologies, and results interpretation. Compliance with guidelines from major regulations such as ICH Q5A(R2) focusing on viral safety is indispensable. Additionally, documentation should include:

• Standard Operating Procedures (SOPs): Clearly defined SOPs for conducting E&L studies serve as a standard for compliance and ensure reproducibility and reliability in testing.
• Data Management Systems: Implement databases to track E&L data, ensuring complete traceability and chain of identity custody for materials used in the process.

Step 5: Implementing the Results in Aseptic Processes

Results from E&L studies should inform many aspects of the production process, including risk management strategies and control measures. Specific actions may include:

• Control Defined Parameters: Based on E&L results, establish control limits for the materials used in SUS, ensuring that they fall within acceptable thresholds dictated by guidelines.
• Operational Procedures: Develop and implement operational procedures to mitigate risks associated with leachables, particularly during late-stage development and commercial manufacturing.
• Ongoing Monitoring and Reassessment: Conduct continual monitoring and reassessment of E&L profiles, especially when there are changes to the system or the process, ensuring compliance with EMA guidelines.

Step 6: Spiking Studies: Tailoring Viral Clearance Validations

In parallel with E&L assessments, spiking studies play a critical role in establishing viral clearance validation, particularly pertinent for ATMPs. This step ensures that the system can robustly eliminate viral contaminants.

• Designing Spike Studies: Plan spike studies to include the relevant viral strains that are most likely to be encountered in the process. The aim is to simulate exposure to viruses during manufacturing.
• Evaluating Viral Clearance:** Conduct thorough assessments post-spiking to evaluate the efficiency of the single-use system in removing these viral entities.
• Data Reporting: Compile and report findings, focusing on the efficacy of the single-use process and its contributions to product safety.