Extractables and Leachables (E&L) in Single-Use Bags: Impact on Bioprocess Safety and Regulatory Compliance

The adoption of single-use systems (SUS) has simplified biopharmaceutical manufacturing, but it introduces a variable that demands rigorous management: the release of chemical substances from polymeric materials into the product. This phenomenon, known as extractables and leachables (E&L), has been identified in industry surveys as the leading perceived barrier to adopting single-use technologies, and controlling it is now an unavoidable requirement in any pharmaceutical manufacturing process.

What Are Extractables and Leachables (E&L) in Single-Use Bags for Bioprocessing

Extractables are chemical compounds released from a component under deliberately forced analytical conditions (solvents, temperature, or exposure time more aggressive than those used under normal conditions), while leachables are the compounds that actually migrate into the product under typical process conditions; not every extractable becomes a leachable. The distinction between extractables and leachables in single-use systems is an operational one: extractables define the universe of compounds that must be monitored, but only leachables determine the product’s actual exposure. When these substances persist throughout the process and reach the final product, they are referred to as PERLs (process equipment-related leachables), a term that covers any polymer-derived impurity capable of interfering with process performance or product quality.

Among the substances most commonly found in single-use bioprocess bags are:

• Antioxidants and their degradation products

• Plasticizers and slip agents

• Pigments and stabilizers

• Residual monomers

Reviewing the data generated through E&L studies is the mechanism by which SUS suppliers demonstrate the safety of the polymers and chemical substances used in manufacturing their products. This data also represents the best tool available to end users for assessing whether a given SUS component is suitable for use in their specific biopharmaceutical manufacturing processes. E&L study data provided by suppliers must be properly documented, reproducible, and easily interpretable, so that biopharmaceutical companies can take a science- and risk-based approach when determining whether they have the information needed to support submissions to regulatory authorities.

How E&L Can Affect Product Quality and Cell Viability in the Bioreactor

The impact of E&L depends on the polymeric material of the single-use system, the concentration released, and the point in the process where contact occurs. In a single-use bioreactor, leachables originating from the film itself or from components in contact with the culture can act as cytotoxic agents or inhibitors of cell growth, compromising batch performance.

A second risk mechanism is the degradation of formulation excipients in contact with the system. Polysorbate 80 (PS80) is a representative example. Its degradation through hydrolysis and oxidation generates dozens of secondary compounds (aldehydes, carboxylic acids, PEGs, peroxides) whose profile varies with storage time and temperature. This adds a dynamic layer to the problem: a batch’s impurity profile is not static throughout the process. A component qualified at one end of the operating range does not guarantee the same behavior at the other end.

Finally, some leachables can interact directly with the therapeutic molecule, complicating both the analytical detection of the compound and the assessment of patient risk. For this reason, the biocompatibility of every component in a single-use system should be treated as a design criterion from the outset, not as a verification step performed after the material has already been selected.

From Bioprocess to Patient: Why Material Selection Makes the Difference

The risk posed by a single-use component depends on its position in the production chain. A component located downstream, after the final purification step (formulation, final fill), carries the greatest risk, because there is no subsequent operation capable of removing or diluting the leachable before it reaches the product. Upstream components (cell banking, inoculum, expansion) benefit from intermediate purification steps that act as an additional barrier. This is a key criterion for well-grounded selection of bioprocess bags: it is not enough to evaluate the material in the abstract; it must be assessed at the exact point where it will be used.

For this reason, a component qualified for one specific indication or route of administration does not automatically carry over its safety profile to another product: the acceptable risk threshold varies according to dosing regimen, dose volume, and the patient’s route of exposure. Every assessment of leachable safety in a pharmaceutical product must be tied to the specific case at hand, not to a generic material standard, which makes it especially valuable to work with a single supplier capable of documenting the risk profile of its components across the entire chain under a consistent set of criteria.

Regulatory Framework for E&L in Single-Use Systems: ISO 10993, BioPhorum Operations Group Guidance, and ICH Q3E

The regulatory framework for single-use systems does not rest on a single standard, but on the convergence of several references that have been consolidated over the past decade, each addressing the issue from a different angle:

• ISO 10993-18 and ISO 10993-17: although originally developed for medical devices, both standards also apply to single-use components under that same consideration. ISO 10993-18 establishes the framework for identifying and quantifying substances released by the material; ISO 10993-17 (recently renamed Toxicological risk assessment of medical device constituents) defines how to derive tolerable patient exposure limits from that data, the same reasoning that underlies the concept of the Analytical Evaluation Threshold (AET).

• BioPhorum Operations Group (BPOG): this industry guide provides the criteria for deciding how much rigor to apply to each component. Its risk model weighs factors such as the material’s position in the process, exposure temperature and duration, and surface-to-volume ratio, in order to classify each component as low, medium, or high risk and determine the level of qualification required.

• ICH Q3E: currently under development as a harmonized international guideline, its goal is to bring under a single framework what is today managed in a fragmented way across USP standards, industry guidance, and each company’s internal practices, aligning with the risk management principles of ICH Q9 and reinforcing compliance with GMP Annex I in single-use systems wherever the two frameworks overlap.

Criteria for Selecting Single-Use Bags with a Low E&L Profile in Pharmaceutical Manufacturing

Selecting bioprocess bags cannot be resolved simply by comparing polymer datasheets: two materials that appear equivalent can have very different E&L profiles depending on the supplier, the component’s own manufacturing process, or the sterilization method used. Translating the regulatory framework into an actual purchasing decision requires several criteria to be applied at once:

• Evidence of low risk at critical process stages. An extractables profile that is acceptable overall can still pose a meaningful risk at formulation or final fill, where there is no subsequent operation to remove the leachable. The assessment must be carried out at the exact point of use.

• Documentation that allows the Analytical Evaluation Threshold (AET) to be recalculated for the actual product. Data valid for one product is not automatically valid for another with a different dosing regimen or route of administration; the supplier must provide the information needed to recalculate the threshold for each case.

• Traceability at the individual component level, not just at the assembly level. In complex systems, each part must be identifiable and qualifiable on its own, so that the entire study does not need to be repeated if a single component changes.

Taken together, these criteria shift the selection of bioprocess bags from a decision about material to a decision about the entire process: where the component is used, with which product, and what its traceability looks like.

At Bexen Bioservices, we offer solutions designed to minimize E&L risk across the entire bioprocess chain, including bags in 2D and 3D configurations, configurable assemblies and manifolds, and automated filling systems compatible with cryobags and closed-system cryogenic vials. We also provide the technical documentation needed to support customers’ risk assessments and facilitate their regulatory justification.

If you’re evaluating single-use systems for your process, let’s talk.

References

BioPhorum Operations Group. Best practices guide for evaluating leachables risk from polymeric single-use systems used in biopharmaceutical manufacturing [Internet]. Sheffield: BioPhorum Operations Group; 2021 [cited 2026 Jul 14]. Available from: https://www.biophorum.com/download/best-practices-guide-for-evaluating-leachables-risk-from-polymeric-single-use-systems/

Dorival-García N, Carillo S, Ta C, Roberts D, Comstock K, Lofthouse S, Ciceri E, D’Silva K, Kierans G, Kaisermayer C, Lindeberg A, Bones J. Large-Scale Assessment of Extractables and Leachables in Single-Use Bags for Biomanufacturing. Anal Chem. 2018 Aug 7;90(15):9006-9015. doi: 10.1021/acs.analchem.8b01208

European Medicines Agency. ICH Q3E Extractables and leachables – scientific guideline [Internet]. Amsterdam: European Medicines Agency; 2025 [cited 2026 Jul 14]. Available from: https://www.ema.europa.eu/en/ich-q3e-extractables-leachables-scientific-guideline

Hammond M, Nunn H, Rogers G, Lee H, Marghitoiu AL, Perez L, Nashed-Samuel Y, Anderson C, Vandiver M, Kline S. Identification of a leachable compound detrimental to cell growth in single-use bioprocess containers. PDA J Pharm Sci Technol. 2013 Mar-Apr;67(2):123-34. doi: 10.5731/pdajpst.2013.00905

Hauk A, Bossong M, Pahl I, Maier TV, Menzel R. Application of clearance strategies for extractables and leachables and advances in process modeling. Appl Microbiol Biotechnol. 2026 May 20;110(1):146. doi: 10.1007/s00253-026-13874-2