Reducing the Need for Animal Testing for Biological Reactivity in Polymer Characterization

It is recognized that qualification of plastic polymers used in single-use systems require different considerations than multi-use stainless steel equipment used in manufacturing. In response, the United States Pharmacopeia (USP) assigned classes to plastics based on in vivo testing; this USP chapter was subsequently renamed Biological Reactivity Tests, In Vivo <88>. In 1990, USP added the Biological Reactivity Test, In Vitro <87> to the compendia. The companion chapter, Biocompatibility of Materials Used in Drug Containers, Medical Devices, and Implants <1031> was intended to provide guidance based on the route of administration and duration of exposure.

Read more about

• USP Updates to Biological Reactivity Chapters
• Comparing Bioreactivity Tests
• Transitioning to USP <87> and ISO 10993-5 In Vitro Testing
• How This Transition Impacts Our Product Testing
• Related Products

USP Safety Testing for Plastic Components Used in Pharmaceutical Manufacture

In vitro and in vivo biological reactivity testing are used to determine the biological responses of mammalian cell cultures and animals, respectively, to elastomeric, plastic, and other polymeric materials which might have direct or indirect patient contact. These tests were originally applied to medical devices such implants or storage containers, with a goal of minimizing patient risk due to direct contact with plastic.

A lack of industry standards for material qualification of plastics used in bioprocessing led the industry to adopt the most stringent medical device standard (Class VI) as the default for qualification of all polymeric materials used in single-use components. This approach resulted in excessive animal testing and a reconsideration of the appropriateness of the tests in USP <87> and <88>. As the industry matures, USP is evaluating strategies to:

• Minimize redundant testing of existing plastic and elastomeric materials and eliminate unnecessary animal testing for new materials
• Refine testing to align with the potential risk
• Replace in vivo testing with in vitro testing or use other information based on an understanding of the material and pharmaceutical application to guide a risk assessment

This page provides an overview of USP <87>, <88>, and <1031>, compares bioreactivity testing, and describes the transition of our organization towards in vitro test methods.

USP Updates to Biological Reactivity Chapters

The summary below outlines planned USP updates to the three biological reactivity chapters.¹

• USP <88> In vivo Testing: Remove the implantation test and safety test, especially for components that are not implantable medical devices. Class I-VI testing would be removed, but Class VI testing might be renamed as “pharmaceutical grade polymeric material” with same test procedures as for Class VI plastics and elastomeric material for packaging and delivery systems.
• USP <87> In vitro Testing: Revisions to cytotoxicity testing to include addition of neutral red update (NRU) assay for In vitro Cytotoxicity. Addition of Genotoxicity Tests.
• USP <1031> Biocompatibility of Materials Used in Drug Containers, Medical Devices, and Implants: Will focus on the overall process of biocompatibility evaluation and risk-based approach while defining pharmaceutical grades and the risk of bioreactivity failures.

Comparing Bioreactivity Tests

USP <88> in vivo tests include systemic injection, intracutaneous injection, and implantation with each test requiring 40 mice and 6 rabbits. Animals are scored based on their response to the plastic which includes:

• Injection test: changes in body weight or death
• Intracutaneous and implantation tests: erythema and eschar formation, edema, or capsule width.

USP <87> includes three in vitro tests, each conducted using mammalian cells:

• Direct contact: Cells in a culture dish are placed in direct contact with the product or packaging samples then cell toxicity is evaluated.
• Agar diffusion: Cells in a culture dish are protected by an agar overlay which enables leachable chemicals to diffuse from the product or packaging samples to the cells. Cell toxicity is evaluated.
• Elution assays: Evaluate the extracts of polymeric materials applied directly to tissue culture media.

The cytotoxicity testing described in USP <87> and ISO 10993-5 provide alternatives to the in vivo animal testing described in USP <88>. As in vitro testing using mammalian cell lines is more objective and quantitative than in vivo animal testing, these tests are more appropriate for assessing the risks of polymers used in biopharmaceutical manufacturing.

Transitioning to USP <87> and ISO 10993-5 In Vitro Testing

USP, the US Food and Drug Administration (FDA), and the European Medicines Agency (EMA) are focused on minimizing animal testing and improving animal welfare and there is general industry consensus to replace animal testing with in vitro test methods for qualification of filtration and single-use products. In line with shifts in the industry, we are developing alternatives to animal testing across our life science, healthcare, and electronic businesses. As a first step, the risk associated with this change has been assessed in terms of:

• Risks associated with customer acceptance of the change
• Product claims
• Impact on additional testing completed on subcomponents
• Finished goods
• Internal procedures

A regulatory assessment was also performed to evaluate the risk to patient safety from eliminating USP <88> Class VI testing of our filters and single-use components. The assessment concluded that changing our component testing practices from in vivo bioreactivity testing as outlined in USP <88> Class VI to an in vitro testing method as detailed in USP <87> / ISO 10993-5 resulted in a negligible risk to patient safety.

How This Transition Impacts Our Product Testing

Qualification of new raw materials or products undergoing re-evaluation or requalification as a result of raw material changes will no longer be evaluated according to USP <88> Class VI testing; only USP <87> in vitro testing will be used.

The bioreactivity claim on certificates of quality will reflect either the ISO 10993-5 and/or USP <87> and/or USP <88> Class VI testing until all affected products have undergone a change. Filters and single-use products that are part of the Emprove^® program will have associated bioreactivity testing results included in their Material Qualification Dossiers.

The biopharmaceutical industry continues to find alternatives to animal testing during drug development and, in line with this effort, the FDA recently proposed a New Alternatives Methods Program that focuses on replacing, reducing, and refining the use of laboratory animals. The evolution of testing from the in vivo methods outlined in USP <88> to in vitro approaches described in USP <87> will make important contributions to the goal of minimizing animal testing and our organization is proud to be a leader in this important transition.

If you are interested in bioreactivity testing results, extractables data or other premium content, Demo dossiers are available to download including data for custom assemblies, chemicals, and consumables.

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