USP <87> has long been associated with cytotoxicity testing, and for many pharmaceutical packaging teams it was historically treated as a narrow, qualitative screen performed late in qualification. Passing USP <87> was often viewed as a binary outcome rather than as part of a broader scientific evaluation.

The revised USP <87> represents a fundamental change in both scope and intent. Rather than prescribing a single test, the chapter now defines a flexible, risk-based in vitro biological screening framework. This change reflects advances in cell biology, toxicology, and regulatory thinking, and it materially alters how packaging biocompatibility should be approached.

From Single Assay to Screening Framework

Under the revised chapter, USP <87> encompasses multiple in vitro biological endpoints that may be applied depending on the material, contact scenario, and route of administration. These endpoints include:

  • Cytotoxicity testing using agar diffusion, direct contact, and elution methods
    • Quantitative cytotoxicity assays such as neutral red uptake
    • Skin irritation testing using reconstructed human epidermis (RhE) models
    • In vitro genotoxicity screening assays, including bacterial reverse mutation and mammalian cell mutation tests

Crucially, USP <87> does not require that all of these endpoints be applied universally. The chapter explicitly emphasizes that test selection must be driven by scientific rationale and patient exposure, not by precedent.

What This Means for Pharmaceutical Packaging

For most pharmaceutical packaging systems (particularly indirect-contact plastics and elastomers) cytotoxicity remains the primary and often sufficient biological endpoint. Packaging materials typically do not contact patient tissue directly; instead, any risk arises from chemical migration into the drug product.

As a result, qualitative or quantitative cytotoxicity testing is usually appropriate to screen for overt biological reactivity. Skin irritation or genotoxicity assays may be relevant only in higher-risk scenarios, such as components associated with prolonged contact, high extractable burden, or specific routes of administration.

This clarification is critical. One of the most common misconceptions surrounding revised USP <87> is that the expansion of endpoints implies expanded testing obligations. In reality, the opposite is true: the revised framework allows teams to apply the *right* test, rather than *more* tests.

USP <87> as the Front-Line Biological Gatekeeper

The revised positioning of USP <87> elevates it from a checkbox activity to the primary biological decision point within a modern biocompatibility strategy. When applied early, during material selection, supplier qualification, or change impact assessment, USP <87> can resolve biological risk before it escalates.

This upstream application offers tangible benefits:
– Earlier identification of problematic materials
– Reduced reliance on downstream in vivo testing
– Faster resolution of change-control questions
– Improved alignment between biological data and chemical characterization

Within the broader USP <1031> framework, USP <87> serves as the first biological gate. Only when in vitro screening raises unresolved concerns does escalation to additional testing become appropriate.

Integration with Chemical Characterization and Toxicology

USP <87> is not intended to stand alone. Its true value emerges when integrated with chemical characterization and toxicological risk assessment. Chemical data identify potential migrants; USP <87> evaluates biological response; toxicology translates findings into patient-relevant risk.

This integration allows packaging teams to answer the question regulators care most about: not simply whether a test passed, but whether the available evidence adequately demonstrates patient safety.

Common Pitfalls to Avoid

As organizations adapt to the revised chapter, several pitfalls are emerging:
– Treating USP <87> as a menu rather than a decision framework
– Applying higher-tier endpoints without exposure justification
– Using USP <87> results in isolation from chemistry and toxicology
– Deferring USP <87> testing until late-stage qualification

Avoiding these pitfalls requires a shift in mindset. USP <87> is no longer a late-stage hurdle; it is an early, informative tool that guides smarter decisions.

Why This Matters Heading into 2026

As the December 1, 2026 effective date approaches, organizations that fail to modernize their use of USP <87> risk unnecessary escalation to USP <88> testing, longer timelines, and increased costs.

By contrast, teams that adopt the revised USP <87> framework early can resolve biological questions upstream, reduce animal testing, and enter 2026 with a defensible, risk-based biocompatibility strategy already in place.

In short, revised USP <87> does not increase burden, it increases precision. For pharmaceutical packaging teams, that precision translates directly into better decisions, stronger regulatory positioning, and more efficient programs.