Insight

Comprehensive Comparison of the Three Major Guidelines and Risk Assessment Models for Extractables & Leachables (E&L) of Plastic Components

In the manufacturing of biopharmaceuticals and chemical drugs, the risks posed by Extractables & Leachables (E&L) from single-use plastic components directly impact drug quality and patient safety. Three core guidelines issued by BPOG, USP and CDE have established the primary framework for E&L risk assessment of plastic components across the industry.

Many practitioners often face practical dilemmas: the R&D team requires E&L testing for single-use bags, while the Quality department questions which guideline to follow — CDE, USP or BPOG? Enterprises targeting both domestic inspections and FDA submissions wonder if a single report can satisfy both sets of requirements. Confusion also arises over risk scoring: whether to adopt a 1–9 scoring scale or a 1–3 tiered system, and how to set weight coefficients to avoid regulatory challenges.

This article systematically elaborates on the underlying logic, key differences and practical application strategies of the three guidelines to resolve relevant concerns.

Core Questions to Address

Do the three guidelines share the same fundamental logic?

What are their primary distinctions?

Which guideline is preferred for biopharmaceutical manufacturers?

Which one is applicable for international registration (FDA/EMA)?

Which guideline should be adopted for domestic chemical injectables?

Concise Summary

All three guidelines follow consistent core principles: risk-based classification and control, safety evaluation, and assessment against five key influencing factors, aligning with the scientific tenets of ICH Q3E.

Their differences lie in risk scoring methodologies (LRR scoring, numerical tiering and hybrid frameworks), scope of application and deliverable formats.

BPOG: Tailored to pharmaceutical manufacturing processes, enabling risk-based optimization of validation scope.

USP: A standardized compendial requirement mandated by the FDA with global mutual recognition.

CDE Guidelines: Fully compliant with domestic registration and inspection requirements in China.

Core Positioning of the Three Guidelines: Differentiated Application Scenarios

While all three documents govern E&L risk control for plastic components, they differ distinctly in applicable fields, original intent and industrial positioning:

BPOG Guidelines (Bioprocessing Industry Organization Group)

Representing industry best practices, this set of guidelines is dedicated exclusively to Single-Use Systems (SUS) in biopharmaceutical production. It focuses on leachable migration risks and fits bioprocess workflows including cell culture, drug substance storage, filtration and filling. Flexibility and process compatibility are its prominent features.

USP <665> / <1665>

As a pharmacopoeial statutory standard, it covers plastic components across the entire pharmaceutical sector. Centered on quantitative risk matrices, it advocates standardized and unified assessment criteria and serves as the fundamental basis for global pharmaceutical registration.

CDE Technical Guideline for Compatibility Study of Plastic Component Systems Used in the Production of Chemical Injectables (Trial)

Regarded as the mandatory compliance standard for domestic registration in China, this guideline is specially formulated for chemical injectables. Drawing on the scientific rationales of BPOG and USP, it fully adapts to domestic regulatory inspections with strong operability and compliance clarity, and defines explicit testing items and risk judgment criteria.

Shared Underlying Logic: Common Fundamentals

Despite divergent application scenarios, the three guidelines adopt identical core logic for E&L risk assessment:

Unified assessment scope: Evaluation focuses primarily on plastic components with direct contact with process solutions. Components not in contact with fluid are generally exempt from E&L control, while case-by-case assessment is required for specific high-risk scenarios.

Unified assessment dimensions: Risk grading is performed based on five core factors: process location, contact temperature, contact duration, properties of contact fluid and material characteristics of components. Variations only exist in the definition and scoring rules of individual factors.

Unified control principle: The depth of compatibility studies is determined by risk tier. Higher risk levels correspond to more stringent testing requirements.

Aligned with international standards: All frameworks comply with the scientific principles of ICH Q3E (Draft Guideline on Extractables and Leachables), which emphasizes identification, qualification and quantification of leachables based on patient safety thresholds. This drives the global transition from fragmented compliance to harmonized risk-based E&L assessment.

Key Differences: Assessment Criteria & Regulatory Focus

1. Distinct Risk Scoring Methodologies

BPOG: Adopts the LRR weighted scoring system (1–9 scale). The Device Application Site (DAS) in the production workflow carries the highest weight. Components located closer to the final product (e.g., filling processes) are assigned higher risk levels.

USP: Applies a 3-tier numerical risk ranking (Grade 1/2/3). The final risk level is further adjusted by process mitigation factors and clinical exposure factors.

CDE Guidelines: Establishes an independent risk assessment framework referencing international practices. It directly specifies mandatory test items including Non-Volatile Residues (NVR), Ultraviolet (UV) detection and elemental impurities based on risk tiers, delivering superior practicality.

2. Different Regulatory Priorities

BPOG: Prioritizes the potential for leachable migration, focusing on the actual in-use conditions of single-use systems in biomanufacturing processes.

USP: Focuses on patient exposure risks. Rigorous quantitative analysis and mitigation factor evaluation ensure compliance for global registration.

CDE Guidelines: Oriented toward practical compliance for domestic chemical injectables, with clear specifications for supplier documentation, test methodologies and reporting standards.

Practical Compliance Recommendations: Select Guidelines for Scenario-Based Compliance

Combined with the features of each guideline, enterprises may select the optimal assessment solution according to business demands:

Biopharmaceutical manufacturers using single-use systems: Prioritize BPOG Guidelines. They align well with bioprocess characteristics, differentiate risks across upstream and downstream workflows reasonably and avoid excessive validation work.

Enterprises with global layout and international registration plans: Adopt USP standards. Standardized assessment results are recognized worldwide and meet submission requirements of the FDA and EMA.

Domestic manufacturers of chemical injectables: Follow the CDE Guidelines directly to fully satisfy domestic registration and inspection requirements, with standardized testing and reporting procedures.

Common Pitfalls to Avoid

Subjective risk scoring: Arbitrarily downgrading risk levels without following the official scoring rules will lead to challenges during regulatory inspections.

Extractables-only testing: For high-risk components, leachables testing is mandatory. Reports covering only extractables will be deemed incomplete.

Conclusion: Suitability Prevails over Absolute Superiority

None of the three guidelines is universally superior; the core consideration is scenario adaptability.

E&L risk assessment is evolving toward standardization and systematization, with the overall control model transforming into full-lifecycle risk management. E&L evaluation is not merely a procedural task. It requires scientific risk grading integrated with guideline requirements, process features and product attributes. A universal consensus remains unchanged across the pharmaceutical industry: higher risk tiers for plastic components mandate more rigorous compatibility studies, so as to fully safeguard drug safety.

Moving forward, pharmaceutical enterprises are advised to establish a closed-loop management system covering information collection, risk modeling, experimental verification and continuous control. Proactive capacity building will help address increasingly stringent global regulatory requirements.

Insight

Comprehensive Comparison of the Three Major Guidelines and Risk Assessment Models for Extractables & Leachables (E&L) of Plastic Components

1. Distinct Risk Scoring Methodologies

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