Why Chemical Characterization, Cleaning Validation, and Sterilization Must Work Together
If you're in quality or regulatory at a medical device company, you've likely managed cleaning validation, sterilization validation, and biocompatibility testing as separate work streams—each with its own protocols, timelines, and headaches. But here's what's different now in 2026: regulators and auditors increasingly expect you to demonstrate how these three critical processes work together, not just individually.
Chemical characterization according to ISO 10993-18 sits at the heart of biocompatibility evaluation and is required for device approval. Yet many quality and regulatory professionals don't realize that their cleaning validation data and sterilization process choices directly impact what shows up in chemical characterization testing—and ultimately, whether your biocompatibility assessment holds up under regulatory scrutiny.
Here's the challenge: your device composition isn't static. It changes throughout production as materials encounter processing aids, cleaning fluids, mold release agents, process contaminants, sterilization residues, or undergo degradation. Each of these changes can introduce extractables that affect your biocompatibility profile.
The regulatory landscape has fundamentally shifted with ISO 10993-1:2025 now in effect. The standard requires a biological evaluation plan that integrates risk management, material characterization, and chemical assessment early in the device lifecycle. More importantly, it clarifies the direct link between chemical characterization and toxicological risk assessment—no longer can these be treated as disconnected activities.
This builds on the groundwork laid in recent years. ISO 10993-1 was updated in 2018 with increased emphasis on chemical characterization, followed by ISO 10993-18 updates in 2020 that introduced new expectations for replicates, intensified extractions, and analytical evaluation thresholds.
For quality and regulatory teams, this means your documentation strategy must evolve. Auditors will ask how your cleaning validation protocols consider extractables. Reviewers will question whether your sterilization residue testing connects to your biocompatibility conclusions. The integrated approach isn't just good practice—it's becoming the regulatory expectation.
Chemical Characterization: Your Foundation
Chemical characterization offers three possible approaches: compositional evaluation, extractables evaluation, and leachables evaluation. The good news? Not all approaches are required in every case. The challenge? Knowing which combination provides sufficient evidence for your specific device.
Here's a critical insight that catches many manufacturers off guard: supplier data and raw material certificates don't tell you which substances your finished device actually releases under clinical conditions. Material suppliers often don't provide detailed identities and quantities of all components, and certificates provide no information about releasable substances. The chemical composition on paper tells you nothing about what leaches out when your device contacts tissue or bodily fluids after it's been cleaned, sterilized, and put into service.
Cleaning Validation: More Than Process Control
Your cleaning validation program serves two masters, and understanding both is crucial. First, it ensures acceptable levels of contaminants that could compromise manufacturing quality—this is verification at the process level. Second, and often overlooked, it directly impacts biocompatibility by controlling what remains on device surfaces.
The strategic opportunity here: by implementing a robust cleanliness concept adapted for your product portfolio, you actually facilitate your biological evaluation. Think about it—if your monitoring results consistently show stable cleanliness levels and no changes occur in production processes, the potential impact on biocompatibility is substantially lower. This gives you defensible rationale for streamlined biocompatibility testing strategies.
But there's a caveat. Every stage of your manufacturing process must be controlled, and all changes to processing steps must be evaluated. Even seemingly minor process changes can impact both cleanliness and biocompatibility. Your change control system needs to explicitly trigger assessment of these interconnections.
Sterilization: The Variable That Changes Everything
For reusable devices especially, sterilization validation becomes even more critical. Your biocompatibility testing must account for device materials and any residues remaining after reprocessing, considering the entire lifecycle through repeated reprocessing cycles.
Common tests for reusable devices include cleaning validation to prevent contaminant buildup between uses, disinfection validation, sterilization and drying validation, and biocompatibility testing that explicitly considers lifecycle effects after repeated reprocessing.
Start Early, Save Later
Testing optimizations become possible when sterilization, cleaning, and biocompatibility are considered simultaneously and early in development. This isn't just theory—it's the difference between smooth submissions and costly redesigns.
During design phase, bring your cleaning validation engineer, sterilization specialist, and toxicologist into the same room. Map out how material choices affect cleaning efficacy, how cleaning agents might create extractables, and how sterilization methods could generate residues or modify materials. This cross-functional collaboration up front prevents expensive surprises during validation.
Build Your Integrated Testing Strategy
The minimum requirements for chemical characterization according to ISO 10993-18 should guide what information and data you collect during cleaning validation and monitoring. This ensures your efforts serve both purposes efficiently.
Consider your analytical method selection strategically. Use techniques that meet requirements across all three domains: liquid chromatography-mass spectrometry for semi and non-volatile organic compounds, gas chromatography-mass spectrometry and headspace GC-MS for volatiles and semi-volatiles, and inductively coupled plasma spectroscopy for elemental analysis. One well-designed analytical program can feed data into multiple validation efforts.
Adopt Lifecycle Documentation Thinking
Your quality management system should explicitly connect these three areas. When cleanliness monitoring shows consistent results, document how this supports your biocompatibility risk assessment. When you validate a sterilization process change, evaluate and document the implications for chemical characterization and extractables.
This lifecycle approach is particularly powerful for post-market changes. If you need to modify a cleaning agent or sterilization parameter, your documentation trail showing the original interplay makes the impact assessment straightforward and defensible.
If you manufacture reusable devices, the complexity multiplies. You're not just proving initial biocompatibility—you're demonstrating that the device remains biocompatible through repeated cycles of use, cleaning, and sterilization equivalent to its maximum useful life.
Your validation program must show that devices maintain functionality, physical integrity, and biocompatibility after multiple cycles including all cleaning steps performed between uses. Material selection must account for biocompatibility across multiple reprocessing cycles, not just initial state.
This is where end-of-life biocompatibility evaluation under ISO 10993-1:2025 becomes critical. Your test samples should represent worst-case conditions after maximum lifecycle exposure.
Pitfall 1: Sequential Thinking
The biggest mistake quality teams make is treating these as separate, sequential activities with handoffs between departments. Cleaning validation finishes, then sterilization validation starts, then biocompatibility testing happens. This linear approach misses optimization opportunities and creates gaps in your rationale.
Instead, create an integrated validation master plan that addresses all three areas with clear connections documented throughout.
Pitfall 2: Incomplete Chemical Information
Don't assume your material suppliers have given you everything you need. Certificates are a starting point, not an endpoint. Your chemical characterization must account for what's actually released from your finished, processed device.
Pitfall 3: Change Control Blind Spots
Manufacturing changes affect all three areas simultaneously, yet many change control procedures only trigger re-validation in the obviously affected area. A cleaning agent substitution might seem like purely a cleaning validation issue, but it could introduce new extractables that affect your biocompatibility profile.
Build explicit triggers into your change control system that require assessment of cross-domain impacts.
Here's what regulatory and quality leaders should do now:
1. Audit Your Current Approach Review your most recent device submission or validation package. Can you clearly trace the connections between cleaning validation data, sterilization parameters, and chemical characterization results? If not, you have documentation gaps that auditors will find.
2. Build Cross-Functional Teams Stop having cleaning validation, sterilization, and biocompatibility experts work in silos. Create integrated project teams for new device development and major changes. Schedule regular touchpoints to assess interdependencies.
3. Update Your Biological Evaluation Plans Your BEP should explicitly address how cleaning and sterilization processes impact chemical characterization. Document your rationale for test strategies that leverage data across these domains.
4. Engage Toxicologists Early Bring toxicological expertise into design review and material selection discussions, not just at the testing phase. Early engagement prevents expensive redesigns and testing delays.
5. Strengthen Your Documentation Links Ensure your quality management system explicitly connects these activities. When cleanliness monitoring results are reviewed, the implications for biocompatibility should be assessed and documented. When sterilization validation is updated, the impact on extractables profiles should be evaluated.
6. Invest in Method Development Work with your analytical lab to develop methods that serve multiple purposes. Well-designed chemical characterization testing can provide data valuable for cleaning validation, sterilization residue testing, and biocompatibility assessment simultaneously.
The regulatory landscape demands integrated thinking. Chemical characterization, cleaning validation, and sterilization validation are not independent activities—they're interconnected elements of your device safety evidence. Quality and regulatory professionals who recognize and leverage these connections will achieve faster development timelines, more robust validation packages, and clearer regulatory pathways.
The manufacturers who thrive in 2026 and beyond will be those who break down the traditional silos and build truly integrated validation strategies. The question isn't whether to make this shift—it's whether you'll do it proactively or wait until an auditor or reviewer forces the issue.