Scientific protocols and controls should be designed and validated to characterise and, where required, reduce potential leachables and extractables, including unreacted constituents, reaction by-products, impurities, contaminants and residuals. Raw-material selection and validated printing/post-processing steps should be defined for the specific device, intended use and applicable biological-evaluation requirements.
Designing out extractables and leachables
Both 3D resin systems and finished devices should be engineered to control potential extractables and leachables during use. This includes selecting appropriate raw materials and, where relevant, integrating tuning additives to support performance and process stability. Any effect of additives or auxiliaries must be included in the final workflow validation.
Conversion control and post-processing responsibility
Medical-device manufacturers should define and validate appropriate controls for conversion, cleaning, post-curing and residue removal. The target degree of conversion and acceptance criteria must be appropriate to the specific material, device and intended use rather than assumed from a generic “fully cured” condition.
Responsibility for the final device, manufacturing validation, release criteria and regulatory compliance remains with the device manufacturer under the applicable regulatory framework.
Qualified workflows and equipment are essential
Materials intended for biomedical workflows and finished medical devices should be used within qualified printing and post-processing systems appropriate to the intended application. Printer, post-processing and quality-control requirements depend on the specific material, device class, intended use and applicable regulations.
- Reference workflows and processing discipline: qualified Instructions for Use (IFU) and workflow relevance
- Example of printer variability impact: power differences across DLP, LCD and LCD systems
Regulatory context: materials are not medical devices
3D resin suppliers provide photoreactive raw materials and technical documentation, not finished medical devices. Material-level test reports or compliance statements do not replace the device-level validation, quality-system and regulatory obligations applicable to the final device manufacturer.
FDA guidance highlights
The FDA guidance document Technical Considerations for Additive Manufactured Medical Devices emphasizes that complex geometries can increase the difficulty of cleaning and sterilization, and that manufacturers must validate residue removal and sterilization under worst-case conditions.
Additively manufactured devices can increase the difficulty in removing manufacturing material residues (cleaning) and in sterilization.
Conclusions
- Any material-level compliance statement should identify the applicable standard, endpoint, specimen, processing conditions, report and scope. Raw-material documentation should not be presented as certification or approval of the finished medical device.
- Supplier documentation and material test reports can support a device technical file, but they do not replace the certifications, validations or conformity-assessment activities applicable to the final device manufacturer.
- Medical-device manufacturers remain responsible for defining and validating materials, workflows, cleaning/residue controls, sterilisation where applicable, and final-device safety and performance for the jurisdictions in which the device is placed on the market.