Scientific protocols and controls must be designed and validated to minimize potential leachables and extractables, including unreacted monomers, reaction byproducts, impurities, contaminants, and residuals. This is achieved by selecting high-purity biocompatible raw materials and implementing effective elimination and extraction steps before commercialization, thereby reducing the risk of exposure during use.
Designing out extractables and leachables
Both 3D resins and medical devices must be engineered to reduce potential extraction and absorption during use. This includes selecting appropriate raw materials and, where relevant, integrating tuning additives to support performance, process stability, and safer conversion profiles.
Conversion control and post-processing responsibility
Medical device manufacturers must control and minimize leachables and extractables by implementing suitable removal steps prior to use, and must maximize polymer conversion (from a photoreactive liquid resin into a fully cured device) through validated printing and post-processing.
Delivering devices without trapped unreacted monomers or other residual constituents is the responsibility of the medical device manufacturer, who remains legally accountable for the quality of products placed on the market.
Qualified workflows and equipment are essential
Biocompatible resins and medical devices must be developed and used within qualified printing set-ups and workflows to meet quality requirements for medical devices (Class I, IIa, IIb, III) or food/pharma packaging. Not all printers, post-processing units, and quality controls meet the minimum specifications needed for regulated manufacturing.
- 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
Biocompatible 3D resin suppliers provide photoreactive materials, not finished medical devices. Consequently, certification claims at the raw-material level do not replace the legally required certifications and validations performed by medical device manufacturers for their products, processes, facilities, and quality systems.
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
- 3D resins should be compliant (not “certified”) and designed in accordance with the quality requirements relevant to their intended biomedical applications.
- Raw-material supplier certifications are not legally valid replacements for the certifications required of medical device manufacturers.
- Medical device manufacturers remain responsible for validating materials, workflows, residue removal, sterilization, and final device safety and performance in the jurisdictions where products are commercialized.