What Is Medical Grade Plastic?

Medical-grade plastic offers consistent performance, compatibility with sterilization processes, and the ability to meet strict regulatory requirements, making it suitable for a wide range of medical plastic components. As the demand for safer, cleaner, and more efficient medical technologies continues to increase, the use of medical-grade polymers also continues to expand.

What Is Medical Grade Plastic?

Medical grade plastics are polymers engineered to meet specific healthcare requirements such as biocompatibility, chemical resistance, sterilization stability, and mechanical consistency.

A medical-grade plastic is typically produced using controlled raw materials, validated manufacturing processes, and strict traceability systems. These materials undergo biological evaluation to ensure they do not cause irritation, toxicity, or other harmful reactions when used in close contact with the human body.

Standards Required for Medical Grade Plastics

To be classified as medical grade, a polymer must meet several regulatory standards. The exact requirements vary depending on the device’s classification and contact level.

ISO 10993 Biocompatibility Testing

The primary standard remains ISO 10993, a series of more than 20 parts that evaluate biological risks. Every plastic medical device that comes into contact with skin, tissue, or fluids must meet the appropriate ISO 10993 tests. Key sections include:

• ISO 10993-5: Tests for cytotoxicity in cell cultures
• ISO 10993-10: Tests for irritation and skin sensitisation
• ISO 10993-11: Systemic toxicity evaluation
• ISO 10993-18: Chemical characterisation of extractables and leachables

USP Class VI Testing

USP Class VI represents one of the most rigorous voluntary tests. Materials that pass USP Class VI undergo acute systemic toxicity, intracutaneous reactivity, and implantation tests in animals for seven days. Many manufacturers specify USP Class VI compliance for medical grade plastics intended for longer contact durations.

FDA Compliance and Master File

The U.S. FDA classifies medical devices into Class I, II, or III and reviews materials accordingly. European MDR and other regions follow similar risk-based approaches.

ISO 13485 Manufacturing Controls

Materials may need to be produced in facilities that follow quality-management systems aligned with ISO 13485, ensuring traceability and consistent production.

REACH and RoHS Compliance

These standards restrict hazardous substances and ensure environmental safety, which is relevant for global distribution.

Sterilization Methods for Medical Grade Plastics

Medical devices must withstand multiple sterilization procedures without losing functionality. Common sterilization methods include:

Steam autoclaving (121–134°C, high pressure): Widely used for reusable instruments. Materials such as polypropylene (PP), polycarbonate (PC), and polysulfone (PSU/PPSU) tolerate hundreds of cycles.

Ethylene oxide (EtO): Low-temperature process suitable for heat-sensitive devices. Requires aeration to remove residuals. ABS, PVC, and many silicones work well.

Gamma and electron-beam radiation (25–50 kGy): Effective for single-use items. PEEK, UHMWPE, and certain grades of PP maintain stability, while some polymers may cross-link or degrade.

UV Sterilization: Useful for surface disinfection, though prolonged exposure may degrade polymers unless they contain stabilizers.

Hydrogen peroxide plasma or vapor: Low-temperature option for delicate electronics-containing devices.

Dry heat or newer methods (e.g., supercritical CO₂): Used in specialized cases.

Advantages of Medical Grade Plastics

Medical plastics offer multiple practical benefits compared to traditional materials:

• Consistent Biocompatibility: These materials are designed to avoid adverse biological reactions, which is critical for patient-contact components.
• High Chemical Resistance: Medical plastics maintain stability when exposed to disinfectants, bodily fluids, and various pharmaceutical substances.
• Lightweight and Durable: Compared with metals and glass, plastic medical components offer reduced weight without compromising strength or reliability.
• Design Flexibility: Injection molding allows complex shapes, thin-wall geometries, and integrated features that simplify assembly and improve function.
• Cost Efficiency: For high-volume medical plastic devices, the cost per unit becomes highly competitive due to automation and mold optimization.
• Sterilization Compatibility: Many medical-grade polymers withstand repeated sterilization cycles, making them suitable for reusable devices.
• Transparency or Opacity Options: Depending on clinical needs, manufacturers can select materials that are fully transparent, slightly translucent, or opaque.

Differences Between Implantable and Non-Implantable Materials

Implantable Materials

These medical-grade plastics must remain safe inside the body for extended periods. Requirements include long-term biocompatibility, extremely low levels of leachables, and resistance to mechanical and chemical degradation. The materials must undergo a full ISO 10993 test battery, including chronic toxicity, carcinogenicity, and degradation studies.

Common implantable polymers include PEEK, medical-grade silicone, and ultra-high-molecular-weight polyethylene (UHMWPE).

Non-Implantable Materials

These materials are used in external devices, housings, diagnostic tools, fluid-handling components, and disposable parts. While biocompatibility remains important, the requirements are less stringent due to the shorter exposure duration.Testing primarily focuses on cytotoxicity, sensitization, and irritation.

These materials include polypropylene, polycarbonate, ABS, PVC, and nylon.

Commonly Used Medical Grade Plastics in Injection Molding

The following is common plastic for medical device:

1. PP: Syringes, vials, surgical trays, suture containers, and disposable forceps.
2. PC: Clear housings, IV connectors, blood oxygenator windows, and dialysis cartridges.
3. PE: Pharmaceutical bottles, catheter tubing, and orthopedic joint bearings (UHMWPE).
4. PEEK: Spinal fusion cages, trauma plates, dental implant components, and suture anchors.
5. PVC: Flexible tubing, blood bags, IV bags, and oxygen masks.
6. ABS: Device enclosures, inhaler bodies, and diagnostic instrument casings.
7. PPSU & PEI: Reusable surgical instrument trays, sterilization cases, and dental mirrors.
8. LSR & HCR: Seals, gaskets, long-term catheters, prosthetic components, and infant care products.
9. PMMA: Bone cement, intraocular lenses, and cranial plates.

Production Considerations When Using Medical Grade Plastics

Manufacturing with medical grade plastics requires careful control to ensure safety and regulatory compliance.

Material Selection: The selected plastic must demonstrate biocompatibility by meeting standards such as ISO 10993 and/or USP Class VI, which require testing for cytotoxicity, sensitization, systemic toxicity, and hemolysis. Mechanical properties, including strength, transparency, and flexibility, as well as chemical resistance, are critical to the device’s functionality.

Sterilization Compatibility: Medical plastics must consistently withstand frequent sterilization methods, such as autoclaving, gamma radiation, ethylene oxide, and plasma, without deterioration or loss of integrity.

Regulatory Standards: Compliance with FDA, ISO 10993, USP Class VI, and ISO 13485 standards is essential. This includes both the materials used and the manufacturing environment, such as cleanroom requirements for processes like injection molding.

Production Process Control: Maintaining precise conditions, such as temperature, pressure, and mold design, during the manufacturing process ensures dimensional stability and consistent, high-quality output. Effective monitoring minimizes defects and supports regulatory compliance.

ISO 13485 Quality Systems: Facilities producing medical-grade plastics must implement formal quality management systems. All process steps and material sources must be fully traceable, supported by audits and documentation to ensure compliance with regulatory requirements.

Cleanroom Manufacturing: Many medical devices require plastic parts to be molded or finished in cleanroom environments environments, typically ISO Class 7 or 8. This process prevents contamination and ensures compliance with certification requirements.

Product Certification: Long-term or high-risk products (e.g., implants) must meet the highest standards of biocompatibility, such as USP Class VI and advanced ISO 10993 testing, as demonstrated by independent laboratory studies before market approval.

Device Approval: Ultimately, the device itself, not just the raw plastic, undergoes FDA and regulatory scrutiny to ensure safety, material consistency, and suitability, considering manufacturing variations.​

Finding the Right Medical Grade Material to Start Your Project

Selecting the appropriate medical-grade plastic is the first critical step in successful medical injection molding development. Begin by defining the type and duration of contact, sterilization method, mechanical requirements, and regulatory pathway. Partner with us, and we can recommend grades that balance performance, cost, and compliance.