Twenty years ago, almost all intravenous infusion bottles and supplemental medicine ampoules were made from glass. Nowadays, with the introduction of new high-quality polymers, which offer cost-effectiveness, production feasibility, advanced mechanical properties and ease of use, such medical packaging and devices are transitioning to plastic materials. Alongside this shift, international standards agencies have implemented regulations governing medical devices, which partially dictate the requirements for materials used. Consequently, the definition and comprehensive certification systems for medical-grade plastics worldwide are gradually established.

 

Polyolefin for medical applications

 

What is medical grade plastic?

There is currently no regulatory definition of a medical-grade polymer. In general, medical-grade plastic refers to polymers that comply with specific standards and possess desirable properties for specific medical applications, such as:

– Biocompatibility

– Non-permeability

– Sterilization resistance

– Lightweight

– Durability

In this article, we focus on the basic polyolefin polymers: polyethylene and polypropylene, which are among the various types of plastic used in medical applications.

 

Polyethylene (PE)

 

Polyethylene is the most common plastic used in medical devices. Its inertness, flexibility, toughness, affordability, & ease of processing

make it well-suited for:

•  Ampoules and vials for infusion and injection solution made with blow-fill-seal (BFS) technology.
• Tubings, lab equipments, surgical trays, etc.

 

Polypropylene (PP)

 

Polypropylene is appreciated for its high-temperature resistance, low density, chemical resistance, and economical cost. It is ideal for:

 

• Syringes, housings, vials, test tubes, and medical packaging
• Urine bags, filters, and autoclavable trays
• Surgical masks and gowns

Explore our PE and PP medical-grade portfolio at the end of this article.

 

How medical-grade plastic is made?

Unlike commodity polymer grades, medical-grade plastics must meet higher levels of safety standards. Depending on specific medical packaging and devices being targeted, medical-grade plastics are intentionally developed and manufactured with a focus on:

• Construction of material(s): used highly purified feedstocks at proper content and production mode to meet the requirements of finished medical product.
• Catalyst, intended additives, process contaminants, and residues: employ advanced catalysts to ensure the absence of high-risk substances; minimize the use of additives or refrain from their use entirely.
• Operation and quality management: reaction occurs at the maximum conversion rate and maintain stable operation; setting narrow control ranges and implementing stringent quality management.

 

Standards for medical plastic materials

 

The manufacturing process can alter how materials react, leading to current standards in medical applications primarily applying to devices, with limited direct imposition on materials themselves. For instance: if the device as a whole meets FDA, EU (MDR) regulations or ISO standard, there’s no need to prove that the material itself is suitable. On the other hand, it’s never possible to say Material A is acceptable for all medical devices, each case must be evaluated individually. Below, we outline all standards indirectly and directly related to medical grade materials.

Basic Standards

There are no current standards in place for what exactly “medical grade” means, what is agreed is that patient-contact materials must be biocompatible, and the safety standards should be at least equivalent to or higher than those for food contact materials. Below are some of the basic standards typically requested:

• FDA have described Food Contact Materials in the Code of Federal Legislation (CFR)
• Regulations (EU) No 10/2011: is a specific measure for plastic food contact materials by EU
• REACH 1907/2006/EC (Registration, Evaluation, Authorization and Restriction of Chemicals) and the REACH SVHC (Substances of Very High Concern)
• RoHS 2.0 (Restriction of Hazardous Substances) and the latest amendment was published on July 11, 2023, and it is amending Annex IV, namely applications exempted from the restriction in Article 4(1) specific to medical devices and monitoring and control instruments.

Biocompatibility

Medical materials on the device that come into contact with the human body will be tested for biocompatibility and safety. This will include testing for toxicity, degradation, and skin sensitivity. The testing should be carried out by following the relevant ISO standards, which are recognized the world over. The U.S. uses USP testing for polymers, but also recognizes ISO.

– ISO 10993: The ISO standard for biocompatibility. Testing your device’s biocompatibility involves collecting qualitative and quantitative data on the materials in the context of biological safety Meeting ISO 10993 requirements designates the device’s material as medical grade. Specifically, your material will need to meet the relevant standard in order to achieve ISO 10993 certification. The primary ones are:

Standard	Title	What it involves
ISO 10993-1	Evaluation and testing within a risk management process	Detailed guidance on assessing potential biological hazards associated with all types of medical devices, including active, nonactive, implantable and non-implantable
ISO 10993-18	Chemical characterisation of medical-device materials within a risk-management process	Involves three possible approaches: compositional evaluation, extractables evaluation and leachable evaluation
ISO 10993-17	Establishment of allowable limits of leachable substances	Identifies the leachable substances, quantifying the associated risks and limiting exposure within tolerable levels
ISO 10993-5	Tests for in vitro cytotoxicity	Specifies the incubation of cultured cells in contact with a device and/or extracts of a device either directly or through diffusion

• USP Class VI: While ISO standards are the most well-known around the world for all materials, they’re not alone when it comes to polymers. The U.S. Pharmacopeial Convention (USP) dictates testing for plastic medical devices to evaluate biological responses. Their standards are recognized in 140 countries, including the UK. In the U.S., their standards are enforceable by the Food and Drug Administration (FDA). There are no FDA-approved plastics for medical devices. It’s the entire device that is tested, as variables such as manufacturing processes can alter the material’s properties. Each USP device class is based on duration of use and the application, requiring a different level of regulation and compliance. The important one here for a device to be anywhere close to medical plastics is Class VI. In order to meet Class VI standards, the product/material must exhibit a very low level of toxicity. The tests are similar to ISO 10993 and have some cross-over. However, the USP classification only outlines the tests needed. Unlike ISO standard, it doesn’t include the risk management of medical devices.

USP Class VI and ISO 10993: USP Class VI demands an intracutaneous irritation test. So does ISO 10993. However, Class VI also requires subacute toxicity and implantation effects, which many ISO 10993 categories do not. That said, the lack of risk assessment in USP Class VI can be a problem. It’s possible that USP Class VI material can also comply with ISO 10993. But USP Class VI by itself is not adherence to ISO 10993.

EU Medical Device Regulation

The European Union’s Medical Device Regulation (MDR) establishes requirements for the safety and performance of medical devices and materials used in the EU market.

 

European Pharmacopoeia (Ph. Eur.) 11th Edition

(Ph. Eur.), Section 3. Materials and containers: establish standards for pharmaceuticals and medical devices, including materials used in their production.

 

Quality Management

ISO 9001 is a globally recognized standard for quality management. Its requirements define how to establish, implement, maintain, and continually improve a quality management system (QMS).

ISO 13485 ensures that the manufacturer’s quality management systems meet ISO standards specific to medical devices.