Medical Grade Plastic: Just What the Doctor Ordered

Purchasing and receiving medical grade plastic resins can be, well, a headache. How do you know if you’re purchasing a quality product? Will it stand up to the test of time and biological function? What do you need to know and what should you look for during your purchase decision? These are all questions you need answered before you’re able to make the best decision for your project and its end user.

Consistency and Reliability of Medical Grade Plastic

It’s simple—quality products are essential to the success of your product and need to be held to the highest standard because of the nature of your industry. You need peace of mind that your plastic product will be able to perform at the highest level to get the job done, no matter what comes its way. With respect to this, there are two things to look for: consistency and reliability. Though it’s easy to mistake one for the other, they mean entirely different things and you need to be able to count on both.

Consistency means that the plastic will perform in a repeatable manner. Think about an implanted plastic elbow joint. You can be sure it will flex and extend as many times as you like. That’s consistency. Reliability, on the other hand, means that you can count on something to perform to the degree it’s supposed to. Using our example above, the elbow always flexes inward and extends outward correctly. You should be able to expect and anticipate a high level of both consistency and reliability from your polymer as you make your purchasing decision.

In addition to consistency and reliability, your product should have the right amount of tensile strength, flexion and elongation. If you expect your product to break when force is applied (for example a safety seal on a bottle cap), you want tensile strength to be high enough that a child won’t be able to open it, but also low enough that an adult can easily break the seal.

Chemical Resistance, Sterilization and Biocompatibility

A couple of unique necessities that are imperative in the medical field are chemical resistance, ability to be sterilized and biocompatibility. When in practice, plastics that can stand the test of drugs and their byproducts are crucial to medical grade plastics. A pacemaker that can’t withstand beta-blockers after a heart attack does a patient little good when they’ll likely need both for the rest of their lives. With this in mind, the purchaser will need to find another, more resistant, plastic to fill the need of their design.

Products that can be sterilized are another important asset, whether sterilization is by steam, ethylene oxide (ETO) or radiation. Plastic devices like IV tubing, syringes, vials, and countless others all need to be sterilized before use to prevent the spread of bacteria or harmful diseases. Some plastics may be prone to breaking down under the intense heat, pressure or exposure, and can cause harmful chemicals to be absorbed. Likely, you’ll want a polymer that’s strong enough to prevent breakdown under exposure.

In addition to these, the plastics must also be biocompatible, meaning they aren’t toxic to biological systems. Look for plastics that promote cleanliness. They should have a low amount of extractables and leachables, which are compounds that seep out of the plastic. These elements can be harmful and absorb into the skin or be ingested, causing harm or worse.

Barrier Properties and Molding

The plastic you use in medical grade equipment should have good barrier properties for water, gases, microbes and more. Imagine an implant that disintegrates in water or collects microbes (gross, we know). That’s not a good thing for the implant wearer. What about plastic tubing or an emergency inhaler that collects gases from inhaled medication? The patient is getting an unknown amount of medication than they’re prescribed, it’s a dangerous situation with potentially life-threatening consequences.

Your plastic should also have color that’s consistent in appearance, without any marbling or streaks. This indicates that the product you’re paying for is purer for your program and what you intended to purchase. Marbling and inconsistency means that the pellets were cut with another product at the manufacturer, which brings down the cost, but also the quality.

Finally, your product should be easy to form. Dentures with a sharp, hard ridge around the edges? No, thank you. A plastic that’s easily malleable and able to hold shape is a necessity for these types of situations.

Federal and International Regulations

In addition to what you’re looking for as you search for a match to your product, medical grade plastics will also need to meet specific regulatory requirements, including:

  • FDA (U.S. Food and Drug Administration) regulations for food contact
  • RoHS (EU Directive on Restriction of Hazardous Substances)
  • WEES (EU Directive on Waste Electrical and Electronic Equipment)
  • REACH SVHC (EU system for Registration, Evaluation, Authorization, and Restriction of Chemicals, of Substances of Very High Concern)
  • USP (U.S. Pharmacopoeia) Class VI
  • ISO (International Organization for Standardization) 10993

It’s also helpful to reference a Drug Master File (DMF) at the FDA for the resin you’re interested in. A DMF is a submission of information [covering the chemistry, manufacturing and controls (CMC)] of a resin) to the FDA to permit a review of this information in support of a third party’s submission for approval without revealing their information.

As you can see, there are innumerable factors at play when you’re looking for the perfect plastic for your medical grade products. The good news is that there are medical grades available for most of the thermoplastic polymer types that CPA sells, making it much easier to access and able to be quickly delivered. Polymer producers usually identify these grades as being “medical grades” on the data sheets, so be on the lookout for those as you browse for your best polymer. With these tips in mind, you’re ready to choose your product!