3 Step Process to Evaluate Plastics for MedTech

Finding the proper plastic material for your medical device, in-vitro diagnostic or pharamceutical packaging is vital. Not only for patient safety. But also for production cost, product compliance, the ability to deliver and your companies sustainability. Therefore a structured material evaluation process is essential for not only determining all stakeholders requirements, but also the documentation and tracability of samplings and material recommondation as well as final plastic choice.

1. Define your Requirements properly

The material evaluation starts with the most vital point. The requirements. Here you involve the relevant stakeholders and their requirements. Keep in mind, that stakeholders will be thinking in terms of product or customer requirements and your job is to translate these into material requirements. A structured interview with the stakeholders will reveal these requirements most efficiently.

The following incomplete list of aspects has to be considered:

  • Intended use and patient contact
  • Target markets
  • Production location
  • Necessary Production environment according to ISO 14644
  • Target Price
  • Color
  • Material Compliance and Biocompatibility
  • Technical Properties such as mechanical, physical, thermal, chemical or tribological properties needed in order to fullfill the product requirements
  • Sterilization and other post processing requirements
  • Processing method and process requirements
  • Sustainability Requirements

Some of the requirements are difficult to translate into material requirements. For example the specified plunger friction of a syringe is difficult to translate into friction coefficients without significant effort. In these cases proxy requirements can be defined instead of material properties. In the above mentioned syringe examples one would simply mold syringes and test the plunger friction on the final part. These samplings and tests will be carried out in stage three of the material evaluation.

It is of the utmost importance to conscientiously gather all requirements from the stakeholders. A material evaluation is only as good as it’s material requirements and in case requirements are wrong or missing the material evaluation cannot discover these flaws. The GIGO (garbage in, garbage out) principle of computer science applies also to material evaluations.

It is advisable to review the material requirements in the team to identify eventual flaws. The team is also responsible to define the priorities of the material requirements. It has to be clearly defined which requirements are MUST and which are NICE TO HAVE. After release of the material requirements the material expert can go ahead and scout for possible medical grade plastics to be used.

2. Search for several medical grade alternatives

There are several ways to optain potential medical grade plastic candidates. One option is of course to scout the materials already in use. There are several advantages in using materials that are already used in your company. There is no need to open new suppliers, create and maintain a new material ID, there is also a potentially tremendouse experience with the plastic grade already existing in house. Logn term processabiltiy is known as well as regulatory compliance and customer acceptance.

Sometimes however a totally unknown material has to be scouted for. Maybe you are looking for a sustainable alternative or your innovating in a completely new field. In this case you have two options. Material databases and supplier contacts. Both of them can be equally usefull but both have there drawbacks.

Material databases such as UL-Prospector and CAMPUS Plastics, can be very usefull. However pro-versions of material data bases can cost a few thousand bucks a year. Unfortunetly that is were all the really usefull tools are.

Your suppliers on the other hand will supply you with material reccommendations and material data as much as they can. However their search field will be limited to what they have in their portfolio. If you rely soly on supplier reccommendations you are best adivsed to include several of your potential suppliers in your search.

After your have composed a potential plastic material list, you can start to compare the alternatives on a paper basis. Sort out the plastic grades that violate your MUST criteria. Then you can proceed to compare and rank the materials. At this stage one would usually also request material certificates, price offers and avialabilities. After a comprehensive data comparison a selection of the best materials should be recommended for sampling.

3. Sample, Test and Decide

You have your material recommendation, now the real work begins. Sample your product with the different recommended materials, conduct the required tests to verify your requirements. These tests may include:

  • Processabiltiy tests, short term and long term
  • Sterilization studies
  • Metrology
  • Short term mechanical properties (Burst pressure, tensile testing, kink testing)
  • Long term mechanical properties (fatigue, creep, relaxation)
  • Chemical resistance
  • Barrier Properties
  • Tribology (such as plunger friction)
  • Biological saftey tests (ISO 10993 ff, USP VI, ISO 18562 ff or similar)
  • Electrical safety tests
  • Product performance tests

After this potentially long and effortful jorney you have condesed all your test and sampling results into the essential information for a material decision. The only thing left to do is now to gather your stakeholders and validate your material choice. After documenting the decision your job is done.

For further info on how to exacly execute these steps or how to set up the process of the material evaluation please contact Gradical, we can help!