Selecting materials for implants to comply with ISO 10993 biocompatibility

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shalom1234

We're a young start-up medical device company, and we develop a blood-contact long-term implant. We're evaluating materials to use in our product and should prepare for most stringent biocompatibility evaluation per ISO 10993.
Our suppliers suggest USP Class IV compliance documentation, and general statements regarding "medical-grade" and "biocompatibility", which are not concrete nor relevant to ISO 10993.
We're looking for polymer (PTFE, PVC etc.) to construct the device, and we're trying to get some information to make our initial selection of materials.

Any suggestion on possible biocompatible materials that we should evaluate?
any suggestion on what to ask the suppliers to improve the biocompatibility evaluation?
Thanks!
 

pkost

Trusted Information Resource
I'm not sure our responses here will be of much use, you are essentially asking for a list of polymers that have been implanted into the body with a degree of acceptance from a biocompatibility standpoint. This is long list - there is more than one type of PTFE


I would suggest you put together a spec for your "ideal" material (include tolerances), then approach materials suppliers that specialise in the medical industry with your specific needs
 

Pads38

Moderator
PEEK (poly ether ether ketone) is quite popular for implants now.

You should be able to get a "medical grade" one. It is a good material for machining and you can get mould able grades.
 

rangani_rj

Involved In Discussions
Some examples of plastics/polymers used in Medical device which might be useful to you

http://www.plastics-themag.com/appl...tics/engineered-plastics-keep-the-body-moving

Some points you need to consider while selecting the material are
1) Whether implant is for bone or soft tissue
2) Whether its absorbable/ non absorbable (like sutures and some tissue adhesives)
3) Strength required
4) Leachability or frictional release of particles from implant
5) MRI compatibility
 

planB

Super Moderator
shalom1234,

first you have to focus on the intended use / functionality of your device and choose appropriate material choices accordingly. Only then you start considering biocompatibility.

No general statement can be made what materials are suitable for blood-contact long-term implant other than the final product shall not pose any inacceptable biological risk for these kind of devices. Keep in mind that materials are only precursors, and that manufacturing processes can have a major impact turning a principally suitable material into an incompatible final product or vice versa.

Specifically, when you think of using PVC, keep in mind that when you want to sterilize the product by means of ethylene oxide, you may end up in sterilization residuals beyond the limits defined in ISO 10993-7. Other sterilization methods like irradation may also alter your product material properties into a favourable or unfavourable direction.

You may also want to think about the plasticizers contained in PVC and their bad reputation with potential customers. But they also get closer scrutiny by regulators around the world.

A USP class VI certificate for materials is a nice starting point, but does not spare you from gathering and maybe generate more evidence (literature and /or test data) for a permanent blood-contacting device as part of your biological evaluation process. If your potential supplier claims "medical grade", inquire on what testing according to which standard this claim is based upon. Request summary or original test reports, material data sheets showing purity and nature of additives (sometimes hard to get and not disclosed) including colours, FDA Master File number (if there).

And do not forget the packaging of your final product, which might also have an impact on your final device's biocompatibility.

HTH,

Gerhard
 
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