Biocompatibility of Lexan 244 - Is anyone using Lexan 244?

yodon

Leader
Super Moderator
Hello all,

We have a client that has a product that fluid flows through and then eventually enters the body. The device is also 'advertised' such that it can be strapped to the body (direct contact with skin, possibly wounds).

When they were first cleared / first developed the product, they chose Lexan 244 for the case (which can contact skin) and for a connector in the fluid path. At the time, Lexan 244 was advertised by GE as cleared for medical devices. Apparently now, though, that claim has been rescinded (by GE). Apparently they are not saying it's not safe, just not saying that it is cleared.

They don't have any biocompatibility testing since it was previously considered safe for use.

Does anyone have any experience with this material in a device? They're a small shop and may not be able to afford biocompatibility testing but they may not have a choice. Any advice? Thanks.
 
M

MIREGMGR

As far as I know, once the FDA has granted pre market approval to a Class II device, that approval lasts forever even if the pre market approval rules change or the science changes.

For instance, we have a 510(k) from 1978, when there were no FDA procedures or guidelines to speak of. One of my predecessors simply wrote the FDA a letter, about a page and a half long, telling them what the device class was intended to do, the general materials from which it would be made, and some general info about the intended labeling. They wrote back to approve it, and it's still in effect.

Maybe there are exceptions to this, but as far as I know in the general case, legal biocompability status for a particular material formulation once attained is persistent, and the same with pre market approval for a device design as long as it remains unchanged.

So if you're still using the same Lexan grade, and you don't have specific knowledge that GE/Sabic has actually changed its formulation...as opposed to just become more conservative about making a biocompatibility marketing claim, given the onward march of scientific discoveries as to ways that plastics can be bio-harmful, followed closely by the plaintiffs' attornies...then I think your pre market approval would remain in effect as well.

Of course, if on the other hand you have some knowledge that the formulation has actually changed, or you've already changed the formulation number you use, then a Special would been needed (or would already have been filed) to update the PMA status.

Of course, on the other hand if GE/Sabic's science knowledge now is such that they're aware that the material has an established harm mechanism, and anybody within your client has become aware of that fact in the course of continuing engineering and sourcing interactions with GE/Sabic, continuing to use the material might entail accepting a very bad liability position, in addition to being ethically problematic.

Is this problem possibly recent and related to the oncoming concerns about long term bisphenol A hormone-mimicking behavior? My company is beginning to think about replacing polycarbonate in patient contact applications because of that one, irrespective of published ratings or short-term-exposure biocompatibility data. Partly because of the Canadian ban for some applications and the current activity toward a similar California ban, we've had roughly ten distributor/OEM-customer questionaires within the past two months asking that we state for the record whether particular products contain any bisphenol A.
 
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yodon

Leader
Super Moderator
As it turns out, I misunderstood just a bit. The lack of 'support' for medical grade has been withdrawn on a different grade of Lexan. I'm not even sure why the client mentioned it since it's not used and never has been used.

Ajit, you are right about 244R, sort of. I did find it on the SABIC site but it's listed as discontinued. My client is saying that their contract manufacturer is still able to get it, though. No telling how much longer, though.

So the real question is if anybody has any biocompatility data on Lexan 244? Thanks for the replies so far.
 

Al Rosen

Leader
Super Moderator
As it turns out, I misunderstood just a bit. The lack of 'support' for medical grade has been withdrawn on a different grade of Lexan. I'm not even sure why the client mentioned it since it's not used and never has been used.

Ajit, you are right about 244R, sort of. I did find it on the SABIC site but it's listed as discontinued. My client is saying that their contract manufacturer is still able to get it, though. No telling how much longer, though.

So the real question is if anybody has any biocompatility data on Lexan 244? Thanks for the replies so far.
I believe you will need your own data based on your own device and its use unless you can show its use in marketed device with the same use. If you haven't already, look at the blue book memo G95-1.
 
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M

MIREGMGR

I believe you will need your own data based on your own device and its use.

My understanding of the current requirement for material biocompatibility evidence is freestanding data per ISO 10993. That data could come from one's own commissioned testing, or from the material manufacturer or the original resin manufacturer, or from some other source if the provenance of the data can be appropriately established.

I don't know of a way that the specific nature of the intended device design and use would enter into ISO 10993 qualification of a raw material, other than in determining which ISO 10993 tests are applicable.

For FDA qualification, that ISO 10993 test applicability would be determined per guidance document G95-1 and its Table 1.
 

Al Rosen

Leader
Super Moderator
My understanding of the current requirement for material biocompatibility evidence is freestanding data per ISO 10993. That data could come from one's own commissioned testing, or from the material manufacturer or the original resin manufacturer, or from some other source if the provenance of the data can be appropriately established.

I don't know of a way that the specific nature of the intended device design and use would enter into ISO 10993 qualification of a raw material, other than in determining which ISO 10993 tests are applicable.

For FDA qualification, that ISO 10993 test applicability would be determined per guidance document G95-1 and its Table 1.
Looks like I was editing my post at the same time you were posting.
 
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