Biocompatibility Impact on Autoclaved Silicone

[HelviReg]

Hi everyone,

We currently manufacture an accessory made of silicone, to be used with our parent MD. The accessory is not intended to be sterilized and its biocompatibility has been assessed as such.

We would like now to assess to possibility to autoclave it. According to the silicone manufacturer, that type of material withstands autoclaving. Additionnaly we will perform a verification of the product after being autoclaved (based on our specifications).

However I'm concerned about the biocompatibility status of our product. Can the autoclave adversely affect its biocompatibility ? (as EtO or gamma sterilization do) Can I justify not to perform new biocompatibility tests ?

A second question deals with cleaning agent. Prior to be autoclaved, the product shall be cleaned. Can I justify not to perform new biocompatibility test if I choose some kind of "neutral" agent ?

Thank you very much for your help !

 

[Ronen E]

Re: Autoclaved Silicone - Is Biocompatibility Impacted?

You will need to build a case with a qualified and experienced toxicologist. Alternatively you could try to establish equivalence between the two states of the material (with cleaning and autoclave, and without), perhaps involving some tests. I recommend you discuss this with your 3rd party biocompatibility lab.

 

[Remus]

As far as I know there isn't any data for justification on literature. So either you have to show chemical equivalence according to EN ISO 10993-18 (before and after sterlization) or biocompatibility testing.

 

[planB]

iVivien,

Can the autoclave adversely affect its biocompatibility ? (as EtO or gamma sterilization do) Can I justify not to perform new biocompatibility tests ? A second question deals with cleaning agent. Prior to be autoclaved, the product shall be cleaned. Can I justify not to perform new biocompatibility test if I choose some kind of "neutral" agent ?

You are changing manufacturing processes, and thus, have to walk through the risk management process according to ISO10993-1 again.

In case you have a predicate device at hand, you may be able to assess whether the new cleaning and sterilization process introduce new biological risks or not based on existing data only.

Without a predicate device at hand you have to at least test whether cleaning and sterilization have an impact on

1. the leachables/extractables profile of you product: Typically, you will perform a comparative material characterization study according to ISO10993-18 as Remus suggested, and
2. a comparative cytotoxicity strudy according to ISO10993-5, to assess the manufacturing change with a readily available and sensitive biological endpoint

In case these two studies allow you to demonstrate equivalence, you may be able to make the case for not repeating any further biocompatibility test.

However, in case your change also implies change of intended use, you may introduce additional risks, which need to be addressed:

Since you change from a non-sterile to a sterile device, you may also want to consider bioburden and endotoxin levels. Do you allow/plan for repeated cleaning/sterilization? If yes, you might want to think about device degradation. Do you also change the device's nature of patient contact? If yes, additional biological risks may have to be considered, which were not relevant for the original unsterile device.

HTH,

Gerhard