Implantable Hydrophilic Coatings

Posted by Josh Simon on Mon, Nov 21, 2011 @ 03:59

In a previous blog post on permanent hydrophilic coatings, I noted that really all hydrophilic coatings have some sort of bioerosion, degradation, and/or resorption rates in vivo.  For most coatings of this nature, those rates are high, which means they are not always suitable for implantation.

Honestly, that's a rather broad and general statement about the utility of implantable hydrophilic coatings.  In reality it goes back to a question I like to ask a lot on this blog:  What is your application?

Let me break that out into some more specific thought questions:

What kind of device do you want to coat?

WHY do you want to coat it?

Do you want it to be slippery?  Non-thrombogenic?  Closely associated with water to prevent fogging or misting?

Given your answer to the question above, exactly WHEN do you want the coating to possess those properties during the life of the device?  Pre-implantation? During implantation?  During explantation?  The whole time?

Given that last answer, how long is that time period?  Minutes?  Hours?  Days?  Weeks?  Forever?

In many cases, for example in the case of an implantable cardiac pacemaker, surgeons may be complaining that it is difficult to squish the leads into place during the procedure.  A lubricious coating might help with that.  However, once the device is implanted, who cares about what happens to the coating as long as it is biocompatible?  Or maybe I should ask:  do you care what happens?

If you do care, then you need to ask yourself why.  Is there some other function a slippery, non-thrombogenic, water-loving coating will serve a purpose after implanting that pacemaker?

Most of the time, when clients come to me asking for permanent hydrophilic coatings, it actually turns out that they do not need them to be permanent.  They just need them to fulfil a temporary role, which the coating can do easily, and then when it goes away it is of no consequence.


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Tags: advanced coating, lubricious coating, medical device coating, Hydrophilic Coating, biomaterials, hydrophilic coatings, lubricious coatings, non-thrombogenic coating

Leachables vs. Extractables - Hydrophilic Coating Considerations

Posted by Josh Simon on Mon, Sep 26, 2011 @ 10:00

The Qmed blog has an insightful article on differentiating between leachables and extractables in medical devices.  Though the article does not specifically mention lubricious hydrophilic coatings, it is still an important consideration. 

Something to know:  All hydrophilic coatings contain multiple ingredients, some of which are not completely bound within.  Even crosslinked coatings that purport to be chemically resistant still contain unreacted products from whatever reactions are used in the crosslinking.  The article at Qmed makes us aware that these sorts of leftovers can either leach out or be extracted out, and there is a difference.

The author notes that leaching occurs under "normal" conditions of use, i.e. what will come out of your coating when you place it in the body at 37C for some length of time?  Extraction is what happens during exaggerated conditions, i.e. what will come out of the coating at 50C in an acidic water bath, or an oil bath?

Extractables can give clues to what the leachables might be.  They can also tell you how stable your material is, chemically.  The presence of an extractable is not necessarily a show-stopper.  Unwanted leachables might be harder to explain, however.  Either way, both of these things will make up part of the larger picture of biocompatibility for your material.


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Tags: lubricious coating, medical device coating, Hydrophilic Coating, biomaterials, medical device development, medical device coatings, hydrophilic coatings, lubricious coatings, FDA regulation of coatings, extractables, leachables

Hydrophilic Coatings Webinar Available Online

Posted by Josh Simon on Fri, Sep 23, 2011 @ 02:11

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An archive of the webinar we recently announced on hydrophilic and hydrophobic coatings is now available to everyone for download.  Please stop by and grab the file and listen to it.

Click here to download the hydrophilic coatings webinar.

The webinar was sponsored by Biocoat and Specialty Coating Systems. Half of the presentation by Josh Simon is actually about hydrophilic coatings and the second half by Lonny Wolgemuth talks about hydrophobic coatings. Remember, hydrophilic means "water loving". Hydrophobic means "water fearing". The webinar sets the record straight on which is which and why you would want to use some in specific applications.

For both coatings, lubricity is discussed, i.e. how slippery they are respectively, as well as some basic mechanical properties and medical device applications. 

All in all, I am told this is a pretty good overview of coatings, and it is a nice place to start if you are just beginning your research on this area for possible future products or medical devices. 


Tags: advanced coating, lubricious coating, medical device coating, Hydrophilic Coating, hydrophobic coating, Biocoat, parylene, coatings companies, coating company, business of hydrophilic coating, coating manufacturer, biomaterials, basecoat, durability, durability testing, coating cost, coating costs, Specialty Coatings Systems, medical device coatings, hydrophilic coatings, lubricious coatings, coatings customers, coatings manufacturer, coatings supplier