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Product vs. Process Feasibility for Hydrophilic Coatings

  
  
  
I just got back from an interesting business trip that touched on a central theme: product vs process feasibility.

I frequently get the question "Is your hydrophilic coating good for X application?" Where "X" is anything from bread and butter catheters to the bizarre non-medical application. The answer to that question is never a yes or no. It always depends on who's asking. The proper question is, "Is your hydrophilic coating good for MY X application, under MY circumstances and environments?" This is what product feasibility is really about.

Let's say you have a catheter and you are making over 100 passes with it into and out of the body in a single surgery. I know that's extreme, but stay with me here. Now let's say you ask me the question, "Can I sterilize this twice with ethylene oxide?" For most hydrophilic coatings, in this case, I would answer, "I wouldn't do that, but you can test it and see." Why? Because every time you sterilize a polymeric coating, no matter whose coating it is, you lose a little bit of the coating. Losing coating is a foregone conclusion, but it is ONLY a bad thing if you lose too much. The object is to retain enough coating to be "good enough" to get through one of your procedures with lots of room to spare.

Now let's say a different person comes to me with an identical catheter that only makes 1 pass in a single surgery. It goes in and out and that's it. When asked the same question about sterilizing twice with ethylene oxide, I would answer, "Yeah, I bet you could! But you should test it and see." See the difference? From what I know about my company's coating, I know it could easily handle something like that. (However, I still always make sure to add in that the medical device company that uses it on their device is ultimately responsible for verifying.)

Great, so now we understand how to think about whether or not a coating SHOULD be used on a product. The next question is CAN it?

That is a different question all together. That is process feasibility. If you give a sample to Biocoat and tell us to coat it, we will. We will slap a coating on that thing any way we can, just so you can get a chance to see if it works or not in your application. That does not mean, however, that what we did is reproducible or controlled. It's only research. After or in parallel with your product feasibility testing, you need to think about process feasibility.... and you need to think about it early:

What is the general coating process?

What parameters control coating quality?

How robust is the process? Is it forgiving, or a bear?

How far can I change things like temperatures, speeds, humidity readings, cure times, etc. without messing something up?

How does the geometry of my device affect the coating thickness, adhesion, and lubricity?

What kind of unique equipment will my device need for coating? (Very rarely can two different devices use the same tooling and equipment for coating.)

How repeatable is this process? How much do lubricity and durability vary normally?

What are my cycle times and throughput?

It is quite possible that you will get a beautiful coating on your test device, but later find out you can't scale it up.... or that you can't scale it up cheaply. So, having a coating is not just dependent on the coating itself, but also the process involved with applying it. Thus, both the concept of product feasibility and process feasibility need to be managed simultaneously, and you should always start EARLY.

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