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.

Poll: Sterilization methods for hydrophilic coatings

Hydrophilic Coatings for Urological Catheters

I briefly mentioned this issue over a year ago here, and honestly I have been holding back on the subject for a few reasons which I won’t get into. However, now I’m going to ask the question: Why the heck would anyone want to put a hydrophilic coating on a urological catheter?

Seriously, if anyone reading this has an explanation, post a comment or email me.

I will tell you why I think it is not a sound idea.

Urological catheters, by and large, are CHEAP. Foley catheters cost less than a dollar to make. Many other uro-catheters cost not much more than that. In turn, the catheters are sold for only about $2 to $3, for the most part. Think of the many million, if not a billion, Foleys that are sold every year. The urological catheter portion of the market is approaching $5 billion in 2010. Nearly all of these are cheap disposable items that are used for a relatively short period and then thrown away.

Now think of a hydrophilic coating. I don’t care whose coating you think about, whether it’s Biocoat, or Surmodics, or Coatings2Go, or AST, which is similar to Coatings2Go. No matter whose coatings you use, someone has to be paid to put them on. Someone has to be paid to validate the GMP process you use to coat them. They are medical devices after all. If you are talking about volumes of 50,000 to 100,000 per year, you are talking about a cost of at LEAST $8 to $10 PER CATHETER to coat the things. Much of that cost includes labor. The materials cost will vary from company to company, but no matter which company’s coating you pick, you will still pay that much, ultimately…. even if your actual material costs are 5 cents a piece. You will even pay that much if you outsource to a contract manufacturer, maybe more so.

So, again, I ask why would someone pay $8 to $10 to coat a $2 to $3 urological catheter? It’s a mystery to me.

I have been told by elder businessmen that companies sometimes use these as loss-leaders. They take the profit hit on the urological catheters so they can get other products in their product line into the hospital, and these products have a much higher profit margin…. you know, like greater than zero.

The problem with this explanation is I don’t see it. I get calls at least once a day from urological catheter companies seeking to use our coating. Each one usually tells me that these are the only products they plan to have…. They are not loss leaders.

Why should I not dissuade such customers from approaching the likes of us and other hydrophilic coating companies?

Article in Medical Design Magazine

If you get a hold of the May 2009 issue of Medical Design magazine, check out my article there on hydrophilic coatings. It’s a brief history and overview of the technology. Comments and questions are welcome.

A link to the online version of the article can be found here.

New type of antimicrobial coating

A press release in Medical News Today talks about a new type of possible antimicrobial coating in the form of positively charged short chain peptides. In a nutshell, the article talks about the possibilities of immobilizing these peptides onto a surface so they stay active and continue to act against microorganisms. My question is: Since they are peptides, would they set off a chronic immune response at the surface? Depending on the type of implant, that may not be desirable.

Nevertheless, as was discussed at the last BioInterface meeting, the concept of creating a surface that inhibits bacterial colonization and formation of biofilms is a good one. It is unclear to me upon reading the article if the peptides inhibit biofilm formation or if they are actively bacteriocidal. If they are bacteriocidal, it would be interesting to know what kind of half-life they have at the surface, i.e. how long they remain active. The drawbacks of releasing antibacterial agents from surfaces is that they eventually run out and the local concentration of antimicrobial agent can drop below the minimum inhibitory concentration (MIC) thereby promoting drug resistance. Immobilizing an antimicrobial agent on the surface could get around this, depending on how long it stays active.

I wonder if a surface like this could be combined with other agents that inhibit bacterial attachment?

Managing expectations of coatings clients

When developing a medical device, cost is almost always a primary issue. Product development engineers try to piece together the best design they can, and often they find themselves outsourcing components. I have been there. Each time outsourcing is suggested on a project, a mini-battle occurs.

“Why are you outsourcing that?”

“Who are you outsourcing it from?”

“What does it cost and how long does it take to deliver?”

And the all important….

“Can’t we do that ourselves?”

and

“Can’t we do that cheaper ourselves?”

That last questions were always ones that made me roll my eyes. Management professionals tend to not to see the intricacies involved in certain process steps sometimes, and coating steps are notorious for that. For some reason, a lot of project team members and managers think that coating a medical device is a trivial thing. “Hey, why can’t we just dip this thing and be done with it?”

Getting past this first hurdle is important. Developers need to convince their managers that coating is NOT trivial and involves a lot of process design and validation for consistency. After all, these are medical devices. It is not just about dipping it, spraying it, plasma treating it, spin coating it, or what have you. All of those methods have serious process control issues, and QA/QC issues along with that. That’s before you even think about GMP’s.

So, once that hurdle is passed, an engineer is then allowed to call up a hydrophilic coating company, unless he’s doing it anyway before getting permission, which happens too. Then the next most common hurdle arises. Developers sometimes think that a coating system is no more than a Bottle of A and a Bottle of B which you mix together and then dip your widget in it. So they ask, “Hey, can you send me some bottles of A and B, so I can coat some of my stuff?”

The disconnect here is that coating processes can often be extremely technique sensitive. If Joe Schmoe, Development Engineer, does the coating himself without ever seeing it before, chances are it is not going to turn out great, because Joe hasn’t gotten the hang of the nuances. Granted, with time, Joe could learn. However, if Joe coats his widget and it turns out crappy, because he did not have the hang of it, Joe is not going to want to buy that coating. Coating companies are aware of that. They do not want Joe to falter and then lose business because of it.

Alternatively, coatings may require expensive equipment, even to do on bench tops, so Joe would not be able to do it at all.

Either way, the second hurdle is about getting the client company to send samples to the hydrophilic coatings company for test coating. Sometimes this is easy. Sometimes this is a lost sale.

After working for a while with a client company, there is often some surprise expressed at how much there is to think about when putting a coating step into a medical device manufacturing process. So the answer to “Can’t we do that ourselves?” is YES, but there is more to it than you think there is, and if coating medical devices is way outside your core competency or financial means, you may want to think of having a third party manufacturer do it.