Lubricious Coatings in spec, on time, and on budget - Part 2

Posted by Josh Simon on Mon, Sep 24, 2012 @ 09:38

In the previous article, I focussed on getting a lubricious hydrophilic coating to market in spec, and what goes into specifications.  I gave references to other articles that can help with finding out more about coating selection.  In this article I want to focus on time, as in, the time to market for a medical device with a hydrophilic coating.

The first thing to do here is point you to an article from this blog called Why You Won't Get Your Coated Medical Device to Market in 6 Months.  This article explains exactly that. 


Next I want to elaborate on some of the points I made in that article about time to market.  The biggest killer of timelines is not taking into account the time it takes to set up and validate a coating process.  I have experienced several cases DipTech Systems where a customer has Biocoat do some test coatings for a client successfully, to then have the client say, "Ok, so let's just have you make another 10,000 and we'll be set."  Hold the phone!  That is not how it works, even if we were a contract manufacturer.  "But why doesn't it work like that?  You made some great samples, just make more!", says the customer.

Understandable question if you are not working for a hydrophilic coating company, so let me explain.

As I have said before, hydrophilic coatings are not trivial.  They are a sophisticated component that forms a substantial piece of the manufacturing process.  There is a big difference between whipping up 4 or 40 samples versus producing 10,000 GMP-grade medical devices suitable for use in vivo.  If I am doing research samples, I can put a coating onto a device anyway I know how, and as long as it works on a small scale, that is all I care about in the initial stage because I just want the customer to successfully test it on an animal or mechanical tester.  Once the device is to come into contact with human subjects, a whole new world of laws and regulations apply.

To make a GMP-grade medical device, a GMP-grade (Good Manufacturing Practice) process is needed.  That requires that each device or lot of devices has a batch record and full set of SOP's for the creation of the device, and all of that made on a process that has itself been validated for its installation, operation, and performance (IQ, OQ, PQ).  There is no magic validated process anywhere in the world for applying a hydrophilic coating to any device that it may come across, even "easy" devices.  Every new device that comes along requires new SOP's and a new process.  That requires time to set up.  Contract Manufacturers make their living by doing this very thing, but even they need time.

Moreover, the scaleup from making 10 to 100 devices is not a one-to-one thing when making 10,000 devices or 100,000 devices.  In each level of production there will be different degrees of automation.  There will be different numbers of each piece of equipment, and different numbers of operators.  This all has to be planned out.

Medical Device Engineers are so focussed on the processes for extruding their tubing and drawing their wires, and validating those processes, that they forget all about the fact that they need to do the same thing for their hydrophilic coatings.  Except here it is worse, because there ARE magic machines and validated processes for making some kinds of tubing and wires, but that is not so for lubricious hydrophilic coatings.

So, again, if you want your coated device on time, make sure you factor in the process development time.  You will need anywhere from 6 months to a year to do this properly.





Tags: lubricious coating, Hydrophilic Coating, coatings vendor, coating company, coating manufacturer, medical device development, hydrophilic coatings, lubricious coatings, coatings manufacturer, coatings supplier

Lubricious Coatings in spec, on time, and on budget

Posted by Josh Simon on Mon, Aug 13, 2012 @ 12:02

Ultimately on this blog, I try to keep the marketing of my own products to a minimum because what I am trying to do here is provide an educational resource.  The title is deceptive, therefore, because I am actually thinking broadly and more literally about how any lubricious coating can be applied in spec, on time, and on budget.  I do this because I was recently presented with a marketing piece from a medical device development company that broke their services down into precisely those three categories.

So, what is involved with getting a hydrophilic coating onto a commercial device in spec, on time, and on budget, and how much of that is dependent on the vendor versus just plain old reality?

Let me focus on specs in this article.  Maybe later I will cover the others.

A couple of years ago, I posted a checklist for hydrophilic coatings.  That post explained many of the questions a potential client should answer before contacting a vendor.  Like the coatings white paper I wrote on the same basic subject, it explains that you need to at least know what the device will be used for, i.e. what industry, what procedure, as well as what the materials used in the device are, among other things.

Once those things are known, there is another layer below that.  For example, lubricity is a broad term to mean slipperiness, but just how slippery should the medical device surface be?  What coefficient of friction do you want?  0.1?  0.01?  Teflon is a great hydrophobic coating that can go as low as 0.1, but true hydrophilic coatings are needed to get to 0.01. 

After understanding the friction (or lack thereof) at the surface, what sort of use will the device experience?  Is it going to be quickly inserted in vivo and then removed after a few seconds, or is it going to abrade against the inner lumen of a blood vessel, or maybe even another hard plastic catheter?

Being able to tell your coating vendor what you want is important, and that is independent of the coating vendor.  In some ways, most hydrophilic coatings on the market are the same, but they do differ in other important ways as far as processing, composition, and business models.  They also can influence the other two pieces of this puzzle:  time and budget.

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Tags: medical device, advanced coating, lubricious coating, medical device coating, Hydrophilic Coating, medical device development, medical device coatings, hydrophilic coatings, lubricious coatings

Lubricity Testing - Manipulation of Data for a Smoother Outcome

Posted by Josh Simon on Thu, Jul 05, 2012 @ 04:27

I've been locked in my office all day today working on the slides for this upcoming webinar.  You can registor for it by clicking this link:


 Coating Pinch Test Webinar


Depending on how you test a hydrophilic coating, you will get different outcomes, for the same coating, and some may be "good" and others not.  Moreover, companies that sell hydrophilic coating frequently "massage" the data, usually by leaving out some particulars, to make their coatings seem more lubricious or durable than they really are.

What I aim to do here is not directly attack printed data, but rather educate the public on the proper questions to ask about data, so they can think critically about it themselves.  I will go over several different types of  lubricity and durability tests, as well as their pro's and con's, and then focus on a particularly common coating test called a Pinch Test.  From there, I will talk about how you can get different results from that test depending on how you run it, and what things you should look out for when trying to make "apples to apples" comparisons between lubricious coatings.

The slides should be informative and I at least try a little to make them entertaining as well, so come on by!

Tags: lubricious coating, Hydrophilic Coating, penton webinar, pinch tester, pinch test, hydrophilic coatings, lubricious coatings, Webinar, pinch testing

Why you won't get your coated medical device to market in 6 months

Posted by Josh Simon on Wed, Jun 13, 2012 @ 04:23

If anyone has ever been starry-eyed, it's me.  "I am going to get my PhD in only three years!"  "I will have all this extra money with this new job!"  "I will probably retire at 55!"  Of course, at that point reality rudely awakens me.  Shucks.

I am not old yet, but I am old enough to try and catch myself now when I start convincing myself about things like this.  I smile it away and shake my head.  Back to reality.

So it goes for other people, too.  In my job, the one I hear most often is, "I will get my medical device with a hydrophilic coating through clinical trials and to market in six months!" 

Well, if today is the first day you have talked to me about a hydrophilic coating on your medical device, no you won't.  Sorry!  Maybe six months from now, if all goes well, you can say that, but certainly not in our first conversation.

I have written similar articles on this blog before, and I still need to get the word out:  Hydrophilic coatings are not trivial.  They are sophisticated and advanced additions that add real value to some medical devices, and they require an entire level of attention to detail, all their own.

If you are coming to me with a six-month deadline to market, you are TOO LATE.  My next line to you will be, "Can you extend your timeline?"  By the way, this does not only occur with inexperienced startups developing their first medical devices.  This sometimes happens with veteran engineers too.

So, why then?

It breaks down into a few reasons:

  • Coating equipment always needs customization
  • The coatings themselves often need customization
  • Ordering machinery has a lead time
  • IQ, OQ, PQ take time
  • Devices with coatings must go through Verification and Validation, as per Design Controls, at least in the US
  • Clinical trials, at least in the US, require an IDE if they are significant risk, which takes time to get
  • FDA Clearance or Approval always takes at least 60 days

So, just do the math.  A proper aging study on a hydrophilic coating takes 4 months if you want a three-year shelf life.  You can do other things in parallel with that, certainly.  The lead time on the equipment alone can be four to six months, so even if you get the equipment in just three months, you still need to do IQ, OQ, PQ on it.  Also, this is if the type of equipment is exactly known from day one.  That never happens because every catheter shaft has holes at different spots, or different diameters, or shapes, etc, or maybe it is not even a catheter so it needs a different kind of machine invented entirely.  However, will that be possible if you still do not have your coating formulation nailed down yet?  If you are assuming that you will get a perfect coating on your first sample run and simply scale things up from there, you are mistaken most times.

These things take time.  Believe me, I would also love it if you could get to market in six months.  It makes the money come in a lot faster.  Reality is different.  Usually all of these things take the better part of a year, if everything goes smoothly, and in many cases they take the better part of two or three years.

I do not want to discourage anyone from trying a coating.  It can add real value to your device, and some devices may not be able to exist without one.  I do want to educate people about how long this stuff can take, however.

Tags: advanced coating, lubricious coating, medical device coating, Hydrophilic Coating, process development, medical device coatings, hydrophilic coatings, lubricious coatings

Lubricious Coating - HydroSleek2 Information

Posted by Josh Simon on Wed, Jun 06, 2012 @ 10:45

I would like to draw your attention to a new video available that details a new lubricious coating called Hydrosleek2.  To access the video click on the button below, and enjoy.

Within the presentation, you will find information on coefficient of friction and processing of the coating, both before and after sterilization and aging.  In previous posts I have talked about the importance of this sort of data:  a company displaying friction data must qualify whether the data is for aged and/or sterilized coating or virgin coating.  They must also talk about the nature of the testing that was performed on the coating to obtain the friction data, especially for durability.  Recall a study we did on the effects of pinch testing parameters on hydrophilic coatings


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Tags: lubricious coating, medical device coating, Hydrophilic Coating, Biocoat, hydrophilic coatings, lubricious coatings

Hydrophilic Coatings Particulate

Posted by Josh Simon on Fri, May 11, 2012 @ 02:54

As promised to one reader, I am putting a little bit more information here on particulates and particulate testing with regards to hydrophilic coatings.

The first thing I want to do is point you to some great information on general theory and the regulatory status of particulates for medical devices.  There is an excellent article by Susan Reynolds and Ryan Lunceford on the basics of particulate testing.  It talks about the prevalent use of USP 788, as I have done in my previous article on medical device particulates here, including some specifics on the differences between laser counting versus microscopic counting of particles.

The article is a few years old, and at that time, the AAMI was not yet finished writing its report on setting medical device particulate limits.  However, now that report is out, and you can find it here.  Personally, I found it a little vague.  It does not give any sort of concrete limits to follow, and is not any sort of draft guidance.  It is good for figuring out how to think about this when going about your own particulate tests, however.

One item touched on by both the AAMI report and the article is composition.  Specifically for hydrophilic coatings and/or lubricious coatings, these particles have characteristic identities.  Like anything else, a major consituent of particulate could be clean room dust, which originates from human skin or clothing, or other particles tracked in from the outside.  However, after abrasion, it can also be due to coating wear particulate.  In fact, one method of testing durability for a hydrophilic coating is to run it through a tortuous path test and then measure the amount of particulate in the path after multiple cycles.  For increasing number of cycles, you can track the increase in particle count.

Again, this is just an idea and not a standard.  There are no suggested limits for a test like this right now.  Everything in this field is at this point "unregulated", and we are all concerned about what the FDA will eventually do to throw a wrench in the innovation in the name of hypersensitivity. 


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Tags: lubricious coating, Hydrophilic Coating, medical device coatings, hydrophilic coatings, lubricious coatings, particulate testing

Biocoat Releases Three New Hydrophilic Coatings

Posted by Josh Simon on Mon, Apr 30, 2012 @ 03:50

Biocoat, Inc., maker of lubricious HYDAK® hydrophilic coatings introduced three new hydrophilic coatings for medical devices to its classic lineup. "HydroSleek2", the new successor to the original HydroSleek lubricious coating, with improved processing and biocompatibility. "The HydroSleek Kit" is another variation on the HydroSleek coating, which allows the product to be stored and transported under a wider array of conditions. Third, the "Hydak® T-040 Kit" is a remake of another classic, Hydak® L-110, also allowing for wider availability to Asian and European markets.

All of these coatings are based on high molecular weight Hyaluronic Acid (HA). This technology has applications among a range of fields including ophthalmology, urology, cardiology, endoscopy, and neurovascular. HydroSleek coatings have overcome the trade off between lubricity and durability seen in cross-linked coatings. Additionally, HydroSleek involves a heat-cure process so both ID and OD may be coated without the concerns surrounding UV curing.

These new products will act as Biocoat's front line solution to medical device firms seeking to reduce surface friction for their devices. Each of these new products possesses the same beneficial characteristics of the family of HYDAK® coatings, plus advancements device manufacturers have requested.

For further comments or questions, email Dr. Josh Simon, Senior Product Manager at jsimon at biocoat dot com.

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Tags: lubricious coating, medical device coating, Hydrophilic Coating, Biocoat, hydrophilic coatings, lubricious coatings

Lubricious Coating Biocompatibility - Verification

Posted by Josh Simon on Wed, Mar 28, 2012 @ 03:03

At the request of a fan of this site, I am devoting a post to Verification of biocompatibility of lubricious hydrophilic coatings.  Next article, I might talk a little bit about particulate and give an update on that, so stay tuned.

The first thing you need to do when looking into biocompatibility for a medical device, coated or not, is think about your application and categorize it on this chart:

biocompatibility chart

For most hydrophilic coatings, the application requires a Limited exposure (<24 hrs) in a Circulating Blood environment.  Therefore the chart reveals that you will need to do cytotoxicity, sensitization, irritation, systemic toxicity, in some limited circumstances genotoxicity, and finally, haemocompatibility.  If your application is different, look it up on the chart and see which tests you need.

First, make sure that your devices are tested exactly as they are delivered clinically, i.e. coated and sterilized.  You do not want to find out that your coating is fine but when sterilized it suddenly becomes cytotoxic, for example. 

The other thing you really should do is look at each bicompatibility test and understand how it works.  Do not just send out your samples with a checklist and rely on the results without thinking. 

For example, the cytotoxicity test can be complicated, and that's one of the simplest ones.  There are different variations on the MEM Elution test.  In the first phase, the test article is submerged in a fluid to extract substances into it.  This extraction can be done at different temperatures and for different lengths of time.  Obviously a longer extraction time at a higher temperature is the toughest test.  If you think you can pass the toughest test, go for it.  If you can't, then you just need to go for the test that is acceptable to the Regulatory body you work with.  In the second phase of the MEM Elution test, the extracted solution is exposed to cells, usually L929 fibroblasts.  This extraction can be done for different lengths of time too, from 24 hrs to 72 hrs.  The longer the exposure, the tougher the test.  Extractions can also be done with polar and non-polar solvents, and the tests can be run by weight or by surface area which has a big effect on the results.  Usually for hydrophilic coatings, you want to run the test by weight.

There are also vendor differences for these tests.  For example, they use different amounts of serum in their media, and some add antibiotics to the solution and some do not. Ask your testing vendor to see the protocols.  I am not able to conclude whether or not these protocol differences influence results but I can definitely tell you that different vendors give different results.  In my experience, Toxikon is really easy to pass, almost too easy, whereas Nelson Laboratories is tougher, but very reliable.  NAMSA is somewhere in between, and Apptec is probably on the tougher side.  Again, this is just my experience.  Your mileage may vary.

Generally, you should just figure out the minimum test protocol your Regulatory body will accept, and do that.  As long as in reality your device is not harmful to humans, you can rely on the results.





Tags: lubricious coating, biocompatibility, Regulatory, hydrophilic coatings, lubricious coatings, cytotoxicity

Verification of Lubricious Coatings on Medical Devices

Posted by Josh Simon on Wed, Mar 21, 2012 @ 10:43

I have hinted much on this blog about ways to go about verifying hydrophilic coatings on medical devices.  When I speak of "verification", I am talking about the first "V" in "V&V", i.e. the Verification step in Design Controls that may or may not precede a Validation step, depending on the device.  As you may quickly realize, speaking about specific verification steps for any device is a huge task, because verification is nothing more and nothing less than confirming that design inputs = design outputs.  Does your device prototype meet specification?  Since every device in the world has different specifications, it is impossible to come up with ways that apply to all devices.

However, for lubricious coatings there are some general themes that pop up which are widely applicable, even though specific verification tests may vary per device. 



In all but rare cases, if you are coating a device, you want the coating to stick, at least for a while.  You may not care if the coating ultimately resorbs, or you might care.  However, in most cases, you would not be satisfied if the coating flaked off and left material behind in the body.  Thus, some sort of adhesion test is necessary.  For flat surfaces, ASTM D3359-78 may be appropriate.  This is known as the "tape test". Modifications to this test would be necessary for curved or irregular surfaces.  Adhesion can also be tested with a pinch test indirectly.


If using a lubricious coating, you obviously want it to be slipperier than a device without the coating.  Thus, your verification process will require some testing of lubricity against a control, and/or to your spec.  Pinch testing is also an option for this, and you can click on the button below to get an article that goes into details on that.  There are also other tests you can rig up, such as an anatomical model for sliding your coated article through it and measuring force or ease of insertion/withdrawal.  The pinch test paper mentions four major kinds of lubricity tests. However, the limitation of most lubricity tests is that they do no correlate to clinical use.   Despite this limitation, they can still be a good basis for making an engineering decision.


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Most sterilization testing involves bioburden analysis, i.e. making sure that you get a 4-log kill (or whatever your spec states).  The other thing to think about is how the sterilization method will affect your coating, so you will need to do coating performance tests after sterilization, as well as before (if that is still relevant to you).  Performance testing can be the same type of tests mentioned above for Adhesion and Lubricity.


Once you have a favored set of tests and output variables, such as lubricity via pinch testing, or adhesion via tape test, you can keep using those tests over and over for environmental effects, such as Aging.  Does your coating remain lubricious after aging?  This can be accelerated aging, but make sure the conditions of acceleration do not adversely affect the coating.  For example, if your coating is sensitive to water vapor, do not run an aging study at 100% Relative Humidity, because it will not correlate with real time.

Transportation and Handling

How will people treat your lubricious coating on the road, in the doc's office, during shipping, at the patients' houses?  The first step is to do a shipping study.  Send the coated article somewhere and test its performance.  Make sure it stands up.  From there, you can gradually get more nasty by subjecting it to harsher environments, mimicing the trunk of a sales rep's car on a hot day in Puerto Rico, for instance.  Again, you will be using your preferred performance output variables.

Differences in testing will be dictated by what your device actually is.  Is it an IOL Cartridge?  Is it a Jamshidi needle?  Is it a coronary guidewire? 

Also, this list is by far not exhaustive.  I have not even mentioned things like biocompatibility and particulate testing.  I wonder if I should make several parts to this post?


Tags: medical device, medical device coating, lubricity, medical device development, medical device coatings, hydrophilic coatings, lubricious coatings, lubricity testing

5 Critical Questions to Ask About Pinch Testing Data

Posted by Josh Simon on Thu, Jan 26, 2012 @ 04:54

Pinch testing data can be used to make or break a lubricious hydrophilic coating.  It can also be used to lie.  When you see any graph depicting lubricity and durability for a coating, it is time to stop and take a breath before absorbing the data.  Ask yourself about the nature of the test used to get the information. 

pinch tester

Some hydrophilic coatings can be painted as amazingly slick and durable, but when put to a rigorous test, not so much.  Others shine and duke it out among the top.  I will soon be publishing a white paper demonstrating how differences in testing methods can make big variations in friction outcomes.  Below is a preview table of the 5 questions to ask yourself whenever you view friction data for a lubricious coating.



For what Load does the current data display?

Tests using lower loads can give the appearance of a durable coating.

What is the pinch pad material used in the test?

Soft pinch pad materials are easier on the coating, and can portray favorable results.

What is the substrate material used in the test?

Soft substrates are easier on the coating, and can portray favorable results.

Was the test conducted under saline, pure water, or dry?

For medical devices, performance in saline is most clinically relevant, but dry or pure water performance can be used to artificially portray a coating in a positive or negative light, compared to actual in vivo performance.

How many cycles are displayed in the test data?

Low cycle numbers may not show a difference between two coatings, or be used to sidestep durability issues.

Tags: lubricious coating, medical device coating, pinch tester, medical device coatings, lubricious coatings, pinch testing, lubricity testing