Lubricious Coating: Regulatory & Economic Landscape

Posted by Josh Simon on Thu, Oct 06, 2011 @ 03:54

The folks at MDDI have posted an article contributed by me on the Regulatory and Economic Landscape for Hydrophilic Coatings, in my opinion. Normally I post these musings here, but MDDI wanted to pick up the article from me, so enjoy!

If you are looking for coatings, and want to talk personally with the big players in that arena, do not hesitate to attend the MDM Minneapolis trade show coming up.


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Tags: medical device coating, coatings companies, coatings vendor, coating company, business of hydrophilic coating, coating manufacturer, medical device development, medical device coatings, lubricious coatings, coatings customers, coatings manufacturer, FDA regulation of coatings, coatings supplier

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

Medical Device Coating Processes

Posted by Josh Simon on Tue, Jul 05, 2011 @ 02:56
Coatings exist in multiple industries, aside from medical device coatings. In fact, there is an index of all kinds of coating methods on Wikipediathat is enlightening. When it comes to medical device coatings, I tend to think that the industry is behind on its technology, when compared with circuit board coating technology, for instance. Most of the coating processes in that index are never used in medical device manufacturing, as near as I can tell. The main reason for this is demand. Not all of those coating methods are necessary for medical devices, even though they are required for circuit boards or electronics. So, what are the most-used methods for coating medical devices?

Dip Coating

One of the most common processes for coating medical devices is dip coating. There are generally five steps to it: 1) Surface preparation/washing 2) Submersion of the device in a coating liquid (with a certain dwelling time in some instances) 3) Dip coating machineWithdrawal from the coating liquid, i.e. coating application/deposition 4) Drying and/or Curing of the coating (via heat or UV) 5) Post processing, if any. Especially with heat curing, this is a batch process. With proper equipment, the batches can be quite large, giving a decent effective throughput.

Spray Coating

Spray coat systems use a special nozzle and driver to nebulize the coating solution and apply it to the surface as a mist. Some of these systems, like the one from Sono-Tekuse ultrasound transducers to control spray droplet size, whcih can impact the thickness and quality of the coating. In general, spray coating systems can be set up as continuous processes. While they are often too slow for mass-produced electronics, they can work well for most normal medical device volumes. (Of course, that is not the case if you are in the business of medical disposables sold by the millions per week.)

Reel-to-Reel Coating

Reel-to-Reel coatings are most often seen for guide wires and films. They are usually not applicable to small intricate devices. Essentially, this method is literally what it says it is. One reel of wire or film is unravelled and travels through a resevoir of coating solution and then into an oven for drying/curing, before being rolled up onto the second reel. As far as continuous processing goes, reel-to-reel coating is effective. The trick is to align it with the idiosyncracies of a given coating. It can be difficult to make a reel go slow enough or through a big enough oven to cure a coating, for example.

Robotic Coating

This method is used mostly on complicated shapes, like stents. Tiny nozzles directed robotically can trace along struts and other structures with precision. By dialing in the viscosity of the coating solution, a set amount of coating with a set thickness can cover the surface. If all things are equal with the type of coating, this process is amenable to a continuous system.

Brush Coating

Of all methods, brush coating is most primitive. Using a brush, a skilled operator applies a coating to a surface. Since this is a manual process, there can be a lot of variability in coating quality. However, with skilled operators it can be quite acceptable. Naturally, as one may suspect, this process is not amenable to large volumes. However, it is surprising to inspect some facilities and see 300+ individuals brushing on coating at a rate of several devices per minute. It deserves some consideration.

Spin Coating

In this method, a flat surface is set onto a plate and locked down, usually with a strong vacuum or magnet. A motor then spins the surface quickly, while a droplet of coating solution is deposited at the exact center of the spinning surface. Centrifugal force instantly draws the droplet out away from the axis of rotation, causing the surface to be coated. Parameters like solution viscosity and angular velocity are important for determining coating thickness and quality. It can be difficult to produce large numbers of devices with this method.

Inevitably, there will be other methods for coating medical devices. At this time, these seem to be the most popular. Each method has inherent pros and cons, and not all methods are applicable to all devices or materials.

Tags: medical device coating, industrial coating, dip coating machine, coating equipment, medical device coatings, coatings manufacturer, industrial coatings, Dip coater, dip coating

Medical Device Coating Particulate

Posted by Josh Simon on Tue, May 24, 2011 @ 07:27

At the time of this writing, there is no official FDA Guidance Document detailing allowable particulate from medical devices.  You can imagine that this would be an issue especially in blood-contacting applications.  Particulate escaping into the vasculature can ultimately accumulate in the brain, occluding small vessels and leading to ischemic stroke.  At the very least, insoluble particulates will accumulate in the lymph nodes where they may just hang out forever, participating in a life-long chronic immune response in much the same way those ink particles in your tatoo are doing.

Word reaching my ears from the street is that the FDA is concerned about particulate in medical devices and is asking companies who are developing catheters and other blood contacting devices to run particulate tests.  Since there is no official medical device particulate test, it looks like they are requesting USP 788.

USP 788 is actually a test for particulates in injectible formulations.  It involves streaming a liquid exudate from a device through a sensor that can count the particles, usually with a laser.  Some of the newer equipment used for this can even "see" clear particles and count them.  For medical devices, it looks like the FDA is specifically asking for "Text 1B" in the USP 788 document, which is a test for particulates in a container with a nominal volume of 100 mL.  The allowable limits are also given in the document.

ParticleCounterFor those that sell or use hydrophilic coatings, this is something to look out for.  I dare say you should even design this requirement in ahead of time, even though it is not official yet.  I believe that in the future there will be a medical device coating requirement on particulates.

Tags: medical device coating, coating particulate, USP 788, particulate testing, FDA