From Josh Simon, exclusively for MD+DI:To paraphrase Carly Simon, you probably think this post is about you. It is and it isn't. This post is about many people who have brought up this same exact issue on numerous occasions: making a hydrophilic drug releasing coating.

December 13, 2010

6 Min Read
This Is Your Song: Approaches to the Coating Process

Most commonly, these are sought after by companies in the cardiac stent business, a multibillion dollar per year industry dominated by big-wigs like Cordis and Abbott. However, it is not uncommon for smaller startups to go after these kinds of devices too. It is these startups that usually call me with wide-eyed renditions of how they will take on the big-wigs, with my coatings company's help, within six months.

Their first contact with my company is innocent enough in their eyes: they need to make a decision on which drug releasing hydrophilic coating they will use by next week, so they can move on with the project and be done with it in six months. Moreover, they need to do it on the cheap. (Doesn't everyone?) So, if they could make a decision on the coating next week and do the entire development on it for less than $10,000, that would be great.

Naturally, they want my company to "just stick" some drug into our coating and give it to them and put it on their device and go.

If you are a startup reading this, and you have not seen any problem with what I've written so far, this post is about you.

Let me begin by saying that this type of thing is certainly possible, but not within six months. Indeed, a company developing a drug releasing device with a hydrophilic coating can and should partner with a hydrophilic coating company to help ensure a successful project as early as possible. The "problem" as I see it, is that some entrepreneurs start waving their hands around and ultimately convince themselves wrongly that great things can be done in short periods of time. Here's why their expectations are heavy on hope and light on substance:

* If you are trying to release a drug like Sirolimus, which has already been done with other coatings, that does not automatically mean that all the work is already done. Releasing Sirolimus out of a coating that hasn't been used specifically for Sirolimus before is not much different than releasing a totally new drug out of a totally new coating: you have to start from scratch.

* Starting from scratch means figuring out a basic release profile for the drug, first. Depending on the relative chemistries of the drug and coating, this may not be straightforward and may take months, or even a year if the coating formulation needs to be modified to accommodate the drug

* In parallel with that, you need to figure out how the drug affects the properties of the coating. Does it change the lubricity? Does it change the adhesion? Does that pose a risk of embolism? What other ingredients in the coating might cause issues in the bloodstream?

* Both points above must be proven in animal studies after you have proven them in vitro, along with any other animal testing your team deems necessary

* Finally, once the coating formulation is finalized and tested, you now have to think about manufacturing. Even if the basic layout of a process already exists for your exact device (which it probably doesn't), you will still need to acquire equipment, validate it, and run it. This bullet point is a whole industry and science unto itself, which can take up several more articles, even books.

* As the process design is being completed, do not forget about quality control. What control measures will be used on the coating to ensure quality? How will you determine and validate those?

If nothing goes wrong, the release studies could take six months to a year. The coating properties evaluation will take a minimum of 4 months from the time you have a final formulation, because the aging and sterilization studies must be done on the final formulation. The animal studies will take two to six months if they are just for minor IV devices. The process design, implementation, and construction will take at least six months to a year, and the validation will take about that long too. Again, this is if nothing goes wrong. Some of these things can be done in parallel, of course, but they cannot all be squeezed into less than six months if the coating has never been used with that particular drug before.

You may ask about some large companies that do coatings for drug delivery that seem very successful, and you may be under the impression that these companies can deliver such a thing in less than six months. They cannot. The only difference between one of them and a small company is that the large companies have labs with teams of scientists ready to go where they can start working on your experiments. They still have to do the experiments. It still takes time.

You may also ask about various small companies online that claim to already have drug releasing coatings, whereby you can plug in your drug, or even just use their drug. They do have these. However, they are almost always completely untested. Any company can successfully dissolve a drug in a solvent and mix that with a coating material, and then go on the internet and claim a drug releasing coating. However, do they truly understand the mechanical properties of the coating initially, under aging, after sterilization... and on YOUR device? Do they have any idea how to modify the process they have in mind to put the coating on your device? Most of them do not. They have simply dissolved a drug in their coating and claimed a drug releasing coating. When you go to use it, you will need to do all the testing I mentioned again, anyway. It will take time.

What about cost? The things I have listed here require a lot of labor. If you want to pay $10,000 in labor to get this done, and the coatings company charges a conservative $100/hr, you are saying that they should be able to complete all the necessary research I've just listed in 100 man-hours or less. Good luck. What we are really talking about here is something on the order of $100,000 or more, and yes, at least 1,000 man hours. That's probably underestimating. To get a hydrophilic coating company to commit to something like this, you will need to assure them that you will not bail out in the middle. Chances are, they will need to see this project as something worth doing, and worth dumping other projects for it. If you and ten other companies are calling them up and asking for separately developed drug eluting coatings, the company may not be able to serve all of you. The company will want to serve the best one with a chance of getting through, and the one who has the best understanding of what is involved in a project like this.... probably not the one who thinks it can be done in six months.

—Josh Simon, Biocoat Inc.

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