One of my avocations when I’m not completely immersed in the wonderful world of medical device labeling is kayaking.  Not the shoot the rapids type of whitewater kayaking in a boat that resembles a giant clown shoe, but sea kayaking on Lake Superior for multi day trips in long, skinny boats.  We don’t always find beer (see Shelf Life post earlier) but its always interesting and exciting.  Minnesota, a state that loves a good fee as much as any state, has us register our kayaks and, in exchange for our Krugerrands, give us two nice 4 x 4 labels with a big date on them to stick on our boats.  This allows law enforcement to easily view the date and fine us if it’s expired.  A stickers is issued for each side of the bow.  I noticed the other day that the port sticker had ‘fallen off’ my boat.  This sure looked like a classic adhesive failure to me but which adhesive property caused the failure?

There are  3 basic properties of pressure sensitive adhesives.  The first one is tack or quick stick.  It is the force of the label being pulled directly away from the substrate being labeled.  Depending on what you are labeling, aggressive tack can be good or bad.  Most hot melt adhesives have high initial tack while most acrylics have lower tack and adhesion that builds over time.  If you are slapping a label on a damp 35F milk jug or a small diameter vial then tack is desirable.  If you are labeling an expensive part or have critical positioning where the label might need to be adjusted, then that high initial tack is a bad thing.  Tossing or reworking mislabeled packages is something that line personnel hate almost more than anything.

Shear is the force across the adhesive, the ability to slide on a surface.  Shear is probably the least important of the three main adhesive characteristics for medical device packaging but it can be important.  If the label falls off, it may have really, really low shear properties on that particular substrate.  The one classic example of shear coming into play on a device package involves a cardiac product and a polyprop box that replaced a paper based set up box.  During ETO cycles the paper label wrinkled due to the expansion and contraction of the polyprop box.  By recommending an adhesive with lower shear the label was able to react and move a bit with the box and avoid wrinkling.  It still adhered just fine.

Last but certainly not least we have peel.  Peel is a crucial as well as easily measured characteristic.  There are ASTM tests and various 90 degree and 180 degree peel testers, a couple of which we have in the AW packaging lab.  There is also the time honored standard of picking at the corner of a label with the fingernail, lifting it, and either peeling it off cleanly, wrecking the label, or wrecking the substrate its adhered to.  The ensuing comments from ‘damn that came off easy’ to ‘s**t, I just trashed the label and package’ can be discussed and evaluated.

The three of course, are related.  If you think of a teeter totter, tack is the fulcrum.  Peel and shear are generally opposed.  A high peel strength adhesive generally has low shear strength and an adhesive with high shear generally has pretty low peel values.  Either one can have high or low tack.  With most device applications shear is the fat kid on the teeter totter, low on the ground and peel is the skinny kid, way up in the air.  The tack fulcrum can be either high or low depending on how strongly you want that label to stay on the package initially.  Tamper evident seals that go around a 90 degree angle come to mind, especially ones with the reinforced tear strip.  Those need some initial tack to stick reliably in order to give the adhesion time to build to full strength for the tamper evident feature.

So what the hell happened to my kayak registration sticker?  Taking the substrate out of the equation (that could be another whole post), most registration/license tab adhesives have very high tack.  The sticker was on there for a few months, plenty of time for the peel properties to build to full strength.  Shear is not an issue because I can’t imagine it sliding off the boat.  That leaves peel.  I suspect that someone, using the manual peel test I described above, heisted the thing because they were too cheap to register their own kayak.  No, you conspiracy theorists out there, I didn’t peel it off to stick it on another one of my kayaks.  I tried peeling another expired one off and it was extremely difficult but not impossible.  The bottom line is that it could not possibly have fallen off and  I guess that’s the end goal for our medical device packages as well.  It can’t fall off.  Peel strength criteria is set, hopefully using a pass/fail criteria of some sort, in the validation and qualification process, and the label and package are on their merry way to the end user.  Now all I have to do is decide whether to spring for the six bucks for duplicate stickers or attempt to talk my way out of a fine if the warden spots me.  Advice will be appreciated.

A few years back I had a couple  hernias repaired using surgical mesh, a product much like those rolls of garden mesh that keep hilly areas on your property from eroding.  When asked in post op to describe my level of pain from 1 to 10, I was unable to come up with a number because at that point the anesthesia made it impossible for me to locate my own ass with either hand.  However when asked if I’d like a morphine drip I knew the answer to that question immediately.  Surgery went great and I was back at my desk early, wading through emails.  About the 5th one I looked at was an FDA alert describing counterfeit hernia mesh that had been discovered in the US healthcare system.  I got on the phone to my doc, who knows me well and kept waiting for the punch line when I described the ersatz mesh.  I had to send him the email, more than a bit perturbed that a lowly label bum knew about the problem before the guy that probably stuffs several of these mesh products into patients every week.  As it turned out I was fine as the mesh that was placed in me, ruining the look of one of the finest navels around if I do say so myself, was from a different manufacturer than the one the counterfeiters had targeted.  It may or may not have helped, but having an additional level of security provided by a well designed tamper evident label on the package may have made the counterfeiting more difficult.  In the actual alert the very first criteria that they used to describe the bad device was, “A packaging seal that does not tear open smoothly”.

Tamper evident labels are pretty simple.  Notice I don’t say tamper proof, since that’s an impossible claim.  Nothing is tamperproof, waterproof, or idiot proof.  The goal is to make it evident and obvious that someone has attempted to breach the package to get at what’s inside.  This is done by by either the label fracturing, delaminating, or leaving a gooey mess where it was on the package or the adhesive bonding with the package substrate to the point that it destroys the package material if removal is attempted.  The most basic illustration of this concept is the simple price sticker on a product that can’t be removed in one piece.  The epitome would be a package like a CD jewel case or any electronic device that practically requires a switchblade, hammer & chisel, and a pound or two of C4 plastic explosive to open it up.  Which brings up a critical point with medical device packaging.  It has to be tamper evident yet easy for the OR staff to open, use, and offer a good solid visual as to whether the package has been tampered with.  The original tear tab or tear strip was developed as a result of physician complaints.  The simple round or rectangular destructible label worked OK but to get it off required either a fingernail, tough when a person is wearing surgical gloves, or the use of a scalpel which then had to be tossed.  The simple label is also pathetically easy to copy and fake.  So……..tamper evident/indicating and simple and reliable for surgical personnel to open. That seems pretty straightforward but, like most things in our industry, it just ain’t that simple.

There are a few issues that complicate the medical device tamper evident package label and they can loosely be grouped under sterilization, package conditioning, label function, and good ‘ol ASTM 4169.  Certain films commonly used for tamper evident seals do not like gamma radiation and they also do not do well at the higher accelerated aging and conditioning temps sometimes used when…gasp….validations and quals are behind schedule.  Also, using the tamper evident label to hold together a SBS folding carton that’s stuffed with the double barrier package, a warranty card, and a big thick manual will almost certainly cause it to fail ASTM 4169, the shake, rattle, and roll test.  So will the theory “gee, it passed ASTM 4169, lets add a ‘spike the football’ test to the protocol as well”.  You think I’m exaggerating?  Unfortunately only slightly.  Frankly, if the seal breaks when you thump the package you should think about what’s happening inside the box, the canary in the coal mine theory. Finally, when the label is placed on the package there needs to be a clear work instruction about where it goes on the edge of the box.  We often print tick marks to aid in this process.  These labels typically have a reinforced peel area with small nicks to make sure the peel is reliable and secure.  If it’s lined up wrong it can tear prematurely.

Actually there are a few more nuances but the ones above are plenty for a blog post like this one.  Levels of security can be added like adhesive void components, holograms, color shift inks, etc., but the basic version seems to be functioning quite well and has been well received in the medical device marketplace.  Its a small item that can pay big dividends if any product integrity issue do arise.

Foreign material or FM can be loosely defined as something that’s not supposed to be present or part of the base material that’s  being produced.  The fact is that foreign material is always present in everything that is produced, no matter how much we wish that it wasn’t or how strictly we word our engineering drawings.  It will be there so the key issue, twin issues actually, are how much is allowable and what exactly is the composition of the FM.

In the photo above its pretty clear that the allowable ppm of foreign material as well as the maximum size of the particulate has been exceeded.  That’s what can happen when a couple of guys are tinkering with ink pump hoses that are under pressure.  We know what the ‘foreign material’ is however.  It is solvent safe water based black ink, approved for indirect food contact under FDA regs.  Is it a health hazard?  Not according to the MSDS sheet.  Does it pose some disturbing cosmetic issues for those who might encounter these two yahoos?  I would say the answer there is yes.  So we have a known substance that is relatively inert, but just doesn’t look that great. Coincidentally, we had the same issue with some laser face stock from one of our suppliers.  It opened up a large can of worms in regard to what it actually was, how much was allowable, and the perception of how it looked on a package.

In November of 2010 we began to see large (some half the size of a fingernail) spots on one of the paper laser sheets that’s qualified and validated at a number of our device customers for labeling terminally sterilized medical device packages.   The paper industry has not been exempt from the go faster/make it cheaper pressures of the marketplace and we suspect that increased machine speed and less inspection might be the culprit. We discovered that the foreign material was calcium carbonate (which would actually make it parent material by definition) used in the paper making process. It’s a naturally occurring mineral and is commonly used, among other things, as a calcium supplement in diets and a key ingredient in antacids. Basically, people can eat it.  Unfortunately, these specks had a rust colored hue, a color that looked very similar to dried blood.    Our supplier had no interest in attempting to correct the issue since medical device usage is the proverbial flea on the elephants butt of total laser paper usage.  We were sent a letter informing us that our vendor would no longer support our medical device application in early May of 2010. We informed our device customers and the gnashing of teeth and over thinking of the issue began in earnest.

The perfect solution would be not to have any at all. Unfortunately, a line on a  drawing or print that says “There shall be no foreign material present on the printed side or adhesive side of the label” does not make the FM go away or even scares it a little bit.  For example, neither you nor I want insect and rodent parts or mouse dung in our bread.  Yet the FDA, those same guys that regulate our industry, have an allowable ppm for those very substances in flour.  I worked in a bakery during part of college and one of my jobs before the inspectors came  through was to thoroughly clean the dough mixer and vacuum up all flour bug tracks underneath it.  At times it looked like Grand Central Station under there. So the real question becomes how much FM would be allowable?

Enter the venerable TAPPI chart.  The most widely accepted particluate standards were developed in 2004 by Tyvek and film converters. Some of you may remember the 1073B Tyvek recall in 2001, when black FM from deteriorated brushes in the Tyvek production line in Richmond broke off and became embedded in the sheet.  Many device manufacturers had standards before that and an ASTM group headed by some J&J folks attempted to come up with a standard but it never came to fruition. The current most commonly accepted working standard combines both embedded and loose FM with a maximum allowable size and maximum particulate count for smaller sizes.  It addresses both parent material, components of the actual structure itself, whether it be Tyvek, film, or paper, and foreign material that is not part of the manufacturing process.  If you sent him a nice email, Mr. Curtis Larsen of Spartan Design Group might send you a copy of some work that he did on FM on various substrates.  Just don’t mention this years MSU basketball team.  The other key part of FM evaluation is that the parts need to be examined at 18″ with the unaided human eye for two seconds.  Poring over a label or lid for 20 seconds with a 6x magnifying loop is definitely not the accepted procedure.

The FM in the laser sheet face stock issue is still unresolved.  Qualification and validation of the alternative cleaner, more bright white materials is crawling along at glacial speed at exactly 100% of our customers.  However the main thing that dealing with the medical device industry has taught me is patience.  One of my MedDev buddies, an engineer at a large device manufacturer, counseled me, “Olson, you gotta be patient.  If the FDA regulated the auto industry your car would not have an electronic ignition and it wouldn’t even have points and a condenser.  You’d have a magneto because magnetos are historically proven to be reliable”.  It is the same with implementing  the commonly accepted FM standards.  2004 to now is a mere blink in both geological and medical device time.  I would encourage medical device companies to at least lurch forward toward adopting a practical and workable FM standard

Healthpack was the usual rousing success with a sellout crowd at the Gunther Hotel and along San Antonio’s Riverwalk. There were some casualties in the rough and tumble world of terminally sterilized medical device packaging but for the most part things were under control. I think the gentleman in the photo was an innocent bystander in a river front brawl between the ISTA and ASTM 4169 gangs over the package distribution standards turf. Another rumor was that the E labeling posse and the printed leaflets/IFU boyz came to blows again, but it’s unclear at this time. It was a good conference though, and many of the topics were germane to the issues of the day and a number of new ideas were explored.

When good HealthPacks go bad...

One of the more interesting ideas was proposed by Nicholas Berendt of the Sealed Air Corp., a converter of sterile barrier packaging. The theory was if the converter, (eg the company that takes raw material and prints, diecuts, laminates, folds, spindles, and mutilates it into pouches, lids, labels, IFU’s, etc.), could to a series of tests up front and provide data, it could seriously reduce package engineering  time validating new packaging films as well as increase speed to market.  I have thought for a number of years that the same thing could be easily done with new label stock.  The testing is not nearly as rigorous as what would be needed for a barrier film and pre qualification might make it easier to qualify and validate new label material.  As I mentioned in my Healthpack presentation, labeling is usually a very small part of the total package as far as cost and time and effort thats devoted to it.  Because of this, available engineering time to test new materials, including label stocks, is generally limited and not in the number one spot on the package engineering agenda. Due to this ‘fact of packaging life’, the older, larger, more established companies are driving the ’89 Chrysler Cordoba of label stocks while newer companies, who have to evaluate all their new packaging materials anyway, are zipping along in the ’09 VW Passat, 1.8L Audi Turbo label stocks.  While it’s true that the established firms have the fine Corinthian leather, they don’t have all the new innovations and added features of the newer models.  These would include brighter, whiter, more opaque face stocks and tackfied emulsion adhesives that have decent repositionable characteristics in final pack yet superior ultimate bond to tough substrates like tyvek.  Plus the new materials are a solid 25% less costly than the older materials.  That should make the purchasing and sourcing peoples ears perk up but again, as a percentage of the total expense of the product the label part is still puny; we’re talking about a deck chair on the Titanic here.

Distinguished gents of HealthPack

The question then, is if we performed a series of ASTM and other tests on new label stock that addressed the twin FDA regulatory concerns in CFR 21, Part 820, the Quality System Regulations, of adhesion and legibility, would that be of value to device manufacturers and in particular packaging engineers?  I realize that package size and weight are crucial to package testing and that special conditions need to be considered for various configurations, but I can’t help but think that if you need to get from Minneapolis to Milwaukee, that starting out in Madison would be a lot quicker, less costly, and less painless than starting out in Minneapolis.  Please weigh in on the attached poll and let me know how you feel your company, particularly your Reg Affairs folks, would react to this concept.  I will anxiously await your feedback.

Almost 174 years to the day, after Jim Bowie, Davy Crockett, William Travis, and a couple hundred others were killed defending the Alamo, the upteenth annual Healthpack Conference is coming to within 4 blocks of the historic mission in San Antonio, TX.  In a weak moment I was approached by the instigators (agitators?) of the event, Messers Spitzley and Larsen, and agreed to craft a presentation which they entitled, “How to test your package system labels for materials compatability and adhesion over time“.

It’s a critical topic but what we discovered in a survey that was taken by the IOPP Medical Device Technical Committee’s Labeling Task Group, no one does it exactly the same.  The FDA gives us a broad and general edict in the Quality System Reguilations, CFR 21, Part 820, Subpart K.  “Label Integrity.  Labels shall be printed and applied so as to remain legible and affixed during the customary conditions of processing, storage, handling, distribution, and where appropriate, use”.  In a nutshell, the label needs to stick to the packaging component substrate and stand up to the abuse of sterilization, shipping, handling, and storage until it gets thrown away.  It also needs to remain readable after this journey from manufacturing final pack to the landfill.  How to test for these qualities and predict how well the labeling on a terminally sterlized device package will survive is the topic I’ll try to address.

Rather than standing up there and presenting what I think people  are interested in, I thought I’d use this forum to see what people that work with device labeling day in and day out actually want to hear.  Take a look at the survey that we took last fall (attached below), which had ten basic questions.  Part of the presentation will be based up on those responses, which come from a broad spectrum of device manufacturers, but I know there are additional  issues, test methods, and techniques that should be addressed.  One of the things we are working on in the Labeling Task Group is some sort of protocol or guidance that can be used to help qualify and validate pressure sensitive labeling of terminally sterilized device packaging.  Any feedback via email or blog comment section would be helpful to the group.

Labeling Task Group 09

I know budgets are tight but Healthpack is a pretty useful conference for those of us in medical device packaging.  I can’t pretend that all the presentations have been scintillating over the years, but there are a heck of a lot more useful and interesting presentations at this event than at most others I’ve attended.  There is nothing wrong with San Antonio, the historic Gunther Hotel, or Riverwalk either, for that matter.  Please take a couple minutes to give me some feedback on the topic of pressure sensitive labeling.  If you don’t who knows what you might wind up with in early March…..

Due to a number of reasons, the main one being my chronic TCS (Time Compression Syndrome, a malady that consistently has victims attempting to shove ten pounds of fertilizer into a five pound bag), this blog has not appeared since about March of last year.  That flaw will be remedied this year with a regular monthly post, maybe more if there is breaking news, which I plan on posting the first week of each month.  There is plenty to write about in the field of terminally sterilized medical device packaging and labeling these days and I hope to hit a few germane topics as we progress through 2011.

One of the things that we worked on last year was an expansion of the small one page handout that many of you picked up at either Healthpack or one of the MDM shows.  Its a neat little retro-looking spiral bound booklet with a bunch of good stuff in it, ranging from design tips to a bunch of label related websites.  If you would like one, either shoot me an email or give me a call at 612.706.9554.

MDM West is coming up in a couple weeks and MDRG, the Medical Device Resource Group, will be hosting a reception at the Hilton Anaheim on February 8th.  Healthpack 2011 is right around the corner as well, rapidly approaching in early March in the Queen City of Cincinnati.  More to follow on both items. 2011 is out of the blocks rapidly and there is a lot of labeling stuff in the hopper. Blog post 2 for 2011 will be out in two weeks.

 One of the first label questions I get from startup medical device manufacturers, or existing companies implementing a new line, is whether its best to use laser or thermal transfer for in house printing.  The way this normally gets decided is by utilizing what I call the Pioneer Theory.  This states that since pioneers stand a risk of getting arrows shot at them, most people want  to circle the wagons and do what they were comfortable with at their former place of employment.

Thus if the group of engineers at the new startup or assigned to the new production line  is familiar with laser printers and had good luck with them, then there is a 90% chance that’s what they will use at the new company.   There are actual properties that can be considered however, beyond the Pioneer Theory, when choosing a print method for a new company or  new manufacturing line.

The first thing that needs to be discussed is  the stock itself.  Due to the properties of toner vs TTR ribbon, laser stock is almost always uncoated with a relatively rough surface while a TTR ribbon works best on a smooth coated stock.  This is where marketing input comes into play.  Printers match ink to the coated side of the PMS book for coated TTR material and to the uncoated side of the book for the uncoated laser stock.  Seems pretty simple but if marketing has approved a beautiful SBS shelf carton with aqueous or UV coating, and insists the the label ‘match the box’ then that label needs to be on coated stock.  Take a look at your official, corporate style book approved logo color in both sides of a PMS book.  On a densitometer they are identical but to the human eye the reflectivity is completely different and they appear to be different colors.  A marketing guru once brilliantly and somewhat condescendingly suggested that we should just match all stock to the coated side of the PMS book and eliminate the issue.  Rather than break his nose on the bar, like Gus McCrae did to the smug and self assured bartender in Lonesome Dove (see below), I calmly explained that were it that simple, ink companies would have quit going to the expense  and effort of producing the uncoated side of the PMS book sometime shortly after World War 1. Coated laser materials exist but at this point I don’t have any customers who have successfully ran them through the validation and qualification process.  And it has been tried on a few occasions.

We have a number of customers at Advanced Web who have gone to laser printing their packaging labels in full color.  The 600 dpi color laser is the undisputed way to go for that process.  Color TTR printers exist but the quality, reliability, and media expense are all inferior to the laser printer.

Print durability is another story.  In general, most of our customers who use laser printers also shrink wrap the outer carton of their device package.  This is not necessary and usually not done for TTR printed labels since the anchorage and abrasion resistance of the ribbon is far superior to most toner and will usually pass the transportation testing process. When it comes to equipment, the TTR printers tend to be cheaper, more reliable, and less costly to repair.  Most laser printer manufacturers only grudgingly admit that people actually run pressure sensitive label stock through their printers.  Problems like stock curl, adhesive ooze, environmental sensitivity, and spotty toner coverage seem to be more common on sheet fed laser stock.  Roll stock is a bit more forgiving and problems like ribbon wrinkling or a deep die cut on the roll label stock are a bit simpler to fix.  In both cases a well thought out and executed preventative maintenance schedule can avert a lot of issues.  With any luck you will not need a house call from Dr O, seen above analyzing some balky laser material in a clean room final pack area (Photo credits to M, Heckley, renowned packaging pro).

Whichever method you are choosing rest assured that both have an extensive track record in labeling terminally sterilized device packaging.  Both toner and TTR ribbon survive most of the common sterilization environments and provide that durable package labeling required by our friends at the FDA.  In fact for a limited time only, if you send me a stamped, self addressed envelope and two Wheaties box tops, I’ll send you your very own copy of the Code of Federal Regul

ations, CFR 21, Part 820.  It even has the almost Tom Clancy/ John Grisham-like excitement filled Part 11, which deals with electronic records and signatures.  Actually, if you just send your email and address I’ll mail one of handy, checkbook sized booklets out while supplies (about 35 of em) last.  If you act now you will not get a Ginsu knife or Popiel Pocket Fisherman.  Since it could be out of date before it was printed, no accuracy guarantees are included.

Also remember MDM Midwest is rapidly approaching in less than a month. Stand by for an update on an exciting educational opportunity on this site in a couple weeks.

Temperature extremes are one of the most common physical properties that can impact label adhesion.  Most label adhesives have a minimum application temperature and then, once the adhesive bond is solidly made, a much broader ‘operating temperature’.  Fortunately, this is usually a rather wide range with -20F to 176F being fairly typical.  Transport testing of packages is usually at -20F on the cold side and 100F and 85%RH, and/or 140F and 30%RH for the heat (ISTA P2A, 2008).  Accelerated aging of labeled packages is typically at 130F.  Unfortunately, temperature is not all that easy to control and can do fun and crazy things when it decides to fluctuate.

Heat is usually the culprit that causes trouble with labels as well as me personally. 

I’ll take -5F over 90F any day of the week, no matter how sick people think that is  (take the poll!).  

Heat can cause outgassing, plasticizer bleed, and also cause substrates to expand at rates different from the label that is stuck on them.  In one incident, a polyprop case with a paper label passed the accelerated aging tests at 130F but failed the back-window-of-car-in-Arizona-in-July test, the BWCAJ test. The guidance doc for this test will be approved shortly, I’m sure.   We also put together a package for a mechanical heart valve a few years ago.  This project had me more excited than when I look at a  ladder with its 37 “please don’t be an idiot” labels (thanks for that, plaintiff’s bar!).  This package had tyvek lidding, paper tamper evident seals, a clear polyprop info wrap, a TTR imprinted PET label set that was used on the package and shelf carton, and a vinyl seal strip around the entire polycarb cylinder.  This was an autoclavable package and everything worked fine in the testing but when some prototypes hit the field everything went to hell.  Tyvek tranparentized, vinyl oozed, and the package looked really, really ugly.  The culprit?  Using a flash autoclave cycle rather than a regular cycle.

Its impossible to avoid all the pitfalls but there are a few things to keep in mind.  First of all, try to stay around nominal on your adhesive temp range selections rather than at either ragged edge.  3M’s 467 or 468 adhesives, familiar to  many as the product used on hardgoods nameplates,can’t be removed most of the time with dynamite and a chisel.  At -40F however, it falls off so its probably a bad choice for your Alaskan Pipeline drill labeling needs.  Think about the adhesive properties that will be critical for your app as well.  The package that failed the BWCAJ test worked when an adhesive with low shear strength was used, allowing the label to move with the expansion and contraction of the package.  Matching face stock and the substrate being labeled is a good idea as well.  Not only does it make recycling easier but if you have a polyprop label on a polyprop package, the expansion coefficient is the same. 

Having different materials causes an effect like a bi metal thermostat, where the different rates of expansion/contraction cause the metal sensor to actually bend one way or another.  Finally, conditions that replicate the actual usage are a good idea.  While most medical devices don’t sit in someones car window in a mall in Scottsdale in July, most do get shipped somewhere.  Whether those devices are shipped to Bismarck, ND in January or Oxford, MS in July can most certainly make a difference in label performance.