Adding Options in Blister Films

New PVdC films present cost-effective choices for higher barrier needs.

By David Vaczek, Senior Editor

 

INEOS Films maintains a PVdC coating line in Germany.

New PVdC materials as well as advances in coating technology have made PVdC films more suitable for a broader range of applications, and newer blister film solutions are also being explored.

“Pharmaceutical companies traditionally carry two or three materials on the shelf for their packaging needs. These include PVC, some form of PVdC-coated PVC, and often a cold-form aluminum composite. These materials have been around for some time, but do not provide optimal cost-effective options,” says Remco van Weeren, senior vice president of films and foils, United States, Bilcare Inc. (Phoenixville, PA).

“What is changing is that pharmaceutical companies are more likely to evaluate alternative materials to reduce cost in the higher-barrier–packaging arena. As companies enhance their supply chains globally, they are opening up the process of material evaluation to find what works best for an application. We have seen that customers are more willing to do risk assessment for alternate packaging for commercialized product,” van Weeren says.

“There is a rush to develop cost-effective, higher-performance materials. We are constantly developing materials to derive optimal packaging based on products’ stability characteristics and to populate a range of cost/barrier alternatives,” van Weeren says.

MORE CHOICES

New films employing PVdC-coated PVC are expanding the choices available in protective blister packaging, addressing demand for cost-effective, higher-barrier alternatives. Some films are featuring new Super B grades in the Diofan PVdC product line from Solvin SA (Brussels, Belgium). The high-crystallinity PVdC offers more barrier per gram weight than standard PVdC. Among the advantages of this next-generation PVdC are that processing costs can be minimized with fewer coating passes.

Klöckner Pentaplast (Gordonsville, VA) and Perlen Converting LLC (Whippany, NJ) have launched new PVdC films that provide comparable moisture barrier to mid-barrier PCTFE laminates at an equivalent or better cost. Klöckner Pentaplast incorporates Super B in a triplex PVC film structure.

“Super B is a very recent introduction. Industry will have to see what the interest is from pharma companies,” says Michiel van den Berg, director, global pharmaceutical packaging development, Tekni-Plex Inc. (Somerville, NJ).

Perlen Converting says its Perlalux Tristar ultra PVdC film features comparable moisture barrier to Aclar Ultrex 2000.

“There is some overlap now between PVdC films and the lowest grades of Aclar [PCTFE]. Super B offers a new route to start developing higher barriers with less coating weights. This will redefine the threshold in the mid-barrier range, providing higher-barrier films that compare favorably to higher grades of PCTFE. We expect to see many new specifications using Super B launched into the market,” van den Berg adds.

Klöckner Pentaplast extended its offerings in PVdC-coated films with the Pentapharm alfoil E S03 film (PVC/PVdC/PVC), employing Super B PVdC.

“Our customers wanted a transparent film with a barrier comparable to high-barrier grades of Aclar. Pentapharm alfoil E S03 features a high-crystallinity PVdC dispersion that is flexible enough to support bending without cracking. The film forms as well as any PVC mono film,” says Daniel Stagnaro, business manager of pharmaceutical films for Klöckner Pentaplast.

Pentapharm alfoil E S03 features high moisture and oxygen barrier, with better resistance to higher temperatures that degrade PVdC barrier, compared with standard PVdC coatings, he says.

Pentapharm alfoil E S03 delivers a cost-effective barrier alternative to lower barrier Aclar-grade films and a favorable cost-to-barrier ratio compared with standard PVdC films. For example, a 120-g-weight Pentapharm alfoil E S03 film features twice the oxygen barrier of a 90-g weight of standard PVdC, Stagnaro says.

“Barrier in [standard] PVdC starts to fade when ambient temperatures rise above 22°C (70°F). Pentapharm alfoil E S03 was engineered to have moisture barrier equivalent to Aclar Ultrex 2000 at up to 40°C temperature,” says Stagnaro.

“When you are designing packaging to meet ICH [International Conference on Harmonization of Technical Requirements of Pharmaceuticals for Human Use] stability packaging guidelines, Pentapharm alfoil E S03 will be the best choice for many environmental conditions because it is equivalent to Aclar in both cost and economical performance,” he adds.

The triplex structure of the alfoil E S03 supports enhanced thermoforming, addressing PVdC’s tendency to stick to equipment and to crack when bent. The PVC layer is sealed to conventional foil, without special heat-seal coatings, he says.

“PVdC has a wonderful resistance to compression, but is highly susceptible to cracking under traction. Pentapharm alfoil E S03’s symmetrical structure addresses the brittleness of the highly crystalline PVdC dispersion,” says Stagnaro.

For medium- to higher-barrier moisture-protection needs, Klöckner Pentaplast offers new Pentapharm alfoil SG (Super Glide) films in PVC/PVdC and PVC/PE/PVdC. The films use a proprietary application of the final PVdC coating to minimize sticking during thermoforming, Stagnaro says.

INEOS Films Inc. (Delaware City, DE) is testing a new-generation barrier film and plans to offer it in the coming months, says Todd Swartz, commercial engineer, INEOS Films.

“These films will offer better moisture barrier than the current PVdC structures and moisture barrier that is equal to or better than some of the other barrier materials currently on the market,” says Swartz.

ENHANCED BARRIER

Perlen Converting has launched Perlalux Tristar ultra, offering the company’s highest level of moisture and oxygen barrier in a PVdC film. The film uses a 120-g weight of PVdC, with a proprietary PE inner layer. Moisture barrier is equivalent to PCTFE films, at a cost advantage, says Fredy Brunner, director of sales, North America.

“Tristar ultra (PVC/PE/PVdC) competes equally with PCTFE on moisture barrier and delivers high oxygen barrier. With Tristar ultra, we are offering the highest barrier of any PVdC film on the market,” Brunner says.

The film allows diffusion of 0.11 g of water per square meter at 38°C and 90% RH over 24 hours, a step up in barrier from Perlen’s StarFlex film (PVC/TE/PVdC). Perlen has offered StarFlex as “a very cost-efficient,” high-barrier alternative comparable to lower-barrier-grade PCTFE films, Brunner says.

“Tristar ultra delivers a higher barrier than Starflex using the same gram weight of PVdC material. Processing requires fewer layers and machine cycles. The film is solvent-free and a clean solution for recycling, ecologically friendly attributes for which we have seen increasing demand,” Brunner says.

The film is produced at Perlen’s Switzerland coating facility, where capacity is being increased with the installation of a fifth coating line. Perlen this year acquired Müllheim, Germany–based ac-folien GmbH. That firm supplies PVC films on calenders employing the latest technology and process controls in a fully GMP-compliant facility, Brunner says.

Bilcare offers a range of barrier film choices. The firm’s excel and super films target low- to mid-range barrier needs. For lower-barrier needs, excel (PVC/PE) offers better barrier than a mono PVC film, at an equivalent or better cost than mono PVC. The PE layer allows the use of a thinner PVC layer for cost reduction, while supporting more-uniform blister forming. “The forming characteristics of excel are better, so you end up with a better overall barrier performance,” says van Weeren.

Super film (PVC/PVdC) features a thin PVdC coating for targeting barrier between PVC and 40-g-weight PVdC. For higher moisture and oxygen barrier performance at a comparable cost to a PVC/PVdC film, Bilcare’s triplex film (PVC/PE/PVdC) is suitable. The ultra and ultra tx metallized PVC/PVdC films in the firm’s patina line of colored films provide ultimate barrier levels in a film structure. The products add to the barrier of the PVdC with a thin coating of aluminum, with cost advantages over Aclar grades Rx 20e and Rx 160 (Bilcare’s ultra) and Aclar Ultrex 2000 (ultra tx).

“The metallized film is a unique industry application. We can put them down in a variety of colors for brand enhancement and anticounterfeiting,” van Weeren says.

DUPLEX FILMS

INEOS Films manufactures duplex PVC/PVdC films using a proprietary coating application and drying technology. Swartz says the duplex films feature comparable or better moisture and gas barrier properties to triplex PVdC films, with cost-efficiency promoted by the elimination of the traditional PVC/PE lamination.

“We have found that duplex films are less prone to delamination than are triplex specifications. They are easier to ­form, work better in deep draw applications, and offer better yields. You have wider forming windows because you are not forcing the heat through the insulating PE layer,” says Swartz.

“A distinct advantage of a PVdC film over an Aclar laminate is that you can use it as the direct-contact layer, increasing the barrier by putting the barrier closer to the product. PVdC’s adhesive properties create a wide window for heat sealing,” he adds.

Tekni-Films has joined Klöckner Pentaplast as the only provider with installed PVdC-coating capacity in the United States, after launching manufacturing of pharmaceutical-grade PVdC films at its Flemington, NJ, facility this year. Tekni-Films has sourced higher-grade PVdC films from partners in Europe, says van den Berg.

“Customers now have a choice for domestic-sourced PVdC-coated films. This will eliminate the longer lead times and higher costs that firms have faced in sourcing the master reels from Europe,” says van den Berg, noting that Tekni-Plex is sourcing the PVC base film from a Tekni-Plex plant in Canada. The Flemington line is retrofitted for the heavier-gauge coatings, with a state-of-the-art pressurized closed-pan gravure coating system. A pressure-coating system allows better control over the coating process to support consistent coating weights and more-predictable barrier properties, van den Berg says.

“Our first priority is the steady and reliable production of 40-, 60-, and 90-g-weight PVdC using standard Diofan grades. These weight specifications cover 98% of PVdC volume for medium-barrier requirements. For economy-to-performance ratio, we consider the Tekni-Film 40- and 60-g-weight films to be best-in-class,” he says.

As a barrier choice for blister packaging, Swartz notes that PVdC films provide adequate protection for most drugs, and the best “barrier for the dollar.” INEOS’s higher-coat-weight PVdC films offer equivalent barrier to lower-barrier PCTFE laminates.

“Moisture, light, and oxidation are the three mechanisms for product degradation. You can’t overlook a barrier material that addresses two of the three. It can also be designed using colored PVC or UV inhibitors to address all three,” Swartz says.

He adds that “a distinct advantage of a PVdC film over an Aclar laminate is that it provides excellent functional properties as a drug contact layer. PVdC is unique in that it functions as an adhesive with barrier. Sealing to PVdC can lower temperatures and widen heat-seal processing windows, which can create the opportunity to increase machine throughput as well. Barrier, too, is improved when utilized for direct contact, as there is no better place to put your barrier material than right next to your drug product. Aclar too, can be utilized for direct contact, but it requires a special adhesive, whereas PVdC does not.”

PCTFE AND COC

Though PVdC films are reaching higher-barrier applications, very high barrier is increasingly required, driving use of high-barrier PCTFE grades and foil.

“We have noticed a clear market shift to higher or ultrahigh-barrier materials with newer, more-sensitive drugs, drugs at smaller doses, and new drug-delivery systems such as for inhalables. Also, there is a shift toward markets requiring stabilities in ICH conditions, such as Zone 4 tropical areas,” says Keith Wilbourn, applications development manager for Alcan Packaging Pharma Center (Shelbyville, KY), Alcan Global Pharmaceutical Packaging Inc.

“Cost is always a focus regarding Aclar films. However, PVdC grades are not viable in the large subtropical market because they have difficulties passing ICH condition stabilities. This drives many people to put up stability samples in our thicker Polybar Aclar structures and Formpack cold-formable materials,” Wilbourn says.

Notes Stagnaro: “Aclar will be preferred if you need a bullet-proof package for severe conditions, because it is more resistant to temperature.”

Klöckner Pentaplast has offered G03 PVC/EVOH/Aclar for products requiring high moisture and oxygen barrier. The new Pentapharm alfoil E S03 delivers comparable moisture and oxygen barrier to G03, at a lower cost. In Klöckner’s S03 PVC/Aclar/PVC, the triplex structure allows reducing the gauge of the PVC layer by half. Barrier compared with a duplex Aclar/PVC film is enhanced because the PCTFE is situated closer to the blistered product.

Van den Berg notes an increased interest in Tekni-Plex’s COC film (Tekni-Flex COC) after recent upgrades to coextrusion lines that enhanced film quality. Recent price reductions in COC (which is manufactured by Topas Advanced Polymers Inc.; Florence, KY) have made the material more attractive for medium-barrier applications. “COC fits our strategy of offering only products that make sense from a value/performance point of view. It offers barrier at an economy that makes sense, with its own space in the range of blister solutions between PVdC and PCTFE,” says van den Berg.

COC’s biggest advantage as a coextrusion with PP is that it is halogen-free, he says.

“PCTFE is typically laminated with PVC, and PCTFE itself contains chlorine. Wal-Mart has initiated a rather important movement, in my opinion, where they have indicated they will attempt to ban PVC from their stores. I don’t think you will see an outright ban that would require pharma companies to revalidate packaging, but more of our customers are now looking for PVC alternatives,” he says.

Alcan Packaging’s Polybar COC structures fit with the company’s sustainability focus, providing medium to high barrier for the “green packaging” market, says Wilbourn.

“COC combined with polypropylene or PETG features excellent thermoforming properties, with no halogenated components or chlorinated materials to landfill,” he adds.

Bilcare has announced a regional development collaboration with Honeywell’s Health Care Film Business (Morristown, NJ) to provide a new Aclar high-barrier application for the pharmaceutical sector. Rick Knight, Honeywell global business manager, says that the partnership will address the pharma challenges of drug shelf-life protection, counterfeiting, and accidental misuse of drugs.

Van Weeren notes that product stability testing—before packaging—offers an opportunity to refine packaging selection. Companies often use more barrier in films and foil than is actually necessary. “Aclar has a more shallow degrade curve than does PVdC [as temperature increases], so it performs better in accelerated testing at 40°C,” says van Weeren. Accelerated testing, however, “gives packagers a perception that product needs more barrier than it does,” he says.

Bilcare offers product stability testing technology that determines critical product characteristics before packaging. By first testing the product, customers can narrow material choices for testing and potentially use lower-cost materials. “Weight gain from moisture diffusion has an effect on factors such as tablet hardness, dissolution of disintegration behavior, and how the active [product] chemically degrades. You have to test the actual dosage form in an ‘open dish’ environment to see what barrier you need at these elevated testing conditions,” van Weeren says. “This testing done early enough in the product cycle could influence formulation and extend shelf life or enhance product integrity.”

Whatever blister films may be preferred, better barrier properties will be required for new hygroscopic solid-dose forms. And the increase in globally shipped product will provide traction for blisters as a preferred packaging format.

“Some of our customers are Aclar barrier customers, others are PVdC barrier customers. I’m a big believer in helping my customers pick the right material that fits not only their barrier requirements, but also their budgets,” says INEOS’s Swartz.

Says Perlen’s Brunner: “The demand for barrier continues to grow as sophisticated tablet forms require higher humidity protection. We are seeing increased demand for UV stabilizers in the PVC as a result of weaker UV protection in the stratosphere, and UV-barrier requirements for packaging shipped to southern markets.

“Bottle packaging cannot ensure that tablets remain sterile and protected from moisture and oxygen. High-quality blister packaging following GMPs is the only way to guarantee high-quality, shelf-stable product,” Brunner adds.

 

 
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