Manufacturers can now specify cost-efficient peelable packaging for small-volume medical devices without forgoing quality. A collaborative effort between DuPont Deutschland (Bad Homburg, Germany) and Sengewald (Halle, Germany) has resulted in a new packaging system, which combines DuPont's Tyvek 2FS, a new uncoated plastic fabric, and Sengewald's peelable bottom web.

Traditionally, Tyvek materials have only been used to package heavy and high-value medical products because of their high cost, while coated paper was used for smaller-volume, less-demanding medical products. Tyvek 2FS offers manufacturers the possibility to pack simple products in a Tyvek-quality package.

A peelable bottom web combined with Tyvek 2FS plastic fabric results in a Tyvek-quality package suited for small-volume medical products.

As well as being suited for the packaging of simple goods, the DuPont-Sengewald system can also be used for high-value medical products. The material is thinner than conventional Tyvek, but still provides the same advantages, including tear resistance and protection from bacteria.

In addition, the soft-peel material offers greater air permeability than the coated variant, which shortens the gas sterilization and aeration processes. The combination of materials also allows for cleaner peeling. Typically, nonsterile fibres become detached when the top sheet is pulled off peelable packaging. In the soft-peel system, there is less damage to the Tyvek 2FS surface, thus reducing the number of detached fibres.

—Jamie Graham

Testing Equipment

Amanufacturer of testing equipment recently acquired intellectual property that provides a unique method for detecting defects in porous packages. Mocon Inc. (Minneapolis, MN, USA) purchased technology from True Technology Inc. (Boston, MA, USA) for the nondestructive testing of packages made of DuPont Tyvek. The technology promises to provide an attractive alternative to current methods, which rely on destructive dye or pressure tests.

"Tyvek-containing packages breathe—how do you know if they are leaking?" asks Dane Anderson, chief financial officer at Mocon. The company's new test relies on tape placed over a porous Tyvek package. A tracer gas is introduced, and a sensor detects any leakage of the gas from within the package.

Technology for the nondestructive testing of Tyvek packaging will be integrated into machines like Mocon's Pac Guard 400, which is designed for production-line quality control and package development applications.

According to Anderson, the advantages of the new testing method for medical OEMs are twofold: "First, it's sensitive; the test gives a specific signal with defective packages," he says. This is in contrast with the visual inspection methods currently employed by device manufacturers. "Secondly, the test is nondestructive, so you are not losing package and product," he adds, explaining that this is particularly important for high-value products.

Mocon is a provider of testing systems and consulting services for the assessment of materials and processes. The company plans to incorporate its new technology into a new whole-package integrity testing device that will join its standard product line early next year. "This patented technology will enable us to introduce other instrumentation and services for testing the integrity of a variety of sterile medical packages," says the company's president and CEO, Robert Demorest. Mocon began by manufacturing permeation-testing equipment, but now also offers technology for leak-testing nonbreathable packages for drugs and medical devices.

—Benjamin Lichtman

Surface Treatment

Born out of a stent design project, a nonleachable, radiopaque coating promises to improve the visualization of implants, wires, and catheters under fluoroscopy or x-ray. The new polymeric coating, developed by Hydromer Inc. (Branchburg, NJ, USA), is based on a radiopaque organic compound designed to eliminate the need for ion implantation and gold banding, two popular methods of increasing stent visibility in vitro. It also allows manufacturers to avoid the use of heavy, metallic additives, which can complicate extrusion and compromise a product's mechanical properties.

Joseph Ehrhard, vice president of new business and R&D at Hydromer, sees the development of the coating as an event that will have a great impact on implantable technology. "What we believe we've created—which is novel—is a material that departs from the current use of barium sulfate or metallic ions to achieve radiopacity." According to Ehrhard, the radiopaque coating presents a safer option for the treatment of implantable devices than does the compounding of metallic ions. "You can now achieve radiopacity without the leachables, the heavy-solid content, or the potential for galvanic corrosion that you had in the past," adding that these considerations become particularly important in the case of long-term implants.

The technology for the coating sprang from a partnership between Hydromer and a Canadian device company, Symbiotech Medical (Quebec), which was developing an intravascular stent with minimal strut thickness (0.002 in.). While the coating was primarily conceived to improve the stent's visibility, in the end it offered several advantages, including lubricity, antithrombogenicity, and durability. "If you're going to open up a blood vessel, you'd like to do more than just prop it open," says Ehrhard. "You'd like to stop the disease or slow it down, and make sure it doesn't cause any other problems," he says. "Devices have to go beyond what people conceive of as a single function—prop open a vessel, visualize a vessel, deliver something. They've got to do five or six things at the same time."

The permanent radiopaque coating, which can be applied to any substrate, is the subject of multiple patent filings. Ehrhard notes that the radiopaque organic compound developed by Hydromer doesn't have to be supplied as a coating. "Our patent filing takes a couple of approaches," he notes. "Obviously, our core business is coatings, but we've also looked at making an extrudable, radiopaque polymer with this, a thermoplast. You can do a lot more cutting-edge extrusion work when you can take out the 45–50% barium sulfate content," he says, adding that the addition of barium sulfate necessitates thicker walls and hinders the creation of smaller structures.

Hydromer supplies a range of specialty coatings and hydrogels that provide medical devices with lubricity, biocompatibility, antithrombogenicity, and anti-infection properties.

—Benjamin Lichtman

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