* Originally printed in Dupont's Tyvek^® RX newsletter.
* (May 2000 Volume 9, Issue 1)

"We wanted a kit that was, above all, easy to open," said Richard Gaeto, Senior Director, Materials and Logistics for Immunex Corporation in Seattle, Wash., makers of ENBREL^® (Etanercept), an injectable medication used to treat patients with rheumatoid arthritis. Gaeto was describing why his company chose lids of Tyvek^® for packaging individual dosage trays of the successful arthritis medicine. Each tray contains everything a patient needs to self-administer a single dose of the arthritis medicine -- a syringe, sterile water and alcohol swabs.

"When we developed the kit back in 1997, we set out to design a tray with a lid that would be easy to remove, but one that would also provide the strength and cleanliness needed to keep the contents free from contamination," he said. "Because most ENBREL^® kits are stored in the home refrigerator, lids on the trays have to be an effective barrier against liquids and odors, and they need to be highly resistant to puncturing. An ordinary paper lid couldn't meet these requirements. That's when our team turned to coated Tyvek^®."

After setting the specifications for their package, Immunex engineers reviewed the project with Packaging Coordinators, Inc. (PCI), the firm they had chosen to package the kit on one of its form-fill-seal lines in Philadelphia, Pa. PCI agreed to thermoform the PETG plastic tray on its Multivac equipment, insert the kit components and heat seal the lid of Tyvek^®. "But first we needed to find a low-strength adhesive that would provide a good seal, yet allow the lid to be removed without a lot of effort," said Mike Bergey, engineering manager at PCI. "For that we turned to our supplier of Tyvek^® TOLAS Health Care Packaging in Feasterville, Pa., a specialty manufacturer of lids and pouches for sterile medical devices."

Working together, packaging engineers at PCI and TOLAS developed a heat-sealable adhesive system that would provide the easy-peel properties that Immunex wanted for its arthritic customers. "We came up with a proprietary formulation that gave us less than one pound per square inch of bond strength and would be easier to peel open than conventional lids adhesives," said Pat Tonrey, sales engineer at TOLAS. "While it was very easy to peel from the tray, the adhesive still gave us the strength needed for PCI's high-speed packaging operation."

The new soft-peel adhesive was tested by a panel of typical arthritis patients, who found that the lids could be removed with very little effort. In early 1999, Tolas began supplying rolls of the printed and die-cut lids of Tyvek^® -- with adhesive pre-applied -- for use on the automated packaging equipment at PCI.

PCI's form-fill-seal packaging line for the ENBREL^® kits started up in April 1999. "We're delighted with the lot-to-lot quality and repeatability of the preprinted Tyvek^® as a lidding material," said Bergey. "And we're especially pleased with its dimensional stability."

Immunex is equally pleased with the new easy-open lids of Tyvek^® on their packaged kits. "Working with PCI and TOLAS in selecting Tyvek^® was a decision that enhanced our packaging presentation and delivered an easy-to-open package for our patients," said Gaeto. "We're very satisfied with our selection of Tyvek^® for the lid as well as the overall success of ENBREL^®."