Cyclic Olefin Copolymer: Alternative Resin For Medical Packaging
Polyacrylonitrile (PAN)-based polymers, best known under the Barex brand, have been a staple of the packaging industry for decades, serving as a barrier and sealant layer in a range of food and medical packaging. However, recent inroads into the food-packaging market by barrier materials such as ethylene vinyl alcohol (EVOH) have eroded PAN’s sales to the point where the sole remaining supplier of the material, Ineos in Lima, Ohio, announced over a year ago that it would stop making the product.
Replacing Barex is an urgent matter for OEMs in the healthcare market due to the regulatory constraints involved in switching packaging materials. A poor choice of packaging material will compromise pharmaceutical purity and potency, so it is essential to identify a material that delivers the required barrier and adsorption profile while also exhibiting low leachables and extractables and meeting regulatory requirements—often in multiple global markets. Significant testing is required when changing pharma packaging materials, hence a high degree of confidence in alternative materials is necessary before undertaking what can be an expensive and time-consuming process with multiple regulatory checkpoints.
Topas cyclic olefin copolymer (COC) from global thermoplastic material supplier Topas Advanced Polymers, Florence, Ky., is one material that has already emerged as a viable alternative to Barex PAN in healthcare and other applications. For several years, Topas Advanced Polymers has worked closely with leading global packaging suppliers to introduce COC polymers in pharmaceutical packaging materials such as medicinal pouches and blisters for patches and other end uses that require strong chemical resistance and low permeation. While COC has already been successfully substituted for Barex in some commercial applications, Ineos’ recent announcement to stop producing Barex has put additional focus and priority on these efforts.
A clear, high-purity thermoplastic with a long, proven track record of successful medical applications, Topas COC is now filling the needs of many healthcare companies who seek a safe and readily available replacement for Barex materials. Although PAN and COC come from the opposite ends of the polymer spectrum, they offer similar barrier/permeation performance and strong chemical resistance. Topas COC is well known for its purity, which is generated via an advanced metallocene polymerization process engineered for exceptionally low leachables and extractables.
Topas COC delivers broad global regulatory compliance for both healthcare and food-contact applications, and is available in a number of grades to meet specific processing and end-use requirements. The polymer can deliver excellent heat-sealing behavior, facilitating broad use in direct contact with packaged goods. Grades are available with low seal-initiation temperatures for easy sealing, while grades with higher heat resistance are offered for a range of applications that may face significant heat exposure.
KEY PERFORMANCE PROPERTIES
The pharmaceutical packaging industry is already familiar with COC through its use in other flexible, semi-rigid, and container applications such as forming webs, blister packs, and syringes. While not considered a drop-in replacement for PAN, COC delivers effective chemical resistance and low adsorption rates, exhibiting low permeation and migration for medical-grade chemical contents such as nicotine for medicinal patches. COC’s adsorption of nicotine is less than that of glycol-modified polyethylene terephthalate (PETG) and EVOH.
In another example of superlative chemical performance, COC’s resistance to methyl salicylate is similar to PAN and better than PETG. Alcohol resistance is yet another strong suit for Topas COC, with its good alcohol barrier put to the test over the years in many healthcare applications. And the moisture barrier of Topas COC is a known strength, one that has driven its increasing use in healthcare applications such as blister packaging.
Topas Advanced Polymers has developed a web presentation to share its test results . Data on multiple COC grades, as well as competitive materials like PAN, EVOH, and PETG, can be found there. The presentation is updated as new results become available.