Topas Cyclic Olefin Copolymer Used for Plunger of OmniPod Insulin Pump

Cyclic olefin copolymer (COC) from USA-based Topas Advanced Polymers has been used to make the plunger of the latest model of the OmniPod insulin management system, manufactured by US device maker Insulet based in Massachusetts.

The OmniPod, said to be the industry’s first tubeless and wireless insulin pump, was first commercialised in 2005. The latest model received 510(k) clearance from the FDA in December 2012. The plunger, a two component insert moulded part, has been made from Topas COC since the device was first commercialised. It has been said that Topas COC was chosen thanks to its high levels of purity, drug compatibility, biocompatibility and dimensional stability. The plunger is described as being one of “critical high performance”.

The newly released OmniPod is reportedly 34% smaller and 25% lighter than the original model. It is part of a group of products—the OmniPod Insulin Management System—consisting of the OmniPod, which holds and delivers the insulin, and the PDM (Personal Diabetes Manager), which communicates wirelessly with the OmniPod to programme insulin delivery.

The plunger is comprised of a stainless steel lead-screw and fill rod which have been insert moulded with Topas COC resin. The plunger has an elliptical shape and measures approximately 9.5 mm x 15.9 mm (3/8” x 5/8”).

Topas COC’s “critical high performance” is demonstrated in the mechanical performance of the plunger, especially in terms of dimensional stability. The plunger moves just 0.004 mm (0.000156”) per increment of insulin delivery. Strict dimensional tolerance of the plunger and lead-screw is critical to ensure accurate dosing of insulin. A very small amount of insulin can have a significant effect on blood sugar levels.

The OmniPod attaches directly to the body and is usable for up to three days of basal-bolus insulin therapy, delivering boluses of insulin after meals and in steady rates throughout the day. The OmniPod holds 200 units of rapid-acting insulin, which Insulet says meets the needs of most Type 1 diabetes patients’ three-day insulin requirements.

Topas COC’s dimensional stability is also key to the successful management of the interface between the plunger and the insulin reservoir. The material provides adequate compression to maintain seal integrity.

Commenting, Insulet’s vice president of business development and advanced technology, Kevin Schmid, said: “Topas COC fills an important role in the drive system of the OmniPod Insulin Management System. It’s a well-respected material because of its drug compatibility and other high-performance attributes.”

Topas COC offers a non-ionic, minimally reactive surface. This non-polar substrate does not promote adsorption, denaturation, aggregation, or precipitation. The company says that these properties are unlike other engineering thermoplastics or glass.

Furthermore, with lower leachables and extractables, Topas says that its resin preserves long-term drug purity, enabling better quality than comparable materials at high yields.