Five recent FDA-compliant thermoeplastic elastomers (TPEs) provide more choices for designing cleaner and more eco-conscious medical tubing. The material development was prompted by apprehensions regarding the environmental impact of plastics. Medical device manufacturers say concerns have them reconsidering traditional polymers that use halogens, phthalate-based plasticizers, or produce high levels of extractables. These latter compounds leach out of tubing into the fluid it carries and with uncertain results for patients.

The new materials, all Versaflex HC TPEs, from GLS Corp., are made without the phthalates or halogens common to PVC. The omitted additives will help tubing manufacturers comply with current and anticipated regulations while providing new capability, such as tolerance to higher autoclave temperatures than conventional TPEs. To assure sterility, there has been a need for TPEs that can tolerate more than the long standing 121C limit in autoclaves. Hitting the 135C target opens product opportunities that require higher temperatures for sterilization.

A lot of design discussion centers on the health risks of phthalates and plastic additives. How the compiled evidence against the additives may influence regulations is unclear, but what is clear is a trend toward increasing restrictions in the use of these substances. Added to the trend is a mandate to create products that can be recycled, incinerated, or disposed of without releasing halogens. So to help tube manufacturers stay ahead of oncoming regulations, the company has formulated recyclable, medical-grade TPEs that avoid phthalates and halogens yet provide many useful properties.

The recent series of TPEs includes five grades: three provide high clarity for applications such as IV tubing, while the other two are translucent and maintain stability at higher than usual temperatures, making them well suited for devices that must be sterilized by autoclave. All grades can be extruded or injection molded so manufacturers can use a single material for tubing and connectors. It is also possible to customize the materials to meet requirements for feel, modulus, hardness, and other properties. The accompanying table lists a few characteristics.