Considering Single-Use Materials

A good understanding of the properties of the plastic materials used to make single-use biopharmaceutical manufacturing system components is crucial. Polymers can vary in their barrier properties, whether physical properties change at extreme high or low temperatures, in their ability to hold up under sterilization conditions, and in extractables and leachables. Polymers used for single-use bio/pharmaceutical systems can include polyethylene (PE), polypropylene (PP), polycarbonate (PC), and-more recently-fluoropolymers. Pharmaceutical Technology spoke with Eric Isberg, director of Life Sciences at Entegris, which recently introduced its Aramus single-use bag assembly made from a gamma-stable fluoropolymer, about considerations for single-use materials.   

PharmTech: Are there temperature limitations for single-use materials?

Isberg (Entegris): Most single-use bag assemblies are limited to a temperature range of -20 to 40 °C. The limitation is mostly due to the bag film itself. Below this range, the materials become brittle and fail, and above it the materials soften and can melt. Rapid changes in temperature, temperature cycling, or temperatures below -70 °C can cause delamination of the film layers and film failure due to cracking.

The Aramus single-use bag assembly is designed and tested from -85 to 40 °C. However, the film and bag boat fitment are made from a single layer of fluoropolymer material that is suitable for use down to -200 °C and as high as 200 °C.

PharmTech: What are the concerns with single-use materials affecting cell growth?

Isberg (Entegris): All additives-whether they are by-products or purposely added chemicals like antioxidants, UV stabilizers, or processing agents-are potential leachables that can have a negative effect on processes and products.  For example, certain purposely added chemicals have been shown to negatively affect cell growth. Our fluoropolymers have none of these by-products or additives that can leach out into the process.

PharmTech: What are the concerns with particulates coming from the materials? 

Isberg (Entegris): Both foreign particles, as well as particles native to the bag assembly materials, which are generated during manufacturing, are potential process contaminates. Aramus single-use bag assemblies are manufactured in an ISO Class 5 environment, greatly reducing the potential for particulate contamination. The advantage of manufacturing in an ISO Class 5 environment is a reduction in foreign particles from both the manufacturing environment and the manufacturing process itself. Utilizing sufficient laminar air flow across the parts during manufacture can sweep away any airborne particles that are generated. Also, controlling the dryness of the air, combined with other static-elimination methods, can keep airborne particles from sticking to surfaces, including the surface of the single-use components being assembled. Lastly, reducing the number of penetrations on the interior of the bag reduces the chance of particles being introduced. Fluoropolymers are not inherently better than other plastics in terms of native particle generation during manufacture. It is a matter of how those particles are reduced using these steps as well as other proprietary methods, including post-processing procedures.