At the BioProcess International Conference (BPI) in October, EMD Millipore launched their new PureFlex™ Plus single use fluid management film as an addition to their existing PureFlex™ film. The PureFlex™ Plus film provides a more robust option designed for high volume/value applications.

Polymetric film is used in single use technologies for fluid management. The film is a key component and its failure can lead to process failure and loss of buffer, media or product. When film fails it often occurs due to abrasion, cracking during film flexing, punctures and stretching. When considering the film to use in single use technologies it is critical to take into account not only physical strength, but also its extractables profile to be sure that the film isn’t releasing deleterious materials that could impact culture or final product quality.

EMD Millipore had set a goal to create a film that was stronger and more resistant to leaks, but maintained the same consistent, high quality extractables profile that they had achieved with their PureFlex™ film product. Maintaining a consistent extractables profile was important in order to minimize revalidation efforts for customers who would want to make the change from PureFlex™ to PureFlex™ Plus.

After lengthy rounds or research and development, twelve prototypes were developed. Ultimately the current prototype was selected because it offered the best resistance to leaks and tears and involved only a change to the outer layer meaning that there was no change to the layers with fluid contact.

The major changes in PureFlex™ Plus are that it is slightly thicker and the outer layer has been changed from ULDPE (ultra low density polyethelene) to the more abrasion resistant LLDPE (linear low density polyethelene). These changes resulted in many improvements in leak resistance when compared with PureFlex™ film including:

• Abrasion resistance – 2X higher with PureFlex™ Plus
• Flex cracking resistance – statistically fewer pin hole leaks from flex cracking
• Puncture resistance – 13% higher force required to puncture with PureFlex™ Plus
• Stretch resistance – 30% higher tensile strength with PureFlex™

The other critical goal was to maintain an extractable characterization that was equivalent to PureFlex^™ film. As a result of not making any changes to the fluid contact layers, the team did not anticipate any changes in the extractables profile between PureFlex™ and PureFlex™ Plus. After extractables characterization, it was found that PureFlex™ and PureFlex™ Plus had no statistically significant differences in the extractables profile and that PureFlex™ Plus was also in line with industry draft recommendations (BPSA BPOG).

I was able to interview Michael Felo, Product Group Manager, Single Use, EMD Millipore about the new product. He told me the product is perfect for applications greater than 200 liters where physical stresses are higher as the increase in volume adds additional weight. This is particularly important in buffer and media prep where large volumes and storage is fundamental. Michael also shared that all bag sizes are currently available in PureFlex™ Plus, which makes it a very easy transition for customers wanting to move from PureFlex™. While revalidation efforts are always a decision made by the end user, EMD Millipore has taken great effort to make revalidation easier by keeping revalidation in mind during design of the new product and in publishing a white paper that demonstrates equivalency with PureFlex™.