What are some of the Considerations When Selecting Single Use Tubing?

December 6, 2013
C-Flex TPE Tubing in a Peristaltic Pump

C-Flex TPE Tubing in a Peristaltic Pump

To begin, single use tubing is a key part of any single-use system and is critical for secure fluid transport.  It is also a key product contact area that can possibly lead to absorption of product and leaching or shedding of tube particulates if an inappropriate material is selected. This post will focus on the factors that are important to your selection of proper tubing for each application.

Where do I  begin you ask?  Let us help you:  a good starting point would be to bear in mind the process fluid and the conditions in which the fluid transfer tubing will be subjected to. We need to take into account the possible impact on the product and of course the types of tubing and sizes that are available and some other considerations in making your selection.

The first factor to consider when selecting tubing is the type of the fluid you want to transfer. In single-use bioprocessing, fluids can vary from proteins, to other biological active aqueous solutions, to high purity water. Biologicals may be especially touchy with ultraviolet light or oxygen, and in this case may demand opaque or low gas permeability tubing.  Certain types of acids need to be used with chemically compatible tubing.  However, in every case it is vital to choose tubing grades with low extractables and leachables to minimize the chances of product contamination.
As soon as biological solidity and chemical compatibility are clear, processing conditions should be measured, including temperature, pressure, time, and the sterilization environment prior to use. Single-use bioprocesses are commonly run at temperatures below 40 °C, and therefore the majority of tubing options are compatible. If tube welding or sealing is needed on the system then meltable tubing, such as thermoplastic elastomers or TPEs. If the system utilizes sterile connectors and will be steamed in place, temperature must also be considered. More on that later.

The next process situation to consider is pressure. Low-pressure limits of single-use polymer film & biocontainers generally limit pressure requirements for system tubing. In some systems though, test pressures can range from 40 psi to 70 psi or even higher. To accommodate this, high durometer, braided, or reinforced tubing must be included to ensure suitable pressure rating.

Sterilization circumstances must be measured when selecting tubing. Most single-use applications are gamma irradiated for sterilization and therefore require gamma stable tubing (usually up to 50 kGy dosage), but it is not unusual to apply autoclave sterilization for some tubing manifolds and filtration systems.  The preferred sterilization method must be considered in tubing selection.  Other concerns for the tubing’s impact on process fluids are biocompatibility, leachables, adsorption–absorption, and permeability of gas and light (particularly ultraviolet light).

The most familiar types of tubing used in single-use applications are silicone and thermoplastic elastomers. Silicone tubing has a long history of safety for use with a variety of bioprocess fluids, and delivers high temperature and gamma radiation steadiness. Other advantages incorporate flexibility, translucency, biocompatibility, and smooth bore for low absorption and particulates. Peroxide-cured grades have been effectively used in lab and clinical applications, however platinum-cured silicone is favored for single-use systems for the reason of lower extractables. Braided grades are existing for high pressure applications. Silicone tubing cannot be thermo-welded and is restricted to pre-assembled systems or connections using quick-connects or sterile connectors.

Single Use Filling Needle Manifold with both Silicone and FEP Tubing

Single Use Filling Needle Manifold with both Silicone and FEP Tubing

For tube welding and sealing uses, thermoplastic elastomer (TPE) tubing is needed. These proprietary creations have a good history of safe use and are favored where reduced adsorption, absorption or gas permeability is desired, though they do not all have the transparency of silicone tubing. The most popular brand of TPE tubing is C-Flex.  Other specialty formulations of tubing, such as Pharmed BPT, are also available.

Holland carries a broad line of single-use bioprocess products. We generate the same amount of process know-how, product skill, and dedication to quality in our single use program as we have in our stainless process equipment business. Our capabilities allow us to offer a large range of single-use products, stretching from mixing systems to single-use manifolds, disposable sampling assemblies, plastic fittings, valves, tubing and clamps. We carry a broad selection of single-use biopharmaceutical tubing from the best brands available, including C-Flex, Sani-Tech, Pure-Fit and Masterflex. We offer a broad choice of materials; silicones, TPE’s, PVC and fluoroelastomers.

If you have any questions on single use tubing or any of our single use products, contact us via our web site or call us at 800-800-8464.