The end of the weld?

Troy Ostreng, senior product manager for CPC’s biopharmaceutical business, assesses the advantages of aseptic connectors compared with tube welding in small volume biopharma processing.

Historically, tube welding has been the only option for biopharma system designers and processors to make closed sterile connections in small volumes using small-bore tubing. As the industry continues to evolve, we are seeing unprecedented demand for new therapies, efficiencies, and improved speed-to-market. 

The drive to process optimisation has led manufacturers to evaluate all steps in their workflows to determine whether they can make improvements. One such area is the use of aseptic connections to create closed sterile systems. Today, manufacturers can move away from the cumbersome tube welding process toward single-use connectors which are quick and easy to use, require almost no space in a cleanroom and provide efficient, seamless, and sterile fluid transfer.

Space and time

Cleanroom space is extremely valuable; the ability to remove welding equipment in favor of single-use connectors is, therefore, attractive to those looking to optimize the space they have when compared with the expensive and time-consuming process of validating new space. Single-use connectors are ready to use and have been validated for material biocompatibility, extractables, sterility, and leakage (Figure 1). From a practical perspective, once validated, welders also need to be moved into position and the correct size tubing holder must be obtained and inserted. They must then be initialised, the tubing loaded, welded, and then cured — a process that can take an average of 4–7 minutes in total. Multiply the setup time by hundreds of welds each week, operator time stacks up considerably. One hundred welds, for example, would require 6.67 hours of welding time at the lower end of the timescale at 4 minutes, whereas aseptic connectors are pre-sterilised and ready to go in a tubing/bag assembly and require mere seconds to connect and actuate. 

Length and material

Aseptic connectors can also be applied to any tubing length with no minimum requirement, and to any type of tubing, including silicone (Figure 2). Different types can also be connected; for example, silicone to C-Flex, and different hose barb sizes can be used at opposite sides of the connector. Genderless options eliminate the need to carry male/female components, and connectors of the same family can be interconnected. For welding, minimum tubing lengths are often required to fit into the welder, and only the same kinds of tubing materials can be fused together. In addition, welding cannot be used on silicone as the material burns during the process. Welders must also be set up for a specific tubing size and material, adding a further stage to the process.

Risk of contamination

Using aseptic connectors also reduces the risk of contamination as the margin for error is far narrower. For example, not following manufacturers’ recommendations in tube welding can lead to placing tubing with the incorrect diameter in the tube holder. This can cause small pinholes in the weld, due to pinching or squeezing the tubing out of the holder during the weld process. Welding different tubing types together — whether knowingly or unknowingly — can also lead to weld failure. With aseptic connectors there is little to no contamination risk because validated aseptic connectors maintain a sterile boundary between two adjoining single-use systems.

Cost

Finally, there is the question of cost. There is a common misconception that tube welding is more affordable than single-use aseptic connectors, but when the cost of the welder and its upkeep, blade costs and operator hours are taken into consideration, aseptic connectors are clearly an economical alternative. In tube welding, capital equipment and ancillary equipment costs range from a few thousand dollars to tens of thousands per welder in each cleanroom. Aseptic connectors eliminate capital expenditures associated with primary and backup welding equipment as well as maintenance costs.

Conclusion

When properly applied, both sterile tube welders and single-use aseptic connectors can create reliable connections. Factors such as ease of use, downtime potential, operator error risk, cost, and supply management, however, are important factors for system designers and processors. Aseptic connectors — particularly genderless models — deliver the flexibility, ease of use, reliability and cost efficiencies that are highly sought after in state-of-the-art biopharma manufacturing. They also address the challenges to design and operate processes that are robust, reliable, and repeatable. In this respect, the ‘end of the weld’ may be here, and the benefits are clear to see.