In the last few years, the biotech industry has witnessed the rapid adoption of single-use technology in bioprocess manufacturing. Concurrently, there has been a strong push to reduce operating costs by moving manufacturing from traditional stainless steel equipment in a cleanroom to single-use disposable solutions in a “gray space” environment. As contamination risk increases exponentially in gray space environments, it has become imperative to ensure a validated sterile flow path for single-use solutions.
Presterilized single-use connectors perform the critical function of connecting two presterilized single-use components in a nonsterile environment, while maintaining fluid-path sterility. As a result of the increasing use of single-use connectors, many new types of connectors have entered the marketplace. At the same time, their use has expanded beyond the typical upstream buffer and media applications, into high value-added downstream applications like ultrafiltration/dialfiltration and final fill and finish. This makes it extremely important that the choice of a single-use connector should take into consideration robustness of the connector design and sterility claims made by the vendor.
By design, a sterile connector should protect the fluid path by never exposing it to the open environment. For example, Millipore’s Lynx® S2S connector employs a solid plug, not a membrane or peel strip, that could create a gap.
When making sure that a single-use connector maintains a sterile fluid path, it is important to verify that the methods used to support these claims are valid, reproducible, and provide meaningful results. It is equally critical to ascertain that the selected connector will secure the fluid path at a sterility assurance level (SAL) of 10-6 under the most rigorous conditions.
Lynx S2S Connectors
The Lynx S2S connector is a single-use, single actuation device. It is composed of a male and female coupling set (Figure) designed to maintain sterility during the connection of two independent sterile fluid paths. Both units of the connector use a hose barb fitting to connect desired bags, containers, or assemblies to the fluid path.
Each fluid path is then sterilized by either gamma radiation or by autoclave in preparation for a sterile transfer of media, buffer, or even final drug product. The connector’s process contact materials are constructed of high-temperature gamma-stable polysulfone with an over-molded silicone gasket, allowing for autoclaving up to 130°C for 30 minutes and/or gamma irradiation up to 45 kGy.
The male and female coupling sets of the Lynx S2S connector uses solid plugs with silicone o-ring seals and gaskets for containment. This design provides high-pressure sealing and a tortuous path that prevents passage of bacteria. After the couplings have been autoclaved and/or gamma irradiated, two sterilized assemblies can be connected by a series of simple steps in any environment.
During the connection process, the plugs, which will become contaminated in a nonclassifed area, are isolated by moving them up and away from the fluid path within the female coupling body. This process assures a sterile fluid path (SAL of 10-6) for the liquid to flow through the connection.