Plastic Connector Material Options
For hose barb and sanitary flange fittings, in most cases, polypropylene connectors provide sufficient physical, chemical,
and functional properties suitable for single-use systems. In systems intended to be gamma irradiated, the polypropylene must
be formulated as "gamma stable" using appropriate antioxidants to preclude premature degradation after irradiation. For unique
applications, additional parameters to consider would include chemical compatibility with the process fluid formulation, extractables,
mechanical properties such as toughness, ductility, impact strength, and physical properties such as transparency and lubricity.
Connectors should be manufactured from virgin resins, with accompanying certification of lot traceability. Resins that are
either free of animal derivatives or certified to FDA and European Medicines Agency (EMA) BSA/TSK risk per US 21 CFR part 189.5 and EMA 410/01 rev 3, respectively, and meet standards such as ISO 10993 and USP <87> Biological Reactivity, in vitro (MEM Elution Cytotoxicity), and USP <88> Biological Reactivity, in vivo for Class VI plastics are particularly important in biopharmaceutical applications.
A broad spectrum of plastic resins can be selected to produce connectors, each with different characteristics to match the
needs of system designers. The lack of need for sterilization in particular can make this choice easier, as steam or ionizing
radiation exposure generally rules out a number of materials. These plastic resins are commonly employed in producing connectors
used for biopharmaceutical applications:
- Polycarbonate—hard, transparent thermoplastic with moderate chemical resistance. It provides good impact resistance and superior
- Polypropylene—soft thermoplastic polymer that is highly resistant to chemical attack from solvents and chemicals in harsh
- Polyvinylidene fluoride (PVDF)—thermoplastic polymer that is mechanically strong with good ductility over a broad temperature
range, as well as excellent chemical resistance.
- Polysulfone—a hard thermoplastic polymer known for its toughness, chemical resistance, transparency, and stability at high
Connectors are designed to accommodate tubing of varying hardness (durometer), from soft and flexible like PVC, silicone,
and thermoplastic elastomer (e.g., C-flex or Advantaflex brands), to semi-rigid types like polypropylene, polyethylene, polyurethane,
and ethylene vinyl acetate (EVA).
To facilitate these varying styles of tubing and their respective application needs, different connector types are used, including
sanitary fittings, bag ports, tri-clamps, check valves, and barbed luer, quick connect, and tube-to-tube fittings. These basic
connector styles can cover a wide range of liquid and air applications in manufacturing:
- Sanitary fittings are used in applications such as fluid transport systems and wherever sensitive fluids must be transferred.
Flanged fittings are essential in a variety of areas of biopharmaceutical manufacturing including filters, pumps, and bioprocess
- Bag ports are a crucial component of the processing stage due to the effect processing has on media transfer. Therefore, careful
consideration must be taken into flow design.
- Tri-clamps have traditionally been a reusable component; however, single-use systems now require users to dispose of all components
after each process. A user-friendly, affordable clamp is now necessary in each system.
- Tube-to-tube connectors are a popular choice for applications that do not require the disconnection of equipment or parts
at any point during production or use. Hose-barbed tubing connectors are available in many different configurations, sizes,
and material options to adapt different tube sizes or styles, reroute the flow direction without kinking, act as a manifold,
- Luer connectors. Delivery systems can employ conical or taper seal connectors, called luers, to link various system components.
The male and female components of luer connectors join together to create secure, yet detachable, leak-proof connections with
no o-ring or gasket required. Luer connectors are typically sized for quarter-inch and smaller inside diameter (ID) tubing.
- Quick connects allow flexible tubing and/or equipment to be quickly and safely connected and disconnected. They may be preferred
over hose barb or sanitary flange fittings for fluid control because they require less manipulation, can incorporate built-in
shut-off valves that prevent spillage, and allow multiple disconnection and re-connections and faster servicing.
Many of the latest quick-connect designs focus on the user interface and are equipped with intuitively simple latch mechanisms
to make for easy handling in pharmaceutical management applications while mitigating costly leakage.