Making the connection

Integrated syringe closures made of high-temperature plastic

Making the connection

Prefilled syringes are increasingly used in systems for the treatment of chronic diseases, such as rheumatism. It is vital these systems are tamper evident and deliver the intended dose reliably.

Gerresheimer selected Apec® 1745 high-heat polycarbonate from Covestro for the adapter of its Gx TELC system. (Photograph courtesy of Gerresheimer Bünde GmbH.)


The Gx TELC (Tamper Evident Luerlock Closure) from Düsseldorf-based Gerresheimer AG is a closure system for prefillable glass syringes. For ease of use and safety, the component features a combination syringe cap and luer lock adapter system, which connects to a needle for drug delivery.


To simpfly manufacturing, the Gx TELC is created by two-component injection molding. First the adapter is made of a hard thermoplastic, then the cap is injected with a soft elastomer to form a firm adhesive layer. There are no chemical reactions that could cause increased torques.


Covestro provided extensive support during the development of the complex component including material selection, technical application and manufacturing advice. For the adapter, Gerresheimer utilized Apec® 1745 high-heat polycarbonate. This is a biocompatible material that is dimensionally stable and accurate at high temperatures, so that the component does not warp after hot steam sterilization. It also provides high impact strength, protecting the adapter from damage in the event of impact.

Case Profile


Covestro AG


Gx TELC syringe adapter


Apec® 1745 high-heat polycarbonate

Apec® – the state of the art thermoplastic that can beat the heat with phenomenal material properties

  • Apec® 1745 high-heat polycarbonate is appropriate for use in medical applications.
  • Apec® high-heat polycarbonates offer high transparency, toughness and strength.
  • The selected Apec® high-heat polycarbonate grade is suitable for repeated sterilization up to 143°C.
  • The material offers additional benefits including easy release from the mold and high softening temperature and good hydrolysis resistance.
  • Apec® 1745 high-heat polycarbonate is biocompatible according to ISO 10993-1 test requirements.
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