TPE Replaces Rubber in Resealable Closure for Infusion Bags

WEB EXCLUSIVE: A two-component, injection molded resealable closure for infusion bags has been developed by Bolivia’s Matriplast SA using a special TPE from Kraiburg TPE in Germany (U.S. office in Duluth, Ga.). Matriplast specializes in plastic containers and products for the pharmaceutical industry and is also now aiming to produce high-end products such as the new ASEPTIcap closure. They are made of Kraiburg’s medical series Thermolast M TPEs based on hydrogenated styrene block copolymers, which are certified for medical applications in most countries (USP Class VI, USP 661, ISO 10993-5, -10 and -11, as well as Drug Master File).

Thermolast M compounds, available in hardnesses between 35 and 45 Shore A, can be steam sterilized at up to 135 C. Moreover, they have resealing properties which makes them ideal for infusion bags. Since the TPE diaphragm is extremely elastic, it immediately seals the septum when the infusion line is removed from the bag.

In contrast to a conventional septum made of rubber, TPE has the advantage that it can be processed by two-component injection molding and bonded with PE and PP. This eliminates the need for the manual assembly of the rubber bag closures. Matriplast’s new solution also does away with costly storage of the closure components prior to assembly, and the TPE offers high purity with no danger of contamination from crosslinking agents.