Technology focus: Protecting medicines

Frankfurt, Germany – German rubber industry association the WDK has highlighted the role of rubber products in pharmaceutical packaging.

In particular, the association explained how rubber stoppers are critical to the safe storage and use of medicines, vaccines and infusion solutions.

As part of its 'Rubber – we save the world' campaign, WDK said many pharma products are stored in glass containers with closures that must prevent contamination.

"Pharmaceutical closures are about much more than sealing a container tightly," according to Volker Krings, chief chemist at the Frankfurt-based industry body.

"The material comes into direct contact with the drug. It must therefore neither release substances into its contents nor absorb components from them or change the preparation."

At the same time, the rubber stopper must provide a reliable seal while remaining highly elastic, according to the WDK statement.

This, it noted, is particularly important for injection vials, where medicines are withdrawn using a syringe cannula.

Once the cannula is removed, the puncture site in the rubber stopper must close tightly again, Krings emphasising: "Only rubber can do this.

Freeze-dried medicines present additional requirements for pharmaceutical closures, WDK, noting that stoppers used must remain flexible at temperatures down to minus 40 C.

During the freeze-drying process, the rubber products must allow water vapour to escape before subsequently sealing the container against moisture during storage.

Concluded Krings: "At first glance, a small rubber stopper seems unspectacular. In fact, it performs central functions for the safe storage and use of medicines.

"Here, too, it becomes clear that modern medical care would be unthinkable without high-performance elastomers."