Cartridges are glass bodies inside pen and auto-injectors that hold the drug. To mechanically harden the glass to suit these types of situations, SCHOTT has now developed chemically hardened cartridges. Two aspects were particularly important here: “We wanted to retain the original geometry to make sure that the new cartridges still work with standard pen systems,” explains Wesp. Simply shaping the walls to be thicker was therefore out of the question. ”Chemically hardening the glass proved to be an alternative that would not affect the integrity of the drug,” she adds. The goal was to avoid an undesirable reaction between the glass surface and the contents that could impair the drug’s effectiveness.

The answer was to further develop a glass hardening process that has been the industry standard for many years. These efforts proved to be successful at the US development lab in Pennsylvania, where SCHOTT researchers optimized a proven ion exchange process for use in pharmaceuticals. The cartridges bathe in a potassium nitrate solution during this process, whereby the sodium ions in the surface layer are exchanged for larger potassium ions from the solution. This gives the glass greater stability. Tests have shown that the cartridges hardened in this manner are three times as resistant to mechanical stresses. SCHOTT will be introducing the respective product to the market that will be called SCHOTT Cartridges BR. BR stands for ”Breakage Resistant.” The company will offer its chemically hardened cartridges in standard sizes and in customer-specific designs. They can be used in auto-injectors, needle-free injection devices and pen and pump systems. <