Germany's Schott Glas has been granted a US patent on a glass container for storing medicines that incorporates an anti-adherent coating on its inner surface.
Anti-adherent coatings are used to ensure that glass containers for liquid pharmaceuticals allow near-complete emptying, something that is important to ensure accurate dosing in single-use vials, and also in small containers where the contents are very expensive.
Most coatings used for this purpose are based on silicone oils, but these have a number of disadvantages. For example, they can leech off the inside of the container and passing into the patient along with the drug, sometimes contain heavy metal impurities that must be monitored and can bind to protein-based drugs.
Another technique is to use compounds such as silanes or silazanes as a coating. However, these require that the glass container be washed using strong acids prior to administration of the layer, and carefully washed thereafter, which is an expensive process. The resulting coating also has the disadvantage of not being able to withstand the sterilising heat of an autoclave (i.e. 121 degrees C for 20 minutes).
In contrast, Schott's newly patented technology is free of heavy metals and silicones, is stable after autoclaving or hot air sterilisation at 300 degrees C for 30 minutes and copes with all pharmaceutical stress tests.