In a recent poll US drug makers told American Pharmaceutical Review they would like to learn more about glass breakage in relation to primary packaging.
In this video, we discuss what causes glass to break and what pharma companies can do about it.
Glass is basically a very strong material. Its strength is scientifically defined by its absence of flaws: A glass vial with an intact surface can normally drop on the floor without breaking. The problems are the flaws: Scratches and cracks that weaken the glass surface. If too much mechanical stress is applied on these micro-defects, the glass will break.
How to protect the glass surface
Glass breakage during production correlates with the quality of the filling line. On older or poorly adapted production lines, vials often bump into each other, which causes the micro-defects. Furthermore, the vials can rub against each other, and this friction causes glass particulates to come off. Yet, filling line manufacturers have made great progress on handling the glass more smoothly. Moreover, there is a huge trend towards ready-to-use filling, where the containers are safely fixed in a nest – an approach that has been used for syringes for decades.
Reducing glass breakage on existing filling lines
A new system developed by Smart Skin Technologies offers a clever solution for breakage reduction on existing filling lines. Vial clones with a sensitive outer skin are sent through the production line to identify critical areas. A study by Roche and Genentech has shown that making small adjustments based on this analysis reduces breakage significantly.*
Are there better glass types to reduce breakage?
Borosilicate glass remains the gold standard as it has a longstanding track record and demonstrated its compatibility with all kind of medications. The material has been used to package drugs for over 100 years. More than 40 billion containers are made of it per annum, and its chemical behavior is well researched.
Aluminosilicate glass has recently been discussed as a possible alternative, especially to reduce glass breakage. Today, it is mainly used for smartphone displays and needs intense treatment to be suitable for pharmaceutical applications. Hence, incoming inspection is needed to make sure no untreated containers are processed.
Plus, the advantages current Aluminosilicate glass vials offer, such as breakage resistance or less friction and particulates, are independent from the glass type. Rather, they are a result of post-production treatments, such as chemical toughening, which can be applied to Borosilicate glass as well.
The following links provide a comparison of the two glass types:
Extractables Profile of Aluminosilicate Glass Prior to Chemical Treatments
Certain Treatments and Their Impact on Extractables for Borosilicate and Aluminosilicate Glass
* Brückner D., Mehari A.: Yield Optimization in Aseptic Drug Product Manufacturing through Identifying Process Related Glass Defects, Parenteral Packaging Conference, Rome, 2018.