What does the FDA say regarding glass delamination prevention?

Delamination in glass containers of medicines for parenteral use has resulted in numerous recalls lately. Although no case has become known where a patient has come to harm, the FDA sees the risk of vascular injury, embolism and thrombosis through the glass particles. Also, the emission of glass particles into the product violates the requirements according to 21 CFR 211.94, whereby product containers are supposed to be neither reactive, nor additive nor should they affect the quality of the product. The pharmaceutical manufacturers therefore have to ensure that this particle generation is prevented as much as possible.

The following conditions can cause the glass delamination:

• Manufacturing of vials from glass tubing (typically done at higher temperatures). Molded-glass vials are less sensitive to delamination.
• Solutions with higher pH (alkaline) can promote delamination, just as certain buffers such as citrate and tartrate.
• A prolonged contact of product with the inside surface of the glass can also promote glass delamination. This has a direct impact on the shelf life of the product.
• Product stored at room temperature makes delamination more likely than lower temperatures.
• The heat treatment in the terminal sterilisation negatively affects the stability of glass and can lead to delamination.

For products with a higher risk the FDA recommends to use particularly resistant glasses such as borosilicate glass products. Pharmaceutical manufacturers should pay special attention choosing their suppliers for glass vials. They should also re-check already established suppliers or their quality management systems to minimise the phenomenon of glass delamination.