Glass has been a dominant form of packaging for the pharmaceutical industry since the 1700s. A number of properties, including chemical durability and a high-elastic modulus, makes glass an attractive candidate for transporting pharmaceuticals. The evolution of glass packaging rapidly advanced from the early 1700s to the 1930s, with borosilicate glass being the end product of innovation. Since then there have been no significant advances in glass material.

Borosilicate glass is still currently the most popular form of pharmaceutical glass packaging; it has been since the last innovation. As fantastic as borosilicate glass is for pharmaceutical packaging, however, there are plenty of known problems. For example, delamination of pharmaceutical glass during production is an issue that has plagued pharmaceutical glass manufacturers. Glass flakes, or glass lamellae, result from delamination, a failure mode where a material fractures into layers, during production. This can potentially contaminate the end product that the glass will house and may result in glass flakes being directly injected into a patient’s bloodstream.

An old issue

This problem is not a new one. All the way back in 1953, Dimbleby recognized the issue of glass lamellae and created a series of tests that would be able to detect glass flakes in pharmaceutical products. These testing methods have improved along with technology, but the presence of glass flakes persists to this day, as pharmaceutical manufacturers stick to their classic borosilicate glass products. In 2011, the FDA issued an advisory to drug manufacturers about the potential formation of glass flakes present in injectable drugs.

There is no hard data to estimate the number of deaths that are caused by the presence of glass flakes in pharmaceutical products. However, there have been several documented cases where conventional packaging has directly resulted in the deaths of patients. Additionally, glass manufacturers will continue to experience recalls as glass flakes continue to appear in glass packaging. A single recall can cost a pharmaceutical company more than $250 million.

Lamellae glass formation

Borosilicate glass production has streamlined and improved over the past 80 years as new manufacturing techniques have improved production rates. The last hand-blown glass operation closed in 1942. Nowadays, modern production processes create the final product by converting a tube into its applicable shape. Glass is heated up by a flame and then rapidly cooled to accomplish this task.

When the vial cools, the boron and sodium will integrate into the surface of the glass. This completely changes the chemistry of the glass, which can potentially cause the formation of glass lamellae. Pharmaceutical glass manufacturers have been working to reduce delimitation by implementing detection systems to find glass vials with glass lamellae present.

Control processes are only so efficient at reducing the risk of glass lamellae formation during production. No matter what safety precautions are set in place, there will always be a subset of vials that will have glass lamellae. The root of the problem is boron evaporation. Since borosilicate has boron present, there is nothing any pharmaceutical glass manufacturer can do to prevent some level of delamination.

Researchers and manufacturers have found a potential material replacement for borosilicate glass: aluminosilicate glass.

Aluminosilicate glass

One solution to eliminate glass flakes in pharmaceuticals is aluminosilicate glass. This type of glass eliminates the root issue, which is the presence of boron. Thus, the aluminosilicate replaces boron with aluminum. The new material solves the original problem of glass flakes and has other surprising benefits as well.

Unlike boron, aluminum does not have the propensity to delaminate. Current studies have shown that aluminosilicate glass has completely eliminated all traces of delamination from the glass packaging. Patients will no longer have to worry about glass flakes contaminating their treatments.

Strength is another added benefit of aluminosilicate glass, which reduces breakage and cracks in vials. This will, in turn, lower drug shortages as doctors, shipping companies, and nurses will have fewer broken vials. Production lines can also run more smoothly as there is less friction between the vials in manufacturing lines. The benefits of this new glass material are apparent to all parties involved.

Nevertheless, the pharmaceutical industry has been slow to adopt this new type of glass. Change is difficult and resistance is high. Switching from a product that has been used for more than 80 years will be a long process, particularly because the pharmaceutical glass-manufacturing industry is massive. Patients and the pharmaceutical industry will both benefit from the switch to aluminosilicate glass, however, so hopefully things begin picking up.