7 Problems with Using Borosilicate Glass to Package Drugs

9 mins read

By Christopher Weikart, Chief Scientist, SiO2 Materials Science

Even though drugs are meant to save lives, the primary packaging used for delivering drug therapies and vaccines may actually be putting us in danger.

The pharmaceutical industry works hard to create cutting-edge drugs to save lives and keep people healthy. From research to clinical trials, to go-to-market, drug makers are constantly seeking out new drug technologies and approaches to treat everyday illnesses and to end global pandemics.

But the vials and containers that deliver these drugs haven’t evolved at nearly the same rate. In fact, the material used to make pharmaceutical packaging — borosilicate glass — hasn’t evolved much at all since it was created in the 1880s.

It may have served the drug industry for a time, but this type of glass has a number of faults that can cause problems. What’s evident is that we need new alternatives for pharmaceutical packaging, in order to keep up with drug innovations, and to keep patients safe.

7 Problems with Borosilicate Glass for Drug Packaging

While glass is able to contain drugs better than plastic alternatives, glass still isn’t a perfect substance — and those imperfections can cost money, resources, and patient safety. Here’s why we must rethink using glass for pharmaceutical packaging.

Problem 1: Stability and Efficacy

Packaging for today’s biological drugs need to be as complex as they are. Advanced biological drugs are extremely sensitive, which means they need packaging that can withstand a wide range of temperature changes, chemical stress, and physical force. Today, packaging may not just be the container but maybe a working medical device, as is the case with prefilled syringes. However, glass has surface properties that can interact with additives, causing contamination or instability of the drug. Glass properties can also cause aggregation of the drug molecules into clumps that are no longer therapeutically active, impacting dosage and potentially immunogenic to the patient.

Problem 2: Particulate Matter

In addition to affecting stability, as drug formulations interact with the surface of the glass, the glass can shed flakes into the solution called delamination. This is accelerated by drug formulations that are more alkaline or lower in pH. Delamination can also be caused by poor quality glass or poor glass production. These particles, if injected or administered to patients, can cause everything from discomfort to an allergic reaction to even death. Glass particulates found in solution aren’t just isolated incidents, but one of the major causes of drug recalls as well.

Problem 3: Thermal Stability

As we all learned about the COVID vaccine this past year, we often heard about the low temperatures needed for storage, specifically, the Pfizer vaccine that needs a freezer temperature of between -80° C/-112° F and -60° C/‑76° F. That’s because nucleic acids (mRNA, DNA), cell and gene therapy, and viral vectored therapies require similar low temperatures needing to be sustained upwards of six months. This means that their containers need to withstand the same temperatures. The problem has more to do with leakage than breakage. All vials are sealed tight with a rubber stopper to protect the therapy or vaccine contents from the environment and maintain sterility. As the temperature drops through the -50 to -70 °C range, all commercial rubber stopper materials that are ordinarily elastic and pliable become hard and stiff. Additionally, rubber materials shrink at different rates than glass. Both factors contribute to the possibility for the rubber stopper separating from the glass vial during cold temperature storage. This can lead to leakage and compromised sterility of the drug product.

Problem 4: Customized Drug Delivery Systems

As mentioned above, many drug containers also function as delivery systems, which will play an increasing role as drug delivery becomes more personalized and independent of health professionals. Personalized systems like auto-injectors, wearables, and prefilled syringes all designed for at-home self-administration will need to be molded to specific dimensions that glass may not be able to replicate, or that glass may not be durable enough for.

Problem 5: Precise Dimensions

Drug containers also need precise dimensions in order to ensure precise small volume injections. For example, this is particularly critical for therapeutic injections into the eye. Yet containers made with glass often can’t get as precise as needed, and these dimensional variations can lead to drug overfilling by up to 3%, resulting in higher costs. Additionally, the FDA states that “variations in dimensional parameters, if undetected, may affect package permeability, drug delivery performance, or the adequacy of the seal between the container and the closure.”

Problem 6: Product Strength

Glass containers break, and a cracked vial can do everything from shutting down manufacturing for a significant amount of time, to injure health professionals, as was the case in a March 2020 recall of a drug due to “ampules breaking and shattering, upon opening,” with reports of “cuts in skin and lacerations to health care professionals” and the “probability of flying glass injuring the skin, eye and/or other parts which could result in either temporary or permanent injury.” Because of the fragility of glass, added care must be taken through all steps of the manufacturing and distribution process. Glass vials also don’t just break occasionally, but are one of the main reasons for drug recalls.

Problem 7: Inspection

Drug companies require the highest quality containers for their drugs. Yet when it comes to ensuring quality, most glass manufacturers are only capturing between two and five data points per unit during the inline inspection. Additionally, major glassmakers often wait until after delivery to manage defects, which can lead to the aforementioned drug recalls because of breakage.

Why We Must Rethink Borosilicate Glass

Why is the drug industry settling for such a fragile product unable to keep up with the new needs of the pharma industry? Why are next-generation drugs being compromised by legacy packaging like glass, which has shown to be unsuitable for the job at hand?

Such a constantly innovating industry needs innovative solutions in the form of new materials that don’t react with drugs, cause shedding or particulate matter, that can break easily, or that require the inclusion of materials like silicone oil to work. Overall, the pharma industry needs new materials that haven’t changed in over 100 years. Now’s the time to look at alternatives to traditional glass.

Author Bio:

Dr. Weikart has been with the company since its inception for 9 years and was responsible for leading the R&D efforts that resulted in the current parenteral product portfolio. Prior to joining the company, he worked in Central Research at the Dow Chemical Company for 12 years in various R&D, engineering, and leadership roles. Dr. Weikart earned a BS and Ph.D. in chemical engineering from the University of Missouri-Columbia.

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