Constantly rising quality standards for improved patient safety present the pharmaceutical industry with major challenges. Furthermore, new drugs must be packaged in the best possible way. This is particularly true for the packaging of high-value medicines that must meet precise requirements. What is needed is a container that meets all qualitative criteria and at the same time enables a smooth filling process. Traditional fill and finish operations for drugs rely on bulk filling processes, which allow for a high throughput in a short period of time. Yet, a critical factor here is that the glass-to-glass contact and the mechanical stress on the containers can create small glass particles that can get inside and contaminate the medication. In addition, containers may be damaged or even broken. This is particularly problematic when highly potent drugs such as biopharmaceuticals are involved. Here, it is all the more important to avoid glass breakage during filling.
Borosilicate glass that is used for pharmaceutical packaging and has proven itself for many decades offers many advantages: It is chemically very resistant, neutral, dense and, like glass in generalis remarkably strong. But what can be done to also protect the containers from the axial and lateral pressure on the filling lines and consequently protect them from breaking?
Optimizing glass strength
SCHOTT researchers are constantly working on further developing glasses in order to meet customers’ increasingly complex requirements and offer suitable solutions. With SCHOTT EVERIC™, the company has now developed a modular concept for a new generation of pharmaceutical vials. The idea: Pharma companies can combine different features depending on their needs for the drug.
The module option EVERIC™ strong stands for the improved strength of the container. “The prerequisite for this is an enhanced surface of the glass – in combination with an optimized geometry of the vials that deflects mechanical stress that is applied from the outside,” says Dr. Florian Maurer, Senior Scientist Strength, Reliability and Life Time in Material Analysis at SCHOTT. “After all, glass breakage is the result of a too high physical interaction between a glass defect and a mechanical tensile load applied on the defect.” The EVERIC™ strong containers focus on preventing flaws in the vial’s heel area at the bottom of the side wall. “This is because precisely this area of the vial has proven to be particularly critical for breakage. Nevertheless, the geometries are still within the ISO standards,” the expert explains.
Essential for this new development is that the typical stress situations during filling, transport or handling of the vials in the pharmaceutical industry are known. With the help of computer simulation, the SCHOTT researchers transfered the detailed information about which mechanical stresses, in what strength and where, act on the vials to mathematical models of containers with different geometric properties. Dr. Maurer: “EVERIC™ strong is therefore not an artificially hardened vial. Neither the composition of the glass nor its structure are changed. The idea is to maintain the original strength by simply avoiding glass defects.” Expressed in one figure: Hot manufacturing and computer simulation knowhow from SCHOTT achieved an increased axial strength by a factor of four compared to the market standard. EVERIC™ strong and the experts’ knowledge of glass is therefore “real strong.”