Q&A with Graham Reynolds, West Pharmaceutical Services

PharmTech: What do you see as the current and future trends toward using glass or plastic for packaging parenterals and what are the drivers for these trends?

Reynolds: Glass has been the solution for many years in pharmaceutical packaging, but limitations and recent cases of deficiencies in glass containers have guided companies toward alternatives. Plastic has been an option for drug packaging for many years, and in certain markets, such as Japan, has become more widely adopted driven mainly by improved cosmetic quality and break resistance. In other markets, plastics, such as cyclic olefin copolymers (Crystal Zenith, Daikyo), are used due to a broad range of benefits, including compatibility with more sensitive or high pH materials, as well as the broad benefits of improved dimensional precision and/or absence of silicone oil, tungsten, or adhesives in syringe systems. Some of the progression towards plastic includes recalls due to glass breakage and delamination, which leads to increased patient risk. In many cases, a glass container is integrated into a delivery device, which can cause stress on the container as well as the need for the device to compensate for the dimensional variability of glass. The design flexibility of plastic also can be an advantage when considering new integrated systems.

In general terms, glass will not disappear; however, known deficiencies of glass are increasingly driving companies to look at plastic containers as a high-quality alternative for drug containment. Many of these companies find the benefits of plastic increase the attraction of these options as a form of drug packaging and delivery.

PharmTech: What factors should manufacturers consider in choosing a primary containment and/or delivery system for their drug products?

Reynolds: One of the early considerations for any container system is likely to be the interaction between the drug material and the container closure system. Screening of materials and selection of the appropriate container systems is therefore important at an early stage. Companies should also consider the final method of drug delivery at an early stage in the development process. For instance, the determination of dose volume can drive selection toward different types of container closure and delivery systems. In addition, if the drug container has to be integrated into a delivery system as part of a combination product, early understanding is essential to ensure that the necessary work is done to support regulatory submissions. Many customers are choosing to evaluate both a glass and plastic option at an early stage of the development process to ensure that they have an appropriate solution that may help to optimize time to market. As part of compatibility testing, interaction with any materials that might be present in the system, such as silicone oil, adhesives, and elastomer components should be considered.

PharmTech: What are some advantages and disadvantages of using polymers (compared to glass) in these applications?

Reynolds: One of the main benefits of plastic compared to glass is its increased break resistance. This is important at various stages of the process including manufacture, transportation, and subsequent use by the patient or health care administrator. In addition to the breakage factor, it has been shown that challenges of delamination can be eliminated by the use of plastic systems. In cases where a device is incorporated, or the container is incorporated into the device as part of an integrated system, the dimensional tolerance and precision of plastic compared to glass can have a significant advantage in ensuring optimum functionality.

Also, if the application requires a prefillable syringe, there are additional benefits to some plastic systems including the absence of silicone oil, tungsten and adhesive, which have been shown to cause interaction with some sensitive biologics.

PharmTech: Have any recent advances in technology or understanding improved either glass or plastic?

Reynolds: One important consideration for manufacturers of plastic systems has been to ensure that the container is provided to the filling company in an appropriate and validated format. This requires the provision of a sterile, ready-to-fill, validated container that is compatible with existing filling equipment with minimal change. Improvements in glass quality have been aimed at attempting to overcome issues found in many glass recall cases. Further development and optimization of the manufacturing process for plastic containers and systems will continue to enhance the systems, and offer the opportunity for further improvements in the quality and effectiveness of drug products to help improve patient outcomes.

About the Author
Melanie Sena is the Community Manager for Pharmaceutical Technology.