Container Closure Integrity – Challenge for Injectables
For injectable products, assuring the integrity of the container closure system (CCS) and container closure integrity is fundamental to safeguarding product quality and patient safety over the entire shelf life. Developing an inherently robust CCS is an iterative process—guided by an understanding of product stability, manufacturing methods, and anticipated distribution and storage conditions. Product protection begins in development and continues at the fill-finish line, packaging, storage, and distribution processes.
The quest for assuring integrity of such a system by design, and protecting it during its manufacturing, up until use by patients is long! For those of you, like me, who are in the practice of injectables development and manufacturing, you already experienced the journey along its life cycle; you already know that this journey is long and filled with challenges.
One of those is the fact that both the know-how and responsibility to secure integrity does not belong to a single owner, or area of expertise. It passes through and sits at the crossroad between multiple hands and areas of expertise. With that alone comes a different level of understanding of what goes into creating and assuring integrity of a system used for injectable products (CCI) and how it is distinct from container closure integrity testing (CCIT).
A large body of work describes methods available today to evaluate or to verify integrity via testing. USP <1207> is the principal reference for selecting appropriate test methods, setting acceptable leak detection thresholds, and defining strategies to maintain closure integrity until the point of patient use.
Testing integrity of a sterile product in its final CCS is performed for most part on a set of samples after the completion of production (retrospectively). It is performed using selected Container Closure Integrity Testing methods. CCIT is a pass/fail test. Integrity failure can have highly significant consequences for confidence in the quality of the lot, especially when testing is occurring during the stability of a product already in use on the market.
Much like sterility testing, not every unit can undergo destructive closure integrity testing. Therefore, manufacturers must establish robust systems for CCI assurance, paralleling the rigorous controls used for sterility assurance. Also CCIT is required in lieu of sterility testing during product stability.
Despite its significant importance, integrity’s relevance is mostly felt when it is not achieved or is significantly compromised in situations, creating urgency for resolving or improving a situation where a real product lot is called into question. I have been there, most-likely you did too, and it does not have to be that way.
Container Closure Integrity: Opportunities to Change Status Quo
There are proactive ways, and modern technologies one can deploy along the way to better understand how to de-risk, significantly reducing or eliminating failures in integrity along the way. Real-world handling in our practices can challenge even the best CCS designs.
In the case of a vial container closure system (below) one essential element of an integer vial is creating a good seal between the container and the stopper (closure). During production of a vial, compressing forces are applied on the elastomeric closure. The required compression that secures the integrity required to protect the product in the vial must be held in place until vial use. Seal quality tests are a category of integrity tests, specifically for evaluating the seal after vial production is completed.
SmartSkin technologies is a well-known partner in addressing challenges with direct implication on containers’ integrity. This technology is most valuable when used proactively, before a product is manufactured in clinical or commercial settings However, I have also experienced how valuable it can be in solving rapid problems and searching for solutions.
Advanced “digital twin” models of vial systems (stopper, vial, seal) provide deep insights into potential quality risks throughout the product journey.
SmartSkin Technologies has pioneered a technology that allows real-time measurement of capping forces, monitoring the compression forces applied and maintained during sealing. This innovative approach enables the user to record, analyze and optimize capping equipment operating parameters proactively before deploying them into manufacturing a product batch.
In the case of a vial for liquid dosage forms (Figure 1) the sealing tightness linked to the compression force created between the vial and stopper flange during and after capping can be measured via a Seal Assurance Digital Container Twin.
SmartSkin’s solution uses digital twin technology to measure and visualize the mechanical events at the sealing interface during capping directly and non-destructively. By emulating glass or polymer vial’s dimensions into a Digital Container Twin replica, and complementing it with the selected stoppers and seals, SmartSkin’s digitally enabled replicas capture the full dynamics of the capping process in real time. The capper sealing force range will generate a range of seal pressures that are recorded digitally by the digital twin. The compressions measured by the digital twin can be correlated with the integrity testing results generated for the identical glass or polymer vial, stopper, and seal combination to be used for the real product vial.
Improving Outcomes with Pre-Manufacturing, Real-Time Assessment of Capping Operation Performance
Knowledge and insights gained using digital twins is an enhancement with increasing value adding up across the product life cycle. Starting in lab settings when used in the selection of a Vial/Stopper/Seal combination for a new product, the insights on seal quality are transferable to clinical and commercial scale manufacturing operation. Often times the larger scale manufacturing uses a capper technology using multiple capping heads. SmartSkin’s technology yields actionable data, assessing individual capping head performance and assisting manufacturers with refining equipment settings, process parameters, leading to seal uniformity assurance across every batch.
By correlating the measurements acquired using SmartSkin Seal Assurance with Container Closure Integrity testing and visual inspection outcomes, product owners gain a comprehensive understanding of both the inherent (design-based) and the actual (process-based) integrity of a vial system.
Closing Thoughts
Continuous improvement in pharmaceutical quality (by Design) particularly for parenteral products relies on deeper process understanding specific to the selected equipment for production and robust, science-based controls at every lifecycle stage.
SmartSkin’s digital twins are redefining seal assurance, providing actionable, equipment-specific insights that enable proactive quality management. These advancements facilitate not only compliance, but also product quality by design.
Product quality and sterility assurance remain non-negotiable for any injectable, whether in vials, syringes, cartridges, or novel devices. Industry-wide adoption of modern CCI assurance practices—rooted in Quality by Design (QbD) and data-driven process control—marks a significant step forward.
By reducing reliance on destructive testing and minimizing product loss, seal quality assurance is part of best practices in injectable product development and manufacturing, strengthening the trust in science-based quality and process reliability.
