PT  - JOURNAL ARTICLE
AU  - Nieto, Alejandra
AU  - Roehl, Holger
TI  - Sealing behavior of Container Closure Systems under Frozen Storage Conditions: Nonlinear Finite Element Simulation of Serum Rubber Stoppers
AID  - 10.5731/pdajpst.2017.008391
DP  - 2018 Jan 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - pdajpst.2017.008391
4099  - http://journal.pda.org/content/early/2018/03/15/pdajpst.2017.008391.short
4100  - http://journal.pda.org/content/early/2018/03/15/pdajpst.2017.008391.full
AB  - There has been a growing interest in recent years in the assessment of suitable vial/stopper combinations for storage and shipment of frozen drug products. Considering that the glass transition temperature (Tg) of butyl rubber stoppers used in Container Closure Systems (CCS) is between -55°C to -65°C, a storage or shipment temperature of a frozen product below the Tg of the rubber stopper, may require special attention, since below the Tg the rubber becomes more plastic-like and loses its elastic (sealing) characteristics. Thus they risk maintaining Container Closure Integrity (CCI). Given that the rubber regains its elastic properties and reseals after rewarming to ambient temperature, leaks during frozen temperature storage and transportation are transient and the CCI methods used at room temperature conditions are unable to confirm CCI in the frozen state. Hence, several experimental methods have been developed in recent years in order to evaluate CCI at low temperatures. Finite Element (FE) simulations were applied in order to investigate the sealing behaviour of rubber stoppers for the drug product CCS under frozen storage conditions. FE analysis can help reducing the experimental design space and thus number of measurements needed, as they can be used as an ad-on to experimental testing. Several scenarios have been simulated including the effect of thermal history, rubber type, storage time, worst case CCS geometric tolerances and capping pressure. The results of these calculations have been validated with experimental data derived from laboratory experiments (CCI at low temperatures), and a concept for tightness has been developed. It has been concluded that FE simulations have the potential to become a powerful predictive tool towards a better understanding of the influence of cold storage on the rubber sealing properties (and hence on CCI) when dealing with frozen drug products.