CLEAN AND EFFECTIVE CURING VITAL FOR ELASTOMER APPLICATIONS IN PHARMACEUTICAL PACKAGING

摘要

Due to their excellent elasticity, penetrability and resiliency performance, elastomers are being used in a wide range of pharmaceutical packaging. Historically the major use of elastomers in pharmaceutical packaging had transitioned from natural rubber in the early days to regular butyl (isobutylene isoprene rubber, IIR) and then chlorobutyl (CIIR) and bromobutyl (BUR) polymers. The main driver of these transitions is cleanliness improvements. With increasing awareness of the impacts of impurities in drugs on the health of patients, tighter and tighter regulations are being implemented. For example, in recent years the level of extractable and teachable components has become an important parameter for pharmaceutical stoppers to be qualified. The presence of certain impurities can also deactivate active ingredients or cause changes in certain medicines and therefore the drug compatibility of the stopper is important. Cleanliness of pharmaceutical stoppers is determined by the manufacturing process and the cleanliness of each ingredient in the compound, i.e., elastomers, fillers, additives, processing aids, antioxidants, curing agents, accelerators, etc. Elastomers, being a dominant part of stopper composition, play an important role in cleanliness. Any additive, residual curing agent, antioxidant or other impurities present in the elastomer can potentially become undesirable extractables and leachables. Furthermore, the choice of elastomer will inevitably be associated with certain curing systems that could be a major source of harmful extractables. The fact that bromobutyl can be effectively cured via low levels of sulfur-free and / or zinc-free curing systems is the major reason for it to become the number one choice worldwide for pharmaceutical stopper and seal applications today. In this presentation, we will discuss the type of curing systems required for a number of elastomers used in pharmaceutical packaging applications. This includes natural rubber (NR), synthetic isoprene rubber (IR), IIR, CIIR and BUR. We will discuss the clean and effective curing systems that could enable the use of BUR in pharmaceutical stopper and seal applications. Extractables of the BUR compounds cured with various clean curing systems will also be presented.