Mary Tan

Mary Tan

Specialist, Scientific Affairs, Jurong

八月 03, 2020

Elastomer Stoppers – Performance

A good elastomer stopper for a vial container system needs to have the right properties. These properties are largely determined by the elastomer formulation, which comprises the base elastomer, fillers, plasticizers, and curing agents. The interplay among these components is crucial, as they determine performance. For example, hardness is affected by filler type and level, as well as by curing agent and level. West understands these issues, and therefore is able to develop formulations to offer maximum performance. An example is the formulation 4040/40, which was designed according to quality-by-design (QbD) principles.



Performance evaluation is governed by standards published by organizations such as International Organization for Standardization (ISO), United States Pharmacopeial Convention (USP), European Directorate for Quality of Medicines (Ph. Eur.), and China National Medical Products Administration (NMPA). Key properties of a stopper are:

  • Penetrability: force required to penetrate with a needle-
  • Fragmentation: number of fragments released upon needle penetration (essential to understand for multi-use stoppers)
  • Self-Sealing: ability to re-seal after multiple needle penetrations
  • Container Closure Integrity: ability of assembled container system to protect drug product

Acceptable performance depends upon the standard considered, and the drug product for which the stopper is being used. West Analytical Lab Services has the staff, knowledge, and facility to perform evaluations according to all the standards cited, and offers testing through its Integrated Solutions platform.

Selecting the right stopper and making the right evaluations – West has the expertise. For more, contact an Account Manager or Technical Customer Support (TCS) representative.

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