Pharmaceutical stoppers in grey, orange, and purple

Pharmaceutical stoppers and seals  

Achieve a high level of cleanliness and gas/moisture barrier in pharmaceutical stoppers and seals

More than 90 percent of antibiotic, infusion and biomedical stoppers made in Europe, the United States and Asia are based on halobutyl rubber. Exxon™ halobutyl rubber is ideal for stoppers and seals because of its high cleanliness and chemical resistance as well as low permeability to air, gases and moisture.

Because halobutyl rubber is chemically inert and nonpolar, absorption of drugs or water is low. Studies indicate that bromobutyl rubber-based stoppers have much lower drug turbidity than regular butyl stoppers.

Another option for high-end applications is Exxpro™ specialty elastomer, a brominated isobutylene paramethyl-styrene terpolymer (BIMSM). It is the cleanest elastomer available from ExxonMobil that is suitable for pharmaceutical applications. Exxpro specialty elastomer-based stoppers have been shown to exhibit similar drug turbidity performance in comparison to a coated stopper.

Applications and benefits

Exxon halobutyl rubber offers a number of other advantages over natural rubber and other synthetic rubbers in pharmaceutical packaging, including:

  • Chemical and biological inertness
  • Low extractables due to low level of additives and high curing efficiency
  • Resistance to heat, ozone and oxygen
  • Good self-sealing and fragmentation performance
  • Vulcanizable by low level of sulfur-free and/or zinc-free curatives

Product solutions

  • ExxonMobil Chemical Butyl Rubber Plant

    Butyl rubber

    Exxon™ butyl rubber (BR) is a copolymer of isobutylene and isoprene with excellent weathering resistance, good aging resistance, low Mooney viscosity, vibration damping, low modulus, and low compression set.

    Learn more
  • ExxonMobil branded Tire


    Exxon™ bromobutyl is a brominated copolymer of isobutylene and isoprene (BIIR) with low permeability to air, gases and moisture, low glass transition temperature, and a wide vulcanization versatility with fast cure rates.

    Learn more
  • Rack of tires made with Chlorobutyl

    Chlorobutyl rubber

    Exxon™ chlorobutyl is a chlorinated copolymer of isobutylene and isoprene (CIIR) with improved compression set and better resistance to heat, ozone, and flex fatigue compared to regular butyl.

    Learn more
  • BIMSM Pharma Stoppers

    Specialty elastomer for pharmaceuticals

    Exxpro™ specialty elastomers are brominated isobutylene paramethylstyrene terpolymers (BIMSM) help meet the requirements for cleanliness, drug compatibility, low extractables, and leachable.

    Learn more

How would you rate the content on this page?