Glass vs. Plastic – The Right Choice for Prefillable Syringes

Prefillable syringes serve as a convenient option for the delivery and packaging of injectable drug products. There are two major purposes of prefillable syringes for administrating the drug. The first is in the form of primary packaging to assure that there is no unfavorable effect on the strength, identity, potency, purity or quality of the drug during its shelf life. The second is to administer and ensure that the patient gets the appropriate amount of drug in a reliable manner.

The prefillable syringes (PFS) systems come in two types:

  • Glass-based systems
  • Plastic-based systems

Glass-based Systems

Traditionally, glass tubing is used to make a prefillable syringe barrel. The glass tubes undergo heat treatment to transform into the barrel that holds the drug product. The syringe manufacturers all over the world typically form and process the glass and then purchase the additional elastomeric components such as tip caps, plungers and needle shields. This completes the primary packaging after the closure from elastomeric manufacturer.

Benefits

  • The health care practitioners are well familiar with the product. There is a long history of its usage.
  • Glass is the first choice for the manufacturers all over the world, indicating the accessibility of the material.
  • The market is majorly occupied by the prefilled syringes made of glass and elastomeric components.
  • There are multiple reliable suppliers of the glass-based prefillable syringes.
  • Glass is the gold standard in parenteral packaging of pharmaceutical materials.

Drawbacks

  • They are prone to breakages.
  • They have the potential for surface reactivity.
  • Particulate contamination may occur.
  • Silicon oil is added for functionality with inconsistency.
  • There can be variations in functionality.

Plastic-based Systems

Although plastic has made its way into many applications of pharmaceutical packaging, its use for prefillable syringes still remains debatable. However, they are gaining gradual acceptance as the manufacturers are uncovering the benefits it has over glass. The Japanese market, well-known for its high quality, has made a transition to plastic syringes for 50% of the products, simply because of its superior performance.

The most widely used plastic prefillable syringe systems are made from cyclopolyolefin (COP) resin. The manufacturing of these systems involves high quality standards and tight dimensional tolerances. Since there are many types of plastic, it is crucial to understand the unique characteristic of the material to be used, because the packaging of a pharmaceutical or biopharmaceutical product plays a critical role in its long-term success.

Benefits

  • They are break-resistant.
  • They offer flexibility in the design.
  • The dimensional tolerance is kept very tight.
  • There is a lesser risk of surface reactivity.
  • They do not easily absorb or adsorb the drug.
  • These systems are compatible with both high and low pH.

The Verdict

Both glass and plastic hold benefits for their use in prefillable syringe systems. The pharmaceutical companies often find it difficult to choose the right material to ensure that their drug remains unharmed and reaches to the patient in its intended form. The final decision can be made after considering the benefits of both the systems. Glass has been the legacy material for a range of pharmaceutical applications, but the changing designs and demands for flexibility in prefillable syringes are favoring the use of plastic in this particular case.