Secondary seals safeguard against medication errors 8702

Edited by Lauren Hartman

February 4, 2014

4 Min Read
Secondary seals safeguard against medication errors

147775-pdx0708rfid3_46.jpgMedication errors are an unfortunate occurrence in the healthcare-delivery system. In a study released in 2006, the Institute of Medicine estimated that 1.5 million injuries occur each year in the U.S. because of medication errors that could have been prevented. An undetermined number occurred during the administration of injectible drugs. While there is no single solution that can eliminate all injectible drug-administration errors, there are technologies that can be applied to secondary seals to help reduce their incidence.

Secondary seals—the outside closure on a vial that does not contact the packaged drug—serve an important function to ensure patient safety and efficacious delivery.

By incorporating overt, covert and track-and-trace technologies into their seals, pharmaceutical manufacturers can provide vital information throughout the supply chain that can help protect the patient against dosing errors. Safeguarding manufacturers, most secondary seals that are applied to injectible drug vials consist of an aluminum shell with a plastic button attached, assembled to the shell. Removing the button reveals the injection site of the stopper.

The plastic button can be imprinted and molded with conspicuous cautions, warnings and instructions that are useful during manufacturing, storage and at the point of use. The importance of this feature during manufacturing cannot be understated. Drug vials are frequently labeled after being filled, and the filling and labeling operations may be in different facilities and even in different countries. Information printed on the plastic button or seal, such as a bar code, can help identify products during manufacturing and labeling, so the medications are processed and labeled correctly. In June 2006, the U.S. Food and Drug Administration recommended that the pharmaceutical industry adopt a reliable electronic pedigree system for drugs. To address the agency's recommendation, some pharmaceutical companies are investigating packaging their drugs with radio frequency identification (RFID) tags molded into the plastic buttons. RFID technology enables the manufacturer to encode each vial with information critical to the drug's manufacture and distribution. RFID provides track-and-trace capabilities throughout the supply chain, lessening the chance of errors during distribution, repackaging and at the point-of-use. In addition, item-level RFID tags can help determine a product's authenticity from the point of its manufacture to the point of its administration.


Enhanced patient safety with point-of-use instructions and identification can help prevent in-process errors. Printed seals help authenticate products to inhibit improper labeling and enhance patient safety.


Multiple layers of protection can increase patient safety, combat drug counterfeiting and help to keep supply chains secure.

In addition to printed, molded and electronic information, drug manufacturers frequently select unique color combinations for the button and shell to help distinguish between different products. The use of unique color schemes can help differentiate drugs during the manufacturing process, which can help prevent improper labeling. Pharmacists and healthcare providers can also verify the packages' contents by checking the color schemes against the manufacturer's published educational materials related to packaging. Much like in manufacturing, safeguarding patients by applying information on unique characteristics such as the vial's contents and cautionary and warning statements to the plastic button and aluminum shell can help reduce medication errors and prevent drug mixups in the clinical setting. Information can be printed on the button and shell, or can be molded into the button and embossed on the shell.

For some drug products, cautionary statements printed on the button and the seal are required by U.S. Pharmacopoeia. For example, the warning statement, "Must Be Diluted," is required on secondary closures used to secure vials of potassium chloride concentrate for injection. Cautionary statements such as "Paralyzing Agent," are frequently used on packaging for neuromuscular blocking agents, a class of drugs used during surgical procedures. These statements may be imprinted on both the plastic button and the aluminum shell or, if a clear plastic button is used, on the shell only. The button and shell provide two layers of identification. The overt messages on the plastic button are the first check of a product's identity. Because the button covers the top of the aluminum shell, any messages that are printed on the shell provide a covert layer for including additional information. Examples of the types of information that can be applied to the button and shell include:

  • Strength of the packaged drug

  • Storage instructions

  • Dosing instructions

  • Manufacturer's name

  • Product's brand name

  • Manufacturing lot and date

In conclusion, secondary seals are a necessary vial-packaging component and offer practical safeguards that can be implemented, from manufacturing through the point-of-use, to help minimize medication errors for injectible drugs.

With overt and covert technologies, security seals can provide protection by aiding manufacturers in product authentication and providing instructions for storage and usage. Implementing prevention strategies help mitigate risks associated with medication errors.

This article was authored by Carol Mooney, West Pharmaceutical Services, and by Douglas Stockdale, of packaging consulting service Stockdale Associates.


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