Written By Jennifer Roark –  Director of Scientific Affairs

As the pharmaceutical industry increasingly adopts biologics, vaccines, and self-administered therapies, prefilled syringes have become a preferred drug–delivery platform. They offer greater dosing accuracy, a lower risk of contamination, and added convenience for both healthcare professionals and patients. 

Historically, component manufacturers tested syringe barrels, stoppers, and needles separately. However, ensuring the safety and performance of a finished prefilled syringe system requires more than testing its individual components. While component testing remains important, real-world performance depends on how these parts function together after the syringe system is assembled and filled with a drug product. 

ISO 11040-8, Prefilled syringes—Part 8: Requirements and test methods for finished prefilled syringes, addresses this need. Unlike other standards in the ISO 11040 series that focus on requirements for the individual syringe components, Part 8 evaluates the finished prefilled syringe as a complete system and defines specific requirements and test methods to ensure quality, functional performance, and safety based on intended use. The prefilled syringe system must meet specific functional requirements through end of drug product shelf life. ISO 11040-8 details these twelve key functional performance requirements. 

Requirement Description
Flange Breakage Resistance This core functional test measures both the initial force required to move the plunger stopper from its seated position in the barrel and the sustained force needed to expel the drug product from the syringe.
Front-End Closure Pull-Off Forces and Torques This testing verifies that the syringe flange can withstand expected injection forces without breaking or deforming. The test is performed according to the method detailed in ISO 11040-4, Annex C.1 for glass syringes and ISO 11040-6, Annex C.1 for plastic syringes.
Front-End Closure Pull-Off Forces and Torques Needle shields, tip caps, and other front-end closures must remain securely attached during shipping, storage, and use, yet still be removable by the user. The tests are performed according to the methods detailed in ISO 11040-4, Annexes G.3, G.4, and G.5. ISO 11040-8 calls for evaluating pull-off force and removal torque to verify closure integrity and to maintain drug product containment and sterility until use.
Connectivity with Small-Bore Connectors The standard requires assessment of compatibility with small-bore connectors, including Luer-based systems. This requirement addresses concerns previously highlighted by the U.S. Food and Drug Administration (FDA) regarding connectivity between prefilled glass syringes and accessories such as needleless Luer-activated valves. The tests are performed according to the methods detailed in ISO 80369-1, ISO 80369-7, and ISO 80369-20.
Residual Volume Residual volume testing measures the amount of product remaining after administration, which equates to the amount of dead space in the syringe. It is used to define the overfill volume during manufacturing to ensure that the syringe delivers the intended dose accurately while minimizing drug waste.
Needle Penetration Force For syringes supplied with staked needles, this test measures the force required to penetrate a standardized test foil to evaluate needle performance. The tests are performed according to the methods detailed in ISO 11040-4, Annex F for glass syringes and ISO 11040-6, Annex F for plastic syringes.
Needle Pull-Out Force This test verifies that the staked needle remains securely fixed to the syringe and cannot be removed from the syringe under normal use conditions. The tests are performed according to the methods detailed in ISO 11040-4, Annex G.1 for glass syringes and ISO 11040-6, Annex G.1 for plastic syringes.
Sharps Injury Protection Requirements For products with safety mechanisms, ISO 11040-8 includes requirements and evaluations for sharps injury protection. These tests help demonstrate that safety-engineered features operate as intended and reduce the risk of needle stick injury. The tests are performed according to the methods detailed in ISO 23908.
Liquid Leakage Resistance Liquid leakage resistance verifies that the syringe system remains sealed at the plunger stopper and maintains containment of the drug product under expected conditions of use. This function is critical to preserving sterility, product quality, and dose accuracy.
Markings The standard includes a verification that the graduation marks or indicator lines are accurate and appropriate for the intended use. Markings verification supports accurate dose delivery and safe administration.
Administration Time with Defined Constant Test Force Administration time testing performed with a defined constant test force ensures that the dose can be delivered in a reasonable amount of time based on intended use.
Unintended Plunger Stopper Movement of Finished Prefilled Syringes This test addresses the potential movement of the plunger stopper from its seated position in the syringe barrel due to temperature or pressure fluctuations during shipping and distribution. Plunger stopper movement must not exceed the length of the sterile barrier zone to ensure sterility of the drug product at the time of dose administration.

Beyond Mechanical Testing: Risk Management and Intended Use 

In addition to functional requirements, ISO 11040-8 addresses the critical quality attributes (CQAs) of the pharmaceutical drug product that must be maintained by the syringe system.  Specific tests include evaluating interactions between the syringe system and the drug product, biocompatibility assessment, sterility, bacterial endotoxins, container closure integrity, deliverable volume, and testing for both visible and sub-visible particles. 

The standard identifies the following as foundational activities that inform testing and verification of the finished prefilled syringe system: 

  • Definition of intended use
  • Risk management
  • Application of usability engineering

Together, these activities provide the foundation for effective design validation.  

In summary, ISO 11040-8 provides a comprehensive framework for evaluating finished prefilled syringes as complete drug–delivery systems. Overall, the standard is intended to verify that a finished prefilled syringe delivers medication safely, accurately, and consistently while supporting regulatory expectations and patient needs. 

Key Takeaways 

Demonstrating that finished prefilled syringes are suitable for intended use per the ISO 11040-8 requires more than passing a single test.  It requires documented evidence that the prefilled syringe system not only meets functional requirements but also meets the requirements to safely and effectively contain and deliver the pharmaceutical drug product to the patient throughout drug product shelf life. 

The CS Analytical team has extensive hands-on experience with finished prefilled syringe testing per ISO 11040-8. Our scientists and quality professionals work closely with clients to develop fit-for-purpose analytical study designs tailored to specific syringe materials and types, ensuring alignment with intended use and risk profile. 

All testing is conducted under protocol with pre-established acceptance criteria, in a cGMP-compliant, FDA-registered, and FDA-audited laboratory, ensuring data integrity and confidence in the accuracy and reproducibility of the results. 

Whether you are evaluating the break-loose and extrusion forces, flange breakage resistance, residual volume, or any of the other functional testing in accordance with ISO 11040-8; or you are interested in evaluating container closure integrity or performing a plunger movement study to generate data for regulatory submissions, CS Analytical provides reliable and compliant solutions for finished prefilled syringe testing. 

For more information on our finished prefilled syringe testing capabilities, please email us at engage@csanalytical.com or call 1-888-571-1207. 

References 

  1. ISO 11040-8, Prefilled syringes – Part 8: Requirements and test methods for finished prefilled syringes 
  2. ISO 11040-4, Prefilled syringes — Part 4: Glass barrels for injectables and sterilized subassembled syringes ready for filling 
  3. ISO 11040-6, Prefilled syringes — Part 6: Plastic barrels for injectables and sterilized subassembled syringes ready for filling 
  4. ISO 80369-1, Small-bore connectors for liquids and gases in healthcare applications — Part 1: General requirements 
  5. ISO 80369-7, Small-bore connectors for liquids and gases in healthcare applications — Part 7: Connectors for intravascular or hypodermic applications 
  6. ISO 80369-20, Small-bore connectors for liquids and gases in healthcare applications — Part 20: Common test methods  
  7. ISO 23908, Sharps injury protection — Sharps protection mechanisms for single-use needles, introducers for catheters and needles used for blood testing, monitoring, sampling and medical substance administration — Requirements and test methods