Testing of Injection Systems

Injection systems include autoinjectors and pen injectors with variable dosing.

Testing of autoinjectors to ISO 11608-5 and ISO 13849

Testing Autoinjectors to DIN EN ISO 11608-5

An autoinjector is a medical instrument (medical device) with which liquid medication can be administered and is therefore subject to strict quality controls. Years ago, autoinjectors were mainly used by untrained people to administer drugs as quickly as possible. Examples of this are adrenalin injectors used in cases of anaphylactic shock and morphine or atropine injectors used by soldiers in combat missions. Today there are other factors that contribute to the increased use of autoinjectors.

One is the issue of "injection instead of ingestion," meaning certain substances (for example, biopharmaceuticals) cannot be administered in tablet form, because they would be digested in the patient's gastrointestinal tract and would not enter the bloodstream. The other is that the autoinjector functions as the "doctor's extended arm." Injectors guarantee a high level of application safety.

The correct injection and proper dose of medicine are vital to achieve the best therapeutic success. That is why pharmaceutical manufacturers strive to achieve a high level of automation in autoinjector technology. The patient simply removes the safety cap, positions the injector, and injects the drug by pressing a button. The process that follows is completely automated. However, this also means that all of the injector's relevant functions must be checked before the production batch is released on the market. This test is performed to DIN EN ISO 11608-5.

Autoinjector testing with Zwick

Zwick offers testing systems that can perform the following automated tests:

  • Removal force of the safety cap
  • Activation force and displacement of the autoinjector
  • Injector timing
  • Determination of the administered drug volume, including the last drops with an integrated high-resolution scale
  • Effective needle length for injection
  • Safety function of the needle guard

The integrated test offers the benefit that all tests can be performed on a single specimen without changing test tools. The testing system can be expanded to accommodate additional tests, satisfying a variety of market requirements and product developments. With an optional microphone to provide audible feedback, the system can detect autoinjector clicks, which indicate the beginning and end of the injection. In addition, an HD camera can be integrated to document liquid emission. You can save these images with the test results to support traceability. The machine can be equipped with a monitoring mechanism that complies with the requirements of DIN EN ISO 13849. testXpert II software manages the control and evaluation of these additional functions, as well as the entire test control sequence.

Automation Options

It is particularly important that the testing process saves time and resources when dealing with large production batches. The testing system offers different levels of automation— from a manual solution to a fully automated robotic testing solution that places the injectors in the testing machine. A typical market solution is a semi-automated testing machine where the operator inserts the autoinjector into the testing machine, closes the safety door, and starts the test. All test steps are then carried out automatically by the machine.

Tests on Pharmaceutical Pens

Testing of injection pens with a zwicki materials testing machine with torsion drive
The most important requirements when testing medical products are the reproducibility of results and the minimization of operator influences. To meet these requirements, Zwick has developed automated systems for testing pen injectors (for example, for insulin). Insulin therapy normally involves the subcutaneous injection of insulin by means of prefilled syringes or insulin pens. These pens are similar to writing pens and are filled with insulin cartridges. Single-use pens are disposed of after the contents of the cartridge are dispensed, whereas reusable pens can be used year after year. DIN EN ISO 11608 Parts 1 to 3 is the applicable standard for quality assurance tests on insulin pens and cartridges. A testing system consisting of a zwickiLine table-top testing machine with additional torsion drive is used to test insulin pens. This testing system can measure various pen functions, such as the dosage setting, actuation force, glide force, and specified dosage in one continuous process. You can modify and combine the test methods of both test axes to suit your testing needs. The testing system can perform these tests to check the pen's mechanical function without the drug. Along with force and torque, it measures the activation force with the utmost precision. When testing filled prefilled pens, an integrated high-resolution scale is used to measure the dosing accuracy to DIN EN ISO 11608-1.

Automated testing of insulin pens

Together with an automated testing system, the zwickiLine materials testing machine with integrated torsion drive is a safe and cost-effective solution for testing insulin pens. You can check various insulin pen functions with only one test fixture. This system allows you to measure the dosage setting, actuation force, glide force, and specified dosage in one continuous process. You can modify and combine the test methods of both test axes to suit your testing needs. The roboTest R handling system facilitates specimen feeding. It uses the automation software AutoEdition2 to remove insulin pens from the magazine, feed them into the testing machine, and start the test, meaning test results are accurate because operator influence is minimized. Our solution makes the test process significantly more efficient thanks to increased specimen throughput. It is also possible to manually test specimens at any time. The testing system can perform these tests to check the pen's mechanical function without the drug. Along with force and torque, it measures the activation force with the utmost precision. When testing filled prefilled pens, an integrated high-resolution scale is used to measure the dosing accuracy to DIN EN ISO 11608-1. The testXpert II testing software together with the Expanded Traceability option to FDA 21 CFR Part 11 make it possible to create documentation for the testing process that is complete and tamper proof.
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