Function-testing injection pens

An important element of quality control for injection pens is function-testing the mechanism which injects the active ingredient into the body. For these tests Zwick supplies a testing machine with integrated torsion drive plus load cell and torque transducer.

Special testing machines are used in quality control and pre-production development for batch release of injection pens. Among the items tested by these machines is the mechanism which injects a precisely pre-defined quantity of the active ingredient into the body. The leading supplier of such machines is Ulm-based testing machine manufacturer Zwick, with more than 20 successful installations in the international pharmaceutical industry to the company’s credit.

The zwickiLine Z1.0 TN testing machine is designed for use in pre-production development and quantity production and incorporates a laterally offset torsion drive with a maximum torque of 2 Nm, a load cell (1 kN) and a 2Nm torque transducer. The test sequence includes measurement of torque during dosing, axial release force and the distance traveled by the mechanism. Special components are incorporated for torsion testing pens. These include opto-electrical measuring transducers with a resolution of 0.1 µm for travel measurement, deadweights for simulation of the ampoule back-pressure and pneumatic grippers for the rotating knob on the pen. Overload protection for the torque transducer is also included.

Depending on needs and customer specifications, versions are available with different function ranges - from manual loading to full automation (roboTest) plus specimen feeding. With this system the pens are transported from the magazine (capacity 50 specimens) via the AutoEdition2 automation software and into the testing machine, eliminating distortion of test results due to operator influence and significantly increasing test efficiency through increased specimen throughput. If necessary, manual testing can be performed at any time.