Plunger Position Measuring System SPM

SPM – Automated Measurement of Plunger Stopper Movement in Prefilled Syringes and Cartridges

The mobile SPM Stopper Position Measurement System from 3D innotec AG is designed for the automated, reproducible and documented assessment of plunger stopper movement in prefilled syringes (PFS) and cartridges under defined pressure conditions.

During transportation – particularly air freight and transportation at different altitudes – changes in ambient pressure can cause the gaseous headspace inside a syringe or cartridge to expand and contract. The resulting forces may cause unintended movement of the plunger stopper. If the stopper moves beyond the defined sterile barrier zone, this may present a potential risk to container closure integrity and consequently to product sterility.

Reproducible Simulation of Pressure and Transportation Conditions

The SPM enables the controlled simulation of defined pressure cycles based on ASTM D6653/D6653M, reproducing pressure changes such as those that may occur during air transportation.

The system can simulate negative pressure of up to −800 mbar using freely configurable pressure cycles with a total duration of over 15 hours.

Throughout the test sequence, the position of the plunger stoppers is automatically captured using the integrated and calibrated 21-megapixel camera. Product-specific sample holders allow up to 10 prefilled syringes or cartridges to be tested simultaneously.

Pressure cycles and measurement intervals can be individually configured and stored as test recipes within the system. This enables tests to be repeated using identical parameters and allows different product, stopper or container configurations to be compared under reproducible conditions.

Upon completion of the simulation, the SPM automatically generates a test report containing the relevant process and measurement data.

Supporting Assessment According to ISO 11040-8:2026

With ISO 11040-8:2026, Section 6.13 “Unintended plunger stopper movement”, the assessment of unintended stopper movement in finished prefilled syringes has gained additional relevance.

The standard addresses changes in air pressure as one potential cause of unintended plunger stopper movement and requires the associated risks to be assessed during design and development.

The SPM enables controlled simulation of corresponding pressure conditions and quantitative measurement of the resulting stopper movement. The system therefore provides reproducible and documented measurement data supporting the assessment of unintended plunger stopper movement in the context of ISO 11040-8:2026, Section 6.13.

21 CFR Part 11, Audit Trail and Data Integrity

The SPM has been developed for use within regulated pharmaceutical environments. Its integrated IT system meets the requirements of FDA 21 CFR Part 11 for electronic records.

All relevant user inputs, changes, process steps and test results are recorded and traceable through a comprehensive audit trail. Integrated user and access management, storage of defined test recipes, as well as digital acquisition and documentation of measurement data support a high level of data integrity and full traceability of performed tests.

The mobile system can be integrated into existing IT infrastructures. The equipment is designed to meet the requirements of pharmaceutical environments, taking into account current GMP requirements and FDA-compliant materials.

Qualification and Comprehensive Documentation

Upon request, 3D innotec AG provides qualification of the SPM system together with the documentation required for implementation at the customer's site.

The documentation package includes the operating manual and system description as well as the corresponding DQ, IQ, OQ, FAT and SAT protocols.

The SPM therefore provides a specialized in-house solution combining controlled pressure simulation, automated optical stopper position measurement, reproducible test procedures and regulatory-oriented digital documentation within a single system.