Inspection of Single Use Pre-Filled Syringes

The customer required an inspection solution capable of reliably detecting different defects in a device that is small, opaque, and filled with liquid. Automated visual inspection (AVI) needed to assess fill levels, detect particles and cosmetic flaws, identify chipping from reel cutting, evaluate deformation
of the drug reservoir and catch any foreign matter inside the device. Simultaneously, container closure integrity testing (CCIT) had to detect leaks as small as 10 μm as well as delamination at production speeds of up to 500 units per minute. 

Complicating matters, the medication tends to sediment over time, requiring careful handling and optimized movement to ensure particles were not missed. In addition, the inspection machine needed to be fully integrated into the production line to minimize downtime, streamline changeovers, and maintain high throughput without compromising quality.

With our WILCO solution design approach, we started by building lab-based test setups to simulate production conditions.

For AVI, we determined the optimal movement patterns to overcome product sedimentation and ensure all defined potential defects could be identified. Multiple inspection stations were deployed to evaluate cosmetic quality, device form and contour after cutting, tip cap activation, dents in the reservoir, and particle detection from multiple angles. This multi-view approach, combined with a carefully designed agitation profile, ensured that sedimented particles were not missed.

Transportation and handling were addressed through a product carrier system, which maintained syringe stability during loading, unloading, rotation, and acceleration.

For CCIT, conventional methods such as differential pressure or the LFC method® were insufficient, as the required speed would have meant a larger machine setup and correspondingly more production space. That’s why we opted for Headspace Analysis, adding on the patented CO₂ Bombing method. The devices are exposed to CO₂ overpressure in sealed chambers, accelerating air ingress, and any leaks are detected using Tunable Diode Laser Absorption Spectroscopy (TDLAS). The method was carefully developed to balance sensitivity with product integrity, considering factors like pressure, exposure time and CO₂ permeation.

The resulting system integrated Automated Visual Inspection (AV) and Headspace Analysis (HSA) with the Bombing method into a single, high-throughput machine with the speed of 500 units per minute.
The CO₂ Bombing solution featured 12 chambers, each holding 72 samples, with a 30-second cycle time that allowed leak detection inline at production speed.

AVI was performed during continuous rotation, avoiding start-stop agitation and ensuring smooth handling of the devices. The system was designed according to GMP guidelines, fully compliant with USP <1207> deterministic testing and 21 CFR Part 11 for data integrity.

Complex inspection challenges don’t have to slow down production. From opaque liquids to high-speed lines, our tailored, compliant inspection solutions ensure your products are safe and your production keeps running smoothly.