Now, for the first time, you can obtain LO data to meet regulatory guidelines, and also verify your data with real images, all with a single instrument, and one sample run. Our new FlowCam + LO instrument combines our patented flow imaging microscopy technology with an embedded light obscuration module to provide USP 787/788 compliance.
In the FlowCam + LO, a single sample passes continuously through two flow cells. The first uses FlowCam technology to capture digital images (Fig 1), and the second uses a light obscuration module to provide data necessary for USP compliance (Fig 2).
Given that Light Obscuration compares all particles to a sphere (equivalent spherical diameter or ESD), it's possible that extrinsic particles would have the same ESD as your proteins, and would pass the LO test. The image below shows the variety of particles you might see with a similar ESD (shown here: proteins, agglomerates, silicone droplets, air bubbles and other contaminants - silica, glass shards). A sample like this might pass USP size limits, but still fail at the trial stage. Verify your data with images, with the FlowCam + LO.