Flow imaging: moving toward best practices for subvisible particle quantitation in protein products.

The potential impact of subvisible particles (SVPs) in protein therapeutic products has received a great deal of attention recently. As a result, new analytical methods have emerged to characterize and quantify SVPs. Among these, flow imaging (also called flow microscopy) has been widely employed. As we have used both FlowCAM® and Micro-Flow Imaging™ in a variety of development projects, we wished to share our experiences and observations, with the intention of fostering a discussion that will lead to best practices for the use of flow imaging to quantify SVP levels in biopharmaceuticals.