Micro-flow imaging: flow microscopy applied to sub-visible particulate analysis in protein formulations

AAPS J. 2010 Sep;12(3):455-64. doi: 10.1208/s12248-010-9205-1. Epub 2010 Jun 2.


The need to monitor, measure, and control sub-visible proteinaceous particulates in biopharmaceutical formulations has been emphasized in recent publications and commentaries. Some of these particulates can be highly transparent, fragile, and unstable. In addition, for much of the size range of concern, no practical measurement method with adequate sensitivity and repeatability has been available. A complication in measuring protein particulates in many formulations is the simultaneous presence of other particle types such as silicone micro-droplets, air bubbles, and extrinsic contaminants. The need has therefore been identified for new analytical methods which can accurately measure and characterize sub-visible particulates in formulations. Micro-flow imaging has been shown to provide high sensitivity in detecting and imaging transparent protein particles and a unique capability to independently analyze such populations even when other particle types are present.

MeSH terms

  • Biological Products / chemistry*
  • Limit of Detection
  • Microscopy / methods*
  • Proteins / chemistry*
  • Refractometry
  • Reproducibility of Results
  • Viscosity


  • Biological Products
  • Proteins