Overview of Particles and Aggregates

A common challenge during protein and vaccine formulation is the formation of particles ranging from sub-micron to visible particles (100 µm).  These aggregates can adversely affect immunogenicity and pharmacokinetic profiles of the protein.   Further complicating this challenge is that no one instrument or method can precisely measure the size and concentration particles that encompass this range.  Therefore, a variety of methods must be used, as shown below.

Figure 1: Methods used to Characterize Soluble Aggregates and Particles
(click to enlarge)