Determination of filtration and consolidation properties of protein crystal suspensions using analytical photocentrifuges with low volume samples

Proteins and in particular pharmaceutical proteins like monoclonal antibodies are expensive products. Protein crystallization is an interesting alternative process step to the common purification and formulation of such proteins. The
solid-liquid separation of proteins however, is a challenging task because the proteins are sensitive to mechanical stress,
which could lead to crystal breakage and often are only available in small amounts for research and development. In
this study a newly developed filtration cell for the LUMiSizer(R)
centrifuge is used to analyze the filtration behavior
with low volume samples. Isometric and needle shaped lysozyme crystals serve as model protein crystals. The needle
shaped crystals showed about twice as high compressibility and much higher cake resistance than the isometric lysozyme
crystals. After the filtration at maximum pressure in the centrifuge the mean particle diameter decreased compared to
the unstressed median diameter. With the filtration cell the cake height and filter cake compression can be monitored
in-situ and the filter cake resistance and solids volume content can be calculated with one experiment using 200 to 300 μl
... mehr
sample.