Slow filtration is frequently due to particle properties. Typically, the issue is caused by highly anisotropic particles that are difficult to filter, a compressible filter cake (often an accompanying factor with needle- or fiber-like particles), or particle attrition that’s generated by stirring during filtration, which can lead to the generation of small particles on the filter. This clogs the filter, so the next batch might filter very poorly.
Regarding potential remedies, it’s possible to go back to the original crystallization process to manipulate the particle habit. This can be done in several different ways, the simplest of them being a solvent switch, which can influence crystal structure and shape. Temperature cycling is also possible, which can help to manipulate the shape of the particles — sometimes the effect is subtle, and sometimes it’s striking.
This webinar clip, part of "Accelerating speed to market through solid state & crystallization development”, dives deep into each potential remedy, and also explores the importance of choosing appropriate manufacturing equipment based on filtration study findings. Specifically, it delves into key factors related to filter cake resistance and its pressure dependence. Watch the full webinar clip to learn more.