Fluid and impurity transport during online isolation experiments conducted with X-ray tomography

Pharmaceutical ingredients (API’s) need to be pure and have the required particle size distribution, filtration and washing play an important part in achieving this Fluid flow and impurity transport during filtration, washing a drying are observed using tomography to: Visualize the location of impurities during incomplete and complete washing; Visualize the consequences of non-ideal filtration and washing; Visualize residual mother liquor inclusions after washing and link these with agglomeration during drying. A slurry of API particles, and saturated crystallization solution was filtered to dryland or breakthrough. The effect of particle size distribution was evaluated. Iodine was used to mimic impurities dissolved in the mother liquor and the filter cake was washed with n-heptane. The cake was dried at ambient temperature with flowing gas. Tomography was used to identify areas where particle agglomeration during drying is favoured.