Influence of Crystallization Conditions on Rheology and Microstructure of Dense Suspensions of Crystals of Eflucimibe

The crystallization process of eflucimibe, a new ACAT inhibitor, was carried out in a mixture of two solvents, ethanol and n‐heptane, by cooling. During the process, as the volume fraction of crystals was raised, the suspension went towards a very structured gel‐like network. This phenomenon acts as a brake to the extrapolation of the process. Experiments were carried out in a glass double‐jacketed 750 mL reactor in a LABMAX controlled system. At the end of the crystallization, rheological flow characteristics at constant ambient temperature were determined. The samples behave like a plastic fluid. The evolution of the elastic and viscous moduli as a function of the applied strain for a given oscillation frequency was measured. The results showed that the variation of the elastic modulus with particle concentration follows a power law. It was shown that for particle concentration higher than 2 % (volume fraction) needle‐like growing crystals form a network in which solvent is trapped.