Crystal Structure Analysis, Stability, Phase Transformation and Selective Nucleation Mechanism of Fluralaner Polymorphs

To better understand and control the crystallization of different polymorphs, a comprehensive crystal structure analysis was conducted by using fluralaner as model compound, thermodynamic stability, phase transformation, selective nucleation mechanisms were studied. Various analytical techniques such powder X-ray diffraction, thermal analysis, FT-IR spectra used to comprehensively characterize Form I, Ⅱ, III fluralaner, it found that there is structural similarity between I III, which further confirmed single diffraction. However, Ⅱ had unique molecular conformation packing pattern. The lattice energy calculated Materials Studio 7.0 stability three forms explored transformation experiments, suggested order > III. with similar studied through dynamics simulations. results indicated addition n-hexane may hinder solute–solute interaction in solution, thus resulting polymorphs.