Role of Mechanochemistry in Solid Form Selection and Identification of the Drug Praziquantel

Abstract

Identification of all possible polymorphs for a pharmaceutical compound is vital for the better formulation of medicine with desired properties. This study demonstrates the application of a mechanochemical approach to reveal new polymorphs of a drug and the potential of variable amounts of solvent in liquid-assisted grinding for solid form screening. Without solvent and by varying the amount of solvent added, we found two new polymorphs and an amorphous form, which were not reported previously. The finding portrays the advantage of the mechanochemical approach as a means of the polymorph screening strategy. While the focus here was on praziquantel, a similar approach is applicable to other pharmaceutical systems. This study also contributed to reinvestigate the solid-state behavior of the chiral praziquantel system, including the melt phase diagram and the role of experimental conditions on its phase behavior.