Structure properties of scoparone: Polymorphs and cocrystals

Abstract A comprehensive polymorph and cocrystal study for the natural pharmaceutical molecule scoparone ( 1 ) with low solubility was conducted, in which a novel polymorph B and four cocrystals, i.e. scoparone-3,5-difluorobenzoic acid ( 1a ), scoparone-urea ( 1b ), scoparone-pyrimethamine ( 1c ) and scoparone-succinimide ( 1d ), were obtained through solvent crystallization method. The scoparone polymorphs and cocrystals were characterized by powder X-ray diffraction and thermal analysis, the crystal structures of which were determined by single-crystal X-ray diffraction as well. The kinetic dissolution property of polymorphs and cocrystals was conducted in this work. The novel polymorph B is more thermodynamically stable than form A, and exhibits lower maximum dissolution concentration than that of form A. Among the cocrystals, the formation of cocrystal with urea can enhance the drug dissolution concentration compared to form A and form B.