Multicomponent Crystal of Mefenamic Acid and N-methyl-D-Glucamine: Crystal Structures and Dissolution Study.

A novel multicomponent crystal of mefenamic acid (MA) and N-methyl-D-glucamine (MG) had been prepared in order to improve the physicochemical properties of poorly soluble drugs, and was characterized for its physicochemical properties by powder X-ray diffraction analysis, DSC thermal analysis, FT-IR spectroscopy, in vitro dissolution rate and physical stability. Also, the crystal structure was determined by single crystal X-ray diffraction analysis. The DSC thermogram of the MA-MG binary system exhibits a single and sharp endothermic peak at 151.20°C, which was attributed to the melting point of a multicomponent crystal of MA-MG. FT-IR spectroscopy analysis showed the occurrence of solid-state interaction by involving proton transfer between MA and MG. The crystal structure analysis confirmed that MA-MG formed 1:1 ratio salt type multicomponent crystal. The formation of a multicomponent crystal of MA with MG significantly improved the dissolution rate of MA in compared to intact MA, and also the crystal demonstrated a good stability under a high relative humidity. These good properties would be attributed to the layer structure of MA and MG in the crystal.