Characterization of solid-state forms of mebendazole.

This study deals with the generation and characterization of various solid-state forms of mebendazole (MBZ), a benzimidazole antihelmentic. The drug was subjected to polymorphic screen using different solvents to explore the possibility of existence of different solid forms. Different reported polymorphic forms of MBZ, i.e. form A, B and C were found to be recrystallized from acetic acid:methanol mixture (1:1), ethyl acetate and methanol, respectively. N,N-Dimethyl acetamide (DMA) and N,N-dimethyl formamide (DMF) yielded two new solvates of MBZ. These solid-state forms were characterized by thermoanalytical (DSC, TGA, HSM), crystallographic (XRD), microscopic (optical, polarized), and spectroscopic (FTIR) techniques. Solubility studies were carried out for the solvates to identify the solubility advantage. Molecular modeling studies revealed moderately strong hydrogen bonding between the solvent molecules and MBZ.