Study of three solvates of sulfamethazine

Three novel solvates of sulfamethazine (SMT), an anti-microbial and anti-infective sulfonamide drug with the solvents – dimethylacetamide, dimethylformamide and dimethyl sulfoxide have been identified and characterized by analytical techniques including differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and Raman spectroscopy. All three are 1 : 1 solvates. Crystal structure analysis revealed N–H–O type intermolecular hydrogen bonding interactions between SMT and the solvent imparting stability to the solvate structure. Thermal analysis measurements for the stoichiometry of the solvates were in good agreement with the single crystal data. The solubility of the solvates in their respective solvents at 25 °C has been determined.