Solid-state characterisation of a novel chemotherapeutic drug.

We present the results of a thermal, spectroscopic, diffractometric, and microscopic study of a novel DNA intercalator synthesized by Novuspharma S.p.A. (code name BRR 2778, purity by high-performance liquid chromatography: 99.4%). We found that the form that is stable at room temperature contains 1.5 water molecules per unit of formula (or about 4.7% in mass): this water is reversibly lost in two stages below 808 and 908°C in dry and wet nitrogen atmosphere, respectively. The hydrated compound is a pseudo-polymorph and dehydration is accompanied by a structural change that modifies the diffraction pattern without changing the shape of the microcrystals. Annealing above 150°C causes decomposition of the anhydrous form and (above 1908C) amorphization of the solid residue occurs.