A study of variable hydration states in topotecan hydrochloride.

Topotecan hydrochloride, a pharmaceutical compound developed as a treatment for cancer, exhibits variable hydration states in a crystalline solid form chosen for manufacturing. This variability requires additional controls for successful development, and presents a characterization and detection challenge for analytical methods. In this study, overall water content was determined by Karl Fischer titration and thermogravimetric analysis (TGA) on topotecan HCl equilibrated at different relative humidity levels.

Structural analysis of polymorphism and solvation in tranilast.

Five polymorphic forms of tranilast were characterized by thermal, diffractometric, and spectroscopic techniques. The crystal structures of the most stable anhydrous form (Form I), a chloroform solvate, and a dichloromethane solvate were determined from single-crystal X-ray analysis. Two additional anhydrous forms of tranilast (Forms II and III) were also studied, but were not amenable to SCXRD.