High-pressure structural studies of the pharmaceutical, chlorothiazide

The pharmaceutical material chlorothiazide (6-chloro-4H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide) has been studied under high-pressure conditions using single-crystal and powder X-ray diffraction. An isosymmetric phase transition to a second polymorph occurs at 4.4 GPa. An analysis of the structural changes that occur during this phase transition has been performed.