Abstract: Parecoxib sodium is provided in a crystalline form that is substantially anhydrous and substantially nonsolvated. Various such anhydrous, nonsolvated crystal forms have been identified, including Forms A, B and E as described herein. Also provided is a parecoxib sodium drug substance wherein at least about 90% of the parecoxib sodium is in one or more anhydrous, nonsolvated crystal forms. Such a drug substance is a storage-stable intermediate that can be further processed, for example by dissolution or slurrying in an aqueous medium together with one or more parenterally acceptable excipients, followed by lyophilization of the resulting solution or slurry to provide a reconstitutable injectable composition suitable for therapeutic use.