Phase stability and polymorphism of a new naproxen salt

Abstract

We report on the synthesis and structural characterization of a new naproxen salt. In-situ heating X-ray diffraction experiment allows us to determine the phase stability of the various polymorphic phases. Slow heating rate and repetitive scans strategy were essential to probe all phases in presence. Contrary to previously reported absence of polymorphic forms for naproxen salt, this new salt exhibits one metastable dihydrate form and five anhydrous phases. The crystal structures of all phases were determined using the in-situ X-ray powder diffraction data.

Keywords

• naproxen
• polymorphism
• phase stability