Ketoprofen sodium: preparation and its formation of mixed crystals with ketoprofen

A simple two-step process for the preparation of ketoprofen sodium was developed. The procedure involved dissolution of ketoprofen in ethanolic NaOH followed by evaporation of the solvent. The resulting amorphous solid was crystallized by controlled precipitation from 96% ethanol. The sodium salt proved to be stable for 4 years and its aqueous solutions for at least 1 year (investigated period). Ketoprofen sodium appears to be an alternative bulk form to ketoprofen acid for production of formulations after further characterization of the compound.