Decrease of Crystallization of Triturated Mixtures of Mefenamic Acid and Sodium Starch Glycolate by Heating at a Reduced Pressure.

The triturated mixtures of mefenamic acid (MFA) and Explotab ® (EX) were prepared by means of powder/powder mixing technique.After storage under reduced pressure at 60°C for 5 hr, with scanning electron microscopy, it seemed likely that EX was transformed to a porous powder.The crystal peaks of MFA by X-ray diffraction had almost disappeared.The dissolution profiles of MFA from the triturated mixtures stored under reduced pressure at 60°C for 5 hr were enhanced in comparison with that from a freshly prerared mixture.With the increase of either the storage temperature or the time under reduced pressure, the particle size of MFA tended to increase on the surface of EX, and MFA also tended to peel from the surface of EX.Consequently, the crystallization of MFA was accelerated.