Inclusion complexation of tiaprofenic acid (TPA) with cyclodextrins $({alpha}-,;{eta}-,;{gamma}-CyDs)$ in aqueous solution and in solid phase was investigated by solubility method, measurement of partition coefficient, ultra-violet, circular dichroism, infrared spectroscopies, powder X-ray diffractometry and differential scanning calorimetry. Investigations were made to prepare inclusion complexes of TPA with ${eta}-CyD$ in solid powdered form by coprecipitation, freeze-drying, spray-drying and co-pulverization methods. The coprecipitation, freeze-drying and spray-drying methods were successful in obtaining inclusion complexes. The results showed that the latter two methods might be originally superior to the former in obtaining powdered inclusion completes. Especially, it was shown by powder X-ray diffractometry that spray-dried ${eta}-CyD$ alone, TPA-spray-dried ${eta}-CyD$ physical mixture, and spray-dried $TPA-{eta}-CyD$ complex were amorphous. The dissolution behaviours of $TPA-{eta}-CyD$ systems prepared by above four methods were compared with those of TPA alone and $TPA-{eta}-CyD$ physical mixture, and the rates of dissolution of TPA in pH 1.2 buffer were greatly enhanced by inclusion complexation and copulverization.