Tiaprofenic acid is a non-steroidal anti-inflammatory drug substance with poor water solubility. Side effects reported with tiaprofenic acid ale mainly gastrointestinal disturbances. in order to eliminate these problems, to improve its solubility in water and to enhance the dissolution rare, physical mixtures (PM) and solid dispersions (SD) of tiaprofenic acid with skimmed milk (SM) were prepared by grinding and freeze-drying, respectively. X-ray powder diffraction, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) analysis were used to characterize the systems obtained. The solubility of tiaprofenic acid was improved by the solid dispersion in skimmed milk. The results indicate that the solubility of a solid dispersion of tiaprofenic acid with skimmed milk was approximately thirteen times that of the plain drug. Data concerning the dissolution rate indicated that a solid dispersion of tiaprofenic acid with skimmed milk significantly improved the dissolution rate of the drug, compared with a physical mixture or the plain substance.