Abstract: The aim of this study is to increase the solubility of an analgesic, antipyretic and antiinflammatory drug named “Celecoxib” using two types of O/W and IL (ionic liquid)/W microemulsion systems. The pseudo-ternary phase diagram was constructed and four microemulsion formulations were selected (denoted as A, B, C, D) for drug loading. The physicochemical properties such as density, refractive index and electrical conductivity of the four different microemulsion formulations were measured. The solubility of the Celecoxib in the constructed formulations of two different types of O/W and IL/W microemulsions were determined and compared. The results showed considerable increase in solubility of the drug in the microemulsion systems specially when containing ionic liquid.
