Solubility of Diflunisal in Supercritical Carbon Dioxide

Abstract

The solubility of diflunisal, a nonsteroidal anti-inflammatory drug (NSAID), in supercritical carbon dioxide (scCO2) was measured at (308.2, 318.2, and 328.2) K and in the pressure range from (9.0 up to 25.0) MPa. Results were obtained using a static analytical method. Experimental solubility was found to be between 0.54·10−6 and 8.07·10−6 (in terms of diflunisal mole fraction). Experimental data were satisfactorily correlated with an equation-of-state (EOS) model: the Peng−Robinson cubic equation of state (PR−EOS) together with the conventional van der Waals mixing and combining rules. Solid properties were estimated by different methods available in the literature. The solubilities of several NSAIDs in SCFs, namely in scCO2, were obtained from the literature and plotted and represented as a function of the corresponding sublimation pressures and fusion temperatures.