Cubic equation-of-state correlation of the solubility of some anti-inflammatory drugs in supercritical carbon dioxide

The accurate experimental determination of solid drug solubility in supercritical fluids (SCFs) and its correlation are crucially important to the development of supercritical technologies for the pharmaceutical industry. In this work, the solubilities of flurbiprofen, ketoprofen, naproxen and ibuprofen in supercritical carbon dioxide (scCO2) were correlated using the Peng–Robinson (PR), Soave–Redlich–Kwong (SRK) and Patel–Teja–Valderrama (PTV) equations-of-state with van der Waals (vdW), Panagiotopoulos–Reid (mrPR) and Mukhopadhyay–Rao (MR) mixing rules. Several modeling and correlation computational programs were developed in Mathematica®, a powerful symbolic computational language. Correlations were compared and discussed on the basis of the employed equation-of-state and mixing/combining rules. The importance of the estimation methods used for the determination of critical and other drug physical properties (namely drug's sublimation pressure) was also underlined in the discussion of the correlation results quality. A potential helpful procedure (based on simultaneous correlation of one of the critical or physicochemical properties) is suggested, in order to satisfactorily choose property estimation methods to use.