An association model for the solubilities of pharmaceuticals in supercritical carbon dioxide

The equilibrium solubility of a pharmaceutical compound, 1,5-dimethyl-2-phenyl-4-propan-2-ylpyrazol-3-one (propyphenazone, isopropylantipyrine) in supercritical carbon dioxide (SCCO2) was experimentally determined by a saturation method at 308, 318 and 328 K, over the pressure range of 9.0–19.0 MPa. The solubility data satisfied the self-consistency test, proposed by Méndez-Santiago and Teja. A new association model was derived to correlate the solubilities of pharmaceutical compounds in SCCO2. Solubility data from 54 different pharmaceutical compounds including steroids, antibiotics, anti-inflammatory, antioxidants, statins and specific functional drugs were collected from literature. The model successfully correlated the experimental results for the solubilities of all these compounds in SCCO2 within 12% AARD.