Solubility of progesterone, testosterone, and cholesterol in supercritical fluids

One potentially used application of supercritical fluid extraction (SCFE) is isolating and separating pharmaceuticals such as steroids. Experimental solubility data were obtained for testosterone, progesterone, and cholesterol in supercritical CO₂ with and without N₂O cosolvent over a pressure rage of 80 to 250 atm at 308.15-333.15 K. The addition of 10% (volume) N₂O into CO₂ increased the solubilities of these compounds by as much as one order of magnitude with larger effects occurring at lower pressures. Ternary systems (progesterone + testosterone + CO₂, progesterone + testosterone + CO₂, and testosterone + cholesterol + CO₂) were also investigated. The experimental data were correlated by using a modified Peng-Robinson equation-of-state with density-dependent binary mixing rules, treating steroid vapor pressures in the form of the Clapeyron equation as adjustable correlating parameters.