Solubilities of two steroid drugs and their mixtures in supercritical carbon dioxide

The equilibrium solubilities of two steroid drugs, medroxyprogesterone acetate (med) and cyproterone acetate (cyp) in the binary (med+CO2 and cyp+CO2) and ternary (med+cyp+CO2) systems were determined at temperatures ranging from 308 to 348 K and pressures from 122 to 355 bar. The experimental data for med were correlated using a semi-empirical model. Correlation of the results shows good self-consistency of the data obtained and reasonable agreement with the available published data. The crossover region, i.e. the pressure where solubility isotherms cross each other in that region, was observed for med at about 220 bar while for cyp this region was above 300 bar. In the ternary systems the solubility of med increased, but the solubility of cyp decreased (except for lower pressures and/or high temperatures) in comparison to their binary solubilities. tions of binary solid mixtures of these drugs were investigated. The results showed that the med acetate could be separated from this mixture with a yield of 67%.