Solubilities of 5-Fluorouracil and β-Estradiol in Supercritical Carbon Dioxide

Controlled release drug products are gaining importance in the pharmaceutical industry. Impregnation via supercritical fluids is a potential technique for the production of these products. The solubilities of the drugs in supercritical carbon dioxide are being measured, since they control the amount of drug component that can be carried by the mobile phase and therefore the impregnation period and extent. The solubilities of 5-fluorouracil and β-estradiol, used in chemotherapy and estrogen hormone therapy, respectively, are measured at pressures ranging from 100 bar to 220 bar and at 308 K to 328 K. These drugs have mass fraction solubilities of the order 10 - 6 to 10 - 4, which are high enough to make the supercritical impregnation process a feasible alternative to impregnation employing organic solvents. The solubilities are presented as a function of solvent density and indicate higher solubilities at higher temperatures for both of the drugs. Solubilities of β-estradiol are also reported at select conditions with ethanol as a cosolvent.