Determining sublimation pressure of some anti-inflammatory drugs from solubility data in supercritical carbon dioxide

The solubility of a solute in the supercritical fluid is the most important thermophysical property that needs to be determined and modeled as a first step to develop any supercritical fluids application. Solvent effects in the calculation of the sublimation pressure of pure solids using highpressure solubility data are discussed.Three binary Supercritical fluid-Solid drug systems containing flurbiprofen, ketoprofen and iboprofen as solutes and carbon dioxide as solvent considered in the study. The sublimation pressure PSub of the solid drug is correlated using four equations of state along with two mixing rules. The equations of state are Soave-Redlich-Kwong, Peng-Robinson, Streyjek-Vera and Pazuki and some others. Mixing rules are van der Waals-1parameter(vdW1) and van der Waals-2 parameter(vdW2). Correlations were compared anddiscussed on the basis of the employed equation-of-state, mixing/combining rules, the results show that the determination of sublimation pressure using high pressure solubility data is reliable and all systems lead to very good fit results, with almost identical values of AARD.

Keywords:

sublimation pressure , SCF-solid equilibrium , equations of state , mixing rules