Experimental determination and correlation of meloxicam sodium salt solubility in supercritical carbon dioxide

A static analytical method was employed for the experimental measurement of the equilibrium solubility of meloxicam sodium salt (MIX) in supercritical carbon dioxide (scCO(2)), at 303 K, 313 K and 323 K, and in a pressure range from 14.9 up to 25.5 MPa. Experimental equilibrium solubility (in terms of MLX mole fraction) was found to be between 4.41 x 10(-6) (at 323K and 15.2 MPa) and 12.76x 10(-6) (at 323K and 15.2 MPa). To the best of our knowledge, these are the first MLX equilibrium solubility in scCO(2) data to be reported in literature. The obtained experimental data were successfully correlated with three semi-empirical density-based models (Chrastil, Bartle and Mendez-Santiago-Teja models) and with an equation-of-state (EOS) model: the Peng-Robinson cubic equation of state (PR-EOS) together with the conventional van der Waals mixing and combining rules. The best obtained average absolute-relative deviations (AARDs) were 2.7% and 5.3%, for the PR-EOS and for the semi-empirical models, respectively. (C) 2011 Elsevier B.V. All rights reserved.