THE MOBILE ORDER SOLUBILITY EQUATION APPLIED TO POLYFUNCTIONAL MOLECULES - THE NON-HYDROXYSTEROIDS IN AQUEOUS AND NON-AQUEOUS SOLVENTS

The solubility equation for real solutions derived from the thermodyna mics of mobile order in liquids is used to predict the solubility of n on-hydroxysteroids in water and in common polar and nonpolar organic s olvents. Strictly obtained on a thermodynamic basis, the model allows not only correct predictions of the solubilities from the knowledge of a limited number of characteristics of solutes and solvents, but also enables a better understanding of the solution process and of the fac tors that determine solubility. Some practical rules are derived which might help to orient the choice of a solvent for liquid pharmaceutica l forms. (C) 1997 Elsevier Science B.V.