Solubility
of molecular crystals: Polymorphism in the light of solubility theory
P. Bennema, J. van Eupen, B.M.A. van
der Wolf, J.H. Losa and H. Meekes
Int. J. of Pharmaceutics 351 (2008)
74-91
Abstract:
The thermodynamic theory of solubility of
molecular crystals in solvents is reviewed with an emphasis on solutes
showing polymorphism as in case of many pharmaceuticals. The relation
between solubility and binary phase diagrams of the solute solvent
system is treated. The astonishing variety of possible solubility
curves as a function of temperature is explained using simple models
for the solution thermodynamics assuming no mixing between the solvent
and solute in the solid phase, though including the case of solvates or
pseudo polymorphs. In passing a new method is introduced that allows to
estimate the transition temperature of enantiotropically related
polymorphs from melting temperatures and enthalpies of the polymorphs