Water mediated solid state transformations of a polymorphic drug – effect on pharmaceutical product performance

1. INTRODUCTION

Many drugs can exist in different solid-state forms (e.g., crystalline, amorphous, hydrates/solvates, co-crystals). Given forms differentiate from each other by the arrangement of molecules towards each other in three-dimensional (3D) space. In case of crystalline material the molecules have very well defined three dimensional long range arrangement in 3D space whereas the amorphous form is defined by the lack of long range order of molecules. The solvates are crystalline matter that contains solvent molecules in a host crystal lattice. In case of crystal hydrates water molecules are incorporated to the structure.