Morphological and thermodynamic transitions in drugs as well as their amorphous and crystalline content in the solid state have been distinguished by thermal analytical techniques.
Crystalline solids possess a definite and regular geometry and consist of both long-range as well as short-range order of their constituent particles. The particles of the constituents in the amorphous solids are arranged irregularly. They do not possess any kind of definite geometry and have a shorter range order.