[Morphological and structural aspects of solid drug forms]

As a follow-up to a previous article, where the characteristics of the solid state and the X-ray properties and pharmaceutical applications were described ("X-rays, diffractometry in the analysis of drugs and pharmaceutical forms", Boll. Chim. Farm. 128, 149; 1989), the Author has more specifically considered the so-called "variants" of a drug's solid state, which can be employed in the dosage forms (polymorph, solvate, crystalline habitus, amorphous). In addition, mention is made of drugs' isomorphism and the difference between a polymorphic solvate and the polymorphism of a solvate is clearly stressed.