The size of substance particles determines the choice of tablet production technology, the method and equipment for granulation, the strength and density of the obtained granules and, accordingly, the mechanical properties of the tablets themselves, their disintegration and dissolution. For example, in JSC “Chemical-Pharmaceutical Combine “AKRIHIN” as a result of research of a large number of preparations the practical material confirming the influence of the shape and size of crystals of substances on the parameters of the technological process of obtaining tablet masses and modes of their pressing was obtained. For example, for production of aminalon core tablets only fine crystalline substance is necessary, and aminalon crystals of 500-1000 microns in size give unstable, loose tablets. Tablet dosage form of carbamazepine of proper quality by fluidized bed granulation method can be obtained from micronized substance (up to 20 μm), and by conventional wet granulation method – only from powder with particle size from 50 to 300 μm. To obtain acyclovir tablets with a high dissolution index, the particle size of the substance is standardized – not more than 50 microns. It was also found that glibenclamide tablets have good dissolution indexes only when micronized powder is used.
Especially noticeable is the influence of the shape and particle size of substances on the technological characteristics of tablet mass intended for direct pressing.
It is known that only substances belonging to the cubic system are pressed into tablets directly, i.e. by direct pressing, without granulation and auxiliary substances.

The more complex the powder surface, the greater the adhesion and lesser the friability, and vice versa. Since direct pressing is increasingly being introduced into pharmaceutical production due to its clear economic advantages and the emergence of modern high-speed tablet presses with high pressing forces, research aimed at studying and normalizing the technological and rheological parameters of tablet mixtures, as well as their constituents, i.e. active and excipients, is particularly relevant. These studies are especially in demand nowadays, when the number of firms-suppliers of medicine substances has increased dramatically, which often differ significantly from series to series in their physicochemical and technological parameters. Specific surface area is the surface area of a solid substance (powder) referred to the unit of mass or volume. If the substance has a porous structure, the total area of all its pores is taken into account.
Contact surface – surface formed when powder particles come into contact with each other. True density is the limit of the medicine mass to volume ratio at zero powder porosity. Wettability is the ability of powdered medicine substances to interact with various liquids (lyophilicity), and above all with water (hydrophilicity). The surface of solid particles of medicine substances contains a certain number of hydrophilic groups (OH, -SON, etc.) or oxygen atoms, which are structural elements of their crystal lattice, so the wettability of the surface of powders has a different value depending on the intensity of interaction of intermolecular forces.