Fillers with good bulkiness and pressability are used for direct pressing. Binders. Particles-most of the drug substances have a small adhesive force between themselves, so their tableting requires the application of high pressure, which is partly responsible for the untimely wear of the press tools of tablet machines (dies and punches) and the production of poor-quality tablets. In order to achieve the necessary bonding force at relatively low pressures, binders are added to the tabletting substances. Their function is that by filling the interparticle space, they increase the contact surface of the particles and the cohesion capacity. Binders are of particular importance in the pressing of complex powders. In the process of tablet machine operation, they can delaminate, resulting in tablets with different content of incoming ingredients. The use of a certain type of binders and their quantity depend on the physicochemical properties of the substances to be pressed. The function of binders can be performed by various substances.

Water is used in all cases where simple moistening provides normal granulation of powdery mass. Ethyl alcohol is used for granulation of hygroscopic powders, most often when the composition of the mass for tableting includes dry extracts from plant materials – these substances with water and aqueous solutions form a sticky, sticky, poorly granulated mass. The concentration of alcohol used is usually the higher the more hygroscopic the powder. Navy solutions are used for powders that form crumbly, non-pelletizable masses with water and alcohol. The binding capacity is determined not only by the concentration of the solutions, but also by the size of the molecules. Binders are introduced into the mass to be pelletized in two ways: dry and wet (i.e., powder and solution). In wet granulation there is a rule: if it is necessary to add a small amount of humectant, the binders are introduced into the mixture in dry form, if the amount of humectant is large, the binder is introduced in the form of a solution. The solubility of the binder also influences the choice of its introduction method.