Corrective substances are added to the composition of the tablets in order to improve their taste, color and smell. Corrective substances are of great importance in children's medical practice. It has been established that an effective therapeutic agent with an unpleasant taste in children has many times less effect or does not have a therapeutic effect. It is necessary to consider the possibility of changing the absorption of drugs from the corrected dosage forms. It is known, for example, that sugar syrup and some fruit syrups reduce the absorption of amidopyrine, antibiotics from the dosage forms they correct.
One of the problems of tablet production is obtaining good fluidity of granulate in feed devices (funnels, bins). The obtained granules or powders have a rough surface, which makes it difficult to pour them from a loading funnel into the matrix nests. In addition, the granules can adhere to the walls of the matrix and punches due to friction developed in the contact zones of the particles with the press tool of the tablet machine. To remove or reduce these undesirable phenomena, anti-friction substances, represented by a group of sliding and lubricating substances, are used. Sliding substances, adsorbed on the surface of particles (granules), eliminate or reduce roughness, increasing their fluidity (flowability). The most efficient slip is possessed by particles having a spherical shape.
To eject a pressed tablet from the matrix, it is necessary to expend force to overcome friction and adhesion between the side surface of the tablet and the matrix wall. Taking into account the magnitude of the ejection force, additives of antifriction (sliding or lubricating) substances are predicted. As an example, the results of determining the technological characteristics of rounded substances are given. Powders with round-shaped particles with a main particle size of more than 100 microns (ranitidine g / hl, carbamazepine, phenazepam) have high (8–9 g / s) flowability, high bulk density before and after compaction, but low compressibility and a small compaction coefficient. Phenazepam has a slightly lower flowability value (8 g / s), probably because it contains more fine fractions and does not contain particles larger than 250 microns, which are present in ranitidine and carbamazepine.
For most chemical and pharmaceutical preparations, the tablet production technology consists of the following separate operations: Weighing the starting material, grinding, sieving, mixing, granulating, tabletting (pressing), coating. Some of these operations in the manufacture of pharmaceuticals may not be available. The most common are three general technological schemes for producing tablets: using wet granulation, dry granulation and direct compression.
A tablet (from Lat. Tabella - a tablet, a tile) is a dosage form obtained by compressing medicinal products or a mixture of medicinal and auxiliary substances. Designed for internal, sublingual, implantation or parenteral use. The first information about tablets dates back to the middle of the 19th century. In Russia, the first large tablet workshop was opened in 1895 in St. Petersburg. Tablets are one of the most common and promising dosage forms and, as mentioned earlier, currently account for about 80% of the total volume of finished dosage forms. This is due to the fact that tablets have several advantages over other dosage forms, namely: the accuracy of the dosage of drugs introduced into tablets; portability of tablets, providing the convenience of dispensing, storage and transportation of the dosage form; preservation of medicinal substances in a compressed state. For insufficiently stable substances, protective coatings may be applied; masking unpleasant organoleptic ...