GRANULATION PROCESS IN TABLET PRODUCTION

Dry granulation of powders

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Dry granulation is a method in which a powdery material (a mixture of medicinal and auxiliary substances) is compacted to produce a granulate. Dry granulation is used in cases where wet granulation affects the stability and/or physico-chemical characteristics of the medicinal substance, as well as when the medicinal and auxiliary substances are poorly compressed after the wet granulation process. If medicinal substances undergo physical changes during drying (melting, softening, color change) or enter into chemical reactions, they are briquetted, i.e. briquettes are pressed from the powder on special briquetting presses with large matrices (25x25 mm) under high pressure.

Binders for wet granulation

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There are some requirements for the granulating liquid, one of them is that the granulating liquid should not dissolve the active substance. Water, an aqueous solution of ethanol, acetone and methylene chloride can be used as a granulating liquid. A wide range of substances are used as binding agents for wet granulation in modern pharmaceutical production, for example: starch (5-15% g/g), starch derivatives, cellulose derivatives that improve the plasticity of granules, as well as gelatin (1-3% g/ g) and PVP (3-10% g/ g). The most common and effective binder for wet granulation in the modern pharmaceutical industry is a synthetic polymer such as Collidone (PVP), various brands of which (Collidone 25, 30 and 90F) are widely represented on the market.

Powder screening in production

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When grinding solid materials on the equipment discussed earlier, a homogeneous product is practically not obtained, Therefore, such an operation as sieving is necessary to separate larger particles. Sieving is an integral part of grinding to obtain a mixture with a certain granulometric composition. Sieving eliminates soft conglomerates of powders by rubbing them through perforated plates or sieves with a certain size of holes. Sieving, or screening, is the process of separating a mixture of grains of various sizes using sieves into two (or more) groups. The size of the grains passing through the sieve cells is characterized by a number. There are 16 different sieves, which correspond to 7 degrees of grinding.

Equipment for combined processes

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The SG type apparatus manufactured by NPO "Pharmedobrazovanie" is used for granulation of powders in a fluidized bed, subsequent drying and dusting. This process is periodic. The body of the device is made of three all-welded sections, sequentially mounted with each other. The principle of operation is as follows: 30 kg of tablet mixture to be granulated is loaded into the food tank in accordance with the recipe. The trolley with the initial components is rolled into the machine and lifted. The air temperature required for fanulation is set, the mixing, fanulation and drying time is set, as well as the cyclicity and frequency of shaking of bag filters. The fan is turned on with the help of a gate that regulates the flow of...

Equipment for wet granulation process

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The granulate is obtained in the process of granulation of wet mass on special granulator machines. The principle of operation of granulators is that the material is wiped with blades, springy wolves or other devices through a perforated cylinder or mesh. To ensure the wiping process, the machine must operate at an optimal mode without overload so that the wet mass passes freely through the holes of the cylinder or mesh. If the mass is sufficiently moistened and moderately plastic, then it does not seal the holes and the process goes without difficulty. If the mass is viscous and seals the holes, the machine works with overload and it is necessary to periodically turn off the motor and rinse the drum blades. The granulator contains...

Granulation and fluidized bed drying

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Granulation in a fluidized bed (PS) allows you to combine mixing, granulation, drying and dusting operations in one machine. Therefore, the granulation method in PS is increasingly used in the modern pharmaceutical industry. The process consists in mixing powdered ingredients in a suspended layer, followed by their moistening with a granulating liquid with continued stirring. A fluidized bed is formed when upward-directed air lifts a layer of solid particles, which begins to "boil" like a liquid. The layer is in a fluidized state. The forces acting on the particles in the state of fluidization are in equilibrium. The particles in the fluidized bed are mixed so efficiently that the temperature over the entire height of the fluidized bed remains constant. The general design of the...

Granulation and spray drying

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This type of granulation is advisable to use in cases of undesirable prolonged contact of the granulated product with air, if possible directly from the solution (for example, in the production of antibiotics, enzymes, products from raw materials of animal and vegetable origin). This is due to the short drying time (from 3 to 30 seconds), the low temperature of the material (40-60 ° C) and the high temperature of the carrier, which is provided by high relative speeds and high values of the driving force of the drying process. There are two ways to carry out this process: spraying suspensions of fillers with the addition of a bonding agent and baking powder. The amount of solid phase in the suspension can be 50-60%.

Wet granulation of powders

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Wet granulation is subjected to powders having poor flowability and insufficient ability to bond between particles. In both cases, binding solutions are added to the mass, improving the adhesion between the particles. Granulation, or wiping of the wet mass, is carried out in order to compact the powder and obtain uniform grains — granules with good flowability. Wet granulation includes successive stages: grinding of substances into a fine powder and mixing of dry medicinal substance with auxiliary substances; mixing of powders with granulating liquids; granulation; drying of wet granules; powdering of dry granules. Grinding and mixing is carried out in mills and mixers of various designs presented earlier. The resulting powder is sifted through a sieve.