About pressing of tablets

Basic requirements for tablets

The following requirements apply to the tablets:
precise dosing - pills homogeneity, uniform distribution of the active ingredient in the tablet, the exact weight of the tablets and drugs included in the tablet;
mechanical strength - quality characteristic of tablets, including hardness, fragility, brittleness, during packaging, transportation and storage of tablets exposed to mechanical stress and to remain remain intact, must be of sufficient strength;
solubility and disintegration - the ability of certain types of tablets defined in the relevant scientific and technical documentation (NTD) time to dissolve or disintegrate.
Accurate metering is in the quality of tablet weights.
Uniformity tablet weights provides uniform distribution of medicinal substances and their thorough mixing in the total mass. Great importance to ensure the accuracy of dosing has the speed and stability of the filling mass matrix tablet nest tableting machine. Weight of the resulting tablet is insufficient, if at a certain time of the funnel are poured material is less than it might get a die.
The rate of filling the slot matrix influenced by factors such as the shape of a funnel, angle of slope, sliding properties tablet particle mass.
Frequently, the surface roughness of the individual particles is so high that the frictional force causes delays in material hopper and prevents the full matrix filling the slot. To impart a smooth surface of the particles and reduce the friction between them, are added to the powder antifriction material. Fine powders often differ bad slip, as they have to adhere to the surfaces funnel.
In such cases, by granulating the material to artificially increase the size of the particles to achieve optimum values. Changing the tablet weight may be due to of the material. Lamination can be avoided by setting, in some cases, a small stirrer in the funnel, but the method is radical granulating material, aligning the particle size.
The term "uniformity of material" includes as its particle shape uniformity. It is clear that having the same mass but with different spatial shape, the particles in the matrix nest will be placed at different compactness. This factor also causes fluctuations in weight tablets. Granulating process can achieve alignment of the particles form. I must say that is quite difficult to achieve uniformity of the granules.
Empirically by varying the ratio of fractions granulate determines the optimal composition having the best and, at a certain pressure compression provides high quality pills.
Mechanical strength tablets caused particles. When you start pressing process is compacted tablet mass particles approach more closely and there are conditions under which manifested intermolecular forces and electrostatic interactions. At a distance of 10 "6-10" 7 centimeters when approaching particles appear intermolecular forces.
Pressing tablet weights involves a process of three stages.
In the pressing process, it is important to monitor how the pressure increases, because depends on the pressure mechanical strength of the tablet. Eccentric (drums) tablet machine: sharply rising pressure contributes to the transformation of mechanical energy into heat, resulting in the under surface of the tablet punch stroke is strongly heated, fused material, forming a solid cement layer.
Rotary tablet machine: gradually increasing the pressure, providing a more lasting effect, gives the best results compression tableting mass. With prolonged exposure is well removed from the air mass tablet, this air expands after depressurization, can have a devastating effect on the pill. In addition, the heating surface substantially reduces the tablet excluding adverse thermal effects on members of the tablet material.
High pressure during pressing facilitates tablet machine wear, and can also affect adversely the quality of the tablets. Compensate for high blood pressure can be achieved by adding substances with a large dipole moment, which provide adhesion of the particles at relatively low pressures. Link between these particles may be water, because it possesses satisfactory dipole moment. Binding particles of insoluble and poorly soluble drugs will prevent the water.
In this case it is necessary to add substances with a higher adhesion force (gelatin, starch solutions, etc.) and again subjected to granulation to enter with its aid tablet binders in weight, these substances will increase the ductility of drugs; emerge in the adhesion property causes one other particles, called this property - adhesion.

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To all the questions related with production of tablets you can find answers on resource www.Tabletpress.ru