Efficient coatings depend on three main factors: coating prescription: must be based on the purpose of the coating, carefully selected, or finished coating materials, when used; core: surface finish, hardness and The friability must meet the requirements; equipment: the main process parameters must be well controlled throughout the coating process.
Coating means encapsulating a layer of material on the outer surface of the core, which may be powder, granules, pellets or tablets. The coating has various purposes, such as moisture resistance, mechanical resistance, taste masking, coloring or improved release properties of the active ingredient of the drug. The coating process mainly consists of a sugar coating process and a high-efficiency coating machine.
The sugar coating process mainly sprays syrup, talcum powder and pigment onto the surface of the core to form a coating layer; the high-efficiency coating machine sprays a polymer solution or a suspension onto the surface of the core to form a coating layer. The sugar coating process is an old-fashioned pharmaceutical process. The high-efficiency coating machine is a rising star. Now it has been extensively researched. Different formulas and potential uses are being fully recognized, which has attracted the attention of the pharmaceutical industry and rapid promotion.
First, the efficiency coating machine process <br> <br> efficiency coating machine is a new technology developed in the 1940s, it was first produced in the pharmaceutical industry, to protect the drug film. Compared with sugar coating, it has the characteristics of short production cycle, less material consumption and strong moisture resistance. In the coating process, it can be divided into water-soluble coating process and organic solvent coating process depending on the solvent. The purpose of the high-efficiency coating machine is to improve the appearance and to easily identify, mask bad odor, facilitate patient taking, reduce gastrointestinal reactions, control drug release, change drug release curve, protect against moisture, protect from light, and isolate air to increase drug stability. The pharmaceutical ingredients with the compatibility changes are placed in the core and the clothing layer respectively or separately after the coating, so as to avoid other changes.
Second, the problems often encountered in the coating and solutions 1, excessive wet and wet is because the spray speed is too fast relative to the drying efficiency, there is no balance between spray and dry. This phenomenon is more likely to occur during the water-soluble coating process because water is more difficult to dry than organic solvents.
Due to excessive humidity, the tablets stick to the wall of the pot or the tablets stick to each other. This will cause the film to be damaged and uneven. To avoid over-wetting, the spray rate must be carefully controlled and the inlet air temperature can be increased. In addition, the addition of talc or magnesium stearate to the coating solution can improve this phenomenon.
2, the surface is rough, not smooth, in most cases, it is caused by spray drying, because the droplets are not spread when the drying is too fast. In addition, the dried polymer particles stick to the surface of the core, which is liable to cause a rough film. This can be improved by increasing the spray rate, lowering the inlet air temperature or shortening the distance between the spray gun and the bed.
3. Orange peel phenomenon This is a situation in which the surface of the film is rough. The droplets are not completely spread on the surface of the core, and dry polymer particles are irregularly distributed on the surface of the core. This is mainly caused by improper drying, which can be avoided by controlling the evaporation rate, increasing the spray speed or shortening the distance between the spray gun and the bed.
4, bridging and filling phenomenon When the outer surface of the tablet is irregular, engraved with the logo letters, the surface of these signs will disappear, filled with coating liquid. This is usually caused by the viscosity of the coating liquid being too large, increasing the amount of solvent or the amount of plasticizer, and this bridging or filling phenomenon will disappear.
5. Differences in film color In many formulations, there are pigments or dyes that are suspended in the polymer coating solution. If the agitation is too slow, it will cause precipitation, resulting in a difference in color between the batch and the batch. If the temperature is too high, the pigment will be easily diffused and the color of the film will be light. This phenomenon can be improved by reducing the amount of plasticizer and stirring the coating liquid.
6. Film rupture This is one of the problems that often occurs in coatings. The polymer film ruptures and cracks occur. This phenomenon may occur after the coating has been carried out for several hours, which is due to prescription. Adding a larger molecular weight polymer to the coating solution or increasing the amount of plasticizer will prevent this from happening.
Coating means encapsulating a layer of material on the outer surface of the core, which may be powder, granules, pellets or tablets. The coating has various purposes, such as moisture resistance, mechanical resistance, taste masking, coloring or improved release properties of the active ingredient of the drug. The coating process mainly consists of a sugar coating process and a high-efficiency coating machine.
The sugar coating process mainly sprays syrup, talcum powder and pigment onto the surface of the core to form a coating layer; the high-efficiency coating machine sprays a polymer solution or a suspension onto the surface of the core to form a coating layer. The sugar coating process is an old-fashioned pharmaceutical process. The high-efficiency coating machine is a rising star. Now it has been extensively researched. Different formulas and potential uses are being fully recognized, which has attracted the attention of the pharmaceutical industry and rapid promotion.
First, the efficiency coating machine process <br> <br> efficiency coating machine is a new technology developed in the 1940s, it was first produced in the pharmaceutical industry, to protect the drug film. Compared with sugar coating, it has the characteristics of short production cycle, less material consumption and strong moisture resistance. In the coating process, it can be divided into water-soluble coating process and organic solvent coating process depending on the solvent. The purpose of the high-efficiency coating machine is to improve the appearance and to easily identify, mask bad odor, facilitate patient taking, reduce gastrointestinal reactions, control drug release, change drug release curve, protect against moisture, protect from light, and isolate air to increase drug stability. The pharmaceutical ingredients with the compatibility changes are placed in the core and the clothing layer respectively or separately after the coating, so as to avoid other changes.
Second, the problems often encountered in the coating and solutions 1, excessive wet and wet is because the spray speed is too fast relative to the drying efficiency, there is no balance between spray and dry. This phenomenon is more likely to occur during the water-soluble coating process because water is more difficult to dry than organic solvents.
Due to excessive humidity, the tablets stick to the wall of the pot or the tablets stick to each other. This will cause the film to be damaged and uneven. To avoid over-wetting, the spray rate must be carefully controlled and the inlet air temperature can be increased. In addition, the addition of talc or magnesium stearate to the coating solution can improve this phenomenon.
2, the surface is rough, not smooth, in most cases, it is caused by spray drying, because the droplets are not spread when the drying is too fast. In addition, the dried polymer particles stick to the surface of the core, which is liable to cause a rough film. This can be improved by increasing the spray rate, lowering the inlet air temperature or shortening the distance between the spray gun and the bed.
3. Orange peel phenomenon This is a situation in which the surface of the film is rough. The droplets are not completely spread on the surface of the core, and dry polymer particles are irregularly distributed on the surface of the core. This is mainly caused by improper drying, which can be avoided by controlling the evaporation rate, increasing the spray speed or shortening the distance between the spray gun and the bed.
4, bridging and filling phenomenon When the outer surface of the tablet is irregular, engraved with the logo letters, the surface of these signs will disappear, filled with coating liquid. This is usually caused by the viscosity of the coating liquid being too large, increasing the amount of solvent or the amount of plasticizer, and this bridging or filling phenomenon will disappear.
5. Differences in film color In many formulations, there are pigments or dyes that are suspended in the polymer coating solution. If the agitation is too slow, it will cause precipitation, resulting in a difference in color between the batch and the batch. If the temperature is too high, the pigment will be easily diffused and the color of the film will be light. This phenomenon can be improved by reducing the amount of plasticizer and stirring the coating liquid.
6. Film rupture This is one of the problems that often occurs in coatings. The polymer film ruptures and cracks occur. This phenomenon may occur after the coating has been carried out for several hours, which is due to prescription. Adding a larger molecular weight polymer to the coating solution or increasing the amount of plasticizer will prevent this from happening.
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