Analysis on the application of coating machine in the pharmaceutical industry

Coating refers to wrapping a layer of material on the outside of the core, which can be powder, particle, pellet or sheet There are many purposes of coating, such as dampproof, anti mechanical force, masking, coloring or improving the release performance of active ingredients There are two kinds of coating technology, sugar coating technology and coating machine Sugar coating process is mainly to spray syrup, talcum powder and pigment on the surface of chip core to form coating layer; coating machine is to spray polymer solution or suspension to the surface of chip core to form coating layer Sugar coating technology is an ancient pharmaceutical technology Coating machine is a rising star Now it has been widely studied Different formulations and potential uses are fully recognized by people, which has attracted the attention of pharmaceutical industry and rapidly promoted 1 Coating machine process coating machine is a new process developed in 1940s It was first produced in the pharmaceutical industry for the protection of drug films Compared with sugar coating, it has the characteristics of short production cycle, less material consumption and strong moisture resistance In the coating process, according to different solvents, it can be divided into water-soluble coating process and organic solvent coating process The main purpose of the coating machine is to improve the appearance, easy to identify, cover up the bad smell, easy for patients to take, reduce gastrointestinal reactions, control drug release, change drug release curve, moisture-proof, light proof, air isolation to increase the stability of the drug The drug ingredients with compatibility changes are placed in the core and coating layer respectively or uniformly pressed after coating respectively to avoid other changes 2、 The problems often encountered in coating and the solutions 1 Over wet and over wet is due to the speed of spraying liquid is too fast relative to the drying efficiency, and the balance between spraying liquid and drying is not reached In the process of water-soluble coating, this phenomenon is easy to appear, because water is more difficult to dry than organic solvent Because it is too wet, the tablets will stick to the wall of the pot, or they will stick to each other This will cause damage and uneven film In order to avoid over wet phenomenon, it is necessary to carefully control the spray speed and increase the air inlet temperature In addition, adding talcum powder or magnesium stearate into coating solution can improve this phenomenon 2, one side is rough and not smooth In most cases, it is caused by spray drying It is impossible to spread liquid droplets due to drying too fast In addition, the dried polymer particles adhere to the surface of the chip core, which makes the coating film rough This situation can be improved by increasing the spraying speed, reducing the air inlet temperature or shortening the distance between the spray gun and the tablet bed 3 Orange peel is a kind of Coarseness on the surface of coating film The droplet spread on the surface of chip core is not complete, and there are dry polymer particles on the surface of chip core irregularly This is mainly caused by improper drying, which can be avoided by controlling evaporation rate, increasing spray rate or shortening the distance between spray gun and sheet bed 4 Bridging and filling phenomenon when the external surface of the tablet is irregular and engraved with identification letters, these marks on the surface will disappear and be filled by the coating solution This is usually due to the viscosity of the coating solution is too large, increase the amount of solvent or plasticizer, this bridging or filling phenomenon will disappear 5 The color difference of coating film in many prescriptions includes pigment or dye, which will be suspended in polymer coating solution If the mixing is too slow, it will cause precipitation, resulting in color difference between batches If the temperature is too high, the pigment is easy to diffuse and the color of the coating film becomes lighter This phenomenon can be improved by reducing the amount of plasticizer and stirring the coating solution 6 The rupture of coating film is one of the common problems in coating When the problem occurs, it may occur after several hours of coating This is due to the prescription Adding polymer with larger molecular weight or increasing the amount of plasticizer in the coating solution will avoid this situation In short, the success of coating depends on three main factors: coating prescription: it must be determined according to the purpose of coating, it must be carefully screened, or the finished coating materials can be selected and prepared during use; chip core: the surface finish, hardness and brittleness must meet the requirements; equipment: During the whole coating process, the main process parameters must be well controlled Coating machine is a new technology, which is widely used in drug coating This technology is easy to develop and produce, and has a wide range of applications In recent years, we have accumulated rich experience in the formulation and production of coating machine Although there are still some technical difficulties in the coating of traditional Chinese medicine, the application of this technology will be further expanded with the in-depth study of this technology.