The coating process of sugar-coated tablets is complex, time-consuming and prone to many problems, such as cracks, bare edges, hemp noodles, patches and so on. Sugar coating has gradually been replaced by film coating, the following is only the film coating problem.
(1) Foaming is due to improper curing conditions, drying speed is too fast, we should master the film forming conditions and appropriate drying speed.
(2) The physicochemical properties of wrinkled skin tablets and coating materials affect the adhesion. The interval of feeding between two coatings is too short and the amount of spray is too much. The characteristics of coating materials should be mastered, the interval time should be adjusted, the concentration of coating solution should be reduced appropriately, and the amount of spraying liquid should be reduced.
(3) Uneven color pigments and film coating materials are not fully mixed, or the amount of plasticizers, pigments and other additives in the coating prescription is inappropriate, the solvent will bring the soluble materials to the film surface during drying. The thin film coating material can be prepared into a dilute solution and sprayed several times, or the pigment and the thin film coating material can be milled uniformly and finely in a colloid mill or a ball mill before being added. Adjust the air and temperature, slow down the drying speed.
(4) The film strength is not enough, the coating material proportion is not appropriate, the coating and drug adhesion strength is low, the coating thickness is not enough. Change the coating formula and increase the thickness of coat.
In addition to the above problems, enteric coated films also have been disintegrated in the stomach. The reasons are the improper choice or proportion of enteric coatings, the low adhesive strength between coatings and drugs, and the insufficient or uneven coatings. Suitable materials should be selected to control the appropriate proportion, increase the coating layer and coating uniformity, which should be further coated after disintegration. In the intestinal tract does not disintegrate and "platelet", because the intestinal coating material selection is improper, the coating is too thick, changes during storage, and gastric juice infiltration, when the gastric juice into the heart of the tablet, the heart of the tablet swelled, until enteric juice, the intestinal coating dissolved but the heart of the tablet only slightly expanded but not completely disintegrated. Enteric-coated materials can be used to adjust the proportion, to master the coating layer, to select appropriate disintegrants such as carboxymethyl starch instead of starch or to add a small amount of microcrystalline cellulose granulation method to solve the problem.