In this work is presented a study of the viability of the use of the spouted bed for application of the gastric resistant coating on hard gelatin capsules. The parameters studied were the ratio between the mass feed flow rate of the coating suspension to the mass feed flow rate of the gas introduced to the system, (Ws/Wg), the ratio between the flow rate of the spouting gas relative to the minimum spouting, (Q/Qjm), the mass of capsules loaded to the equipment, (M0) and the capsule's size, (Tcaps). The performance of the process as well as the coating quality were evaluated through the increase rate of the particle mass, (K1), by the adhesion efficiency, (·), disintegration and compression tests and by photomicrographs obtained in a scanning electronic microscope. The experiments were carried out in a spouted bed with 15 cm of the cylindrical column and with an included angle of the conical base of the 40º. The results lead to the determination of the best condition for application of the coating on hard gelatin capsules: Ws/Wg = 0.0014 and Q/Qjm = 3.0, for both mass of capsules loaded to the system and capsule's size investigated. The disintegration tests showed that the gastric resistant properties are obtained with a coating mass higher than 0.006 g/cm².
Spouted bed; Enteric coating; Eudragit L-30-D-55; Hard gelatin capsules
