Fig. of dissolution speed with rotating or fixed disc method Dissolution can be increased by mixing, in order to inhibit the creation of process slowed by diffusion layers and to ensure high concentration difference. In this case turbulent flow is beneficial. Dissolution surface may be raised by decreasing the particle size, thus dissolution speed will increase too. Dissolution model regards the equation and dissolution surface too: Brunner és Tolloczko’s Noyer-Whithney (21.) had revealed the further components of previous dissolution constant: Nernst and Brunner (22.) diffusion constant, D surface of solid material, A volume of medium, V thickness of diffusion layer, h dissolution constant k2 had approached the issue in another direction. They had described the cube root law: Hixon and Crowell (23.) dissolution model speed constant k’ initial mass of dissolving particle, mo mass of dissolving particle in t moment. mt With the interpretation of speed constant: k’ (24.) speed constant k’’ particle number N modified the cube root law: Niebergall (25.) dissolution speed constant, k’’ mass of solid material, which is needed to saturate a V volume solvent. ms According to correlation, in the case of particles with sphere shape the radius of dissolving Higuchi-Hiestand particle is depending on the following factors:
Fig. of dissolution speed with rotating or fixed disc method Dissolution can be increased by mixing, in order to inhibit the creation of process slowed by diffusion layers and to ensure high concentration difference. In this case turbulent flow is beneficial. Dissolution surface may be raised by decreasing the particle size, thus dissolution speed will increase too. Brunner és Tolloczko’s Dissolution model regards the Noyer-Whithney equation and dissolution surface too: (21.) Nernst and Brunner had revealed the further components of previous dissolution constant: (22.) D diffusion constant, A surface of solid material, V volume of medium, h thickness of diffusion layer, k2 dissolution constant Hixon and Crowell had approached the issue in another direction. They had described the cube root law: (23.) k’ dissolution model speed constant mo initial mass of dissolving particle, mt mass of dissolving particle in t moment. With the interpretation of k’ speed constant: (24.) k’’ speed constant N particle number Niebergall modified the cube root law: (25.) k’’ dissolution speed constant, ms mass of solid material, which is needed to saturate a V volume solvent. According to Higuchi-Hiestand correlation, in the case of particles with sphere shape the radius of dissolving particle is depending on the following factors: