Mixing of pharmaceutical solids. II: Evaluation of multicomponent mixing of cohesive powders in cylindrical shear mixer.
The mixing of three organic carboxylic acids with micronized lactose, all cohesive in nature, was studied using a cylindrical shear mixer. Three mixing indexes (s/sigma A, s/sigma R, and the Ashton-Valentin mixing index) were used to evaluate mixing of the three drugs with lactose. The results suggested that maximum homogeneity was reached after 45 min of mixing. However, different mixing indexes showed different sensitivity to homogeneity of the individual components. The mixing index s/sigma A, which is based on setting standard specifications, appears to provide a better evaluation of homogeneity of individual components compared to the mixing indexes based on complete random mixing theory. The latter did not approach unity for any drug component used in this study. These results suggested that mixing of cohesive powders is a complex process and cannot be explained fully by simple theory based on complete random mixing.
D010316:Particle Size; D011208:Powders; D013678:Technology, Pharmaceutical
D011208:Powders