Viscous products possessing shear-sensitive behavior, fragile components or abrasive properties require gentle but thorough mixing. In most cases, a double planetary mixer is the best choice for processing such applications.
Low shear mixing of viscous formulations is preferred when incorporating abrasive materials, fibers or delicate solids, such as hollow glass microspheres. Mixing under gentle, laminar flow conditions is also ideal for viscous products with shear-sensitive properties. A number of gel or paste formulations containing active pharmaceutical ingredients fall into this category.