Dilatancy:

This system is the reverse of a pseudoplastic system and is a shear thickening system. An increase in the resistance to flow when stress is exerted the system returns to its original state of fluidity when the stress is removed. Pharmaceutical suspensions that exhibit plastic or thixotropic rheological behavior generally exhibit good physical stability. Such a suspension may prevent sedimentation, aggregation and caking by virtue of its high-yield value at rest.