Thixotropic flow:

Thixotropic flow is defined as a reversible, time dependent, isothermal gel-sol transition. Thixotropic systems exhibit easy flow at relatively high shear rates, but when the shear stress is removed the system is slowly reformed into a structured vehicle. Procaine pen-G parenteral suspension, in conc. above 40% exhibits Thixotropic flow. Thixotropic suspensions have been prepared for oral or topical use with bentonite, colloidal Mg-Al silicate, trihydroxy stearain, and calcium and Mg ion tragacanth combinations.