Comparison of average mean square displacements (MSDs) as a function of time scale of COOH-PS in water (|), HEC (1.5 wt%) (×), and macaque CVM (◼) that are stationary in mucus, F127-HPMC (20/1 wt%, respectively) (★), and F127-F68-HPMC (22.5/2.5/1 wt%, respectively) (◆). The data were obtained at 37°C.