Fig. 3
Scatter plots of unbound tissue extracellular-to-plasma concentration ratio (Kp,uu) at steady-state for the indicated drugs in the specified tissues. This parameter describes the extent of unbound drug transport across the BDB (DRG), BNB (SN), BBB (Br), BSCB (SC), and BSMI (SM), accordingly. A–K Measurements for the different drugs, with their CIPN and PN propensity indicated. Black dashed line, Kp,uu = 1, indicates predominant passive diffusion or mutually compensated influx and efflux; Kp,uu < 1 indicates predominant active efflux, while Kp,uu > 1 indicates predominant active uptake. Data are presented as the mean ± SD estimated using the error propagation method [51]. *p < 0.05, **p < 0.01, ***p < 0.001, or ****p < 0.0001 (ordinary one-way ANOVA with Tukey’s multiple comparison test). NB: note the differences in scale