Table 6 Parameters and units of drug transport within the brain tissue. The physiological range of values of the parameters is given for rat and human, based on references from the literature

D*, effective diffusion constant (10⁻¹⁰ m⁻² s⁻¹)

0.1–1 [129, 203]

0.1–15 [131, 189, 235]

\(\lambda\), tortuosity

1.44–3.5 [69, 168]

1.50–1.77 [69]

\(\alpha\), brain ECF volume fraction

0.05–0.47 [168]

0.23–0.49 [69, 111]

v_ECF, brain ECF bulk flow velocity (10⁻⁷ m s⁻¹)

0.5–50 [22, 236]

2–8 [132]

CSF flow rate (10⁻⁷ L s⁻¹)

0.37 [27, 220]

50–67 [237]