Fig. 9
From: The need for mathematical modelling of spatial drug distribution within the brain
Adapted with permission from [111]
Circular representation of the Krogh cylinder. A brain capillary (red point in the middle) is surrounded by four layers of brain tissue, represented by subunits Sj(\(1\le {\text{j}}\le 4\)) (blue). Here \(\Phi\)0 describes the exchange rate through the BBB and \(\Phi\)j(\(1\le {\text{j}}\le 4\)) describes the drug diffusion flux between the brain tissue subunits.