Apical to basolateral (specific) transport of (a) lactoferrin and (b) iron across the BBB endothelial cells. For figure (a) initial conditions are [AL]0 = 0.375 [nmol / cm3], {R1}0=5.98×10−5 [nmol / cm2], {R2}0=5.91×10−4 [nmol / cm2] and other species values are set as zero. For figure (b) initial conditions are [HL]0 = 0.625 [nmol / cm3], {R1}0 = 5.98×10−5 [nmol / cm2], {R2}0 = 5.91×10−4 [nmol / cm2] and other species values are set as zero. The equivalent fluxes are calculated from the brain side concentration of lactoferrin and iron using molecular weight, brain side volume, and cell surface area.