Drug transport to the brain: Comparison between in vitro and in vivo models of the blood-brain barrier

The aim of the present studies was to compare the transport of drugs using two in vitro models routinely used in our laboratories: a primary culture of brain microvessel endothelial cells and a coculture of brain capillary endothelial cells and astrocytes. For this purpose we selected a set of compounds corresponding to a wide range of lipid solubility. Additionally the in vitro results were compared to in vivo results obtained with the single carotid injection, and a good correlation between in vivo extraction ratios (E(t)) and in vitro permeability coefficients (P-e) was shown as indicated by the Spearman's correlation coefficient (r = 0.90 and r = 0.96 for primary culture and coculture, respectively). The studies show that the use of brain capillary endothelial cells together with astrocytes is slightly more predictive and significantly easier than the use of primary cultured brain microvessels.