In this paper, MDCK-pHaMDR cell line, derived from the parental MDCK cell line after infection with the MDR1 virus produced by the cell line PA-12-MDR1/A1 [27], was obtained from National Institutes of Health (NIH, Bethesda, MD, USA), and utilized to study the BBB penetration of twelve coumarins from APR (chemical structures shown in Figure 1), along with the time- and concentration-dependent absorption. Here, ABCB1 is linked to infection.