KS-176 is a potent and selective inhibitor of the breast cancer resistance protein (BCRP) multidrug transporter (IC50 values are 0.59 and 1.39 uM in Pheo A and Hoechst 33342 assays respectively).
ML230 (CID44640177; SID 88095709) is a selective inhibitor of ATP-binding cassette (ABC) transporter ABCG2, and 36-fold selective for ABCG2 over ABCB1 with EC50s values of 0.13 μM and 4.65 μM, respectively.