GF120918 (Elacridar) is a very potent inhibitor of the ABC transporters (P-glycoprotein, P-gp) and BCRP. It reverses multidrug resistance at 0.02 to 0.1 µM in vitro. By blocking the activity of ABC transporter, GF120918 effectively increases the cellular concentration and subsequently increases the cytotoxicity of anti-tumor drugs. (1)

GF120918A has been used both in vitro and in vivo as a tool inhibitor of ABC transporters (or P-glycoprotein) to investigate the role of transporters in the disposition of various test molecules and to offer additional guidance on preclinical dose regimens likely to produce P-glycoprotein-mediated effects. (2)