For the MATE1 inhibitors that have showed clinically relevant DDI with metformin, most of inhibitors have the Ki value of less than 10 μmol/L for MATE1 such as cimetidine, pyrimethamine, trimethoprim, and vandetanib (isabuconazole and ranolazine have no data for Ki against metformin in this report) . IC50 can be converted to Ki using the Cheng-Prusoff equation assuming the competitive inhibition ;