-based isobologram curves for HB3 (CQS, left) and Dd2 (CQR, right). CQ-PQ (black), CQ-AQ (pink), and TQ-MB (cyan). FICA and FICB correspond to the fractional inhibitory concentrations (see Methods) of the first and second drugs in each pair listed above, respectively. Error bars represent the standard error of the mean (S.E.M.) for duplicate experiments, each performed in triplicate (6 determinations total).