Cytotoxicity and pharmacological interaction of Hex and Erlotinib in Caco-2 cells. (A) Representative curves of growth inhibitory effects of Hex, Erlotinib and Hex-Erlotinib in non-fixed combination after simultaneous incubation for 72 h. (B) CI values for Hex-Erlotinib simultaneous combination, where CI < 1, C = 1 and CI > 1 represents synergism, additive and antagonistic interactions, respectively. Results are shown as mean ± SEM and are the average of at least three independent experiments, each run in triplicates.