Fig. 3.

In vitro IC₅₀ of proguanil, tBuPG and control antimalarials at 48 h, 72 h and 96 h. P. falciparum synchronous ring-stage infected erythrocytes were assayed at 48 h (red circles), 72 h (blue squares) and 96 h (green triangles) in in vitro [³H]-hypoxanthine uptake growth inhibition assays with different antimalarial drugs (a–h). Mean ± SD IC₅₀ values (Log10 scale) are shown for at least three independent experiments, each carried out in triplicate wells. Lines were termed resistant or moderately resistant if the mean 48 h IC₅₀ was > 10-fold or > 5-fold greater, respectively, than the drug-sensitive reference line 3D7 (i and j; red and white, respectively). Statistical analysis (P values) of difference between 48 h, 72, and 96 h assays for each parasite line are shown in Supplementary Table 1