Table 2: Geometric mean EC 50, EC 90, and EC 99, 95% confidence interval (CI) of chloroquine against Plasmodium falciparum isolates.

ChloroquineGeometric mean EC 50, (95% CI) nanomolar (nm/liter)
Sensitive isolatesResistant isolates

EC 501.30 (1.99–1.0)6.07 (02.74–13.42)
EC 903.94 (5.53–1.88)33.33 (16.94–61.09)
EC 955.56 (7.22–2.48)43.44 (19.15–65.78)
EC 996.17 (1.0–0.92)47.40 (21.39–66.98)

EC: effective concentration.