Table 1. EC₅₀ values of drugs under study for HIV-1 and HIV-2 infection.

Drug	HIV-1 EC50 (μM)[95 % confidence interval]*	HIV-2 EC50 (μM)[95 % confidence interval]*	Significant difference in EC50 values (P<0.05)†	EC50 ratio, HIV-1/HIV-2
Gemcitabine‡	1.3×10−3 [2.28×10−4–2.81×10−3]	6.36×10−4 [3.95×10−4−1.67×10−3]	N	2.04
Clofarabine§	1.12×10−1 [3.06×10−2−1.94×10−1]	3.21×10−2 [9.52×10−4−6.32×10−2]	Y	3.78
Resveratrol‡	25.6 [20.1–31.0]	6.08 [4.49–7.68]	Y	4.21
5-Azacytidine§	20.2 [18.7–21.8]	14.5 [10.3–18.8]	Y	1.39
Raltegravir‖‖	1.72×10−3 [8.47×10−4–4.30×10−3]	1.85×10−3 [4.43×10−3−4.15×10−2]	N	0.93
Tenofovir‖‖	1.9×10−1 [49.8×10−2−3.31×10−1]	1.30×10−1 [1.40×10−2−2.73×10−1]	N	1.46
Zidovudine‡	3.67×10−2 [2.72×10−2−4.62×10−2]	4.46×10−2 [2.73×10−2−6.19×10−2]	N	0.823
Nevirapine‡	6.2 [5.31–7.12]	No activity	–	–

^*Curve fitting was performed using log(inhibitor) vs normalized response. If the goodness of fit was not appropriate as determined by the replicates test and residuals, the curves were fitted using either log(inhibitor) vs response or log(inhibitor) vs response (variable slope) as indicated.

^†EC₅₀ values for each replicate were used to perform an unpaired two-tailed t-test to determine differences between HIV-1 and HIV-2. Experiments were performed in parallel with HIV-1 and HIV-2 for each drug at least four times.

^‡log(inhibitor) versus normalized response was used to determine EC₅₀.

^§log response (inhibitor) versus response (variable slope) was used to determine EC₅₀.

‖‖log(inhibitor) versus response (three parameters) was used to determine EC₅₀.