Table 3.

Analysis of the effect of the combination of MEDS433 and NHC on IAV replication.

MEDS433/NHC Combination at Equipotent Ratio (fold of EC50 a)	MEDS433/NHC CI b	Drug Combination Effect c of MEDS433 and NHC
4×	0.075 ± 0.004	Very Strong Synergism
2×	0.484 ± 0.011	Synergism
1×	0.825 ± 0.004	Moderate Synergism
0.5×	0.604 ± 0.028	Synergism
0.25×	0.625 ± 0.019	Synergism

^a Fold of EC₅₀ MEDS433/EC₅₀ NHC yielding an equipotent concentration ratio (approximately 1:5.12) between the two combined drugs. The EC₅₀ values were determined by VRAs against IAV, as described in the Materials and Methods. ^b Combination index (CI), obtained by computational analysis with the CompuSyn software 1.0. Reported values represent means ± SDs of data derived from n = 3 independent experiments in triplicate. ^c Drug combination effects are defined as: very strong synergism for CI < 0.1; strong synergism for 0.1 < CI < 0.3; synergism for 0.3 < CI < 0.7; moderate synergism for 0.7 < CI < 0.85; slight synergism for 0.85 < CI < 0.90; nearly additive for 0.90 < CI < 1.10; slight antagonism for 1.10 < CI < 1.20; moderate antagonism for 1.20 < CI < 1.45 [31].