. 2018 Jul 2;23(7):1599. doi: 10.3390/molecules23071599

Table 1.

Combination index (CI) and dose reduction in inhibition of infection by the HIV-1 strains by combining NNRTIs and AZT.

HIV-1 Strains (Tropism)	CI	DAPA-2e			AZT
		IC₅₀ (nM)		Dose Reduction (Fold)	IC₅₀ (nM)		Dose Reduction (Fold)
		Alone	in Mixture	Dose Reduction (Fold)	Alone	in Mixture	Dose Reduction (Fold)
IIIB (X4)	0.134	99.21	3.05	32.50	39.31	4.07	9.66
Bal (R5)	0.364	70.50	8.42	8.38	34.47	8.42	4.10
94US_33931N (R5)	0.652	11.51	4.23	2.72	148.91	42.32	3.52
93IN101 (C, R5)	0.089	34.24	0.29	116.19	730.12	58.95	12.39
964 (R5/X4)	0.003	3.35	0.01	460.00	15,178.32	7.28	2083.61
629 (R5/X4)	0.156	34.49	2.37	14.52	41,109.61	3562.15	11.54
RTMDR1 (X4)	0.169	24.46	1.61	15.16	935.39	96.82	9.66
HIV-1 Strains (Tropism)	CI	DAAN-14h			AZT
		IC₅₀ (nM)		Dose Reduction (Fold)	IC₅₀ (nM)		Dose Reduction (Fold)
		Alone	in Mixture	Dose Reduction (Fold)	Alone	in Mixture	Dose Reduction (Fold)
IIIB (X4)	0.144	39.12	2.42	16.18	39.31	3.22	12.20
Bal (R5)	0.528	3.77	0.31	12.26	34.47	15.39	2.24
94US_33931N (R5)	0.904	1.65	0.71	2.33	148.91	70.74	2.11
93IN101 (C, R5)	0.141	1.55	0.07	22.09	730.12	70.25	10.39
964 (R5/X4)	0.023	0.62	0.01	54.04	15,178.32	69.23	219.26
629 (R5/X4)	0.109	13.87	0.84	16.55	41,109.61	2010.51	20.45
RTMDR1 (X4)	0.279	1.34	0.20	6.67	935.39	120.26	7.78
HIV-1 Strains (Tropism)	CI	DAAN-15h			AZT
		IC₅₀ (nM)		Dose Reduction (Fold)	IC₅₀ (nM)		Dose Reduction (Fold)
		Alone	in Mixture	Dose Reduction (Fold)	Alone	in Mixture	Dose Reduction (Fold)
IIIB (X4)	0.071	3.98	0.09	44.22	39.31	1.86	21.13
Bal (R5)	0.852	5.36	0.52	10.31	34.47	26.02	1.32
94US_33931N (R5)	0.063	0.47	0.02	20.72	148.91	2.27	65.65
93IN101 (C, R5)	0.095	0.60	0.02	27.72	730.12	43.21	16.90
964 (R5/X4)	0.040	0.74	0.02	32.03	15,178.32	139.03	109.17
629 (R5/X4)	0.237	16.57	2.00	8.29	41,109.61	4797.90	8.57
RTMDR1 (X4)	0.116	1.59	0.09	17.45	935.39	54.48	17.17
HIV-1 Strains (Tropism)	CI	TMC125			AZT
		IC₅₀ (nM)		Dose Reduction (Fold)	IC₅₀ (nM)		Dose Reduction (Fold)
		Alone	in Mixture	Dose Reduction (Fold)	Alone	in Mixture	Dose Reduction (Fold)
IIIB (X4)	0.179	0.89	0.08	10.66	39.31	3.35	11.73
Bal (R5)	0.883	3.20	1.93	1.66	34.47	9.65	3.57
94US_33931N (R5)	0.203	2.09	0.18	11.86	148.91	17.62	8.45
93IN101 (C, R5)	0.110	1.49	0.03	46.05	730.12	64.76	11.27
964 (R5/X4)	0.231	0.73	0.13	5.58	15,178.32	789.89	19.22
629 (R5/X4)	0.292	5.86	1.20	4.89	41,109.61	3599.14	11.42
RTMDR1 (X4)	0.194	1.24	0.17	7.21	935.39	51.74	18.08
HIV-1 Strains (Tropism)	CI	NVP			AZT
		IC₅₀ (nM)		Dose Reduction (Fold)	IC₅₀ (nM)		Dose Reduction (Fold)
		Alone	in Mixture	Dose Reduction (Fold)	Alone	in Mixture	Dose Reduction (Fold)
IIIB (X4)	0.199	11.74	1.47	8.01	39.31	2.93	13.41
Bal (R5)	0.892	307.91	50.25	6.13	34.47	25.12	1.37
94US_33931N (R5)	0.316	24.15	2.91	8.28	148.91	29.15	5.11
93IN101 (C, R5)	0.025	33.64	0.10	343.92	730.12	16.30	44.78
964 (R5/X4)	0.265	1.28	0.27	4.73	15,178.32	809.01	18.76
629 (R5/X4)	0.429	29.68	6.82	4.35	41,109.61	8832.58	5.02
RTMDR1 (X4)	0.132	255.16	18.55	13.75	935.39	55.66	16.81

Note: HIV = human immunodeficiency virus. IIIB and Bal are laboratory-adapted HIV-1 strains, 94US_33931N and 93IN101 are primary HIV-1 strains, 964 and 629 are AZT-resistant HIV-1 strains, and RTMDR1 is the multiple RTI-resistant HIV-1 strain. A CI of >1, 1, and <1 indicates antagonism, additive effect, and synergism, respectively. The strength of synergism is indicated by the following CI values: <0.1: very strong synergism; 0.1–0.3: strong synergism; 0.3–0.7: synergism; 0.7–0.85: moderate synergism; and 0.85–0.90: slight synergism. Dose reduction (fold) was calculated using the following formula: IC₅₀ value of an inhibitor tested alone/the IC₅₀ value of the same inhibitor tested in combination with another inhibitor.