Table 2.

Mean antiviral activity (EC₅₀) and cytotoxicity (CC₅₀) values of reference compounds used for assay development

Compound	HCI EC50 (µM)		PR EC50 (µM)		PR CC50 (µM)
	Mean	SD	Mean	SD	Mean	SD
Chloroquine	19.5	6.47	6.15	1.59	38.1	9.88
Cinchocaine	63.2	40.7	59.6	38.8	38.3	4.94
Hydroxychloroquine	17.7	0.32	13.5	9.04	>50	N/A
Loperamide	8.91a	N/A	11.4	0.81	25.0	5.54
Lopinavir	7.77	0.34	43.2	17.2	31.7	4.30
Nelfinavir	4.21	1.44	3.50	0.17	13.5	3.16
Remdesivir	2.60	0.80	3.62	1.10	>100	N/A

Note: EC₅₀ values computed from 16 replicates (four intraplate replicates and four plate replicates). CC₅₀ values computed from five replicates.

Abbreviations: CC₅₀, concentration of the compound that reduced 50% of the cell viability; CPE, cytopathic effect; EC₅₀, concentration of the compound that inhibited 50% of the virus‐induced CPE; HCI, high content imaging; N/A, not available; PR, plate reader; SD, standard deviation.

^a Could not be reproduced in later experiments.