Antiviral agent 81 

Antiviral agent 81 is an orally bioavailable N-acylated remdesivir derivative and RdRp inhibitor with 45.3% oral bioavailability (based on active metabolite GS-441524 exposure), plasma half-life >8 h, and reduced CYP3A4 inhibition. Antiviral agent 81 exhibits activity against Coronaviridae, Flaviviridae, and Pneumoviridae, and shows no activity against Orthomyxoviridae, Herpesviridae, and Alphaviridae. Antiviral agent 81 can be used for the research of viral infections^[1].

Antiviral agent 81 (4f) potently inhibits SARS-CoV-2 in VeroE6-eGFP cells, with an EC₅₀ of 0.0862 μM, a CC₅₀ of 15.6 μM, and a selectivity index of 181.0^[1].
Antiviral agent 81 inhibits HCoV-OC43 (EC₅₀=0.90 μM) and HCoV-229E (EC₅₀=0.21 μM) in HEL299 cells, as well as YFV (EC₅₀=5.1 μM) and ZIKV (EC₅₀=4.1 μM) in U87 cells, with a CC₅₀ of 20.5 μM in U87 cells^[1].
Antiviral agent 81 (10 μM; 10 min) inhibits the CYP2C19, CYP2C9 and CYP3A4 subtypes in human liver microsomes, with the highest inhibition rate of 36.6% against CYP2C19, followed by 29.9% against CYP2C9 and 23.8% against CYP3A4^[1].
Antiviral agent 81 (100 μM; 0, 10, 30, 60, 120, 240 min) has an ex vivo plasma half-life of >8 h in human heparinized plasma, with a retention rate of approximately 70% after incubation at 37 °C for 4 h^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Antiviral agent 81 (4f) (2 mg/kg; tail vein injection; single dose; 24 h post-administration) is rapidly metabolized to the active metabolite GS-441524 (HY-103586) in male Sprague-Dawley rat models, with a C_max of 95.2 ng/mL, a T_max of 0.500 h, a T_1/2 of 1.60 h, and an AUC_0-last of 248 ng·h/mL^[1].
Antiviral agent 81 (10 mg/kg; p.o.; single dose; 24 h post-administration) is metabolized into the active metabolite GS-441524 in male Sprague-Dawley rat models, with a C_max of 136 ng/mL, a T_max of 1.67 h, a T_1/2 of 2.01 h, an AUC_0-last of 558 ng·h/mL, and an oral bioavailability of 45.3%^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

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Room temperature in continental US; may vary elsewhere.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Song L, et al. Discovery of orally bioavailable N-acylated remdesivir derivatives with potent broad-spectrum antiviral activity. Bioorg Chem. 2026;175:109758.  [Content Brief]