BAY 41-4109 racemate is a potent inhibitor of human hepatitis B virus (HBV) with an IC50 of 53 nM.

HBV:53 nM.

BAY 41-4109 accelerates and misdirects capsid assembly in vitro and stabilizes preformed capsids up to a ratio of one inhibitor molecule per two dimers[2]. It inhibits HBV DNA release and cytoplasmic HBcAg levels equally effectively, with IC50s of 32.6 and 132 nM in HepG2.2.15 cells, respectively, indicating dose-dependent anti-HBV mechanisms associated with HBcAg inhibition[3].

BAY 41-4109 effectively diminishes viral DNA levels in both the liver and plasma in a dose-dependent fashion, showing efficacy on par with 3TC. It also decreases the hepatitis B virus core antigen (HBcAg) in the livers of HBV-transgenic mice. Pharmacokinetic evaluations reveal its rapid absorption and a bioavailability rate of 30%, with dose-proportional plasma concentrations observed, reaching approximately 60% in rats and dogs[1]. Furthermore, BAY41-4109 hampers virus production in vivo by targeting the viral capsid, demonstrating its mechanism of action[2].

Cellular metabolism is evaluated by MTT colorimetry. HepG2.2.15 cells are plated at a density of 2 × 103 cells per well in 96-well plates. After 8 d of treatment with different concentrations of each antiviral compound, 20 μL of MTT solution (5 g/L) are added to each well and incubated at 37°C for 4 h. Next, 150 μL of DMSO is added and stirred for 10 min to dissolve the crystals. Absorbance values are recorded at 490 nm by using an ELISA reader. The MTT values are calculated using the curve regression equation[3].