In vitro activity: Emtricitabine moderately reduces hepatocyte proliferation independent of effects on mtDNA in HepG2 human hepatoma cells. Emtricitabine plus tenofovir slightly reduced cell proliferation without affecting mitochondrial parameters. Emtricitabine efficiently converts to their active metabolites in PBMCs and CEM cells. Emtricitabine combined with Tenofovir displays additive to synergistic activity against HIV replication in PBMCs and results in strongly synergistic anti-HIV activity in MT-2 cells against both wild-type and mutant virus. Emtricitabine demonstrates antiviral activity against laboratory adapted strains of HIV-1 and HIV-2 in various cell system. Emtricitabine also exhibits antiviral activity in cell culture against feline and simian immuno-deficiency viruses (SIVs). Emtricitabine consistently exhibits up to 10-fold greater activity than lamivudine against all viruses tested in all T-cell lines. Emtricitabine generally demonstrates greater potency in vitro in human PBMCs than in MT-4 lines. Emtricitabine also exhibits anti-HBV activity in vitro (EC50, 0.01–0.04 μM) that is comparable to the anti-HBV activity of 3TC. Emtricitabine is approximately fourfold more active than 3TC in assays in the transformed T-cell line MT-4 infected with HIV-(1IIIB), whereas Zidovudine is more active than Emtricitabine. Emtricitabine, Lamivudine and Zidovudine are equally active against a panel of eight primary HIV-1 isolates from antiretroviral-naive subjects in PBMCs.

Cell Assay: Emtricitabine, an antiretroviral agent is used to evaluate degradation pathways under different stress conditions in order to identify degradation products as prescribed by ICH guidelines. Emtricitabine degrades over 51%, 13% and 53% during acid, base and oxidative degradation respectively followed by formation of three major degradation products (Degradant-I to Degradant-III).