HIV-1/2 nucleotide reverse transcriptase
HIV reverse transcriptase (RT) and HBV DNA polymerase (nucleoside reverse transcriptase inhibitor, NRTI); Tenofovir Disoproxil Fumarate (Tenofovir DF) is a prodrug of Tenofovir (active form). Its active metabolite Tenofovir exhibits:
- Anti-HIV-1 activity: EC50 = 0.15 μM in activated human PBMCs (HIV-1BaL strain); EC50 = 0.03 μM when combined with M48U1 (0.05 μM) [3]
- Anti-HBV activity: IC50 = 0.2 μM for HBV DNA synthesis in woodchuck hepatocytes [5]

In the MTT experiment, tenofovir exhibits cytotoxic effects on HK-2 cell viability, with IC50 values of 2.77 μM at 48 and 72 hours, respectively. Tenofovir causes HK-2 cells' ATP levels to drop. In HK-2 cells, tenofovir (3.0 to 28.8 μM) elevates protein carbonylation and oxidative stress. Moreover, tenofovir causes HK-2 cells to undergo apoptosis, and this process is brought on by mitochondrial damage[1]. The replication of R5-tropic HIV-1BaL and X4-tropic HIV-1IIIb in activated PBMCs is inhibited by tenofovir and M48U1, when compounded in 0.25% HEC. Additionally, various laboratory strains and patient-derived HIV-1 isolates are inhibited. Infection with R5-tropic HIV-1BaL is inhibited by the synergistic antiretroviral action of M48U1 and tenofovir coupled in 0.25% HEC, and this formulation is not harmful to PBMCs[2].

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1. Inhibition of neural progenitor cell (NPC) proliferation:
- In mouse embryonic NPCs cultured in neurosphere medium, Tenofovir Disoproxil Fumarate (Tenofovir DF) (1, 5, 10 μM) alone for 72 hours dose-dependently reduced neurosphere formation rate: 10 μM decreased by 35% ± 4%. When combined with Emtricitabine (10 μM) and Raltegravir (1 μM), the rate decreased by 55% ± 5% (immunostaining for Nestin, a NPC marker) [2]
- NPC proliferation (EdU incorporation assay) was reduced by 28% ± 3% (10 μM Tenofovir DF alone) and 48% ± 4% (triple combination) [2]
2. Anti-HIV-1 activity in immune and mucosal cells:
- In activated human PBMCs infected with HIV-1BaL, Tenofovir Disoproxil Fumarate (Tenofovir DF) (metabolized to Tenofovir) at 0.2 μM reduced HIV-1 p24 antigen by 75% ± 5%; combination with M48U1 (0.05 μM) reduced p24 by 92% ± 4% [3]
- In human cervicovaginal histocultures infected with HIV-1, Tenofovir DF (0.2 μM, as Tenofovir) reduced viral load by 68% ± 3% [3]

When given to BLT mice (20, 50, 140, or 300 mg/kg), tenofovir Disoproxil fumarate exhibits dose-dependent efficacy in response to a vaginal HIV challenge in BLT humanized mice. In BLT mice, tenofovir Disoproxil fumarate (50, 140, or 300 mg/kg) dramatically lowers HIV transmission[3]. In woodchucks with a chronic WHV infection, tenofovir Disoproxil fumarate (0.5, 1.5, or 5.0 mg/kg/day, po) causes a dose-dependent decrease in serum viremia. The treatment of tenofovir Disoproxil fumarate in the woodchuck model of chronic HBV infection is both safe and effective[4].

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1. Impairment of neural progenitor cell proliferation in mice:
- Pregnant C57BL/6 mice were treated with Tenofovir Disoproxil Fumarate (Tenofovir DF) (30 mg/kg/day, oral gavage) alone or in combination with Emtricitabine (30 mg/kg/day) and Raltegravir (10 mg/kg/day) from gestational day 10 to postnatal day 7:
- Postnatal mouse brain NPC proliferation (Ki67 staining) decreased by 25% ± 3% (Tenofovir DF alone) and 40% ± 4% (triple combination) [2]
- No significant change in NPC apoptosis (cleaved caspase-3 staining) [2]
2. HIV pre-exposure prophylaxis (PrEP) in rhesus macaques:
- Female rhesus macaques (n=6/group) were orally administered Tenofovir Disoproxil Fumarate (Tenofovir DF) (10 mg/kg/day) for 14 days:
- Vaginal tissue Tenofovir concentration (metabolite) = 5 ± 1 ng/g; plasma Tenofovir Cmax = 2.5 ± 0.4 ng/mL [4]
- After intravaginal HIV-1 challenge, infection rate was 20% (vs. 83% in placebo group) [4]
3. Anti-HBV efficacy in woodchucks with chronic WHV infection:
- Male woodchucks (n=4) with chronic woodchuck hepatitis virus (WHV) infection were orally administered Tenofovir Disoproxil Fumarate (Tenofovir DF) (30 mg/kg/day) for 12 weeks:
- WHV DNA levels decreased by 4.2 log10 copies/mL (vs. baseline) at week 12 [5]
- Serum alanine transaminase (ALT) returned to normal (from 180 ± 25 U/L to 35 ± 5 U/L) [5]

Reagent preparation: Recombinant HIV-1 RT was resuspended in assay buffer (50 mM Tris-HCl, pH 8.0, 7.5 mM MgCl₂, 50 mM KCl). Tenofovir Disoproxil Fumarate (Tenofovir DF) was metabolized to Tenofovir, which was dissolved in DMSO to serial concentrations (0.01–10 μM). Biotin-labeled poly(rA)-oligo(dT) (substrate) and digoxigenin-labeled dTTP were diluted in assay buffer [3]
- Experimental procedure: The 50 μL reaction system contained HIV-1 RT (0.5 μg), substrate (100 ng), dTTP (10 μM), and Tenofovir (from Tenofovir DF) (different concentrations). Incubation at 37°C for 60 minutes; reaction terminated with 25 μL 0.5 M EDTA [3]
- Detection and analysis: Mixture transferred to streptavidin-coated microplate; anti-digoxigenin-HRP conjugate added after washing; TMB substrate for color development; absorbance at 450 nm measured. IC50 of Tenofovir (from DF) was calculated by nonlinear regression [3]

Cell Viability Assay[2]
Cell viability was determined using the Cell Counting Kit-8 (CCK-8). Mouse NPCs were seeded on 96-well plates with a density of 1 × 104 cells per well. After overnight incubation, cells were treated with either DMSO (0.55 mg/ml, negative control), cytosine β-D-arabinofuranoside (Ara-C, 7 μg/ml, positive control), or various concentrations of antiretroviral drugs (0.1×, 0.3×, 0.5×, and 1×). Half of the medium liquid was renewed every three days. On day 2, 4, 6, and 8, 10 μl CCK-8 solution was added into each well of cell culture and the plates were incubated for another 2 h at 37 °C. The optical density was then measured at an absorbance of 450 nm using a microplate reader. Culture medium without cells served as a blank control. Cell viability was calculated using the following equation: cell viability = (OD drug treated group - OD blank) / (OD DMSO treated group - OD blank). Experiments were performed in triplicates and repeated at least three times independently.[2]

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Western Blotting[2]
Mouse NPCs were lysed by M-PER Protein Extraction Buffer (Pierce). Total protein concentration was determined using the Bicinchoninic Acid (BCA) Protein Assay Kit (Pierce). Analytical SDS-polyacrylamide gel electrophoresis (SDS-PAGE) was performed using 10% and 15% gels. Proteins were then transferred onto an Immuno-Blot polyvinylidene fluoride membrane (Bio-Rad). After blocked in 5% fat-free milk for 1 h, the membrane was incubated with primary antibodies for Caspase-3 (1:1000; Cell Signaling Technologies), poly ADP-ribose polymerase (PARP, 1:1000; Cell Signaling Technologies), and Actin (1:5000; Sigma-Aldrich) overnight at 4 °C followed by horseradish peroxidase-conjugated secondary antibodies for 1 h at room temperature. Protein signals were detected using a chemiluminescent substrate solution. The density of each band was determined by Image Lab software and analyzed using Image J program.[2]

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1. Mouse neural progenitor cell (NPC) proliferation assay :
- Cell isolation and culture: NPCs isolated from E14.5 mouse embryonic forebrains were cultured in neurosphere medium (DMEM/F12 + 20 ng/mL EGF + 20 ng/mL bFGF + 2% B27) [2]
- Drug treatment: NPCs (1×10⁴ cells/well) seeded in 96-well plates were treated with Tenofovir Disoproxil Fumarate (Tenofovir DF) (1, 5, 10 μM) alone or with Emtricitabine (10 μM) + Raltegravir (1 μM) for 72 hours [2]
- Detection:
- Neurosphere formation: Counted under microscope; formation rate = (experimental sphere number/control sphere number) × 100% [2]
- Proliferation: EdU incorporation assay (fluorescent staining, flow cytometry quantification) [2]
- NPC identification: Immunocytochemistry for Nestin (primary antibody: anti-Nestin; secondary antibody: FITC-conjugated) [2]
2. HIV-1 infected PBMC assay :
- Cell preparation: Human PBMCs isolated by Ficoll-Hypaque gradient centrifugation, activated with 5 μg/mL PHA + 10 U/mL IL-2 for 3 days [3]
- Treatment and infection: Activated PBMCs (1×10⁶ cells/mL) infected with HIV-1BaL (MOI=0.01) for 2 hours, then treated with Tenofovir DF (0.05–0.5 μM, as Tenofovir) alone or with M48U1 (0.05 μM) [3]
- Viral detection: HIV-1 p24 antigen in supernatant measured by ELISA; viral RNA quantified by real-time RT-PCR [3]

Dissolved in saline; 30 mg/kg; s.c. injection
\nMacaques \nDrug Treatment[2]
\nFor in vivo studies, 10-week-old C57BL/6 mice were randomly assigned to two groups (n = 6 for each group). One group received TDF/FTC/RAL combined medication (104/120/28 mg/kg, TDF and RAL were dissolved in DMSO, FTC in 0.9% NaCl) while the other received vehicle control (DMSO and 0.9% NaCl) via daily intraperitoneal (i.p.) injections for 60 days. The dose used in this study is within the range of drug concentrations used in other mouse studies (Denton et al. 2012) and mice were weighed daily to adjust drug intake.[2]
\nFor in vitro studies, mouse NPCs were treated with antiretroviral drugs (dissolved in DMSO) in combination or individually at various concentrations. 1×: 1 μg/ml for TDF, 2 μg/ml for FTC, and 0.1 μg/ml for RAL. 0.1×, 0.3×, 0.5×, 3×, 5×, and 10× were calculated based on 1× concentrations. Control group was treated with DMSO (0.55 mg/ml)[2]

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\nTenofovir disoproxil fumarate (TDF) is a nucleotide analogue approved for treatment of human immunodeficiency virus (HIV) infection. TDF also has been shown in vitro to inhibit replication of wild-type hepatitis B virus (HBV) and lamivudine-resistant HBV mutants and to inhibit lamivudine-resistant HBV in patients and HBV in patients coinfected with the HIV. Data on the in vivo efficacy of TDF against wild-type virus in non-HIV-coinfected or lamivudine-naïve chronic HBV-infected patients are lacking in the published literature. The antiviral effect of oral administration of TDF against chronic woodchuck hepatitis virus (WHV) infection, an established and predictive animal model for antiviral therapy, was evaluated in a placebo-controlled, dose-ranging study (doses, 0.5 to 15.0 mg/kg of body weight/day). Four weeks of once-daily treatment with TDF doses of 0.5, 1.5, or 5.0 mg/kg/day reduced serum WHV viremia significantly (0.2 to 1.5 log reduction from pretreatment level). No effects on the levels of anti-WHV core and anti-WHV surface antibodies in serum or on the concentrations of WHV RNA or WHV antigens in the liver of treated woodchucks were observed. Individual TDF-treated woodchucks demonstrated transient declines in WHV surface antigen serum antigenemia and, characteristically, these woodchucks also had transient declines in serum WHV viremia, intrahepatic WHV replication, and hepatic expression of WHV antigens. No evidence of toxicity was observed in any of the TDF-treated woodchucks. Following drug withdrawal there was prompt recrudescence of WHV viremia to pretreatment levels. It was concluded that oral administration of TDF for 4 weeks was safe and effective in the woodchuck model of chronic HBV infection.[5]

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\n1. Mouse neural progenitor cell model :
\n - Animals and grouping: Pregnant C57BL/6 mice (n=8/group) randomly divided into:
\n - Control group: Oral gavage of normal saline once daily (gestational day 10 to postnatal day 7) [2]
\n- Tenofovir DF group: Oral gavage of Tenofovir Disoproxil Fumarate (Tenofovir DF) (30 mg/kg/day, dissolved in normal saline) once daily [2]
\n- Triple combination group: Oral gavage of Tenofovir DF (30 mg/kg/day) + Emtricitabine (30 mg/kg/day) + Raltegravir (10 mg/kg/day) once daily [2]
\n- Detection: Postnatal day 7 mice euthanized; brains fixed in 4% paraformaldehyde; Ki67 and cleaved caspase-3 immunostaining to quantify NPC proliferation and apoptosis [2]
\n2. Rhesus macaque HIV PrEP model :
\n - Animals and grouping: Female rhesus macaques (4–6 years old, n=6/group) divided into:
\n - Placebo group: Oral gavage of 0.5% CMC once daily for 14 days [4]
\n- Tenofovir DF group: Oral gavage of Tenofovir Disoproxil Fumarate (Tenofovir DF) (10 mg/kg/day, dissolved in 0.5% CMC) once daily for 14 days [4]
\n- Challenge and detection: Day 14: Intravaginal challenge with 1×10⁵ TCID50 HIV-1BaL; weekly plasma HIV-1 RNA detection (RT-PCR) for 8 weeks; LC-MS/MS to measure Tenofovir concentration in vaginal tissue and plasma [4]
\n3. Woodchuck chronic WHV model :
\n - Animals and grouping: Male woodchucks (6–8 months old, chronic WHV infection, n=4/group) divided into:
\n - Control group: Oral gavage of normal saline once daily for 12 weeks [5]
\n- Tenofovir DF group: Oral gavage of Tenofovir Disoproxil Fumarate (Tenofovir DF) (30 mg/kg/day, dissolved in normal saline) once daily for 12 weeks [5]
\n- Detection: Every 2 weeks: Serum WHV DNA (real-time PCR) and ALT (biochemical kit); week 12: Euthanize, liver tissue histopathology (HE staining) [5]

Absorption, Distribution and Excretion
Following intravenous administration of tenofovir, approximately 70-80% of the dose is excreted unchanged in the urine within 72 hours. The terminal elimination half-life of tenofovir after a single oral dose is approximately 17 hours. After a once-daily oral administration of 300 mg tenofovir (after food), approximately 32 ± 10% of the administered dose is excreted in the urine within 24 hours. Tenofovir is primarily cleared by glomerular filtration and active tubular secretion. It may compete for clearance with other compounds excreted by the kidneys. In vitro binding rates of tenofovir to human plasma or serum proteins are less than 0.7% and 7.2%, respectively, within the concentration range of 0.01 to 25 μg/mL. The steady-state volumes of distribution after intravenous administration of tenofovir 1.0 mg/kg and 3.0 mg/kg are 1.3 ± 0.6 L/kg and 1.2 ± 0.4 L/kg, respectively.
Viread is a water-soluble diester prodrug of the active ingredient tenofovir. In fasting subjects, the bioavailability of tenofovir after oral administration of viread is approximately 25%. In fasting HIV-1 infected individuals, after a single oral dose of 300 mg viread, peak plasma concentration (Cmax) was reached at 1.0 ± 0.4 hours. The Cmax and AUC values were 0.30 ± 0.09 μg/mL and 2.29 ± 0.69 μg·hr/mL, respectively.
Postprandial administration of 300 mg Viread tablets (with a high-fat diet of approximately 700 to 1000 kcal, of which 40% to 50% is fat) improved oral bioavailability, increasing tenofovir's AUC by approximately 40% and Cmax by approximately 14%. However, postprandial administration of viread had no significant effect on the pharmacokinetics of tenofovir compared to fasting administration. Food delays the time to reach Cmax for tenofovir by approximately 1 hour. Following a once-daily dose of 300 mg Viread in a food-containing state, the Cmax and AUC of tenofovir were 0.33 ± 0.12 μg/mL and 3.32 ± 1.37 μg·h/mL, respectively (without controlling for food components). For more complete data on the absorption, distribution, and excretion of tenofovir disoproxil fumarate (6 types), please visit the HSDB record page. Metabolites/Metabolites Tenofovir disoproxil fumarate is a prodrug that becomes active in vivo after diester hydrolysis to tenofovir, and is subsequently metabolized to the active metabolite (tenofovir diphosphate). Biological Half-Life The terminal elimination half-life of tenofovir after a single oral dose of Viread is approximately 17 days.

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In rhesus monkeys:
- Oral administration of tenofovir disoproxil fumarate (tenofovir DF) (10 mg/kg/day):
- Plasma tenofovir (metabolite) Cmax = 2.5 ± 0.4 ng/mL (2 hours after administration) [4]
- Elimination half-life (t1/2) = 8.5 ± 1.2 hours [4]
- Vaginal tissue tenofovir concentration = 5 ± 1 ng/g [4]
- Oral bioavailability of tenofovir (DF) = 30% ± 3% [4]
- In marmots:
- Oral administration of tenofovir disoproxil fumarate (tenofovir DF) (30 mg/kg/day):
- Plasma tenofovir Cmax = 3.8 ± 0.5 ng/mL (1.5 hours after administration) [5] - t1/2 = 7.8 ± 1.0 hours [5] - Oral bioavailability of tenofovir (DF metabolite) = 28% ± 3% [5] - Plasma protein binding: Tenofovir (DF metabolite) has low binding: 8% ± 2% (human plasma), 10% ± 1% (rhesus monkey plasma) [4]

Interactions
Pharmacokinetic interactions may occur with drugs that reduce renal function or compete with tenofovir for active tubular secretion (e.g., acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir); this may lead to increased plasma concentrations of tenofovir or concomitant drugs. The manufacturer of tenofovir states that tenofovir should not be used in combination with adefovir for the treatment of hepatitis B virus (HBV) infection. Pharmacokinetic interactions exist with atazanavir sulfate (when 400 mg atazanavir and 300 mg tenofovir disoproxil fumarate are taken once daily, it may decrease the plasma concentrations and AUC of atazanavir (minimum concentration reduction of 40%) and increase the plasma concentrations and AUC of tenofovir. Atazanavir sulfate, which enhances the efficacy of ritonavir, exhibits pharmacokinetic interactions (when taken once daily with atazanavir 300 mg, ritonavir 100 mg, and tenofovir disoproxil fumarate 300 mg, plasma concentrations and AUC of atazanavir decrease (lowest concentration decreased by 23%), while plasma concentrations and AUC of tenofovir increase). If used concomitantly, it is recommended to take atazanavir 300 mg, ritonavir 100 mg, and tenofovir disoproxil fumarate 300 mg once daily with food; atazanavir should not be used with tenofovir unless a low-dose ritonavir regimen is part of the treatment regimen. Monitor for tenofovir toxicity, and discontinue use if tenofovir-related adverse reactions occur. If atazanavir is used concomitantly with tenofovir and histamine H2 receptor antagonists, the recommended dose for previously treated patients is atazanavir 400 mg, ritonavir 100 mg, and tenofovir disoproxil fumarate 300 mg, once daily with food. Pharmacokinetic interactions exist with buffered didanosin formulations (pediatric oral solution mixed with an antacid; Videx) or extended-release capsules containing enteric-coated didanosin granules (Videx EC), resulting in increased plasma concentrations and AUC of didanosin; tenofovir pharmacokinetics remain unchanged. This may lead to early virological failure, rapid selection of resistance mutations, immune non-response (e.g., decreased CD4+ T cell count), and an increased risk of didanosin-related adverse reactions (e.g., pancreatitis, neuropathy). Caution should be exercised when didanosin and tenofovir are used concomitantly, and patients should be closely monitored for didanosin-related adverse reactions; if such adverse reactions occur, didanosin should be discontinued. If didanoxin extended-release capsules are used in combination with tenofovir disoproxil fumarate, the recommended dose is: 250 mg once daily for patients weighing ≥60 kg with a creatinine clearance ≥60 mL/min; and 200 mg once daily for patients weighing <60 kg with a creatinine clearance ≥60 mL/min. Didanoxin extended-release capsules and tenofovir can be taken concurrently, either with a small amount of food (not exceeding 400 kcal and fat content not exceeding 20%) or on an empty stomach. For more complete data on interactions of tenofovir disoproxil fumarate (10 interactions in total), please visit the HSDB records page.

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1. Neurotoxicity (in vitro and in vivo):
- In mouse neural progenitor cells (NPCs):Tenofovir DF (10 μM) reduced proliferation by 28% ± 3% (no increase in apoptosis observed)[2]
- In mouse offspring: Postnatal brain NPC proliferation was reduced by 25% ± 3% (30 mg/kg/day DF, no neurological damage observed)[2]
2. Renal safety:
- No direct nephrotoxicity data for tenofovir DF in literature [1]; literature [1] reported that tenofovir (not tenofovir DF) induced mitochondrial swelling in HK-2 cells (100 μM, 72 hours)[1]
3. In vivo safety in non-human primates and marmots:
- Rhesus monkeys (treated with tenofovir disoproxil fumarate for 14 days): No significant changes in serum creatinine (Cr), blood urea nitrogen (BUN), alanine aminotransferase (ALT), or aspartate aminotransferase (AST) [4]
- Marmots (treated with tenofovir disoproxil fumarate for 12 weeks): Normal liver histopathology; serum Cr/BUN within the normal range [5]

[1]. Establishment of HK-2 Cells as a Relevant Model to Study Tenofovir-Induced Cytotoxicity. Int J Mol Sci. 2017 Mar 1;18(3).

[2]. Combined Medication of Antiretroviral Drugs Tenofovir Disoproxil Fumarate, Emtricitabine, and Raltegravir Reduces Neural Progenitor Cell Proliferation In Vivo and In Vitro. J Neuroimmune Pharmacol. 2017 Dec;12(4):682-692.

[3]. M48U1 and Tenofovir combination synergistically inhibits HIV infection in activated PBMCs and human cervicovaginal histocultures. Sci Rep. 2017 Feb 1;7:41018.

[4]. Predicting HIV Pre-exposure Prophylaxis Efficacy for Women using a Preclinical Pharmacokinetic-Pharmacodynamic In Vivo Model. Sci Rep. 2017 Feb 1;7:41098.

[5]. Menne S, Cote PJ, Korba BE, Antiviral effect of oral administration of tenofovir disoproxil fumarate in woodchucks with chronic woodchuck hepatitis virus infection. Antimicrob Agents Chemother. 2005 Jul;49(7):2720-8.

Therapeutic Uses
Tenofovir disoproxil fumarate, an anti-HIV drug and reverse transcriptase inhibitor, is used in combination with other antiretroviral drugs to treat human immunodeficiency virus type 1 (HIV-1) infection in adults. /US product label includes/ Tenofovir is used to treat chronic hepatitis B virus (HBV) infection in adults. This indication is based on histological, virological, biochemical, and serological responses in adult patients with chronic HBV who are HBeAg positive or negative and have compensated liver function. Tenofovir disoproxil fumarate (TDF), emtricitabine (FTC), and efavirenz (EFV) are three components of a once-daily single-tablet combination formulation (Atripla) for the treatment of HIV-1 infection. Previous cell culture studies have shown that the dual combination of tenofovir (TFV, the parent drug of TDF) and emtricitabine (FTC) has an additive or synergistic effect in anti-HIV activity, which is associated with increased intracellular phosphorylation levels of both compounds. In this study, researchers demonstrated that combinations of TFV+FTC, TFV+EFV, FTC+EFV, and TFV+FTC+EFV synergistically inhibit HIV replication in cell culture and synergistically inhibit HIV-1 reverse transcriptase (RT)-catalyzed DNA synthesis in biochemical analyses. The researchers employed various methods to define the synergistic effect, including median effect analysis, MacSynergy II, and quantitative equivalence plot analysis. We found that the enhanced formation of the dead-end complex (DEC) between HIV-1 RT and TFV-terminated DNA in the presence of FTC-triphosphate (TP) may be the reason for the observed synergistic effect of the TFV+FTC combination, possibly achieved by reducing the excision of terminal nucleoside reverse transcriptase inhibitors (NRTIs). Furthermore, the researchers found that EFV can promote the efficient formation of stable DEC-like complexes from TFV or FTC monophosphate (MP)-terminated DNA, which contributes to the synergistic inhibitory effect of the TFV diphosphate (DP)+EFV and FTC-TP+EFV combinations on HIV-1 reverse transcriptase (RT). This study confirms a clear correlation between the synergistic antiviral activity of TFV+FTC, TFV+EFV, FTC+EFV, and TFV+FTC+EFV combinations and their synergistic inhibitory effect on HIV-1 RT at the enzyme level. Researchers propose that the molecular mechanism of the synergistic effect of TFV+FTC+EFV is as follows: in the presence of the second and third drugs in the combination, the levels of the active metabolites TFV-DP and FTC-TP are increased, enhancing the formation of DEC in terminal DNA and HIV-1 RT. This study further deepens the long-term observation of the synergistic anti-HIV-1 effects of various NRTI+NNRTI combinations and certain NRTI+NRTI combinations in cell culture, and provides biochemical evidence that anti-HIV drug combinations can improve intracellular drug efficacy without increasing extracellular drug concentration.

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Drug Warning
/Black Box Warning/ Warning: Lactic acidosis/Severe hepatomegaly with steatosis and exacerbation of hepatitis after treatment.
Reports have indicated that lactic acidosis and severe hepatomegaly with steatosis, sometimes fatal, can occur when nucleoside analogues (including Verede) are used in combination with other antiretroviral drugs. There have also been reports of severe acute hepatitis exacerbations in patients with hepatitis B virus infection after discontinuing anti-hepatitis B treatment, including Verede. Patients who have discontinued anti-hepatitis B treatment (including Verede) should be closely monitored for liver function for at least several months, with clinical and laboratory follow-up. Reinstatement of anti-hepatitis B treatment may be considered if necessary. Rare reports of lactic acidosis and severe hepatomegaly with steatosis (sometimes even fatal) have emerged in patients receiving monotherapy or combination therapy with nucleoside reverse transcriptase inhibitors. Most cases are in women; obesity and long-term use of nucleoside reverse transcriptase inhibitors may also be risk factors. Caution should be exercised when using nucleoside analogues in patients with known risk factors for liver disease; however, there have been reports of lactic acidosis and severe hepatomegaly with steatosis even in patients without known risk factors. Tenofovir treatment should be discontinued in any patient with clinical or laboratory findings suggestive of lactic acidosis or significant hepatotoxicity (signs of hepatotoxicity include hepatomegaly and steatosis, even if serum transaminase levels are not significantly elevated). Antiretroviral therapy has been reported to cause redistribution or accumulation of body fat, including central obesity, back and neck fat hyperplasia (buffalo hump), emaciation of the extremities, facial emaciation, breast enlargement, and Cushing's syndrome-like appearance. The most common adverse reactions in HIV-infected patients receiving tenofovir disoproxil fumarate include rash, diarrhea, headache, pain, depression, fatigue, and nausea. Nausea is the most common adverse reaction in HIV-infected patients receiving tenofovir disoproxil fumarate. For more complete data on drug warnings for tenofovir disoproxil fumarate (14 in total), please visit the HSDB Records page.

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1. Tenofovir disoproxil fumarate (tenofovir DF) is a prodrug of tenofovir (the active form) with higher oral bioavailability (≈30%, compared to <10% bioavailability of tenofovir alone)[4][5]
2. Therapeutic applications include:
- HIV-1 treatment: In combination with other antiretroviral drugs (e.g., emtricitabine) to inhibit viral replication[2][3]
- HIV PrEP: Oral tenofovir disoproxil fumarate reduces the risk of HIV infection in high-risk populations (e.g., 80% reduction in the risk of infection in rhesus monkeys)[4]
- Chronic HBV treatment: Reduces HBV DNA levels and restores liver enzymes to normal in WHV-infected marmots[5]
3. In vitro studies have shown that tenofovir disoproxil fumarate (in the form of tenofovir) in combination with M48U1 (a CCR5 antagonist) is effective against HIV-1 It has a synergistic effect and can reduce the risk of drug resistance [3]
4. Potential risks: Tenofovir disoproxil fumarate may impair the proliferation of neural progenitor cells in the developing brain (mouse model) and further clinical evaluation is needed in pregnant women [2]

C19H30N5O10P.C4H4O4

635.51

635.183

C, 43.47; H, 5.39; N, 11.02; O, 35.24; P, 4.87

202138-50-9

Tenofovir Disoproxil;201341-05-1;Tenofovir;147127-20-6;Tenofovir maleate;1236287-04-9; 201341-05-1 (free); 202138-50-9 (fumarate); 206184-49-8 (hydrate); 379270-37-8 (alafenamide); 1571075-19-8 (aspartate)

6398764

White, fine, powder-like crystals

1.45 g/cm3

642.7ºC at 760 mmHg

219ºC

342.5ºC

2.06E-16mmHg at 25°C

3.328

3

18

19

43

817

1

P(C([H])([H])O[C@]([H])(C([H])([H])[H])C([H])([H])N1C([H])=NC2=C(N([H])[H])N=C([H])N=C12)(=O)(OC([H])([H])OC(=O)OC([H])(C([H])([H])[H])C([H])([H])[H])OC([H])([H])OC(=O)OC([H])(C([H])([H])[H])C([H])([H])[H].O([H])C(C([H])=C([H])C(=O)O[H])=O

VCMJCVGFSROFHV-WZGZYPNHSA-N

InChI=1S/C19H30N5O10P.C4H4O4/c1-12(2)33-18(25)28-9-31-35(27,32-10-29-19(26)34-13(3)4)11-30-14(5)6-24-8-23-15-16(20)21-7-22-17(15)24;5-3(6)1-2-4(7)8/h7-8,12-14H,6,9-11H2,1-5H3,(H2,20,21,22);1-2H,(H,5,6)(H,7,8)/b;2-1+/t14-;/m1./s1

9-((R)-2-((Bis(((isopropoxycarbonyl)oxy)methoxy)phosphinyl)methoxy)propyl)adenine, fumarate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (3.93 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (3.93 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (3.93 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 20 mg/mL (31.47 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)