Tenofovir Disoproxyl Fumarate Research Articles

Chitosan-poly(ethylene oxide) nanofibrous mat as a vaginal platform for tenofovir disoproxyl fumarate – The effect of vaginal pH on drug carrier performance

In the present work, a solution blow spun nanofibrous mat comprised of chitosan (CS) and poly(ethylene oxide) (PEO) was obtained as vaginal platform for tenofovir disoproxil fumarate (TDF) to prevent sexually transmitted infections. Apart from physicochemical and mechanical analysis, the specific steps involved studies on nanofibrous mat mucoadhesive and swelling characteristics upon pH fluctuations over the physiological range. Physicochemical analysis showed uniform drug distribution within the CS/PEO mat volume and pointed toward physical interactions between the drug and polymers. TDF-loaded CS/PEO nanofibrous mat was shown potentially safe when evaluated by the MTT metabolic activity and JC-1 assays in human vaginal epithelial cells VK2-E6/E7. In vitro antiviral studies indicated inhibition efficacy of TDF-CS/PEO nanofibrous mat toward HSV-2 virus and proved the SBS process does not change the microbicidal activity of drug molecule. Fluctuations in the physiological vaginal pH range of 3.8 to 5.0 substantially affected mucoadhesive and swelling behavior of chitosan which in turn impacted drug dissolution rate from polymer carrier. The rate of permeation and accumulation of TDF in vaginal tissue differed in response to vaginal pH. Faster drug permeation assessed at pH 5.0 suggests that an increase in vaginal pH could improve TDF bioavailability at earlier time points.

The transformation of HIV therapy: One pill once a day.

A co-formulated, one pill once a day antiretroviral regimen (single-tablet regimen), containing efavirenz, emtricitabine, and tenofovir disoproxyl fumarate (Atripla), revolutionized the antiretroviral therapy landscape. Single-tablet regimens provide not only dosing convenience but help optimize adherence and persistence with antiretroviral therapy to achieve durably suppressed viremia with both individual and societal benefits. Given the many excellent options available now, single-tablet regimens are the preferred choice for initiating antiretroviral therapy in almost all patients with rare exceptions for drug interactions and pregnancy, and for simplification of more complex antiretroviral therapy to a single-tablet regimen. In this special commemorative article, we celebrate this astounding advancement in antiretroviral therapy, championed by John C. Martin while CEO of Gilead Sciences, and its transformative impact on HIV care nationally and globally.

Miscibility and thermal properties of poly(vinylpyrrolidone-vinyl acetate)/lamivudine and tenofovir binary blends prepared by hot melt extrusion

Preparation of amorphous solid dispersions (ASD) by hot melt extrusion (HME) of poly(vinylpyrrolidone-vinyl acetate) (Kollidon) and the active pharmaceutical ingredients (API) Lamivudine (3TC) and Tenofovir Disoproxyl Fumarate (TDF) was investigated aiming to study their miscibility and thermal behavior. These two drugs are currently used as drugs in first line treatment of patients with Acquired Immunodeficiency Syndrome (AIDS). In order to predetermine parameters for extrusion and the maximum concentration of API to be used without any recrystallization, binary blends were first processed in the mixing chamber at 130°C using a roller type rotor at 10, 20 and 30 rpm for 7 min, giving rise to ASD of both API, at least up to 20 wt% of the drug. Both 3TC and TDF were then extruded individually with Kollidon in a single screw extruder. HME produced ASD with high concentration of both Kollidon/API combinations, being part of the API soluble in the polymer matrix. From HME, Kollidon/3TC forms ASD in concentration up to 50 wt%, but from 30 wt% 3TC, the ASD has no time stability, showing recrystallization in less than 5 months, while the Kollidon/TDF system forms ASD up to 30 wt% of TDF, but it has aging stability inferior to 4 months.

Emtricitabine, Tenofovir, and Rilpivirine from their degradation products Analysis by HPLC

A simple, expeditious, and explicit stability-indicating High-Performance Liquid Chromatography (HPLC) analytical test method was developed for the quantitative analysis of Emtricitabine, Tenofovir, and Rilpivirine in bulk drugs and combined dosage formulations. Using the ICH guidelines method was validated using a C18 column of size 250 mm X 4.6 mm, 5µ, maintained at 25oC. The total run time maintained was 10 min. Acetonitrile and 0.1% TEA prepared in water adjusted with pH 3.0 was adapted as a mobile phase. The injection volume of samples was 20μL and UV-DAD detector system set at 265 nm used for UV detection. As per the ICH guidelines method was validated. The retention times were observed as 2.52, 3.27, 6.70 min for Emtricitabine, Rilpivirine, and Tenofovir disoproxyl fumarate, respectively. Linearity ranges were observed 24-56 µg/mL Emtricitabine, 3-7 µg/mL Rilpivirine and 30-70 µg/mL Tenofovir. Relative Standard Deviation not exceed 2%. In contract to the conventional method of HPLC, a method developed was able to give better resolution of swift retention times in the separation of various degradation products along with the pure active pharmaceutical ingredients. The proposed method exhibited excellent reproducibility and repeatability. The stress studies performed by following ICH guidelines indicated that the present HPLC method is explicit and stability-indicating. Since the present HPLC method has the capacity to separate the drugs with high resolution in tablet dosage forms, hence the method can be exploited for routine analysis of quality control sample and stability analysis.

Pharmacogenetic determinants of kidney-associated urinary and serum abnormalities in antiretroviral-treated HIV-positive patients.

Tenofovir disoproxyl fumarate (TDF) has been associated with renal tubular abnormalities, phosphaturia and proteinuria (retinol binding protein, RBP, loss): vitamin D (VD) and PTH affect these markers. Aim was to understand if some single nucleotide polymorphisms (SNPs) were predictors of renal abnormalities in an Italian cohort of HIV-affected patients. DNA was analyzed through real-time PCR, urinary RBP corrected by creatinine (uRBP/Cr). The majority of patients received TDF. Abnormal uRBP/Cr was more frequent in TDF recipients: eGFR <90 mL/min and TDF were predictors in the whole cohort, whereas eGFR <90 mL/min, TDF concentrations and CYP24A1-3999TT in TDF-treated patients. Phosphate levels were higher low VD level patients: age <50 years, CYP27B1 + 2838CC genotype and non-European ancestry were predictors. PTH levels were border-line higher in TDF patients: non-European ancestry, females, TDF, VD levels < 30 ng/mL and SLC28A2-124CT/TT and ABCC2-24CC were predictors. For the first time, SNPs were associated with PTH, phosphate, calcium and tubular dysfunction in HIV-infected patients.

Prevalence of chronic kidney disease among HIV-1-infected patients receiving a combination antiretroviral therapy.

Chronic kidney disease (CKD) has become one of the most frequent non-infectious comorbidities in the aging HIV-infected population on long-standing combination antiretroviral therapy (cART). We conducted a retrospective, cross-sectional study including HIV-infected adult patients attending our HIV outpatient clinic during the years 2017 and 2018 to assess prevalence and associated risk factors of CKD. Estimated glomerular filtration rate (eGFR) was measured by Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation. CKD was diagnosed and classified according to the National Kidney Foundation guidelines. Logistic regression was employed to identify factors associated with CKD. We enrolled 2339 HIV-infected patients (91% were Caucasian) with a mean age of 45.3years and a mean current CD4 lymphocyte count of 531 cells/mm3. CKD was diagnosed in 311 subjects (13.3%). Overall, 294 (12.6%) patients had albuminuria, 108 (4.6%) had eGFR < 60mL/min/1.73 m2, and 78 (3.3%) had albuminuria plus eGFR < 60mL/min/1.73 m2. Stages 4-5 of CKD were documented in 23 (1%) cases. Age greater than 50years, male gender, hypertension, diabetes mellitus, high triglycerides, nadir CD4 cell count < 200 cells/mm3, current use of tenofovir disoproxyl fumarate (TDF) and of TDF plus a ritonavir-boosted protease inhibitors were independently associated with CKD, while current use of abacavir plus one integrase inhibitor was associated with a reduced risk of CKD. There is a significant prevalence of CKD among HIV-infected persons in association with both traditional and HIV-specific risk factors, requiring a careful periodic monitoring of renal function in these patients.

Long-term Efficacy of Tenofovir Disoproxil Fumarate Monotherapy for Multidrug-Resistant Chronic HBV infection

There are no globally agreed upon treatment guidelines for patients with chronic hepatitis B virus (HBV) with multidrug resistance (MDR). We conducted a multicenter, prospective, real-world cohort study of effects of tenofovir disoproxyl fumarate (TDF) monotherapy and TDF-based combination therapy, as rescue therapy, in patients with multidrug-resistant chronic HBV infections. We recruited patients with chronic HBV infection with resistance to antivirals from 8 tertiary hospitals in Korea. Patients (n=423) received rescue therapy with TDF monotherapy (n=174) or TDF-based combination therapy (n=249). The median follow-up period was 180 weeks. A virologic response was defined as a serum HBV DNA level of <20 IU/mL. Cumulative rates of virologic response did not differ significantly between the groups that received TDF monotherapy vs combination therapy at 48 weeks (71.7% vs 68.9%), 96 weeks (85.1% vs 84.2%), 144 weeks (92.1% vs 92.7%), 192 weeks (93.4% vs 95.7%), or 240 weeks (97.7% vs 97.2%). Serum levels of HBV DNA below 4.0 log10 IU/mL (odds ratio, 2.478; 95% CI 1.959-3.135; P < .001) and the absence of mutations associated with resistance to adefovir (odds ratio, 1.570; 95% CI 1.279-1.926; P < .001) were associated with virologic response in patients with MDR. There was no significant difference of virologic response among patients of different ages, sex, patients with vs without cirrhosis, positivity for hepatitis B e antigen, or renal function (all P > .05). In a multicenter, real-world cohort study, long-term use of TDF monotherapy showed non-inferior antiviral efficacy compared with that of TDF-based combination therapy in patients with MDR.

Herpes Simplex Virus Type 2 Acquisition Among HIV-1-Infected Adults Treated With Tenofovir Disoproxyl Fumarate as Part of Combination Antiretroviral Therapy: Results From the ACTG A5175 PEARLS Study.

Tenofovir disoproxyl fumarate (TDF) disoproxyl fumarate (TDF) has in vitro activity against herpes simplex virus type 2 (HSV-2) and reduced HSV-2 acquisition as preexposure prophylaxis. Whether TDF-containing antiretroviral therapy (ART) reduces HSV-2 acquisition is unknown. Secondary analysis of AIDS Clinical Trials Group A5175, a randomized, open-label study of 3 ART regimens among 1571 participants. HSV-2 serostatus was assessed at baseline, at study exit, and before a change in ART regimen. Of 365 HSV-2-seronegative persons, 68 acquired HSV-2, with 24 receiving TDF-containing ART and 44 receiving ART without TDF (HSV-2 seroconversion incidence, 6.42 and 6.63 cases/100 person-years, respectively; hazard ratio, 0.89; 95% confidence interval, .55-1.44). HSV-2 acquisition was not reduced in HIV-infected, HSV-2-uninfected persons during TDF-containing ART.

Discovery and Development of the Anti-Human Immunodeficiency Virus Drug, Emtricitabine (Emtriva, FTC).

The HIV/AIDS epidemic, which was first reported on in 1981, progressed in just 10 years to a disease afflicting 10 million people worldwide including 1 million in the US. In 1987, AZT was approved for treating HIV/AIDS. Unfortunately, its clinical usefullness was severly limited by associated toxicities and the emergence of resistance. Three other drugs that were approved in the early 1990s suffered from similar liabilities. In 1990, the Liotta group at Emory University developed a highly diastereoselective synthesis of racemic 3'-thia-2',3'-dideoxycytidine and 3'-thia-2',3'-5-fluorodideoxycytidine and demonstrated that these compounds exhibited excellent anti-HIV activity with no apparent cytotoxicity. Subsequently, the enantiomers of these compounds were separated using enzyme-mediated kinetic resolutions and their (-)-enantiomers (3TC and FTC, respectively) were found to have exceptionally attractive preclinical profiles. In addition to their anti-HIV activity, 3TC and FTC potently inhibit the replication of hepatitis B virus. The development of FTC, which was being carried out by Burroughs Wellcome, had many remarkable starts and stops. For example, passage studies indicated that the compound rapidly selected for a single resistant mutant, M184V, and that this strain was 500-1000-fold less sensitive to FTC than was wild-type virus. Fortunately, it was found that combinations of AZT with either 3TC or FTC were synergistic. The effectiveness of AZT-3TC combination therapy was subsequently demonstrated in four independent clinical trials, and in 1997, the FDA approved Combivir, a fixed dose combination of AZT and 3TC. In phase 1 clinical trials, FTC was well tolerated by all subjects with no adverse events observed. However, the development of FTC was halted by the aquistition of Wellcome PLC by Glaxo PLC in January 1995. In 1996, Triangle Pharmaceuticals licensed FTC from Emory and initiated a series of phase I/II clinical studies that demonstrated the safety and efficacy of the drug. In August 1998, FTC was granted "Fast Track" status, based primarily on its potential for once daily dosing. While the outcomes of two subsequent phase III trials were positive, a third phase III clinical trial involving combinations of 3TC or FTC with stavudine and neviripine had to be terminated due to serious liver-related adverse events. Although analysis of the data suggested that the liver toxicity was due to neviripine, the FDA decided that the study could not be used for drug registration. Ultimately, in January 2003, Gilead Sciences acquired Triangle Pharmaceuticals and completed the development of FTC (emtricitabine), which was approved for once a day, oral administration in July 2003. A year later, Truvada, a once a day, oral, fixed dose combination of emtricitabine and tenofovir disoproxyl fumarate received FDA approval and quickly became the accepted first line therapy when used with a third antiretroviral agent. In July 2006, the FDA approved Atripla, a once a day, oral, fixed dose combination of emtricitabine, tenofovir disoproxyl fumarate, and efavirenz, which represented the culmination of two decades of research that had transformed AIDS from a death sentence to a manageable chronic disease.

Treatment options after virological failure of first-line tenofovir-based regimens in South Africa: an analysis by deep sequencing.

In a South African cohort of participants living with HIV developing virological failure on first-line tenofovir disoproxyl fumarate (TDF)-based regimens, at least 70% of participants demonstrated TDF resistance according to combined Sanger and MiSeq genotyping. Sanger sequencing missed the K65R mutation in 30% of samples. Unless HIV genotyping is available to closely monitor epidemiological HIV resistance to TDF, its efficacy as second-line therapy will be greatly compromised.

Simultaneous determination of 2',3'-dideoxyinosine and the active metabolite, 2',3'-dideoxyadenosine-5'-triphosphate in human peripheral-blood mononuclear cell by HPLC-MS/MS and the application to cell pharmacokinetics.

A specific and reliable HPLC-MS/MS method was developed and validated for the simultaneous determination of 2',3'-dideoxyinosine (ddI) and the active metabolites, 2',3'-dideoxyadenosine-5'-triphosphate (ddA-TP) in human peripheral-blood mononuclear cell for the first time. The analytes were separated on a HILIC column (100mm×2.1mm, 1.7μm) and a triple-quadrupole mass spectrometry equipped with an electrospray ionization (ESI) source was used for detection. The cell homogenates sample was prepared by the solid phase extraction. The calibration curves were linear over a concentration range of 0.5-200.0ng/mL for ddI and 0.25-100.0ng/mL for ddA-TP. The intra-day and inter-day precision was less than 15% and the relative error (RE) were all within ±15%. The validated method was successfully applied to assess the disposition characteristics of ddI and support cell pharmacokinetics after the patients with AIDS were orally administrated with ddI and tenofovir disoproxyl fumarate (TDF).

Tenofovir-induced Renal Tubular Dysfunction in Vertically HIV-infected Patients Associated With Polymorphisms in ABCC2, ABCC4 and ABCC10 Genes

Tenofovir disoproxyl fumarate is a known cause of kidney tubular dysfunction in HIV-infected patients. Recent studies reported significant association between specific allelic variants in ABCC2, ABCC4 and/or ABCC10 genes and the development of kidney tubular dysfunction in HIV-infected adults. We describe the first 2 cases of vertically HIV-infected patients affected by kidney tubular dysfunction associated with polymorphisms in the ABCC genes.

Compared to Subcutaneous Tenofovir, Oral Tenofovir Disoproxyl Fumarate Administration Preferentially Concentrates the Drug into Gut-Associated Lymphoid Cells in Simian Immunodeficiency Virus-Infected Macaques

To compare tissue-based pharmacokinetics and efficacy of oral tenofovir disoproxyl fumarate (TDF) versus subcutaneous tenofovir (TFV), macaques were treated for 2 weeks starting 1 week after simian immunodeficiency virus inoculation. Despite lower plasma TFV levels in the oral TDF arm, similar TFV diphosphate levels and antiviral activities were measured in lymphoid cells of most tissues. In intestinal tissues, however, oral TDF resulted in higher active drug levels, associated with lower virus levels and better immune preservation.

Compared to Subcutaneous Tenofovir, Oral Tenofovir Disoproxyl Fumarate Administration Preferentially Concentrates the Drug into Gut-Associated Lymphoid Cells in Simian Immunodeficiency Virus-Infected Macaques

Compared to Subcutaneous Tenofovir, Oral Tenofovir Disoproxyl Fumarate Administration Preferentially Concentrates the Drug into Gut-Associated Lymphoid Cells in Simian Immunodeficiency Virus-Infected Macaques

Population Pharmacokinetics of Emtricitabine in Human Immunodeficiency Virus Type 1-Infected Pregnant Women and Their Neonates

The objectives of this study were to evaluate emtricitabine (FTC) pharmacokinetics in pregnant women and their neonates and to determine the optimal prophylactic dose for neonates after birth to prevent mother-to-child transmission of human immunodeficiency virus (HIV). A total of 38 HIV-infected pregnant women were administered tenofovir disoproxyl fumarate (300 mg)-FTC (200 mg) tablets-two tablets at the initiation of labor and one daily for 7 days postpartum. By pair, 11 maternal, one cord blood, and two neonatal FTC concentrations were measured using a high-performance liquid chromatography-tandem mass spectrometry validated method and analyzed by a population approach. Model and mean estimates (interpatient variability) were a two-compartment model for mothers, with an absorption rate constant of 0.54 h(-1) (61%), apparent elimination and intercompartmental clearances of 23.2 (17%) and 6.04 liters x h(-1), and apparent central and peripheral volumes of 127 and 237 liters, respectively; an effect compartment linked to maternal circulation for cord blood and a neonatal compartment disconnected, after delivery, with a 10.6-h half-life (30%). After the 400-mg FTC administration, the median population area under the concentration-time curve and the minimal and maximal plasma FTC concentrations in pregnant women were 14.3 mg x liter(-1) x h and 1.68 and 0.076 mg/liter, respectively. At delivery, median (range) predicted maternal and cord blood FTC concentrations were, respectively, 1.16 (0.14 to 1.99) and 0.72 (0.05 to 1.19) mg x liter(-1). We concluded that the 400-mg FTC administration in pregnant women produces higher exposition than does the 200-mg administration in other adults, at steady state. FTC was shown to have good placental transfer (80%). Administering 1 mg FTC/kg as soon as possible after birth or 2 mg/kg 12 h after birth should produce neonatal concentrations comparable to the concentrations observed in adults.

Measurement of Intracellular Didanosine and Tenofovir Phosphorylated Metabolites and Possible Interaction of the Two Drugs in Human Immunodeficiency Virus-Infected Patients

Recent work has demonstrated the existence of a systemic interaction between didanosine (ddI) and tenofovir disoproxyl fumarate (TDF) that leads to a significant increase in plasma ddI levels when coadministered with TDF (40 to 50% increase). These two drugs are, respectively, nucleoside and nucleotide analogues of adenosine and efficiently inhibit the human immunodeficiency virus (HIV) reverse transcriptase when transformed to their triphosphate moieties in the intracellular (IC) medium (ddA-TP and TFV-DP, respectively). Since ddI and TDF partly share the same IC metabolic pathway leading to the active triphosphates, we investigated a putative IC interaction. We used high-performance liquid chromatography-tandem mass spectrometry techniques to determine ddA-TP and TFV-DP IC levels in HIV-infected patients cotreated with both drugs, in comparison with patients treated with just one of the two drugs. These measurements revealed no significant differences in IC levels of the corresponding triphosphates when ddI (250 mg, once a day [QD]) was coadministered with TDF (300 mg, QD) compared to ddI 400 mg (QD) administered without TDF, thus supporting the dose adaptation proposed for this combination. However, we observed that both ddA-TP and TFV-DP have very long IC half-lives, resulting in unusual IC pharmacokinetic profiles with no significant changes in triphosphate concentrations between two dosings. In the case of TFV-DP, this t(1/2) of elimination was roughly estimated to be 180 h (7.5 days). This characteristic is certainly interesting in terms of efficacy but could have some drawbacks in terms of virus resistance for patients discontinuing these drugs.