Synthesis and anti-HIV activities of symmetrical dicarboxylate esters of dinucleoside reverse transcriptase inhibitors

Three nucleoside analogues, 3′-fluoro-2′,3′-dideoxythymidine (FLT), 3′-azido-2′,3′-dideoxythymidine (AZT), and 2′,3′-dideoxy-3′-thiacytidine (3TC) were conjugated with three different dicarboxylic acids to afford the long chain dicarboxylate esters of nucleosides. In general, dinucleoside ester conjugates of FLT and 3TC with long chain dicarboxylic acids exhibited higher anti-HIV activity than their parent nucleosides. Dodecanoate and tetradecanoate dinucleoside ester derivatives of FLT were found to be the most potent compounds with EC50 values of 0.8–1.0 nM and 3–4 nM against HIV-1US/92/727 and HIV-1IIIB cells, respectively. The anti-HIV activity of the 3TC conjugates containing long chain dicarboxylate diester (EC50 = 3–60 nM) was improved by 1.5–66 fold when compared to 3TC (EC50 = 90–200 nM). This study reveals that the symmetrical ester conjugation of dicarboxylic acids with a number of nucleosides results in conjugates with improved anti-HIV profile. [Refer to PDF for graphical abstract

Synthesis and Biological Evaluation of 5′-O-Dicarboxylic Fatty Acyl Monoester Derivatives of Anti-HIV Nucleoside Reverse Transcriptase Inhibitors

A number of 5′-O-dicarboxylic fatty acyl monoester derivatives of 3′-azido-3′-deoxythymidine (zidovudine, AZT), 2′,3′-didehydro-2′,3′-dideoxythymidine (stavudine, d4T), and 3′-fluoro-3′-deoxythymidine (alovudine, FLT) were synthesized to improve the lipophilicity and potentially the cellular delivery of parent polar 2′,3′-dideoxynucleoside (ddN) analogs. The compounds were evaluated for their anti-HIV activity. Three different fatty acids with varying chain length of suberic acid (octanedioic acid), sebacic acid (decanedioic acid), and dodecanedioic acid were used for the conjugation with the nucleosides. The compounds were evaluated for anti-HIV activity and cytotoxicity. All dicarboxylic ester conjugates of nucleosides exhibited significantly higher anti-HIV activity than that of the corresponding parent nucleoside analogs. Among all the tested conjugates, 5′-O-suberate derivative of AZT (EC50 = 0.10 nM) was found to be the most potent compound and showed 80-fold higher anti-HIV activity than AZT without any significant toxicity (TC50 \u3e500 nM)

Carbocyclodipeptides as modified nucleosides: synthesis and anti-HIV activities

A new class of nucleoside analogues were synthesized using cyclic dipeptides and modified 2′-deoxyfuranoribose sugars to introduce flexibility by peptides in place of common nucleoside bases and to determine their biological properties. The synthesis was carried out by coupling of a protected ribose sugar with synthesized dipeptides in the presence of hexamethyldisilazane and trimethylsilyltriflate. The final products were characterized by NMR and high-resolution MS-TOF spectroscopy. The compounds were evaluated for anti-HIV activities. 1-(4-Azido-5-(hydroxymethyl)tetrahydrofuran-2-yl)-3,6-diisopropylpiperazine-2,5-dione (compound 14) containing 3- and 6-isopropyl groups in the base and 3′-azide (EC50 = 1.96 μmol/L) was the most potent compound among all of the synthesized analogs

Griffithsin tandemers: flexible and potent lectin inhibitors of the human immunodeficiency virus

The lectin griffithsin (GRFT) is a potent antiviral agent capable of prevention and treatment of infections caused by a number of enveloped viruses and is currently under development as an anti-HIV microbicide. In addition to its broad antiviral activity, GRFT is stable at high temperature and at a broad pH range, displays little toxicity and immunogenicity, and is amenable to large-scale manufacturing. Native GRFT is a domain-swapped homodimer that binds to viral envelope glycoproteins and has displayed mid-picomolar activity in cell-based anti-HIV assays. Previously, we have engineered and analyzed several monomeric forms of this lectin (mGRFT) with anti-HIV EC50 values ranging up to 323 nM. Based on our previous analysis of mGRFT, we hypothesized that the orientation and spacing of the carbohydrate binding domains GRFT were key to its antiviral activity. Here we present data on engineered tandem repeats of mGRFT (mGRFT tandemers) with antiviral activity at concentrations as low as one picomolar in whole-cell anti-HIV assays. mGRFT tandemers were analyzed thermodynamically, both individually and in complex with HIV-1 gp120. We also demonstrate by dynamic light scattering and cryo-electron microscopy that mGRFT tandemers do not aggregate HIV virions. This establishes that, although the intra-virion crosslinking of HIV envelope glycoproteins is likely integral to their activity, the antiviral activity of these lectins is not due to virus aggregation caused by inter-virion crosslinking. The engineered tandemer constructs of mGRFT may provide novel and powerful agents for prevention of infection by HIV and other enveloped viruses.https://doi.org/10.1186/s12977-014-0127-

Susceptibilities of Simian Immunodeficiency Virus to Protease Inhibitors

We used a focal infectivity assay with HeLa H1-JC.37 cells to directly compare susceptibilities of simian immunodeficiency virus (SIV) and human immunodeficiency virus type 1 (HIV-1) to protease inhibitors. SIVmac239 was inhibited by indinavir, saquinavir, and ritonavir, with 50% effective concentrations (means ± standard deviations) of 39 ± 8, 55 ± 3, and 13 ± 5 nM, respectively. The corresponding values for inhibition of HIV-1 were 66 ± 4, 47 ± 10, and 25 ± 14 nM, respectively

Swelling of the transdermal patches.

<p>The patches were placed under various environmental conditions: ambient humidity (grey), 75% Relative humidity (striped), and 95% relative humidity (white). The patches remained under these conditions until a stable mass was measured. Swelling was calculated from the percent change in film weight from water uptake. n = 3 ± standard deviation (SD).</p

An intravaginal ring for the simultaneous delivery of an HIV-1 maturation inhibitor and reverse-transcriptase inhibitor for prophylaxis of HIV transmission

Nucleocapsid 7 (NCp7) inhibitors have been investigated extensively for their role in impeding the function of HIV-1 replication machinery and their ability to directly inactivate the virus. A class of NCp7 zinc finger inhibitors, S-acyl-2-mercaptobenzamide thioesters (SAMTs), was investigated for topical drug delivery. SAMTs are inherently unstable because of their hydrolytically labile thioester bond, thus requiring formulation approaches that can lend stability. We describe the delivery of N-[2-(3,4,5-trimethoxybenzoylthio)benzoyl]-β-alaninamide (SAMT-10), as a single agent antiretroviral (ARV) therapeutic and in combination with the HIV-1 reverse-transcriptase inhibitor pyrimidinedione IQP-0528, from a hydrophobic polyether urethane (PEU) intravaginal ring (IVR) for a month. The physicochemical stability of the ARV-loaded IVRs was confirmed after 3 months at 40°C/75% relative humidity. In vitro, 25 ± 3 mg/IVR of SAMT-10 and 86 ± 13 mg/IVR of IQP-0528 were released. No degradation of the hydrolytically labile SAMT-10 was observed within the matrix. The combination of ARVs had synergistic antiviral activity when tested in in vitro cell-based assays. Toxicological evaluations performed on an organotypic EpiVaginal™ tissue model demonstrated a lack of formulation toxicity. Overall, SAMT-10 and IQP-0528 were formulated in a stable PEU IVR for sustained release. Our findings support the need for further preclinical evaluation