Intracellular metabolism and pharmacokinetics of 5'-hydrogenphosphonate of 3'-azido-2',3'-dideoxythymidine, a prodrug of 3'-azido-2',3'-dideoxythymidine

[The experience in the application of nikavir in the schemes of perinatal chemoprophylactics of HIV infection: evaluation of the immunological and virusological effectiveness.]

OBJECTIVES

The goal of this work was to study the immunological and virological efficacy of the domestic antiretroviral drug nicavir (at the optimal dose, as proven by previous clinical studies) with lamivudine, in comparison with other drugs of the group of nucleoside reverse transcriptase inhibitors in combination with kaletra in perinatal HIV chemoprophylaxis regimens.

METHODS

658 pregnant women aged 16-39 years and children born to them were examined. The first group (281 people) and the third group (66 people) received the nicavir (manufactured by AZT PHARMA KB LLC) with lamivudine in combination with calyx; the second (281 people) and the fourth (30 people) of the comparison group, stag and zidovudine, respectively, with lamivudine in combination with calyx. The effectiveness of CP was assessed from the increase in the number of CD4 lymphocytes, reduction of the viral load, and the number of children born without HIV DNA in the blood.

RESULTS

Against the backdrop of the therapy, the viral load below the detectable level and the positive dynamics of CD4 lymphocytes were registered in all examined women prior to childbirth. When applying the scheme of niacavir + lamivudine + kaletra, a more rapid decrease in the level of BH, most pronounced by week 4 of therapy, was found, as compared with the rate of decline of the same index in pregnant comparison groups.

CONCLUSIONS

The obtained results allow us to consider ART with the inclusion of nicavir effective and recommend its priority use in perinatal prevention of mother-to-child transmission of HIV.

New dinucleoside phosphonate derivatives as prodrugs of 3'-azido-3'-deoxythymidine and β-L-2',3'-dideoxy-3'-thiacytidine: synthesis and anti-HIV properties

[Formula: see text]New phosphonate homodimers of 3'-azido-3'-deoxythymidine (AZT) and a phosphonate heterodimer of β-L-2',3'-dideoxy-3'-thiacytidine (3TC) and AZT were synthesized. The compounds demonstrated moderate anti-HIV activity. Stability of the compounds in human blood serum was studied. A correlation between anti-HIV activity and stability was defined.

Design, Synthesis, and Antiviral Evaluation of Chimeric Inhibitors of HIV Reverse Transcriptase

In a continuing study of potent bifunctional anti-HIV agents, we rationally designed a novel chimeric inhibitor utilizing thymidine (THY) and a TMC derivative (a diarylpyrimidine NNRTI) linked via a polymethylene linker (ALK). The nucleoside, 5'-hydrogen-phosphonate (H-phosphonate), and 5'-triphosphate forms of this chimeric inhibitor (THY-ALK-TMC) were synthesized and the antiviral activity profiles were evaluated at the enzyme and cellular level. The nucleoside triphosphate (11) and the H-phosphonate (10) derivatives inhibited RT polymerization with an IC50 value of 6.0 and 4.3 nM, respectively. Additionally, chimeric nucleoside (9) and H-phosphonate (10) derivatives reduced HIV replication in a cell-based assay with low nanomolar antiviral potencies.

Synthesis and anti-HIV properties of new carbamate prodrugs of AZT

A series of new 5'-O-carbamate prodrugs of AZT have been prepared. The stability in biological media, anti-HIV properties and pharmacokinetic parameters in dogs were evaluated. The compounds display moderate anti-HIV activity in cell culture. After oral administration of carbamate IV in dogs, both intact prodrug IV and released AZT were discovered in dog blood. Pharmacokinetic parameters of the compound IV were estimated. Half-life (T(1/2)) of AZT released after oral administration of IV in dogs was close to that after administration of AZT itself, and time to the maximum concentration (T(max)) of AZT released from IV was two and three times longer compared with that of AZT and H-phosphonate AZT, respectively. Acute toxicity was more than five times less if compared with AZT. As a result, we consider this series of carbamate derivatives of AZT as perspective for development of anti-HIV agents.

5'-phosphonate derivatives of 2',3'-dideoxy-3'-thiacytidine as new anti-HIV prodrugs

Two new phosphonate 3TC prodrugs were synthesized and studied in MT-4 cells as inhibitors of HIV replication. Their pharmacokinetic parameters were evaluated following intragastric administration in rabbits and oral administration in dogs. Both compounds were much less toxic than parent 3TC in cell cultures and could generate the active nucleoside in laboratory animals.

Antiviral properties, metabolism, and pharmacokinetics of a novel azolo-1,2,4-triazine-derived inhibitor of influenza A and B virus replication

Influenza viruses of types A and B cause periodic pandemics in the human population. The antiviral drugs approved to combat influenza virus infections are currently limited. We have investigated an effective novel inhibitor of human influenza A and B viruses, triazavirine [2-methylthio-6-nitro-1,2,4-triazolo[5,1-c]-1,2,4-triazine-7(4I)-one] (TZV). TZV suppressed the replication of influenza virus in cell culture and in chicken chorioallantoic membranes, and it protected mice from death caused by type A and B influenza viruses. TZV was also effective against a rimantadine-resistant influenza virus strain and against avian influenza A virus H5N1 strains. The pharmacokinetic parameters and bioavailability of TZV were calculated after the administration of TZV to rabbits. The TZV metabolite AMTZV [2-methylthio-6-amino-1,2,4-triazolo[5,1-s]-1,2,4-triazin(e)-7(4I)-one] was discovered in IAK 293T and Huh7 cell cultures, a liver homogenate, and rabbit blood after intragastric administration of TZV. AMTZV was nontoxic and inactive as an inhibitor of influenza virus in cell culture. Most likely, this metabolite is a product of TZV elimination.

Novel compounds for the treatment of HIV type-1 infection

Despite the recent licensure of several new antiretroviral compounds, there is still a need to develop additional agents. Problems with antiviral activity, tolerability, ease of administration, extent of cross-resistance and pharmacokinetic as well as pharmacodynamic interactions still represent important obstacles to life-long control of HIV type-1 replication by highly active antiretroviral therapy. Several compounds stem from the same classes as currently available drugs: apricitabine and elvucitabine (nucleoside reverse transcriptase inhibitors), rilpivirine (non-nucleoside reverse transcriptase inhibitor), vicriviroc and INCB009471 (CCR5 inhibitors) and elvitegravir (integrase inhibitor). The potential of other compounds with new modes of action is less clear. Currently, maturation inhibitors appear promising but for other drugs, obstacles to continued development, such as the need of parenteral application (that is, monoclonal antibodies) or toxicity (for example, immune modulating agents and pegylated interferon), are already apparent. For even more compounds in the preclinical development phase, an assessment of their possible clinical role is still premature. This review provides an overview and a summary of the current status of drug development in the field.

5'-carbamoylphosphonyl-[6-3H]-AZT as a tool for studying metabolic transformations of the nonradioactive counterpart, an inhibitor of HIV replication

An effective synthesis of 5'-carbamoylphosphonyl-[6-3H]-AZT was developed from [6-3H]-AZT. For the synthesized compound, chemical and enzymatic stability were determined and its penetration across HL-60 cell membranes was studied.

Tannic acid prevents azidothymidine (AZT) induced hepatotoxicity and genotoxicity along with change in expression of PARG and histone H3 acetylation

Azidothymidine (AZT) is known to decrease HIV virus replication and is one of the most frequently prescribed antiretroviral drugs used for AIDS treatment. Dose-limiting toxicities are the major curse associated with AZT therapy. Recently, we have reported that tannic acid; a PARG inhibitor prevents cisplatin induced nephrotoxicity. The present work was conceived to study the effect of tannic acid on AZT induced hepatotoxicity and genotoxicity. AZT induces increase in plasma levels of ALT, AST and alkaline phosphatase along with increase in micronucleus (MN) count in peripheral blood. Suggesting, AZT is hepatotoxic and genotoxic to mice. Treatment of tannic acid protects AZT induced hepatotoxicity by decreasing the ALT, AST and alkaline phosphatase levels. It also significantly reduces the oxidative damage by preventing reduction in glutathione and decreasing the level of malondialdehyde in liver of AZT treated mice. In addition, tannic acid decreases the PARG expression, PARP cleavage and histone H3 acetylation in liver of AZT treated mice. Moreover, treatment of tannic acid also decreases MN count in peripheral blood, suggesting its anti-mutagenic effect. In light of these findings we suggest the potential role of tannic acid treatment in preventing AZT induced toxicity.

Cell metabolism of acyclovir phosphonate derivatives and antiherpesvirus activity of their combinations with alpha2-interferon

The combinational use of acyclovir (ACV) phosphonate esters and alpha(2)-interferon was shown to produce a synergistic effect on inhibition of HSV-1 replication in Vero cell cultures. Unlike other acyclovir phosphonate derivatives studied earlier, ACV H-phosphonate is not an ACV prodrug. On penetrating into the cells, it may be directly converted into ACV monophosphate escaping dephosphonylation-phosphorylation steps.

AZT 5'-Cholinephosphate as an anti-HIV agent: the study of biochemical properties and metabolic transformations using its 32P-labelled counterpart

Biochemical and metabolic transformations of 3'-azido-3'-deoxythymidine 5'-choline phosphate (1) were studied using its 32P-labelled counterpart for the evaluation of possible reasons for its enhanced anti-HIV activity. An effective synthesis of 32P-labelled 1 with a specific activity >1,000 Ci/mmol was developed by esterification of 32P-phosphoric acid with choline in the presence of BrCN followed by the coupling of the resulting choline phosphate with 3'-azido-3'-deoxythymidine (AZT). Chemical and enzymatic stabilities of 1 as well as the dynamics of penetration through HL-60 cell membranes were studied at the concentrations comparable to its antiviral concentrations. The products of intracellular transformations of the studied nucleotide were identified.

Aryl nucleoside H-phosphonates. Part 15: Synthesis, properties and, anti-HIV activity of aryl nucleoside 5′-α-hydroxyphosphonates

Aryl nucleoside 5'-H-phosphonates 4 bearing AZT or 2',3'-dideoxyuridine moieties were subjected to reaction with various aromatic aldehydes to produce nucleoside 5'-alpha-hydroxyphosphonate derivatives 2 as potential anti-HIV agents. Stability of the title compounds in cell culture media was investigated and three distinct decomposition pathways were identified. The anti-HIV activity of hydroxyphosphonates 2 correlates well with the type and extent of their chemical or enzymatic degradation in culture medium (RPMI 1640 containing 10% FBS), suggesting that aryl nucleoside 5'-hydroxyphosphonates 2 act as depot forms of the parent antiviral nucleosides.