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The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), urgently needs effective prophylactic and therapeutic drugs. RNA-dependent RNA polymerase (RdRp), essential for replicating and transcribing a viral RNA genome, is highly conserved in coronaviruses, thus, it is a potential target for inhibiting coronavirus infection. In this study, we generated the cell-based SARS-CoV-2 RdRp activity assay system by modifying a previously reported cell-based MERS-CoV RdRp activity assay system to screen for SARS-CoV-2 RdRp inhibitors. The assay system consisted of an expression plasmid encoding SARS-CoV-2 RdRp and an RdRp activity reporter plasmid. RdRp activity in the cells could be conveniently detected by luminescence after transfection. We confirmed that SARS-CoV-2 RdRp replicated double-stranded RNA using immunofluorescence staining and the inhibition of RdRp activity by remdesivir and lycorine using this system. Moreover, the Z-factor of this system was calculated to be 0.798, suggesting the reproducibility and reliability of the high-throughput screening system. Finally, we screened nucleoside and nucleotide analogs and identified adefovir dipivoxil, emtricitabine, telbivudine, entecavir hydrate, moroxydine and rifampin as novel SARS-CoV-2 RdRp inhibitors and therapeutic candidates for COVID-19 This system provides an effective high-throughput screening system platform for developing potential prophylactic and therapeutic drugs for COVID-19 and emerging coronavirus infections.

Current therapy against herpes simplex viruses (HSV) relies on the use of a few nucleoside antivirals such as acyclovir, famciclovir and valacyclovir. However, the current drugs are ineffective against latent and drug-resistant HSV infections. A series of amidinourea compounds, designed as analogues of the antiviral drug moroxydine, has been synthesized and evaluated as potential non-nucleoside anti-HSV agents. Three compounds showed micromolar activity against HSV-1 and low cytotoxicity, turning to be promising candidates for future optimization. Preliminary mode of action studies revealed that the new compounds act in an early stage of the HSV replication cycle, just after the viral attachment and the entry phase of the infection.

In this work, a chromatography column comparison and rapid pretreatment development were carried out. A multi-class method was built based on the quick, easy, cheap, effective, rugged and safe pretreatment method (QuEChERS) with hydrophilic interaction ultra high performance liquid chromatography and tandem mass spectrometry for the high-throughput analysis of five antivirals in chicken muscle. The HSS T3 column, BEH HILIC column and BEH Amide column were studied, and their chemical functionalities and chromatographic separation effectiveness were compared. The BEH Amide column was selected to perform the mass spectrometry analysis under the hydrophilic interaction chromatography mode. Firstly, a different strategy without adding MgSO4 and NaCl into the muscle samples was considered. Then, different concentrations of formic acid, acetic acid and ammonia in acetonitrile were compared for better extraction efficiency. Nine sorbents (C18, PSA, NH2, Florisil, Alumina-B, Alumina-N, PestiCarb, NANO, and NANO-NH2) were studied. The optimized procedure consisted of the use of 10% acetic acid in acetonitrile for the extraction solvent and NANO-NH2 for clean-up. NANO-NH2 had not been applied in other matrix and pollutants so far. The developed method provided favorable trueness, precision and acceptable matrix effect. Meanwhile, the method was sensitive, the limits of detection of amantadine, rimantadine, acyclovir, ribavirin and moroxydine achieved were 0.56, 0.50, 0.30, 2.22 and 0.51 μg/kg, respectively, and was successfully applied for the routine detection of antivirals in the chicken samples. This article is protected by copyright. All rights reserved

A fast method for the simultaneous determination of 14 antiviral drugs and relevant metabolites in chicken muscle by ultra-high liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed. The analytes included anti-influenza drugs (amantadine, rimantadine, oseltamivir, oseltamivir carboxylate, memantine, arbidol, and moroxydine), anti-herpes drugs (acyclovir, ganciclovir, famciclovir, penciclovir, ribavirin and its main metabolite TCONH2), and an immunomodulator (imiquimod). The samples were pretreated using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method. The determination of the target compounds was conducted in less than 11.0min, and specificity was ensured by the use of multiple reaction monitoring (MRM) acquisition mode. Good linearities (R(2)>0.9928) were obtained in the range of 0.1-100μg/L, and the recovery rates were 56.2-113.4% with RSDs of 1.7-10.3% for intra-day precision and 2.4-8.8% for inter-day precision. The LODs and LOQs of all analytes were in the ranges of 0.02-1.0 and 0.05-2.5μg/kg, respectively. An analysis of real samples suggested that this method is simple, sensitive, reliable and practical for the detection of antiviral drugs in animal tissue.

An effective sample pretreatment method followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) was first developed for simultaneous determination of five antiviral drug residues including ribavirin, moroxydine, amantadine, rimantadine and memantine in honey. To adsorb analytes with different binding properties and overcome the interference of sugars and uridine as endogenous ribavirin structural analogs in honey, the target drugs were extracted with 1% formic acid and then purified by a phenylboronic acid (PBA) solid phase extraction cartridge using two-step fraction capture prior to LC-MS/MS analysis. This method was validated by analyzing honey samples from nine floral origins including miscellaneous flowers, citrus, vitex, rape, acacia, sunflower, linden, buckwheat and jujube spiking at multiple levels, and the recoveries ranged from 82.46% to 116.34%, with relative standard deviations (RSDs) less than 14.58%. The limits of detection (LODs) and limits of quantitation (LOQs) of moroxydine, ribavirin, amantadine, rimantadine, and memantine were 0.1–2 µg/kg and 0.2–5 µg/kg, respectively. Depletion experiments of five antiviral drugs in honey at different storage and process temperatures demonstrated that moroxydine can potentially be used as a drug to cure sacbrood disease in honeybees.

N-[4-morpholinecarboximidamidoyl]carboximidamidoylmethylated polyphenylene sulfide (MCMPPS) was synthesized by grafting moroxydine on cholomethylated polyphenylene sulfide (CMPPS) resin for removing heavy metal ions from water. Polyphenylene sulfide (PPS) is a health-friendly polymer, moreover, the moroxydine is an antiviral drug. The resin MCMPPS exhibited excellent chemical stability under strong acid, basic and oxidative conditions. The maximum adsorption capacity of resin MCMPPS for Pb(II), Cd(II), Cr(III), Cu(II) and Ni(II) ions were 186.92, 189.75, 120.04, 119.33 and 134.05 mg g−1, respectively, moreover, equilibrium time of MCMPPS adsorbing Pb(II), Cr(III), Cu(II) and Cd(II) ions are about 30 min. Therefore, this new sorbent showed a potential application in the removal of heavy metal ions in water owing to its thermal and chemical stability, healthy safety, and efficient adsorption. The FT-IR spectra and EA data suggested that heavy metal ions were quickly and effective adsorbed on surfaces of the adsorbent by coordination reaction of heavy metal ions with amino and imino groups.

A method of liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the simultaneous determination of five antiviral drug residues, amantadine, rimantadine, memantine, moroxydine and imiquimod in chicken tissues was developed. The compounds were extracted from the samples with trichloroacetic acid solution and acetonitrile, and then cleaned-up by strong cation exchange (SCX) solid phase extraction cartridges. The analytes were separated on a Xamide column (100 mm x 2.1 mm, 5 microm) and determined qualitatively and quantitatively with tandem mass spectrometry using positive polarity mode under multi-reaction monitoring (MRM) scan type. The limits of detection and the limits of quantification were 0.06 - 0.30 microg/kg and 0.2 - 1.0 microg/kg, respectively. The average recoveries of the five drugs were 72.3% - 94.2% in chicken muscle and 70.8% - 92.7% in chicken livers. The relative standard deviations (RSDs) in chicken muscle and livers were 3.5% -11.3% and 5.3% -12.6%, respectively. The method is selective without interference and suitable for the determination and confirmation of the five antiviral drugs in chicken muscle and livers.

Moroxydine hydrochloride (Mor) and ribavirin (Rib) are known for their multi-antiviral activities against DNA and RNA viruses but little information is available about the pharmacological impact in aquaculture. The present study was undertaken to investigate the response of host cells to antiviral compounds during the anti-GCRV treatment. The scanning electron microscope results showed that Ctenopharyngodon idella kidney (CIK) cells have a higher death rate at 72h post virus infection. At the concentration of 40μgmL-1, Mor and Rib had a significant protective effect on virus-infected cells. Moreover, the gene expressions of vp5, vp6 and NS66 were significantly inhibited by treatment with Mor or Rib, especially gene expression of the vp5. For the immunoregulatory action, no distinct induction of the expression of immune genes was observed after the addition of Mor and Rib to the virus-free cells. However, the compounds significantly decreased the virus-induced gene overexpression of Myd88, Mx1, IL-1β, IL-8, I-IFN and TNFα in CIK cells. Moreover, Mor and Rib significantly inhibited the immune genes upregulation which was induced by GCRV in kidney, liver, muscle and gill of grass carp, despite greater partial gene expressions were detected than the virus-free control group. Besides, Mor and Rib blocked cell cycle changes, cytopathic effects, cellular death and virus proliferation in CIK cells thereby maintaining normal morphological structure. Overall, Mor and Rib as antiviral compounds are effective for the control of GCRV replication and the indirectly regulation of cellular immune response.

Moroxydine (Mor.) is an antiviral agent of biguanide structure. The paper presents a new silver amalgam film electrode (Hg(Ag)FE) for determination of Mor. in phosphate buffer, pH 6.2 (LOD=4×10−9 mol L−1, LOQ= 1×10−8 mol L−1) and in spiked urine using square wave adsorptive stripping voltammetry. It was found that the compound can act as an electrocatalyst not only at hanging mercury drop electrode but also at the Hg(Ag)FE. The electrode mechanism is connected with the hydrogen evolution reaction catalyzed by moroxydine. Adsorption of moroxydine at the mercury electrode was studied and special arrangements of molecules enabling electron transfer of the protonated form of moroxydine is suggested.

The discovery of a novel class of HCV inhibitors is described. The new amidinourea compounds were designed as isosteric analogues of the antiviral drug moroxydine. The two derivatives 11g and 11h showed excellent HCV inhibition activity and viability and proved to inhibit a step(s) of the RNA replication. The new compounds have been synthesized in only three synthetic steps from cheap building blocks and in high yields, thus turning to be promising drug candidates in the development of cheaper HCV treatments.

The inhibitory effects of three biguanido-oxovanadium complexes ([VO(L(1-3))(2)]·nH(2)O: HL(1) = metformin, HL(2) = phenformin, HL(3) = moroxydine) against four protein tyrosine phosphatases (PTPs) and an alkaline phosphatase (ALP) were investigated. The complexes display strong inhibition against PTP1B and TCPTP (IC(50), 80-160 nM), a bit weaker inhibition against HePTP (IC(50), 190-410 nM) and SHP-1(IC(50), 0.8-3.3 μM) and much weaker inhibition against ALP (IC(50), 17-35 μM). Complex 3 is about twofold less potent against PTP1B, TCPTP and HePTP than complexes 1 and 2, while complex 2 inhibits SHP-1 more strongly (about three to fourfold) than the other two complexes. These results suggest that the structures of the ligands slightly influence the potency and selectivity against PTPs. The complexes inhibit PTP1B and ALP with a typical competitive type.

The present review has concentrated on chromatographic techniques for the quantitative determination of antiviral drugs in biological samples. Special attention has been paid to the elements of chromatographic assays that are essential to ensure selectivity, sensitivity, accuracy and precision of the various methods. Wherever possible, attempts have been made to determine the suitability of the methods for application to investigations in pharmacokinetics in man and experimental animals, biopharmaceutics, therapeutic drug monitoring, metabolism and pharmacology. Because of the serious consequences of infection from material contaminated with viruses, special consideration has been given to the handling of contaminated samples. It was convenient to divide the antiviral drugs for the purpose of this review into two groups, the nucleoside and the non-nucleoside antiviral drugs. The nucleosides discussed are vidarabine, cytarabine, ribavirin, riboxamide, acyclovir, ganciclovir, desciclovir, carbovir, 2′,3′-dideoxyadenosine, 2′,3′-dideoxycytidine, zidovudine, 2′,3′-dideoxyinosine, 2′,3′-didehydro-3′-deoxythymidine, idoxuridine, 5-(2-bromovinyl)-2′-deoxyuridine, 2′-fluoro-5-iodoaracytidine and 5-iodo-2′-deoxycytidine. The non-nucleoside antiviral drugs discussed are arildone, amantidine, rimantidine, moroxydine, enviroxime, foscarnet and ampligen.

A supramolecular compound Na3(HABOB)(H2ABOB)[MnMo9O32]·5.5H2O (ABOB = moroxydine) has been synthesized and characterized by elemental analyses, IR spectrum, diffuse reflectance spectrum, room tempe...

Moroxybrate, a drug obtained by the reaction of clofibric acid with moroxydine, a biguanide with practically no effect on carbohydrate metabolism, has been examined for its effects on blood lipids, fibrinogen, in-vitro platelet aggregation, and also on experimental atherosclerotic lesions obtained by feeding the rabbits a diet containing 1% cholesterol. At the same dose, moroxybrate has an effect at least equal to those of clofibrate and moroxydine alone, on the lipidic parameters and haemostasis in rat and rabbit. The combination of these actions together with an effect on the prevention of experimental atherosclerosis lesions in the rabbit suggests moroxybrate should be examined for its effects in ischaemic cardiovascular disease.

A simple and specific method for the determination of moroxydine in serum was established by the use of ion-exchange chromatography and a modified Voges-Proskauer colorimetric reaction. Moroxydine over the range of 5 to 70 μg was determined by the measurement of absorbance at the absorption maximum (520 nm) of the colored product formed in the reaction of moroxydine with diacetyl-3, 5-dihydroxybenzoic acid reagent in alkaline solution. An anion-exchange column chromatography (carboxylate resin) was effectively used to remove the interferences present in the serum. The rabbit serum containing moroxydine was applied directly to the column, without pretreatment, and the column was eluted first with 0.01M NaOH, followed by 0.2M NaOH. The recovery of moroxydine added to serum was between 99 and 102% and the coefficient of variation was between 1.49 and 2.27%.

SummaryAn impaired fibrinolytic capacity, defined as an insufficient venous occlusion-induced shortening of the plasma euglobulin clot lysis time, is a common feature in women suffering from primary early recurrent unexplained miscarriages (1,2). We investigated the therapeutic effect of a low-molecular-weight heparin and of a phenformin-like substance.In a prospective, randomized trial, 30 consecutive patients initially received either enoxaparin, 20 mg per day during one month, or moroxydine chloride, 1200 mg per day during one month. In case of fibrinolytic status normalization, they were treated during 6 months by the beneficial treatment which was planned to be continued during eventual pregnancies. Patients with hypofibrinolysis persistence received the alternative treatment during another month and a new evaluation was performed. No treatment was given when a persistent abnormal response to the venous occlusion test was evidenced. In case of positive response, the treatment was continued during 6 months. The primary study end-points consisted of any of the following: effect of the treatments on the fibrinolytic response; number of patients becoming pregnant during the 6 months following the last venous occlusion test; number of full-term pregnancies.Concerning the effects on the fibrinolytic system, 20 out of 29 women responded to the first or second-line enoxaparin treatment whereas only 1 woman out of 19 responded to moroxydine chloride (p=0.00002). Concerning the effects on fertility, responders to LMWH were more likely to initiate a new pregnancy than non-responders (16/20 vs 2/10, p=0.002). In patients conceiving, LMWH responders were more likely to obtain live births than nonresponders (13/16 vs. 0/2, p=0.02). The 9 women who had not responded to both treatments and the one who had responded to moroxydine chloride are still childless. Thirteen of the 20 previously childless women who had responded to enoxaparin had a successful pregnancy whilst taking the low-molecular weight heparin (p=0.0009).The low-molecular weight heparin enoxaparin was associated with successful pregnancies in patients with recurrent unexplained miscarriages associated with an impaired fibrinolytic capacity.