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Compound L-36, a new derivative of 6H-1,3,4-thiadiazine, was studied in in vitro and in vivo experiments. This compound exhibits high antiplatelet and antithrombogenic activity. In in vitro experiments, compound L-36 by its antiplatelet activity (by IC50) was superior to acetylsalicylic acid by 9.4 times. In in vivo experiments, compound L-36 by its ED50 value was close to the comparison drug. On the model of pulmonary artery thrombosis, compound L-36 ensured better survival of experimental animals than acetylsalicylic acid. Morphological studies showed that compound L-36 effectively attenuated the thrombosis processes in the pulmonary tissue induced by intravenous injection of a thrombogenic mixture (epinephrine and collagen). [ABSTRACT FROM AUTHOR]

Hypercytokinemia, or cytokine storm, often complicates the treatment of viral and bacterial infections, including COVID-19, leading to the risk of thrombosis. However, the use of currently available direct anticoagulants for the treatment of COVID-19 patients is limited due to safety reasons. Therefore, the development of new anticoagulants remains an urgent task for organic and medicinal chemistry. At the same time, new drugs that combine anticoagulant properties with antiviral or antidiabetic activity could be helpfull in the treatment of COVID-19 patients, especially those suffering from such concomitant diseases as arterial hypertension or diabetes. We have synthesized a number of novel substituted azoloazines, some of which have previously been identified as compounds with pronounced antiviral, antibacterial, antidiabetic, antiaggregant, and anticoagulant activity. Two compounds from the family of 1,2,4-triazolo[1,5-a]pyrimidines have demonstrated anticoagulant activity at a level exceeding or at least comparable with that of dabigatran etexilate as the reference compound. 7,5-Di(2-thienyl)-4,5-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine has shown the highest ability to prolong the thrombin time, surpassing this reference drug by 2.2 times. This compound has also exhibited anticoagulant activity associated with the inhibition of thrombin (factor IIa). Moreover, the anticoagulant effect of this substance becomes enhanced under the conditions of a systemic inflammatory reaction. [ABSTRACT FROM AUTHOR]

We studied the effect of antiviral agent riamilovir on ADP-induced platelet aggregation in the absence and presence of LPS. Unlike acetylsalicylic acid (reference drug), riamilovir did not exhibit antiplatelet effect in vitro. However, it markedly suppressed platelet reactivity in LPS-treated blood samples and was 2.2-fold superior to acetylsalicylic acid in terms of IC50 value. In in vivo experiments, riamilovir under conditions of hypercytokinemia blocked platelet aggregation in rats by 64%. [ABSTRACT FROM AUTHOR]

Halides of 2-aminobenzimidazolium and derivatives of 9-substituted 2-(4-fluorophenyl)imidazo[1,2-a]benzimidazoles have been studied for ten types of biological activity in vitro. Among the aminobenzimidazolium derivatives, a compound with NHE-1 inhibitory activity has been identified. It has been demonstrated that imidazobenzimidazole derivatives affect the duration of the refractory period of rat atria, platelet aggregation, and hemorheological activity and inhibit the formation of end products of glycation. No DPP-4 inhibitory, antioxidant, kappa-opioid, and 5-HT2A and 5-HT3 antagonistic activities have been found among the studied compounds. [ABSTRACT FROM AUTHOR]

The bioavailability of the tablet dosage form of pharmaceutical substance RU-891, i.e., 9-(3,4-dihydroxyphenacyl)-2,3-dihydroimidazo[1,2-a]benzimidazole hydrobromide, was investigated. The main pharmacokinetic parameters were determined. The relative bioavailability index was estimated at 93.98%. No evidence of drug accumulation from an RU-891 270-mg tablet dosage form was detected in rabbits upon threefold administration at a dose of 23 mg/kg. [ABSTRACT FROM AUTHOR]

We studied the effect of Angipur on the process of experimental thrombosis induced by damage to the carotid artery wall by surface application of 50% ferric chloride (III) solution in rats without comorbidities and with isoproterenol-induced myocardial infarction. In animals without comorbidities, Angipur administered intravenously was 1.2 times less effective, in terms of ED50, than the well-known inhibitor of GPIIb/IIIa platelet receptors tirofiban. However, under conditions of non-coronary myocardial infarction, Angipur significantly prolonged the time of thrombus formation and exhibited 1.4-fold higher activity than the reference drug tirofiban. [ABSTRACT FROM AUTHOR]

A quantitative determination method using HPLC with fluorescence detection for the xanthine derivative 3-methyl-8-(piperazin-1-yl)-7-(thietan-3-yl)-1-ethyl-1H-purine-2,6(3H,7H)-dione hydrochloride (Angipur drug substance) in donor blood plasma was developed and validated. The optimal conditions for quantitative determination of Angipur drug substance were KH2PO4 buffer (50 mM, pH 6.5); aqueous-to-organic phase ratio 55:45 v/v; added sodium heptanesulfonate modifier (0.15%); temperature 40°C; detector extinction wavelength 290 nm; and emission wavelength 340 nm. The method sensitivity (detection limit) for Angipur was 2.5 ng/mL; limit of quantitation, 5 ng/mL. The average measurement error was ≤ 15%. [ABSTRACT FROM AUTHOR]

According to the in silico consensus activity prediction, a series of 3,6-disubstituted 1,2,4,5-tetrazines were synthesized as promising inhibitors of the Maillard reaction. In addition to the studies of antiglycation activity, a comparative in vitro evaluation of the effect of the synthesized compounds on the ADP-induced rabbit platelet aggregation model was carried out. Compounds with antiglycation and antiplatelet activities significantly higher than that of the reference drugs, aminoguanidine and acetylsalicylic acid, were revealed. [ABSTRACT FROM AUTHOR]

Introduction: Cardiovascular diseases are currently the leading cause of global disability and mortality. According to the centers for disease control and prevention, the average life expectancy of a person would be 10 years longer but for a high prevalence of cardiovascular diseases, and if antiplatelet drugs and special therapy were used. Materials and methods: Antiplatelet activity of the novel benzimidazole derivatives containing a sterically hindered phenolic group in their structure has been investigated in vitro, using a model of ADP-induced platelet aggregation of rabbit's plasma. The compounds exhibiting high antiplatelet activity and acetylsalicylic acid, as a reference drug, were examined for antioxidant properties in an ascorbate-dependent model of lipid peroxidation. Results: It was established that the compounds with high antiplatelet activity demonstrated the pronounced antioxidant action. The compound RU-1144 (1-(3,5-ditretbutyl-4-hydroxyphenyl) -1-hydroxypropyl)-phenyl-pyrimidobenzimidazole hydrochloride), in in vitro experiments, had a pronounced antiplatelet activity, surpassing the reference drug acetylsalicylic acid by 21.8 times; in the study of antioxidant activity, the leader compound was inferior to the reference drug dibunol by 1.7 times. By inhibiting intravascular platelet aggregation in vivo, this compound exceeded acetylsali-cylic acid by 1.5 times and was slightly inferior to clopidogrel by 1.4 times. Discussion: Benzimidazole derivatives with a hindered phenolic substituent in their structure exhibited antiplatelet and antioxidant properties. It was established that the compounds with high antiplatelet activity demonstrated the pronounced antioxidant action. Conclusion: The chemical class of benzimidazole derivatives with a hindered phenolic substituent in their structure is promising for the search for new antiaggregant and antioxidant drugs. [ABSTRACT FROM AUTHOR]

A series of N1, N3-bis-hydroxybenzoyl, -acetoxybenzoyl, and -methoxybenzoyl uracil derivatives were synthesized. All compounds were screened for the ability to rupture protein cross links and antiglycating, chelating, and antiaggregant properties, which are most significant for pharmacological treatment of thrombosis and angio-, nephro-, encephalo-, and cardiopathies. 1,3-bis-(4-Methoxybenzoyl)pyrimidine-2,4(1H,3H)-dione was a promising antidiabetic agent with all studied activities. [ABSTRACT FROM AUTHOR]

Antithrombotic activity of a novel tricyclic derivative of diazepino[1,2-α]benzimidazole (DAB-15) was examined on the model of arterial thrombosis developed in rats without concomitant pathology and in rats with experimental myocardial infarction. DAB-15 demonstrated high antithrombotic efficacy in modeled thrombosis of carotid artery in rats without the concomitant pathology surpassing that of the reference drugs acetylsalicylic acid and clopidogrel by 5.1 and 4.8 times, respectively. In rats with experimental noncoronary myocardial infarction, DAB-15 increased the thrombus formation time by 86.2% in comparison with experimental control level in non-treated rats with similar myocardial infarction. [ABSTRACT FROM AUTHOR]

Antithrombotic activity of a novel tricyclic derivative of diazepino[1,2-α]benzimidazole (DAB-15) was examined on the model of arterial thrombosis developed in rats without concomitant pathology and in rats with experimental myocardial infarction. DAB-15 demonstrated high antithrombotic efficacy in modeled thrombosis of carotid artery in rats without the concomitant pathology surpassing that of the reference drugs acetylsalicylic acid and clopidogrel by 5.1 and 4.8 times, respectively. In rats with experimental noncoronary myocardial infarction, DAB-15 increased the thrombus formation time by 86.2% in comparison with experimental control level in non-treated rats with similar myocardial infarction. [ABSTRACT FROM AUTHOR]

The pharmacokinetic parameters of the parent substance and the injectable dosage form of the new antiplatelet drug 3-methyl-8-(piperazin-1-yl)-7-(thietan-3-yl)-1-ethyl-1H-purine-2,6(3H,7H)-dione hydrochloride in rabbit blood plasma upon intravenous administration were compared and analyzed. The relative bioavailability coefficient was determined to be 0.97. [ABSTRACT FROM AUTHOR]

New uracil and thymine derivatives, N1-,N3- and N1,N3-(RO-benzoyl)-(1H,3H)-pyrimidine- 2,4-diones, were synthesized (RO- is hydroxy, acetoxy- or methoxy-group). The compounds were studied in a complex of in vitro tests for the ability to inhibit the development of long-term complications of diabetes. Their ability to cleave cross-links of proteins has been evaluated. The most significant ways of pharmacological correction of thrombosis, angio-, nephro-, encephalo-, and cardiopathy, antiglycation, chelating, and antiplatelet activities, have been established. The most active compound in terms of antiplatelet action, N1- hydroxybenzoyluracil, exceeded acetylsalicylic acid by ~44%. In terms of their ability to chelate copper (II) cations, all compounds (with the exception of 1,3-bis(3-hydroxybenzoyl)-(1H,3H)-pyrimidine-2,4-dione that was not not studied in this test) showed the activity, whose IC50 fell in the range between that for pioglitazone (44.1 μM) and pyridoxamine (136.7 μM) comparison drugs. The best antiglycation effect at the 1 mM concentration was observed for N1,N3-bismethoxy- and N1,N3-bisacetoxybenzoyl derivatives of thymine. The maximum activity to cleave cross-links of proteins (C = 1 mM), comparable to that of alagebrium, was established for 1,3-bis(4-methoxybenzoyl)uracil, for which also high rates of other estimated activities were noted. Thus, the N1-,N3- and N1,N3-(RO-benzoyl) derivatives of uracil and thymine are promising basiсs for creating drugs that suppress the development of long-term complications of diabetes. [ABSTRACT FROM AUTHOR]

Background: A new indole derivative with the lab code-number SS-68 demonstrates a significant antiarrhythmic (anti-fibrillation) activity associated with the predominant influence on potassium and calcium conductivity of cardiomyocytes plasmalemmas. The preliminary data give evidence of SS-68 possessing an antiaggregant activity. Methods: The influence of SS-68 on the platelet formation stage of hemostasis was determined by assessment of the anti-platelet effect (measuring platelet aggregation with Born/ O'Brien method), the dynamics of intracellular concentration of calcium ions in platelets was studied with FURA-2/AM fluorescent probe. Results: Relative efficiency of the SS-68 indole derivative influence on platelet aggregation with the use of various inducers decreases in the following order: collagen > serotonin > ADP. The influence of SS-68 on platelet activity is characterized by pleiotropic effects: calcium-blocking effect, potentiation of cAMP-response, suppression of intracellular mechanisms of transmitting a stimulating signal, caused by the activation of collagen receptors. Conclusion: G-proteins are the most likely molecular targets of pleiotropic antiaggregant effect of SS-68. A more than threefold increase in the anti-platelet effect of SS-68 in vivo suggests the development of an active metabolite (metabolites). [ABSTRACT FROM AUTHOR]

Aseries of 3-(2,2,2-trichloro-1-hydroxyethyl)imidazo[1, 2- a]benzimidazole dihydrochlorides have been synthesized and their pharmacological properties have been studied. It is established that the synthesized compounds exhibit weak antioxidant activity. In addition, they possess platelet and erythrocyte antiaggregant properties, show pronounced spasmolytic action, and have low toxicity. Some of them also exhibit antiradiomimetic, hypotensive, and antiarrhythmic properties. [ABSTRACT FROM AUTHOR]

A series of N-acylmethyl derivatives of 9H-2,3-dihydroimidazo-and 10H-2,3,4,10-tetrahydropyrimido[1,2-a]benzimidazoles and products of their reduction has been synthesized and their pharmacological properties have been studied. Most of the synthesized substances possess weak antioxidant activity. At the same time, they exhibit pronounced antiaggregant and hemorheological properties, possess spasmolytic activity, and influence the blood glucose level. [ABSTRACT FROM AUTHOR]

Hypercytokinemia, or cytokine storm, is one of the severe complications of viral and bacterial infections, involving the release of abnormal amounts of cytokines, resulting in a massive inflammatory response. Cytokine storm is associated with COVID-19 and sepsis high mortality rate by developing epithelial dysfunction and coagulopathy, leading to thromboembolism and multiple organ dysfunction syndrome. Anticoagulant therapy is an important tactic to prevent thrombosis in sepsis and COVID-19, but recent data show the incompatibility of modern direct oral anticoagulants and antiviral agents. It seems relevant to develop dual-action drugs with antiviral and anticoagulant properties. At the same time, it was shown that azolo[1,5-a]pyrimidines are heterocycles with a broad spectrum of antiviral activity. We have synthesized a new family of azolo[1,5-a]pyrimidines and their condensed polycyclic analogs by cyclocondensation reactions and direct CH-functionalization and studied their anticoagulant properties. Five compounds among 1,2,4-triazolo[1,5-a]pyrimidin-7-ones and 5-alkyl-1,3,4-thiadiazolo[3,2-a]purin-8-ones demonstrated higher anticoagulant activity than the reference drug, dabigatran etexilate. Antithrombin activity of most active compounds was confirmed using lipopolysaccharide (LPS)-treated blood to mimic the conditions of cytokine release syndrome. The studied compounds affected only the thrombin time value, reliably increasing it 6.5–15.2 times as compared to LPS-treated blood. [ABSTRACT FROM AUTHOR]