Finding effective and safe medicines to fight SARS-CoV-2 infection is an urgent task. RPH-137 is an original trap fusion protein against SARS-CoV-2 virus. It comprises the angiotensin-converting enzyme type 2 extracellular domain and the human IgG1 Fc fragment.The aim of the study was to carry out a preclinical evaluation of the efficacy of RPH-137 and molnupiravir against SARS-CoV-2 infection.Materials and methods: the authors analysed RPH-137 expressed in a stable CHO cell line and molnupiravir used as an active pharmaceutical ingredient. Drug-mediated inhibition of virus-induced cytotoxicity was assessed in Vero cell culture. In vivo efficacy assessments were performed in Syrian hamsters. The animals were infected intranasally with SARS-CoV-2 (PIK35 clinical isolate) in the dose of 5 log TCID50. The authors evaluated body weight measurements, lung–body weight ratios, and lung histopathology findings and determined viral RNA levels in oropharyngeal swabs by RT-PCR using the amplification cycle threshold (Ct). The statistical analyses involved one- and two-way ANOVA, Student's t-test, and Mann–Whitney test.Results: RPH-137 and molnupiravir inhibited the cytopathic effect of SARS-CoV-2 in Vero cells; the EC50 values of RPH-137 amounted to 4.69 μg/mL (21.3 nM) and 16.24 μg/mL (73.8 nM) for 50 TCID50 and 200 TCID50, respectively, whereas the EC50 values of molnupiravir were 0.63 μg/mL (1900 nM) for both doses. Intramuscular RPH-137 (30 and 80 mg/kg) had no effect on the infection process in Syrian hamsters. The comparison with the challenge control group showed that intraperitoneal RPH-137 (100 mg/kg) had statistically significant effects on a number of parameters, including a 27% reduction in inflammation and a 30% reduction in the total lesion area of the lungs by Day 7. Intragastric molnupiravir (300 mg/kg twice daily) significantly inhibited SARS-CoV-2 infection.Conclusions: both RPH-137 and molnupiravir inhibited the cytopathic effect of SARS-CoV-2 in Vero cells. In Syrian hamsters, molnupiravir demonstrated a more pronounced inhibition of SARS-CoV-2 infection than RPH-137. However, RPH-137 had statistically significant effects on a range of parameters. This offers additional perspectives for further research.

Opioid receptor antagonists are widely used for the treatment of alcohol dependence. Currently, original drug Odelepran (INN: ondelopran) with a unique binding profi le to all three types of human opioid receptors (μ, κ, δ) is being developed by R-Pharm.Aim of the study. To investigate a cancerogenic poten al of the new opioid receptor antagonist ondelopran in a twoyear study in rats Materials and methods. The study cancerogenic potencial was performed in male and female Wistar rats at the age of 8–10 weeks at the start of experiment. All animals were allocated to 8 groups. Each group consisted of 50 animals of each sex. Test item (ondelopran fi lm-coated tablets, 125 mg), was administered to the animals intragastrically as a tablets suspension in 1% starch solution daily, 5 days a week for 24 months in two doses: 10 mg/kg (equivalent therapeutic dose for humans) and 100 mg/kg. Animals of control groups were administered with placebo and vehicle (1% starch solution). Clinical observation and examination of animals were conducted weekly to detect any signs of intoxication; dynamics of the body weight and registration of animal deaths were also assessed. To assess the rate of the pathological changes, the macro- and microscopic examina on of inner organs and neoplasms was conducted.Results. During the study the mortality rates did not diff er between the groups. Clinical signs ts.and symptoms of intoxication upon administration of the tested item and placebo were not observed. Neoplasms were found in the organs of all groups of animals. More than 30 variants of neoplasms were identifi ed upon pathomorphological examination. The identifi ed tumors are typical for rats and considered as spontaneous age-related pathology. There was no statistically signifi cant diff erences between groups in the total incidence of tumors.Conclusion. To conclude the above said, the test item of the ondelopran fi lm-coated tablets, 125 mg have no carcinogenic properties.

Nonclinical studies of biotechnology-derived medicinal products are discussed in the article in terms of new original fusion protein RPH-104 - high potency IL-1β signal pathway antagonist. Specificity of biotherapeutics is connected to complexity of molecules. Efficacy, pharmacokinetic and toxicity nonclinical studies of the biotherapeutics are conducted using relevant species taking into consideration potent immunogenicity. Cytotoxic reactions risk assessment is also important. Accurate nonclinical studies planning can help to obtain sufficient information about potential target organs for toxicity, reversibility of toxic effects and determine safety parameters. According to ethical principles in vivo studies can be optimized using modern in silico analysis, computer modelling and in vitro testing.

Anti-inflammatory effects of GB-115 compound (N-phenylhexanoyl-glycyl-L-tryptophan amide) injected intraperitoneally in doses of 0.1, 1, and 10 mg/kg were demonstrated on the model of ConA- and carrageenan-induced inflammation. Intraperitoneal injection of GB-115 in a dose of 1 mg/kg to C57Bl/6 female mice with experimental autoimmune encephalomyelitis significantly alleviated the pathological symptoms, improved spontaneous locomotor activity, promoted recovery of thymus weight, and reduced edema and neutrophil infiltration of the perivascular space of the brain tissue. Intraperitoneal injection of GB-115 in a dose of 1 mg/kg suppressed generation of active oxygen forms by neutrophils in the chemiluminescence test.

Preclinical safety investigations of newly synthesized dipeptide compound GB-115 (amide N-phenylhexanoyl-glycyl-L-tryptophan), an antagonist of cholecystokinin receptors, were performed. No animals were lost after GB-115 acute oral administration at a maximum dose of 6000 mg/kg in mice and at 3500 mg/kg in rats. GB-115 administered per os during 6 months in rabbits and rats (both males and females) at the doses of 0.1 and 10 mg/kg induced no irreversible pathological changes in organs and systems studied. The tested dipeptide exhibited no allergenic, immunotoxic and mutagenic activity, and did not affect generative function and the antenatal and postnatal development of progeny. GB-115 at a dose of 10 mg/kg produced suppression of the inflammatory reaction to concanavalin A.

A preclinical study of allergenicity of the diabeta drug revealed that its administration doesn't result in an intensified systemic anaphylactic reaction, inhibited allergic reactions, a significant change in an inflammatory reaction. The results of the comprehensive study proved that the diabeta drug has no allergizing effects.

Birch bark dry extract (BBDE) containing no less than 70% of betulin and betulin alone were compared with the reference drugs suprastin and claritine for their antiallergenic action. It is established that BBDE and betulin reduce by half the systemic anaphylactic reaction in guinea pigs immunized with ovalbumin from chicken egg white, their action being comparable with that of suprastin in mild and medium anaphylactic shock. The course of BBDE administration per os or intaperitoneally leads to a significant decrease in the content of IgE antibodies to ovalbumin in mice of various strains immunized in different regimens. The effect of BBDE on anaphylactic contraction of isolated guinea pig ileum samples was evaluated and showed no direct action upon the H1-receptors. Studies on models of pseudoallergenic reaction to concanavalin A in mice and carragenan-induced paw edema in rats showed that the anti-inflammatory action of BBDE is comparable with that of suprastin and claritine and is more pronounced than the effect of betulin.

Birch bark dry extract (BBDE) containing at least 70% betulin and betulin alone were compared with the reference drugs Suprastin and Claritin for their antiallergenic action. It is established that BBDE and betulin reduce by half the systemic anaphylactic reaction in guinea pigs immunized with ovalbumin from chicken egg white, their action being comparable with that of Suprastin in mild and medium anaphylactic shock. The course of BBDE administration per os or i.p. leads to a significant decrease in the content of IgE antibodies to ovalbumin in mice of various strains immunized in different regimens. The effect of BBDE on anaphylactic contraction of isolated guinea pig ileum samples was evaluated and showed no direct action upon the H1-receptors. Studies on models of pseudoallergenic reaction to concanavalin A in mice and carragenan-induced paw edema in rats showed that the anti-inflammatory action of BBDE is comparable with that of Suprastin and Claritin and is more pronounced than the effect of betulin.

We studied the effects of a new dipeptide with anxiolytic activity (GB-115, N-phenylhexanoyl-glycyl-L-tryptophan amide) on parameters of the immune in intact mice and in animals with secondary immunodeficiency caused by cyclophosphamide. GB-115 in doses of 0.1–10 mg/kg stimulated phagocytic activity of peritoneal macrophages and humoral immune response in intact mice. GB-115 exhibited immunocorrecting activity in animals with secondary immunodeficiency.

Noopept, a peptide analog of piracetam, enhanced phagocytic activity of mouse peritoneal macrophages, stimulated humoral and cellular immune response to various antigens, and markedly increased spontaneous proliferative activity of splenocytes. In animals with secondary immune deficiency caused by cyclophosphamide, noopept exhibited immunocorrector properties.

Birch bark dry extract (BBDE) containing no less then 70% of betulin was studied in complex tests on mice and guinea pigs. Administered perorally in doses of 100 and 1000 mg/kg (p.o.), BBDE exhibited neither immunotoxic nor allergenic effects. In luminol-dependent chemiluminescence tests, BBDE administered in mice in a dose of 100 mg/kg (p.o.) during 14 days inhibited the production of active oxygen species by neutrophiles. Upon a single administration in doses of 100 and 1000 mg/kg BBDE suppressed Con-A-induced inflammation in mice. BBDE administered in guinea pigs at doses of 100 and 1000 mg/kg reduced the intensity of systemic anaphylaxis.

Study of polymorphism in 3 genes of the glutathione S-transferase family (GSTM1, GSTT1, and GSTP1) in children with Ehlers-Danlos syndrome whose cells were defective in repair of γ-induced DNA damages revealed accumulation of GSTM1(+) genotypes compared to children of the control group. Generation of reactive oxygen species by neutrophils from patients with this syndrome was higher than in healthy donors. Our results indicate that glutathione S-transferase genes are involved in the resistance to mutagenic agents and demonstrate medical and genetic peculiarities of patients with Ehlers-Danlos syndrome.

Birch bark dry extract (BBDE) containing no less then 70% of betulin was studied in complex tests on mice and guinea pigs. Administered perorally in doses of 100 and 1000 mg/kg (p.o.), BBDE exhibited neither immunotoxic nor allergenic effects. In luminol-dependent chemiluminescence tests, BBDE administered in mice in a dose of 100 mg/kg (p.o.) during 14 days inhibited the production of reactive oxygen species by neutrophils. Upon a single administration in doses of 100 and 1000 mg/kg, BBDE suppressed a model inflammation induced by concanavalin A in mice. BBDE administered to guinea pigs in doses of 100 and 1000 mg/kg reduced the intensity of systemic anaphylaxis.