Inclusion Criteria:  Men or non-pregnant female aged 18 to 65 years hospitalized with moderate COVID-19 infection: body temperature > 37.5 °C; respiratory rate > 22/min; shortness of breath during physical exertion; typical coronavirus-associated chest computed tomography (CT) changes (CT1- CT2); pulse oximetry levels SpO2< 95%. Able to give informed consent and attend all study visits Positive PCR-test for COVID-19 ≤72 hours prior to randomization The patient's ability to inhale the experimental drug Participants must agree to use the reliable contraception while on study medication and for posttrial contraception for 3 month  Key Exclusion Criteria:  Fever > 38.5°C. Cough severity is less than 1 point on a 4-point scale. Respiratory rate > is more than 30 / min SpO2 ≤ 93%. Decreased level of consciousness, agitation. Unstable hemodynamics (systolic blood pressure less than 100 mmHg or diastolic blood pressure less than 60 mmHg). The need to require mechanical ventilation beyond the screening/ randomization. Long-term systemic corticosteroid exposure. Autoimmune or inflammatory diseases (systemic / localized). Positive blood tests for HIV, hepatitis B and С, syphilis. Pregnancy and breast-feeding Previous adverse reactions to the active substance and/or excipients included in the drug. Any use of anti-viral medications or immunomodulatory agents up to 7 days before participating in the study Chronic diseases of the cardiovascular system Type 1 diabetes  The following laboratory parameters are excluded:  Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, total and direct bilirubin >4 x upper limit of normal (ULN);  Treatment with any medicine that have a pronounced effects on the blood coagulation system (expect for COVID-19 treatment), including combined oral contraceptives. Treatment with any medicine that can affect cardiac conduction Participation in other investigational drug or device clinical trials within 90 days prior to screening. History of alcohol, drug or chemical abuse. Mental illness. Receipt of plasma from a person who recovered from COVID-19 (convalescent plasma) up to 14 days before participating in the study, vaccination against SARS-CoV-2 , the need for extracorporeal membrane oxygenation. Any conditions that, according to the researcher's, may be a contraindication to the participation in the study.