An Open-label Clinical Study of the Pharmacokinetics and Safety of Elsulfavirine, 200 mg Tablets, With Single and Multiple Oral Administration in Healthy Volunteers

The present study is an open-label, single-center, clinical study of the pharmacokinetics and safety of Elsulfavirin 200 mg tablets in four dosage regimens: * Cohort I (N = 3). Single oral dose of 400 mg. * Cohort II (N = 3). Single oral dose of 800 mg. * Cohort III (N = 3). Single oral administration at a dose of 1200 mg. * Cohort IV (N = 6). A single 1200 mg oral dose followed by 200 mg daily for 9 days. The study is descriptive and will not test any hypotheses. Based on previous studies and the intended descriptive objectives of the study, no control group is planned. To ensure safety, the following scheme for using the investigational drug is provided: * The inclusion in the study of volunteers included in each subsequent cohort will be carried out strictly after the completion of the study by the last study subject included in the previous cohort and obtaining a safety opinion. * Dosing in the multiple administration cohort will be 2 + 4. Initially, 2 volunteers will be included, after completion of participation, 4 more volunteers will be dosed.