First-in human studies to test a candidate drug. During the studies, the following is established: tolerability and safety, effect on the main physiological parameters, elimination, absorption and excretion rate constants, peak serum concentration, time necessary to achieve the maximum concentration, metabolism and interaction, half-life period, pharmacokinetic and pharmacodynamic values, protein binding, comparison of dosage forms, area under the "concentration – time" curve (AUC), activity.