Before starting clinical trials that involve people scientists conduct preclinical studies that include testing of the studied molecule on animals. Clinical researches are divided into 4 phases
During the first phase the safety of the drug is assessed on healthy volunteers;
Starting with the second phase, a therapeutic effect of medicines is estimated;
During the third phase scientists study suitable dosages of a drug;
The purpose of the fourth phase of an investigation is to gather additional information after drug’s approval by the commission. We choose clinical trials starting from the second phase.