**Conflict of interest**

*Cheminformatics and Its Applications*

dose concentration [17].

*The journey of potential leads from preclinical to clinical trials.*

*7.4.2 Clinical phase II*

**Figure 6.**

information [79].

completed [80].

*7.4.4 Clinical phase IV*

*7.4.3 Clinical phase III*

They may or may not get paid for their participation in drug trial studies. This mini trial is useful in determining the absorption and side effect of drug in relation to its

The second phase of clinical trial may last up to 2 years. It is a totally randomized study which involves the application of drug on a relatively large group of patients. This trial study is divided into two groups of patients, one receiving experimental drug and the other receiving placebo. Sometimes it may be named as a blind application trial. This type of random application of drug allows investigators and pharmaceutics to prove the success and safety of drug to the FDA with comparative

It is a large-scale testing of drugs on hundreds of patients. This third stage testing provides with a more thorough understanding and effectiveness of useful drugs to the FDA and pharmaceutical companies. The pharmaceutical company can request for the approval for commercial synthesis of drug after phase III is

After the approval of a drug for commercial consumption, clinical phase IV trials are used as post marketing surveillance trials. This trial system is based upon the various objectives at commercial levels, i.e., the comparison of newly approved and already-available drugs in market, to evaluate the chronic effects on patients' quality of life and to estimate the economical comparison of newly approved and

already-present drugs as well as the traditional system of medication [81].

**140**

Authors have no conflict of interest.
